WO2019182050A1 - Optical element, transfer foil, authentication object, and method for verifying authentication object - Google Patents
Optical element, transfer foil, authentication object, and method for verifying authentication object Download PDFInfo
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- WO2019182050A1 WO2019182050A1 PCT/JP2019/011841 JP2019011841W WO2019182050A1 WO 2019182050 A1 WO2019182050 A1 WO 2019182050A1 JP 2019011841 W JP2019011841 W JP 2019011841W WO 2019182050 A1 WO2019182050 A1 WO 2019182050A1
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- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
Definitions
- Each embodiment of the present invention relates to an optical element, a transfer foil, an authentication body, and an authentication body verification method.
- This application claims priority based on Japanese Patent Application No. 2018-053545 filed in Japan on March 20, 2018 and Japanese Patent Application No. 2019-014299 filed in Japan on January 30, 2019, and the contents thereof. Is hereby incorporated by reference.
- Optical elements that use holograms, diffraction gratings, multilayer interference films, etc., for the purpose of preventing counterfeiting of securities such as gift certificates, banknotes, and credit cards, and for the purpose of product brand protection Is attached. Since manufacturing of such an optical element is not easy, the optical element has an effect of preventing forgery of an article to which the optical element is attached.
- optical elements described above optical elements that can be verified only by visual inspection without using a special verification instrument when verifying the authenticity of the optical element are widely used.
- those in which the color in which the optical element is visually recognized or the image displayed by the optical element change according to the angle at which the optical element is observed are widely used.
- examples of the optical element whose color changes according to the angle at which the optical element is observed include the above-described diffraction grating and multilayer interference film.
- the diffraction grating and the multilayer interference film have a feature that when the angle at which these optical elements are observed is changed, the color of the optical elements visually recognized by the observer changes continuously. As described above, since a plurality of colors are observed by the observer, it is difficult to clearly specify the color to be visually recognized when verifying that the optical element is an authentic optical element in authenticity verification. In addition, when verifying the authenticity of the optical element, it is difficult for the observer to find an appropriate angle range among the angles at which the optical element is observed.
- a sub-wavelength grating is used as an optical element that develops a predetermined color.
- the period of the fine structure in the sub-wavelength grating is less than the wavelength of visible light.
- the sub-wavelength grating has a characteristic of emitting only light of a specific wavelength in the regular reflection direction among the light incident on the sub-wavelength grating. Therefore, according to the sub-wavelength grating, the observer cannot visually recognize light having a predetermined color in the optical element when observing the optical element from a direction other than the regular reflection direction.
- the angle at which the optical element should be observed and the color visually recognized at the angle can be defined. Therefore, a method for authenticating the optical element can be clearly described.
- the anti-counterfeit optical element using such a sub-wavelength grating include the optical element described in Patent Document 1.
- the optical element described in Patent Document 1 after viewing the optical element at the first angle at which the first color is visually recognized, the optical element is rotated with the normal to the plane in which the optical element spreads as the rotation axis. . Then, the authenticity of the optical element is verified by visually recognizing the optical element at the second angle at which the second color is visually recognized.
- the hand movement performed by the observer to rotate the optical element is not a natural movement compared to the movement of tilting the optical element. Therefore, the workability of the verification work by the observer tends to be low, and the verification efficiency tends to be low.
- the sub-wavelength grating emits light having a predetermined color only in the regular reflection direction. Therefore, at the moment when the observer picks up the optical element or when the observer places the optical element on a flat surface and then observes the optical element, the observer can visually recognize the color that the optical element exhibits. Unlikely. That is, it is unlikely that the observer will observe the optical element in the regular reflection direction at that moment.
- the observer rotates the optical element after finding an angle at which the color exhibited by the optical element can be visually recognized, and further, the angle at which another color exhibited by the optical element can be visually recognized even after rotating the optical element. I need to find it. As a result, since it takes time for the observer to verify the authenticity of the optical element, an optical element that can verify the authenticity more easily is demanded.
- An object of the present invention is to provide an optical element, a transfer foil, an authentication body, and a verification method for the authentication body that can easily perform authentic verification.
- An optical element for solving the above problems includes a first layer, a second layer in contact with the first layer, and a third layer in contact with the second layer, and each layer has light transmittance.
- the first layer is a resin layer having a first refractive index, has a first surface in contact with the second layer, includes a subwavelength grating in at least a part of the first surface, and
- the layer is a dielectric layer having a second refractive index higher than the first refractive index, and has a second surface in contact with the first surface of the first layer, and the first surface is
- the third layer is a resin layer having a third refractive index lower than the second refractive index.
- any one of the first layer, the second layer, and the third layer is a relief layer
- the relief layer includes a relief surface including a plurality of reflection surfaces, and a pitch between the reflection surfaces adjacent to each other. Is larger than the pitch of the sub-wavelength grating.
- a colored image having a color corresponding to a grating period of the sub-wavelength grating is displayed in a reflection direction including a direction, and the relief surface is a reflection image by monochrome reflected light in a reflection direction including a direction different from the regular reflection direction. That is, a monochrome image is displayed, and the optical element has a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, and a third state in which the reflected image is mainly displayed. And an angle formed by a plane in which the optical element spreads and a plane including the observer's line of sight is an observation angle, and the optical element has the first state, the second state, depending on the observation angle, and, Serial observed by any of the third state.
- An optical element for solving the above problems includes a first layer, a second layer in contact with the first layer, and a third layer in contact with the second layer, and each layer has light transmittance.
- the first layer is a resin layer having a first refractive index, has a first surface in contact with the second layer, includes a subwavelength grating in at least a part of the first surface, and
- the layer is a dielectric layer having a second refractive index higher than the first refractive index, and has a second surface in contact with the first surface of the first layer, and the second surface is
- the third layer is a resin layer having a third refractive index lower than the second refractive index.
- the optical element further includes a relief layer including a relief surface different from the first surface and the second surface, the relief surface includes a plurality of reflection surfaces, and a pitch between the reflection surfaces adjacent to each other is A state in which light is applied to the optical element from a light source that is larger than the pitch of the sub-wavelength grating and located on the side opposite to the third layer with respect to the second layer is observed from the light source side.
- the sub-wavelength grating displays a colored image exhibiting a color corresponding to the grating period of the sub-wavelength grating in the regular reflection direction, and the relief surface is reflected by monochrome reflected light in a direction different from the regular reflection direction.
- the optical element has a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, and a third state in which the reflected image is mainly displayed.
- the angle formed by the plane in which the scientific element spreads and the plane including the observer's line of sight is the observation angle, and the optical element is in the first state, the second state, and the plane according to the observation angle. Observed in any of three states.
- a transfer foil for solving the above problems includes an adhesive body including the optical element and an adhesive layer for bonding the optical element to a transfer target.
- the authentication body for solving the said subject is provided with the said optical element.
- the optical element displays a reflected image formed by monochrome reflected light, that is, a monochrome image, and a colored image formed by light having a specific wavelength, that is, a chromatic image.
- the discrimination between the monochrome image and the chromatic image is performed by discriminating between the first monochrome image and the second monochrome image, or distinguishing the first chromatic color image and the second chromatic color image. Compared to the case where the difference between the two images is different, there is less individual difference between the two images.
- the optical element compared with the case where the authenticity of the optical element is verified based on two chromatic color images or two monochrome images, individual differences are less likely to occur in the authenticity verification. Standards for verifying are easily written. Thereby, according to the optical element, authenticity verification can be performed more easily.
- FIG. 1 is a cross-sectional view schematically illustrating the structure of an optical element according to a first embodiment of the present invention.
- 1 is a plan view schematically illustrating the structure of an optical element according to a first embodiment of the present invention together with an enlarged view.
- FIG. 3 is a cross-sectional view schematically illustrating a structure in a cross section taken along line II in FIG. 2.
- the operation of the first embodiment of the present invention is schematically illustrated.
- the operation of the first embodiment of the present invention is schematically illustrated.
- the azimuth angle in the pixel area is schematically illustrated.
- the relationship between the azimuth angle and the wavelength of light emitted from the subwavelength grating is schematically illustrated.
- the relationship between the azimuth angle and the wavelength of light emitted from the subwavelength grating is schematically illustrated.
- the top view in which the 1st state in the 1st example of the optical element of a 5th embodiment of the present invention was illustrated schematically.
- the top view in which the 2nd state in the 1st example of the optical element of a 5th embodiment of the present invention was illustrated schematically.
- the top view in which the 3rd state in the 1st example of the optical element of a 5th embodiment of the present invention was illustrated schematically.
- the top view in which the 4th state in the 1st example of the optical element of a 5th embodiment of the present invention was illustrated schematically. Sectional drawing with which the structure in the 2nd example of the optical element of 5th Embodiment of this invention was illustrated schematically.
- Sectional drawing which shows the structure of a deformation
- the top view which shows the quantization phase difference structure in the planar view which opposes a relief surface in the deformation
- the graph which shows the peak in the spatial frequency component of the quantization phase difference structure which FIG. 25 shows.
- FIG. 26 is a cross-sectional view schematically showing a quantization phase difference structure shown in FIG.
- the top view which shows the 1st example of the 1st image and 2nd image which the optical element of 5th Embodiment of this invention displays.
- Sectional drawing with which the structure in the 2nd example of the optical element of 6th Embodiment of this invention was illustrated schematically.
- FIG. 38 is a cross-sectional view schematically illustrating a structure in a cross section taken along line IV-IV in FIG. 37.
- Sectional drawing with which the structure in the authentication body of 9th Embodiment of this invention was illustrated schematically.
- the operation in the first example of the authentication body of the ninth embodiment of the present invention is schematically illustrated.
- the operation in the first example of the authentication body of the ninth embodiment of the present invention is schematically illustrated.
- the operation in the first example of the authentication body of the ninth embodiment of the present invention is schematically illustrated.
- the operation in the first example of the authentication body of the ninth embodiment of the present invention is schematically illustrated.
- the operation in the second example of the authentication body of the ninth embodiment of the present invention is schematically illustrated.
- the operation in the second example of the authentication body of the ninth embodiment of the present invention is schematically illustrated.
- the operation in the second example of the authentication body of the ninth embodiment of the present invention is schematically illustrated.
- the image which imaged the 1st image which the ID card of Experiment 1 displays.
- the image which imaged the 2nd image which the ID card of Experiment 1 displays.
- FIGS. A first embodiment of the optical element of the present invention will be described with reference to FIGS. Note that, in each drawing, the same reference numerals are assigned to the constituent elements that exhibit the same or similar functions, and redundant descriptions are omitted. Also, the embodiments of the present invention of the present disclosure are a group of embodiments based on a unique single invention from the background. In addition, each aspect of the present disclosure is an aspect of a group of embodiments based on a single invention. Each configuration of the present disclosure may have each aspect of the present disclosure. Each feature of the present disclosure is combinable and can be configured. Accordingly, each feature of the present disclosure, each configuration of the present disclosure, each aspect of the present disclosure, and each embodiment of the present disclosure can be combined, and the combination has a synergistic function, Can be effective.
- the optical element 10 includes a first layer 11, a second layer 12 in contact with the first layer 11, and a third layer 13 in contact with the second layer 12. Each layer has optical transparency.
- the optical element 10 can be all or part of a security seal.
- the security seal can include the optical element 10.
- the optical element 10 can be a visible motif. Security seals can be in the form of patches, stripes, overlays and stickers.
- the state in which light is irradiated from the light source located on the opposite side to the third layer 13 with respect to the second layer 12 is from the side opposite to the third layer 13 with respect to the second layer 12. Observed.
- the surface of the first layer 11 opposite to the surface in contact with the second layer 12 is an observation surface 10S that is observed by an observer.
- the first layer 11 is a resin layer having a first refractive index.
- the first layer 11 includes a sub-wavelength grating 11G on at least a part of the surface 11S in contact with the second layer 12.
- the second layer 12 is a dielectric layer having a second refractive index higher than the first refractive index.
- the second layer 12 has an uneven shape that follows the sub-wavelength grating 11G.
- the third layer 13 is a resin layer having a third refractive index lower than the second refractive index.
- the sub-wavelength grating 11G is formed by a plurality of grating patterns GP arranged along one direction.
- the lattice pattern GP can be one in which a plurality of convex surfaces and concave surfaces are alternately arranged along one direction.
- the lattice pattern GP extends over the surface 11S.
- Each convex surface and each concave surface can be long and thin with a major axis in a direction orthogonal to the direction in which they are arranged.
- the period of the grating pattern GP can be less than the visible wavelength.
- the period of the grating pattern GP can be less than 680 nm.
- the period of the lattice pattern GP may be equal to or shorter than the shortest wavelength of visible light. That is, the period of the lattice pattern GP may be 400 nm or less.
- the sub-wavelength grating 11G can diffract the incident light.
- the sub-wavelength grating 11G can guide the diffracted light having a wavelength corresponding to the grating period into the second layer 12.
- the light guided into the second layer 12 is guided light.
- the guided light is diffracted in the regular reflection direction of the incident light. That is, the sub-wavelength grating 11G selectively emits incident light in the regular reflection direction.
- the refractive index of the first layer 11 may be the same as or different from the refractive index of the third layer 13.
- the difference between the refractive index of the first layer 11 and the refractive index of the third layer 13 is preferably 0.2 or less, and more preferably 0.1 or less.
- the difference between the refractive index of the first layer 11 and the refractive index of the second layer 12 and the difference between the refractive index of the third layer 13 and the refractive index of the second layer 12 can be 0.3 or more, respectively. Can be 0.5 or more.
- the region where the sub-wavelength grating 11G is located is an uneven surface.
- the entire surface 11S is an uneven surface, but only a part of the surface 11S may be an uneven surface.
- FIG. 2 shows the structure of the optical element 10 in plan view facing the observation surface 10S.
- the surface 11S of the first layer 11, that is, the interface with the second layer 12 in the first layer 11 is used using a structure in plan view facing the observation surface 10S.
- the surface to be formed will be described.
- the extending direction of the grating pattern GP included in the sub-wavelength grating 11 ⁇ / b> G is indicated by a straight line.
- the surface 11S which is an example of the uneven surface, includes a first region 11S1 and a second region 11S2 that surrounds the first region 11S1 in a plan view facing the surface 11S.
- the surface 11S includes the first region 11S1 and the second region 11S2, but the surface 11S may include regions other than the first region 11S1 and the second region 11S2.
- the sub-wavelength grating belonging to the first region 11S1 is the first sub-wavelength grating 11G1.
- the sub-wavelength grating belonging to the second region 11S2 is the second sub-wavelength grating 11G2.
- the azimuth angle of the first sub-wavelength grating 11G1 and the azimuth angle of the second sub-wavelength grating 11G2 can be equal to each other.
- the grating period of the first sub-wavelength grating 11G1 and the grating period of the second sub-wavelength grating 11G2 may be different from each other.
- the grating period in the sub-wavelength grating 11G is the period of the grating pattern GP described above.
- the azimuth angle in the sub-wavelength grating 11G is an angle formed by the reference line set in the plane in which the first layer 11 extends and the grating pattern GP.
- each pixel region Px has a square shape in a plan view facing the surface 11S, but the pixel region Px may have a regular triangular shape, a regular hexagonal shape, or the like.
- Each pixel region Px may have a polygonal shape and include sides having different lengths. In each pixel region Px, the length of one side is preferably 0.3 mm or less.
- the length of one side is 0.08 mm or less.
- the length of one side of the pixel region Px is smaller than the resolution of the human eye, each pixel region Px is not visually recognized by the observer. Thereby, the optical element 10 can display a high-resolution image.
- FIG. 3 shows a cross-sectional structure of the sub-wavelength grating 11G along the line II in FIG.
- the cross-sectional structure of the first sub-wavelength grating 11G1 and the cross-sectional structure of the second sub-wavelength grating 11G2 are shown side by side in the vertical direction of the drawing.
- the cross-sectional structure of each sub-wavelength grating schematically shows the cross-sectional structure of the sub-wavelength grating located in one pixel region Px.
- each sub-wavelength grating is shown as a surface constituting a convex portion protruding in a direction away from the flat surface.
- each sub-wavelength grating is a grating pattern GP that has a wave shape that repeats in one direction, and each wave constitutes a sub-wavelength grating.
- the distance between two grating patterns GP adjacent to each other is the grating period of each sub-wavelength grating.
- the plurality of grating patterns GP included in the first sub-wavelength grating 11G1 have the same shape.
- the plurality of grating patterns GP included in the second sub-wavelength grating 11G2 have the same shape.
- the wavelength of light emitted from the sub-wavelength grating changes according to the grating period of the sub-wavelength grating. That is, according to the grating period of the sub-wavelength grating, the hue exhibited by the optical element 10 including the sub-wavelength grating, in other words, the color visually recognized by the observer as the hue of the optical element 10 changes.
- the light source LS and the observer OB are positioned on the plane perpendicular to the observation surface 10 ⁇ / b> S of the optical element 10 so that they are targets with respect to the normal line of the observation surface 10 ⁇ / b> S.
- the observer OB can visually recognize the zero-order diffracted light emitted by the optical element 10.
- the optical element 10 can emit light having a wavelength corresponding to the grating period of the sub-wavelength grating 11G in the direction of regular reflection with respect to incident light incident from the light source LS.
- the grating period of the sub-wavelength grating is set to be shorter than the shortest wavelength of visible light, that is, 400 nm or less.
- the grating period for emitting only light having a specific wavelength by the zero-order diffracted light in a specific direction depends on the refractive index of the sub-wavelength grating and the incident angle of the incident light incident on the sub-wavelength grating. change.
- a condition for the sub-wavelength grating to emit only the zero-order diffracted light in other words, a condition for the sub-wavelength grating not to emit the first-order diffracted light will be described.
- Equation (1) ⁇ 1 is an incident angle of incident light with respect to the diffraction grating, ⁇ 2 is a diffraction angle of diffracted light emitted from the diffraction grating, and m is a diffraction order of the diffracted light.
- ⁇ is the wavelength
- n is the refractive index of the diffraction grating
- d is the grating period of the diffraction grating.
- Equation (2) Since sin ⁇ 2 is not less than ⁇ 1 and not more than 1, Equation (2) does not hold when the right side ( ⁇ / d) in Equation (2) is larger than 1. In other words, when the right side ( ⁇ / d) is larger than 1, the first-order diffracted light is not emitted from the diffraction grating. Therefore, under the above assumption, when the grating period of the diffraction grating is smaller than the wavelength, the diffraction grating emits only zero-order diffracted light.
- the diffraction grating may emit diffracted light of a non-zero order.
- the incident angle ⁇ 1 is 30 ° and the wavelength ⁇ is 600 nm.
- the incident angle ⁇ 1 is 30 °
- the wavelength ⁇ is 600 nm
- the diffraction order m is 1. Therefore, substituting these numerical values into equation (1) leads to the following equation (3).
- the diffraction grating emits the first-order diffracted light by the combination of the refractive index n and the grating period d.
- the combination (n, d) of the refractive index n and the grating period d when the first-order diffracted light is emitted is as follows.
- the diffraction grating emits zero-order diffracted light while diffracting so as not to emit higher-order diffracted light than zero-order diffracted light. It is possible to form a lattice.
- the zero-order diffracted light can be generated in a state where the relative position of the diffraction grating with respect to the observer is fixed. It is also possible to configure the diffraction grating so that the first-order diffracted light is not visually recognized by the observer while visually recognized by the observer. Thereby, the freedom degree in selection of the material which forms a diffraction grating, and the freedom degree in the grating period of a diffraction grating can be raised.
- the optical element 10 is tilted so that the above-described plane and the optical element 10 intersect at an angle other than vertical.
- the optical element 10 does not emit zero-order diffracted light in the direction of the line of sight of the observer OB, the observer cannot visually recognize the zero-order diffracted light emitted by the optical element 10. In other words, the observer cannot visually recognize the color that the optical element 10 exhibits.
- the optical element 10 in both the first sub-wavelength grating 11G1 and the second sub-wavelength grating 11G2, the onset and disappearance of the color due to each sub-wavelength grating occurs in synchronization. For this reason, in the entire optical element 10, the color state and the monochrome state are switched. Therefore, in authenticity verification of the optical element 10, the optical element 10 has a first region 11S1 that exhibits a color derived from the first sub-wavelength grating 11G1 and a second region 11S2 that exhibits a color derived from the second sub-wavelength grating 11G2. Can be grasped at a time. As a result, the authenticity of the optical element 10 can be verified more easily by rotating the optical element 10 than when determining whether or not the optical element 10 has a state of two colors.
- FIG. 6 is another example of the optical element 10 of the present embodiment.
- FIG. 6 shows the structure of the optical element 10 in plan view facing the observation surface 10S, as in FIG.
- the plurality of pixel regions Px may include a pixel region Px including a first sub-wavelength grating 11G1 located in a part of each pixel region Px in a plan view facing the surface 11S.
- the first sub-wavelength grating 11G1 is located in the entire pixel region Px.
- the first sub-wavelength grating 11G1 may be located only in a part of the pixel region Px.
- the ratio of the area of the first sub-wavelength grating 11G1 to the area of the pixel region Px is the area ratio.
- the plurality of pixel regions Px may include pixel regions Px having different area ratios.
- the plurality of pixel regions Px include pixel regions Px having different area ratios, whereby in the colors exhibited by the first region 11S1, it is possible to form shades of brightness in the same hue.
- the shading can be a continuous change.
- the shade may be gradation.
- the area ratio can be determined according to the level of brightness in the stereoscopic image to be displayed by the first region 11S1, that is, the gradation value.
- the optical element 10 includes a portion where the area ratio in the pixel region Px decreases along the direction from the center of the first region 11S1 toward the outer edge of the first region 11S1, and the optical region 10 of the first region 11S1.
- the area ratio at the outer edge is the smallest.
- the optical element 10 of the present embodiment may have a configuration described below with reference to FIGS.
- the azimuth angle in the sub-wavelength grating described above will be described in more detail before another example of the optical element 10 is described.
- an arbitrary direction along the observation surface 10S of the optical element 10 is the X direction, and a direction orthogonal to the X direction is the Y direction.
- the X direction is a reference direction in the azimuth angle
- the angle formed by the X direction and the direction in which the lattice pattern extends is the azimuth angle ⁇ . Therefore, the azimuth angle ⁇ in the first pixel region Px1 is 0 °, and the azimuth angle ⁇ in the second pixel region Px2 is 45 °.
- the azimuth angle ⁇ in the third pixel region Px3 is 90 °, and the azimuth angle ⁇ in the fourth pixel region Px4 is 135 °.
- FIG. 8 shows the structure of the optical element 10 in plan view facing the observation surface 10S, as in FIG.
- the first region 11S1 includes a first element S1A and a second element S1B adjacent to the first element S1A.
- Each element S1A, S1B has a shape that follows the contour of the first region 11S1 in a plan view facing the surface 11S of the first layer 11.
- the first region 11S1 is formed of a first element S1A and a second element S1B, and the first element S1A is located outside the second element S1B.
- the outline of the first element S1A and the outline of the second element S1B are similar in shape to the outline of the first region 11S1.
- the sub-wavelength grating belonging to the first element S1A is the first grating G1A.
- the sub-wavelength grating belonging to the second element S1B is the second grating G1B.
- the grating period of the first grating G1A and the grating period of the second grating G1B are equal to each other.
- the azimuth angle ⁇ of the first grating G1A and the azimuth angle ⁇ of the second grating G1B are different from each other, and the difference between the azimuth angle ⁇ of the first grating G1A and the azimuth angle ⁇ of the second grating G1B is 90 ° or less.
- the azimuth angle ⁇ in the first grating G1A is 0 °
- the azimuth angle ⁇ in the second grating G1B is 45 °. Therefore, the difference between the azimuth angle ⁇ of the first grating G1A and the azimuth angle ⁇ of the second grating G1B is 45 °.
- FIG. 9 shows a cross-sectional structure of the first lattice G1A along the line II-II in FIG. 8 and a cross-sectional structure of the second lattice G1B along the line III-III.
- the cross-sectional structure of the first lattice G1A and the cross-sectional structure of the second lattice G1B are shown side by side in the vertical direction of the drawing.
- the cross-sectional structure of each grating schematically shows the cross-sectional structure of a sub-wavelength grating located in one pixel region Px.
- each sub-wavelength grating is shown as a surface constituting a convex portion protruding in a direction away from the flat surface.
- the grating period of the first grating G1A and the grating period of the second grating G1B are equal to each other. That is, the grating period of the first grating G1A is the first period d1, and the grating period of the second grating G1B is also the first period d1. As described above, the distance between two lattice patterns GP adjacent to each other is the lattice period of each lattice.
- the colors exhibited by the two sub-wavelength gratings are the same.
- the sub-wavelength grating while the grating periods of the sub-wavelength gratings are equal to each other, two sub-wavelength gratings having different azimuth angles ⁇ have different colors. That is, the color exhibited by the first lattice G1A and the color exhibited by the second lattice G1B are different from each other under certain observation conditions. With reference to FIGS. 10 and 11, the reason why the color exhibited by the first lattice G1A and the color exhibited by the second lattice G1B are different from each other will be described.
- FIG. 10 shows a perspective structure of the sub-wavelength grating 11G having an azimuth angle ⁇ of 0 °.
- FIG. 11 shows a perspective structure of the subwavelength grating 11G having an azimuth angle ⁇ of 90 °.
- the polarization whose electric field oscillates perpendicularly to the incident surface of the sub-wavelength grating 11G is s-polarized light.
- the polarized light whose electric field is oscillating in parallel with the incident surface of the sub-wavelength grating 11G is p-polarized light.
- the incident surface is a plane that is perpendicular to the plane in which the sub-wavelength grating spreads and includes incident light and reflected light. Further, each of the s-polarized light and the p-polarized light does not depend on the azimuth angle ⁇ of the sub-wavelength grating 11G. In other words, both incident light incident on the sub-wavelength grating 11G shown in FIG. 10 and incident light incident on the sub-wavelength grating 11G shown in FIG. 11 include s-polarized light and p-polarized light.
- the relationship between the wavelength of light and the diffraction efficiency at that wavelength varies depending on the relationship between the direction in which the groove extends, that is, the azimuth angle ⁇ , and the vibration direction of the electric field.
- a component in which the vibration direction of the electric field is parallel to the azimuth angle ⁇ of the diffraction grating is a TE wave.
- a component in which the vibration direction of the electric field is orthogonal to the azimuth angle ⁇ of the diffraction grating is a TM wave.
- the p-polarized light whose component is a component in which the vibration direction of the electric field is parallel to the azimuth angle ⁇ of the diffraction grating is equal to the TE wave.
- the p-polarized light that is a component in which the vibration direction of the electric field is orthogonal to the azimuth angle ⁇ of the diffraction grating is , Equal to TM wave.
- the color presented by the sub-wavelength grating 11G shown in FIG. 10 is the first color
- the color presented by the sub-wavelength grating 11G shown in FIG. 11 can be the second color.
- the second color is a color different from the first color.
- the optical element 10 described above with reference to FIG. 8 can include the sub-wavelength grating 11G shown in FIG. 10 as the first grating G1A, and the sub-wavelength grating 11G shown in FIG. 11 as the second grating G1B. It is possible to provide.
- the state in which the first element S1A including the first grating G1A exhibits the first color and the second element S1B including the second grating G1B exhibits the second color is the optical element 10, the observer, and , The initial position in the relative position of the light source.
- the s-polarized light corresponds to the TE wave and the p-polarized light corresponds to the TM wave in the first grating G1A.
- the s-polarized light corresponds to the TM wave
- the p-polarized light corresponds to the TE wave. Accordingly, the first element S1A exhibits the second color, and the second element S1B exhibits the first color. Therefore, the observer recognizes that the color of the first element S1A and the color of the second element S1B are reversed by the rotation of the optical element 10.
- the light incident on the sub-wavelength grating 11G from the direction in which the grating line of the sub-wavelength grating 11G extends and the light incident from the direction orthogonal to the direction in which the grating line extends Since the refractive index of the optical element 10 changes as viewed from the above, light of different wavelengths is emitted.
- the azimuth angle ⁇ of the first grating G1A and the azimuth angle ⁇ of the second grating G1B are preferably 90 ° or less for the following reason.
- the angle formed by the observation surface 10S of the optical element 10 and the plane including the observer's line of sight is the observation angle.
- the observation angle at which the color exhibited by the sub-wavelength grating is visually recognized is affected only by the relationship between the relative positions of the light source, the observer, and the optical element 10.
- the observation angle at which the color exhibited by the first grating G1A is visually recognized, and the color exhibited by the second grating G1B are equal to each other.
- the observation angle at which the color exhibited by each grating G1A, G1B appears and the observation angle at which the color exhibited by each grating G1A, G1B disappears are equal to each other between the two gratings.
- the wavelength of the zero-order diffracted light emitted from the first grating G1A and the second grating G1B are emitted.
- the wavelengths of the zero-order diffracted light are different from each other.
- the first grating G1A and the second grating G1A When the difference between the azimuth angle ⁇ of the first grating G1A and the azimuth angle ⁇ of the second grating G1B is set to an angle that is greater than 0 ° and less than 90 °, the first grating G1A and the second grating G1A At least one of the two lattices G1B exhibits an intermediate color between the first color and the second color.
- the color exhibited by the first grating G1A and the color exhibited by the second grating G1B vary depending on the difference in azimuth angle ⁇ .
- the wavelength of light emitted by the first grating G1A is the largest.
- the difference between the azimuth angle ⁇ in the first grating G1A and the azimuth angle ⁇ in the second grating G1B is larger than 90 °, the wavelength of the light emitted by the first grating G1A and the second The difference from the wavelength of light emitted by the grating G1B does not increase.
- the maximum difference between the azimuth angle ⁇ in the first grating G1A and the azimuth angle ⁇ in the second grating G1B is preferably 90 °.
- the optical element 10 has a first region 11S1 exhibiting a color derived from the first sub-wavelength grating 11G1 and a second region 11S2 exhibiting a color derived from the second sub-wavelength grating 11G2. Can be grasped at a time. As a result, the authenticity of the optical element 10 can be verified more easily by rotating the optical element 10 than when determining whether or not the optical element 10 has a state of two colors.
- the plurality of pixel regions Px include pixel regions Px having different area ratios, whereby in the colors exhibited by the first region 11S1, it is possible to form shades of brightness in the same hue.
- the first embodiment of the present invention described above can be implemented with appropriate modifications as follows.
- [Lattice period] The azimuth angle ⁇ of the first grating G1A and the azimuth angle ⁇ of the second grating G1B may be equal to each other, and the grating period of the first grating G1A may be different from the grating period of the second grating G1B. In this case, the following effects can be obtained.
- the colors that the first grating G1A can exhibit by changing the grating period compared to the case where the azimuth angle ⁇ is different between the first grating G1A and the second grating G1B, and The types of colors that can be presented by the two-grating G1B can be increased. Thereby, the freedom degree of the color which the optical element 10 exhibits increases.
- the azimuth angle ⁇ of the first grating G1A and the azimuth angle ⁇ of the second grating G1B may be different from each other, and the grating period of the first grating G1A and the grating period of the second grating G1B may be different from each other.
- FIGS. 12 to 14 A second embodiment of the optical element will be described with reference to FIGS.
- the optical element according to the second embodiment of the present invention differs from the optical element according to the first embodiment in the shape of the grating pattern included in the sub-wavelength grating. Therefore, in the following, such differences will be described in detail.
- the components corresponding to the optical element of the first embodiment are denoted by the same reference numerals as those in the first embodiment. Detailed description is omitted.
- the sub-wavelength grating is shown as a structure in which convex portions protruding in a direction away from the flat surface are arranged for convenience of illustration.
- the color of the sub-wavelength grating observed by the observer may be based on higher-order diffracted light than zero-order diffracted light. Therefore, in the following, the angle at which the sub-wavelength grating has the highest color development efficiency is the mth order, and the diffracted light at the mth order is the mth order diffracted light.
- the sub-wavelength grating 11G includes a plurality of grating patterns.
- the direction in which the plurality of lattice patterns are repeated is the first direction D1, and the direction orthogonal to the first direction D1 is the second direction D2.
- the shape in a cross section perpendicular to the plane in which the first layer 11 extends along the first direction D1 is a cross-sectional shape.
- Each lattice pattern has a shape in which the cross-sectional shape continues along the second direction D2.
- the plurality of lattice patterns include lattice patterns having different cross-sectional shapes.
- the optical element 20 includes a first layer 11, a second layer 12, and a third layer 13, similar to the optical element 10 of the first embodiment.
- the optical element 20 includes three portions in the first direction D1. That is, the optical element 20 includes a first portion 20A, a second portion 20B, and a third portion 20C.
- the first portion 20A, the second portion 20B, and the third portion 20C are arranged in the order described in the direction in which the lattice pattern is repeated.
- the plurality of grating patterns belonging to each part have the same cross-sectional shape.
- the cross-sectional shapes of the lattice patterns belonging to each part are different from each other.
- the portion belonging to the first portion 20A is the first grating 20AG
- the portion belonging to the second portion 20B is the second grating 20BG
- the portion belonging to the third portion 20C is the third grating 20CG. .
- the first lattice 20AG includes a plurality of first lattice patterns AGP.
- the plurality of first lattice patterns AGP are repeated along the first direction D1.
- the cross-sectional shape of the first lattice 20AG is wavy.
- the grating period of the first grating 20AG is the first period d1.
- the first lattice pattern AGP has a shape in which one peak is sandwiched between two valleys in the cross section along the first direction D1.
- the first lattice pattern AGP has a slope connecting one valley and the mountain and a slope connecting the mountain and the other valley. Each slope has an inclination with respect to the plane in which the first layer 11 extends.
- an angle formed by a tangent to one slope and a straight line connecting a plurality of valleys is a first tangent angle ⁇ 1.
- a straight line connecting the plurality of valleys is a straight line substantially parallel to the surface of the first layer 11.
- the first tangent angle ⁇ 1 is equal to the angle formed by the plane on which the first layer 11 extends and the slope.
- the second grid 20BG includes a plurality of second grid patterns BGP.
- the plurality of second lattice patterns BGP are repeated along the first direction D1.
- the cross-sectional shape of the second grating 20BG is wavy.
- the grating period of the second grating 20BG is the second period d2.
- the second period d2 is equal to the first period d1.
- the second lattice pattern BGP has a shape in which one peak is sandwiched between two valleys in the cross section along the first direction D1.
- the second lattice pattern BGP has a slope connecting one valley and the mountain and a slope connecting the mountain and the other valley. Each slope has an inclination with respect to the plane in which the first layer 11 extends.
- the angle formed by the tangent to one slope and the straight line connecting the plurality of valleys is the second tangent angle ⁇ 2.
- the second tangent angle ⁇ 2 is an angle different from the first tangent angle ⁇ 1.
- the second tangent angle ⁇ 2 is equal to the angle formed by the plane on which the first layer 11 extends and the slope. In the present embodiment, the second tangent angle ⁇ 2 is smaller than the first tangent angle ⁇ 1.
- the second period d2 of the second grating 20BG is equal to the first grating period d1 of the first grating 20AG. Therefore, in the cross section along the first direction D1, the cross sectional shape of the second lattice pattern BGP and the cross sectional shape of the first lattice pattern AGP are different from each other.
- the third grid 20CG includes a plurality of third grid patterns CGP.
- the plurality of third lattice patterns CGP are repeated along the first direction D1.
- the cross-sectional shape of the third lattice 20CG is wavy.
- the grating period of the third grating 20CG is the third period d3.
- the third period d3 is equal to the first period d1 and the second period d2.
- the third lattice pattern CGP has a shape in which one peak is sandwiched between two valleys in the cross section along the first direction D1.
- the third lattice pattern CGP has a slope connecting one valley and the mountain and a slope connecting the mountain and the other valley. Each slope has an inclination with respect to the plane in which the first layer 11 extends.
- the angle formed by the tangent to one slope and the straight line connecting the plurality of valleys is the third tangent angle ⁇ 3.
- the third tangent angle ⁇ 3 is an angle different from the first tangent angle ⁇ 1 and also an angle different from the second tangent angle ⁇ 2.
- the third tangent angle ⁇ 3 is equal to the angle formed by the plane on which the first layer 11 extends and the inclined surface.
- the third tangent angle ⁇ 3 is smaller than the first tangent angle ⁇ 1 and smaller than the second tangent angle ⁇ 2.
- the third period d3 of the third grating 20CG is equal to the first period d1 and the second period d2. Therefore, in the cross section along the first direction D1, the cross sectional shape of the third lattice pattern CGP is different from both the cross sectional shape of the first lattice pattern AGP and the cross sectional shape of the second lattice pattern BGP.
- each lattice pattern includes a slope having an inclination with respect to the plane in which the first layer 11 extends.
- the plurality of lattice patterns include lattice patterns having different slope angles with respect to the first layer 11.
- the angle at which the light incident on the optical element 20 is diffracted can be changed by changing the tangent angles ⁇ 1, ⁇ 2, and ⁇ 3 on each slope. That is, by changing the tangent angles ⁇ 1, ⁇ 2, and ⁇ 3 between the first grating 20AG, the second grating 20BG, and the third grating 20CG, m-order diffracted light is emitted from the gratings 20AG, 20BG, and 20CG.
- the angles can be different from each other. Thereby, compared with the case where the tangent angle is equal in the whole sub-wavelength grating 11G, the range of the angle at which m-order diffracted light is emitted can be expanded.
- lattice 20AG, 20BG, and 20CG since cross-sectional shapes differ, a grating
- the width of each of the gratings 20AG, 20BG, and 20CG is preferably 300 ⁇ m or less, and more preferably 85 ⁇ m or less. Since the widths of the respective gratings 20AG, 20BG, and 20CG are 300 ⁇ m or less, the respective gratings 20AG, 20BG, and 20CG cannot be separated with human eye resolution. Therefore, the observer cannot recognize that the gratings 20AG, 20BG, and 20CG are diffracting light at different angles.
- each of the gratings 20AG, 20BG, and 20CG is more preferably 85 ⁇ m or less for the following reason.
- a distance at which a person whose visual acuity is 1.0 can be separated in 1 minute from a position 5 m away from an observation target is 1.454 mm. These matters are explained using the Landolt ring.
- One minute is 1 / 60th of 1 °.
- Equation (4) 1454 ⁇ (30/500) ( ⁇ m)
- the unit of the first term is ⁇ m and the unit of the second term is cm. From equation (4), the resolution R is 87.24 ⁇ m. Therefore, if the width of each of the gratings 20AG, 20BG, and 20CG is 85 ⁇ m or less, it is possible to increase the certainty that the gratings 20AG, 20BG, and 20CG cannot be decomposed with human eye resolution.
- the cross-sectional shapes of the respective grating patterns AGP, BGP, and CGP have wave shapes having different tangent angles from the viewpoint that the direction in which the m-th order diffracted light is emitted can be controlled by the tangential angles.
- the cross-sectional shape of the grating pattern is a rectangular shape formed from a surface parallel to the surface of the optical element 20 and a surface orthogonal to the surface, m-order diffracted light, that is, zero next time The folded light is emitted in the direction of regular reflection with respect to the incident light.
- the incident angle of the incident light with respect to the surface of the optical element 20 is 45 °
- the emission angle of the regular reflection light is also 45 °. Therefore, the observer cannot observe the light emitted from the optical element 20 unless the observer observes the optical element 20 from the direction where the observation angle is 45 °.
- the regular reflection light of the light emitted from the light source toward the optical element 20 is also observed by the observer. Therefore, it may be difficult for an observer to visually recognize the light emitted by the sub-wavelength grating. Further, depending on the relative position of the light source with respect to the optical element 20, it may be difficult to observe the optical element 20 from the regular reflection angle. In this respect, since the direction in which the m-th order diffracted light is emitted can be controlled by the tangential angle, the degree of freedom in the angle at which the optical element 20 emits the m-th order diffracted light is increased. Therefore, it becomes possible to solve the above-described problem.
- the sub-wavelength grating 11G including the three grating patterns may have the following structure. As shown in FIG. 13, the sub-wavelength grating 11G includes a first grating pattern AGP, a second grating pattern BGP, and a third grating pattern CGP. In the sub-wavelength grating 11G, the first grating pattern AGP, the second grating pattern BGP, and the third grating pattern CGP constitute one pattern group GPG. In one pattern group GPG, the first lattice pattern AGP, the second lattice pattern BGP, and the third lattice pattern CGP are arranged in the order described in the first direction D1. In the sub-wavelength grating 11G, a plurality of pattern groups GPG are repeated along the first direction D1.
- the grating period of the first grating pattern AGP is the first period d1
- the grating period of the second grating pattern BGP is the second period d2
- the grating period of the third grating pattern CGP is the third period. d3.
- the first period d1, the second period d2, and the third period d3 are equal to each other.
- the period D of the pattern group GPG is preferably 20 ⁇ m or more.
- the period D of the pattern group GPG is larger, higher-order diffracted light is included in the same observation angle.
- the larger the period D of the pattern group GPG the narrower the range of observation angles including the same order of diffracted light.
- the angle formed by the incident light and the ray of the diffraction grating is the angle ⁇
- the angle formed by the diffraction light and the ray of the diffraction grating is the angle.
- ⁇ is set, the following equation (5) is established. Note that the angle ⁇ is an incident angle, and the angle ⁇ is a diffraction angle.
- d is the period of the diffraction grating
- m is the diffraction order
- ⁇ is the wavelength of light.
- the unit of period and wavelength is nm.
- the period d corresponds to the period D of the pattern group GPG described above.
- the pupil diameter in the human eye is 5 mm and the distance that the observer observes the optical element 20 is 30 cm.
- light included within an observation angle of about 1 ° enters the eyes of the observer. That is, the observer visually recognizes the result of integrating the light within the observation angle of about 1 °. That is, when diffracted light having a wavelength within the range of the observation angle of about 1 ° is included, the diffraction efficiency is increased within the range of the observation angle.
- the optical element 20 is preferably configured to emit at least two diffracted lights having different orders within a range of 2 ° in the observation angle.
- the period D in the optical element 20 is preferably 20 ⁇ m or more.
- the sub-wavelength grating 11G including the three grating patterns may have the following structure. As shown in FIG. 14, the sub-wavelength grating 11G includes a first grating pattern AGP, a second grating pattern BGP, and a third grating pattern CGP. In the sub-wavelength grating 11G, the first grating pattern AGP, the second grating pattern BGP, and the third grating pattern CGP constitute one pattern group GPG. In one pattern group GPG, the first lattice pattern AGP, the second lattice pattern BGP, and the third lattice pattern CGP are arranged in the order described in the first direction D1. In the sub-wavelength grating 11G, a plurality of pattern groups GPG are repeated along the first direction D1.
- the grating period of the first grating pattern AGP is the first period d1
- the grating period of the second grating pattern BGP is the second period d2
- the grating period of the third grating pattern CGP is the third period d3.
- the first period d1, the second period d2, and the third period d3 are different from each other. It is preferable that the difference in the grating period is 20 nm or less between the grating patterns adjacent to each other in the first direction D1.
- the first period d1 can be set to 300 nm
- the second period d2 can be set to 310 nm
- the third period d3 can be set to 290 nm.
- the diffraction angles are different between the grating patterns.
- the difference in the grating period between the grating patterns adjacent to each other in the first direction D1 is 20 nm or less, the diffraction angles of the m-th order diffracted lights emitted from the grating patterns are substantially equal to each other. Thereby, the observer cannot separate the m-th order diffracted light emitted from each grating pattern. Therefore, the observation angle at which the observer can observe the light emitted from the optical element 20 can be widened.
- the following effects can be obtained.
- the observation angle at which the observer can visually recognize the light emitted from the sub-wavelength grating 11G is widened. be able to.
- the sub-wavelength grating 11G corresponds to the difference in the inclination angle between the grating patterns as compared with the case where the inclination angles of the slopes included in the cross-sectional shape along the first direction D1 are the same.
- the observation angle at which the observer can visually recognize the light emitted from the projector can be expanded.
- the sub-wavelength grating 11G may include four or more types of grating patterns having different cross-sectional shapes as described above. Further, the plurality of types of grating patterns may be randomly positioned in the sub-wavelength grating 11G. Further, the plurality of types of lattice patterns may be regularly arranged.
- the cross-sectional shape of the sub-wavelength grating 11G is not limited to the wave shape described above. Even when the sub-wavelength grating 11G has a shape other than the wave shape, the sub-wavelength grating 11G includes the grating patterns having different cross-sectional shapes, thereby obtaining the effect according to the above (5). I can.
- a third embodiment of the optical element will be described with reference to FIG.
- the optical element according to the third embodiment of the present invention is different from the optical element 10 according to the first embodiment in that the first layer includes a filler. Therefore, in the following, such differences will be described in detail.
- the components corresponding to the optical element of the first embodiment are denoted by the same reference numerals as in the first embodiment. Detailed description thereof will be omitted.
- the first layer 11 included in the optical element 30 includes a filler 31 dispersed in the resin forming the first layer 11.
- the average particle diameter of the filler 31 is 400 nm or less.
- At least a part of the light incident on the first layer 11 is scattered by the filler dispersed in the first layer 11. Therefore, the light incident on the sub-wavelength grating 11G includes light having different incident angles.
- each grating pattern GP included in the sub-wavelength grating 11G reflects light in the regular reflection direction according to the incident angle of the light incident on the grating pattern GP.
- the light reflected by the lattice pattern GP is emitted to the outside of the optical element 30 without being scattered by the filler 31 or after being scattered by the filler 31. Therefore, compared with the case where the 1st layer 11 does not contain a filler, the range of the emission angle of the light inject
- the average particle diameter of the filler 31 is preferably 400 nm or less. Thereby, since Mie scattering is suppressed, the transparency of the first layer 11 is improved to some extent.
- the shape of the filler 31 is not limited to a spherical shape. Therefore, in this embodiment, the average value in a plurality of diameters that can be defined in each filler 31 is the average particle diameter of each filler 31.
- the following is known about the relationship between the size of the scatterer such as the filler 31 and the scattering phenomenon. When the average particle size of the scatterer is included in the range of 400 nm or more and 700 nm or less, Mie scattering is generated by the scatterer.
- the light included in the visible range is scattered to the same extent regardless of the wavelength of the light, so that the light scattered by the Mie scattering is visually recognized as white light.
- the light scattering angle is affected by the particle size of the scatterer. In Mie scattering, the larger the particle size of the scatterer, the stronger the scattering toward the front in the light traveling direction.
- the average particle size of the filler 31 is at least equal to or less than the wavelength of light, and It is necessary for the filler 31 to cause Rayleigh scattering. Therefore, the average particle diameter of the filler 31 is preferably 400 nm or less.
- the scattering cross section ⁇ can be calculated by the following equation (6).
- the optical element of the third embodiment the following effects can be obtained. (7) Compared to the case where the first layer 11 does not include a filler, the range of the emission angle of light emitted from the optical element 30 is widened. Therefore, the range of observation angles at which the observer can observe the colors exhibited by the optical element 30 is expanded.
- a fourth embodiment of the optical element will be described with reference to FIGS. 16 and 17.
- the optical element according to the fourth embodiment of the present invention differs from the optical element 10 according to the first embodiment in the state of the surface of the third layer 13 opposite to the surface in contact with the second layer 12. Therefore, in the following, such differences will be described in detail, and in the optical element of the third embodiment, the same reference numerals are given to the components corresponding to those of the optical element 10 of the first embodiment, and detailed description thereof will be omitted. .
- the first example and the second example in the fourth embodiment will be described in order.
- the third layer 13 is an adhesive layer having thermoplasticity.
- the third layer 13 includes a filler 41 dispersed in a portion closer to the surface opposite to the surface in contact with the second layer 12 than the center in the thickness direction of the third layer 13.
- the surface in contact with the second layer 12 is the front surface 13F
- the surface opposite to the front surface 13F is the back surface 13R.
- the filler 41 is preferably located closer to the back surface 13R than the center in the thickness direction of the third layer 13, and is preferably located in the vicinity of the back surface 13R.
- the third layer 13 is an adhesive layer having thermoplasticity.
- an adhesive having thermoplasticity can be used as a material for forming the third layer 13. Since the third layer 13 is an adhesive layer having thermoplasticity, heat and pressure are applied to the optical element 40 in a state where the third layer 13 is in contact with the transfer target, thereby transferring the optical element 40 to the transfer target. be able to. At this time, the heat and pressure applied to the third layer 13 cause unevenness due to the filler 41 on the back surface 13 ⁇ / b> R of the third layer 13, thereby causing unevenness on the surface 13 ⁇ / b> F of the third layer 13.
- the unevenness also occurs in a portion overlapping with the unevenness formed in the third layer 13 when viewed from the thickness direction of the optical element 40.
- corrugation resulting from the filler 41 is added with respect to the subwavelength grating 11G in the interface of the 1st layer 11 and the 2nd layer 12.
- FIG. Examples of the transfer object can be bills, passports, cards, and the like.
- the unevenness at the interface between the first layer 11 and the second layer 12 is adjusted by the size of the filler 41, the thickness of each layer 11, 12, 13 and the conditions of heat and pressure when transferring the optical element 40. can do.
- the plurality of grating patterns GP forming the sub-wavelength grating 11G have different grating patterns GP with different incident angles of light with respect to the grating pattern GP. included.
- Each grating pattern GP reflects m-th order diffracted light at an exit angle corresponding to the incident angle of light in the grating pattern GP.
- the range of the emission angle at which each grating pattern emits m-th order diffracted light varies depending on the curvature of the unevenness imparted to each grating pattern GP. In other words, the observation angle at which the observer can observe the color exhibited by the sub-wavelength grating 11G varies depending on the curvature of the unevenness imparted to each grating pattern GP.
- the color exhibited by the optical element 40 is preferably maintained in a range of 2 ° or more in the observation angle.
- the range of the observation angle in which the color exhibited by the optical element 40 can be observed is preferably 2 ° or more and 10 ° or less, and more preferably 2 ° or more and 5 ° or less. It is preferable that the range of the observation angle includes the emission angle of the m-th order diffracted light emitted by all the grating patterns GP.
- the curvature of the unevenness caused by the filler 41 is not excessively large.
- the following two methods can be used as a method for suppressing the uneven curvature due to the filler 41 from becoming excessively large.
- the heat and pressure conditions in the transfer are adjusted so that the filler 41 is uniformly dispersed in the third layer 13 and the curvature of the irregularities does not become excessively large.
- a filler having a flat shape is used as the filler 41 instead of a spherical filler, and the diameter of the filler 41 decreases in the thickness direction of the third layer 13. Filler 41 is dispersed in layer 13.
- the optical element 40 further includes a fourth layer 42 in contact with the third layer 13.
- the fourth layer 42 includes a surface 42 ⁇ / b> F that contacts the third layer 13.
- the surface 42F includes irregularities.
- the unevenness on the surface 42F of the fourth layer 42 can be formed by various methods. When transferring the third layer 13 to the fourth layer 42 as the transfer target, unevenness may be formed on the surface 42F of the fourth layer 42 so as to follow the third layer 13 deformed by heat and pressure. it can. In this case, an adhesive layer having thermoplasticity can be used for the third layer 13.
- the fourth layer 42 can be made of paper or a resin film. Alternatively, irregularities can be formed on the surface 42F of the fourth layer 42 by dispersing fine particles and fibers in the fourth layer 42. Further, the surface 42F of the fourth layer 42 can be made uneven by defoaming or unevenness generated when the fourth layer 42 is formed.
- the unevenness caused by the surface 42F of the fourth layer 42 can be added to the sub-wavelength grating 11G. Therefore, the same effect as the optical element 40 of the first example can be obtained by the optical element 40 of the second example.
- the average particle diameter of the fine particles is approximately the same as the thickness of the third layer 13 that is an adhesive layer. Is preferred. Further, in the transfer to the fourth layer 42, by adjusting the conditions of heat and pressure, it is possible to suppress the unevenness imparted to the sub-wavelength grating 11G from becoming excessively large.
- the paper-made fourth layer 42 can be used as the fourth layer 42 in which the fibers are dispersed.
- the fibers forming the fourth layer 42 are arranged in parallel to the surface 42F of the fourth layer 42.
- the pulp fiber has a diameter of 20 ⁇ m or more and 50 ⁇ m or less and a length of about 1 mm or more and 5 mm or less. Therefore, the unevenness imparted to the sub-wavelength grating 11G may become excessively large.
- the cellulose nanofiber has a diameter of 4 nm or more and 100 nm or less and a length of about 5 ⁇ m or more. Therefore, it is possible to suppress the unevenness imparted to the sub-wavelength grating 11G from becoming excessively large.
- Cellulose nanofibers are fibers obtained by decomposing pulp fibers.
- the plurality of grating patterns GP can include grating patterns GP having different incident angles of light with respect to the grating pattern GP. Thereby, since the emission angle in the grating pattern GP is also different, the observation angle at which the light emitted from the sub-wavelength grating 11G is observed can be widened.
- the plurality of grating patterns GP include grating patterns GP having different incident angles of light with respect to the grating pattern GP. it can. Thereby, since the emission angle in the grating pattern GP is also different, the observation angle at which the light emitted from the sub-wavelength grating 11G is observed can be widened.
- a fifth embodiment of the optical element will be described with reference to FIGS.
- the optical element of the fifth embodiment of the present invention is different from the optical element of the first embodiment in that it includes a relief layer having a relief surface. Therefore, in the following, such differences will be described in detail.
- the components corresponding to those of the optical element 10 of the first embodiment are denoted by the same reference numerals as those of the optical element 10 of the first embodiment. Therefore, the detailed description is omitted.
- two examples of the optical element of the fifth embodiment will be described in order.
- the optical element 50 includes the first layer 11, the second layer 12 in contact with the first layer 11, and the second layer 12 in contact with the second layer 12, as in the optical element 10 in the first embodiment described above. And three layers 13.
- the first layer 11 is a resin layer including the sub-wavelength grating 11G on at least a part of the back surface 11R in contact with the second layer 12.
- the back surface 11R is an example of the first surface.
- FIG. 18 for convenience of illustration, a cross-sectional shape in which the sub-wavelength grating 11G is located on the entire back surface 11R is shown. Is formed.
- the surface 12F in contact with the back surface 11R of the first layer 11 has an uneven shape following the sub-wavelength grating 11G.
- the surface 12F is an example of the second surface.
- the second layer 12 is a dielectric layer having a second refractive index higher than the first refractive index.
- the third layer 13 is a resin layer having a third refractive index lower than the second refractive index.
- the optical element 50 includes a relief layer including a relief surface 13Re different from the back surface 11R and the front surface 12F.
- the relief surface 13Re includes a plurality of reflecting surfaces, and the pitch between the reflecting surfaces adjacent to each other is larger than the pitch of the sub-wavelength grating 11G.
- the relief layer is the third layer 13 described above. More specifically, the back surface 13R which is the surface opposite to the surface in contact with the second layer 12 in the third layer 13 is the relief surface 13Re.
- the relief surface 13Re is located on the entire surface 13F, but in the optical element 50 of the present embodiment, the relief surface 13Re is located on a part of the surface 13F. Further, the relief surface 13Re may be formed at a position overlapping the sub-wavelength grating 11G in the surface 13F when viewed from the thickness direction of the optical element 50.
- the sub-wavelength grating 11G displays a colored image exhibiting a color corresponding to the grating period of the sub-wavelength grating 11G in the reflection direction including the regular reflection direction.
- the relief surface 13Re displays a reflected image by monochrome reflected light in a reflection direction including a direction different from the regular reflection direction. Examples of monochrome reflected light colors are white, silvery white, silvery, semi-white, pearl white, silky white, milky white, gray, sepia.
- the optical element 50 includes a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, a third state in which the reflected image is mainly displayed, and a fourth state in which the colored image and the reflected image are mainly displayed.
- the angle formed by the plane on which the optical element 50 spreads and the plane including the observer's line of sight is the observation angle.
- the optical element 50 has one of the states depending on the observation angle. That is, the optical element 50 is observed in any one of the first state, the second state, and the third state according to the observation angle.
- the sub-wavelength grating 11G displays a colored image exhibiting a color corresponding to the grating period of the sub-wavelength grating in a predetermined range including the regular reflection direction at the observation angle.
- the relief surface 13Re displays a reflected image of monochrome reflected light in a predetermined range including a direction different from the regular reflection direction at the observation angle.
- the optical element 50 further includes a fourth layer 51.
- the fourth layer 51 may be a reflective layer or a refractive layer.
- the refractive index of the fourth layer 51 is different from the refractive index of the third layer 13. Since the refractive index of the fourth layer 51 is different from the refractive index of the third layer 13, the fourth layer 51 can increase the reflectance at the relief surface 13Re. In two layers adjacent to each other, the reflectivity at the interface is determined by the difference in refractive index between the two layers. Therefore, when the refractive index of the fourth layer 51 is different from the refractive index of the third layer 13, the same effect as when the fourth layer 51 is a reflective layer can be obtained.
- the fourth layer 51 may have light transmittance or may not have light transmittance.
- the fourth layer 51 may be composed of a single layer or a plurality of layers.
- the fourth layer 51 is a refractive layer and includes a plurality of layers, the fourth layer 51 includes a layer having a relatively low refractive index and a layer having a relatively high refractive index. be able to.
- the relief surface 13Re includes a plurality of reflecting surfaces as described above.
- the relief surface 13Re displays a reflected image formed by monochrome light by at least one of diffraction, scattering, and reflection.
- the relief surface 13Re includes a plurality of reflection surfaces, and the plurality of reflection surfaces may be arranged in a predetermined rule or irregularly in the relief surface 13Re.
- the emission direction of light emitted from the relief surface 13Re can be controlled by the direction and angle of each reflection surface.
- the direction of the reflecting surface can be the direction of the normal vector of the reflecting surface projected on the plane in which the first layer 11 spreads.
- the angle of the reflection surface can be an angle formed by the normal vector of the plane in which the first layer 11 extends and the normal vector of the reflection surface.
- the direction of the reflecting surface can be the same as or perpendicular to the orientation of the sub-wavelength grating 11G.
- the average of the orientations can be set as the orientation of the sub-wavelength grating 11G.
- the average can be a weighted average weighted by the area of each region where a plurality of sub-wavelength gratings are formed.
- the card 100 displays the first image P1 and the second image P2 according to the position of the card 100.
- the card 100 displays the first image P1 and the second image P2 (see FIG. 40).
- the sub-wavelength grating 11G emits light in the range of the emission direction including the above-described regular reflection direction. Of the light emitted from the sub-wavelength grating 11G, the intensity of the light emitted in the regular reflection direction is the highest.
- the relief surface 13Re emits light in an emission direction range including a direction different from the regular reflection direction. Of the light emitted from the relief surface 13Re, the intensity of the light emitted in a direction different from the regular reflection direction is the highest. In other words, on the relief surface 13Re, the direction and angle of the reflection surface are set so that the intensity of the light emitted in the direction different from the regular reflection direction is the largest among the light emitted from the relief surface 13Re. Yes.
- the period of the reflection surface may be greater than 400 nm and 1000 nm or less, or may be greater than 1000 nm. In order to prevent the relief surface 13Re from emitting diffracted light, it is preferable that the period of the reflection surface is larger than 1000 nm.
- the shape in a cross section orthogonal to the direction in which the reflecting surface extends may be a sawtooth shape.
- the colored image displayed by the sub-wavelength grating 11G is an image formed by light having a specific wavelength included in the wavelength of visible light.
- Illustrative examples of chromatic images include chromatic images such as red, green, and blue images.
- the sub-wavelength grating 11G displays a red image the light emitted from the sub-wavelength grating 11G includes, for example, light having a wavelength of 620 nm or more and 750 nm or less.
- the sub-wavelength grating 11G displays a green image the light emitted from the sub-wavelength grating 11G includes light having a wavelength of 495 nm or more and 570 nm or less as an example.
- the light emitted from the sub-wavelength grating 11G includes light having a wavelength of 450 nm or more and 495 nm or less as an example.
- the sub-wavelength grating 11G displaying a colored image is synonymous with the sub-wavelength grating 11G exhibiting a chromatic color.
- the reflection image displayed on the relief surface 13Re is an image formed by monochrome light generated by reflection, scattering, and diffraction on the relief surface 13Re.
- the reflected image displayed by the relief surface 13Re is a monochrome image and an image having no hue.
- the relief surface 13Re may be configured such that the intensity of the monochrome light emitted from each position is different from each other. Thereby, the relief surface 13Re can display an image by a difference in light intensity, in other words, by a difference in brightness.
- the relief surface 13Re displays a monochrome reflected image is synonymous with the relief surface 13Re exhibiting monochrome.
- the angle at which the incident light IL emitted from the light source LS enters the optical element 50 is the incident angle ⁇
- the angle at which the emitted light EL emitted from the optical element 50 is emitted is the emission angle ⁇ .
- An angle formed by a plane including the viewing direction of the observer OB and a plane on which the optical element 50 spreads is an observation angle ⁇ OB.
- the above-described regular reflection direction is the direction in which the emitted light EL is emitted at an emission angle ⁇ having the same magnitude as the incident angle ⁇ .
- the sub-wavelength grating 11G displays a colored image in the reflection direction including the regular reflection direction
- the relief surface 13Re displays the reflected image by the monochrome light in the reflection direction including a direction different from the regular reflection direction. indicate.
- the optical element 50 has one of the following four states according to the observation angle ⁇ OB.
- the colored image displayed by the sub-wavelength grating 11G has a moon shape
- the reflected image displayed by the relief surface 13Re has a star shape
- the shape of the colored image displayed by the sub-wavelength grating 11G and the shape of the reflected image displayed by the relief surface 13Re can be any shape.
- the image displayed by the sub-wavelength grating 11G is the first image
- the image displayed by the relief surface 13Re is the second image.
- FIG. 20 shows a first state of the optical element 50.
- both the first image P1 and the second image P2 disappear in the optical element 50.
- the first image P1 and the second image P2 are not identified by the observer OB because of the luminance in the light for forming the first image P1 and the luminance in the light for forming the second image P2.
- the brightness of the light reflected by the sub-wavelength grating 11G and the light reflected by the relief surface 13Re are both media on which the optical element 50 is affixed. Therefore, the first image P1 and the second image P2 are not identified by the observer OB.
- FIG. 21 shows a second state of the optical element 50.
- the first image P1 appears and the second image P2 disappears in the optical element 50.
- the appearance of the first image P1 means that the optical element 50 displays the first image P1 in a state where the luminance of light in the first image P1 is higher than the luminance of light in the second image P2. Therefore, the second state includes a state in which the first image P1 is identified while the second image P2 is not identified. In the second state, the first image P1 and the second image P2 appear in the optical element 50, and the luminance of light in the first image P1 is higher than the luminance of light in the second image P2. included.
- the observer can easily perceive the light reflected by the sub-wavelength grating 11G, while the observer does not easily perceive the light reflected by the relief surface 13Re. .
- FIG. 22 shows a third state of the optical element 50.
- the second image P ⁇ b> 2 appears in the optical element 50.
- the appearance of the second image P2 means that the luminance of light in the second image P2 is higher than the luminance of light in the first image P1, and the optical element 50 displays at least the second image P2. Therefore, the third state includes a state in which the second image P2 is identified while the first image P1 is not identified. In the third state, the optical element 50 displays the second image P2 and the first image P1, and the light intensity in the second image P2 is higher than the light intensity in the first image P1. included.
- the brightness of the light reflected by the relief surface 13Re is such that the observer can identify the image, and the brightness of the light reflected by the sub-wavelength grating 11G is Not enough for an observer to identify.
- FIG. 23 shows a fourth state of the optical element 50.
- both the first image P1 and the second image P2 appear in the optical element 50.
- the optical element 50 identifies both the first image P1 and the second image P2 to the observer.
- the luminance of light in the first image P1 may be substantially equal to the luminance of light in the second image P2.
- the intensity of the light reflected by the sub-wavelength grating 11G and the light reflected by the relief surface 13Re is such that the observer OB can distinguish.
- the optical element 50 should just have a 3rd state from a 1st state. In the optical element 50, the fourth state is not essential.
- the optical element 50 displays a reflected image formed by monochrome reflected light, that is, a monochrome image, and a colored image formed by light having a certain wavelength range, that is, a chromatic image.
- the discrimination between the monochrome image and the chromatic color image is performed by discriminating between the first monochrome image and the second monochrome image, or discriminating between the first chromatic color image and the second chromatic color image. Compared with the case where it does, an individual difference does not arise easily in discrimination
- the optical element 50 does not display both the second state in which the first image P1 is mainly displayed, the third state in which the second image P2 is mainly displayed, and the first image P1 and the second image P2. Including the first state.
- the second state or the third state and the first state are in contrast with each other, individual differences are unlikely to occur in the discrimination between the second state or the third state and the first state. Therefore, individual differences are less likely to occur in authenticity verification, and the criteria for verifying authenticity can be easily described.
- the optical element 50 in the second example includes the first layer 11, the second layer 12, and the third layer 13, as in the optical element 50 in the first example.
- the second layer 12 is a relief layer.
- the relief surface 12Re may be on the surface opposite to the surface 12F of the second layer 12, that is, on the back surface 12R.
- the relief surface 12Re is positioned on the entire back surface 12R, but the relief surface 12Re may be positioned on the entire back surface 12R or only a part of the back surface 12R.
- a colored image by the light reflected by the sub-wavelength grating 11G can be displayed by the difference between the refractive index of the first layer 11 and the refractive index of the second layer 12.
- a reflection image by the light reflected by the relief surface 12Re can be displayed by the difference between the refractive index of the second layer 12 and the refractive index of the third layer 13.
- the surface of the third layer 13 opposite to the surface in contact with the second layer 12 may be a flat surface, or uneven in the relief surface 12Re of the second layer 12. You may have the shape to follow.
- the optical element 50 displays a colored image and a reflected image by monochrome light, individual differences are unlikely to occur between the two images. Therefore, in the optical element 50, individual differences are less likely to occur in authenticity verification, and the criteria for verifying authenticity can be easily described.
- the reflectance at the sub-wavelength grating 11G is determined by the difference between the refractive index of the first layer 11 and the refractive index of the second layer 12.
- the reflectance at the relief surface 12Re can be increased by the difference between the refractive index of the second layer 12 and the refractive index of the third layer 13.
- the fifth embodiment described above can be implemented with appropriate modifications as follows.
- the sub-wavelength grating 11G includes the first region 11S1 and the second region 11S2, but the sub-wavelength grating 11G included in the optical element 50 is configured by only one region. Also good.
- the first layer 11 may be a relief layer. That is, in the first layer 11, the surface opposite to the surface including the sub-wavelength grating 11G may include a relief surface. Even in such a case, the effect according to the above (10) can be obtained.
- the surface that is in contact with the relief surface 12Re in the third layer 13 has a shape that follows the relief surface 12Re. Therefore, the surface of the third layer 13 can also function as a relief surface.
- the back surface 11R of the first layer 11 may include a sub-wavelength grating 11G and a relief surface 11Re.
- the sub-wavelength grating 11G and the relief surface 11Re can be formed simultaneously using one original plate, the accuracy of the position of the relief surface 11Re with respect to the position of the sub-wavelength grating 11G can be improved. .
- the sub-wavelength grating 11G and the relief surface 11Re are located on the same plane, and the region where the first image P1 is displayed when viewed from the direction facing the back surface 11R of the first layer 11 And a part of the area where the second image P2 is displayed can be overlapped. Further, the area where the first image P1 is displayed and the area where the second image P2 is displayed may overlap. Furthermore, a part or all of the outline of the area where the first image P1 is displayed may overlap with a part or all of the outline of the area where the second image P2 is displayed. Since the outlines of the first image P1 and the second image P2 overlap, it is easy to compare the two patterns.
- the sub-pixel region that is the pixel region Px where the sub-wavelength grating 11G is located and the relief pixel region where the relief surface 11Re is located are arranged as follows. Can do.
- the arrangement of the sub-pixel area and the relief pixel area may be a checkered pattern, a stripe pattern, a honeycomb pattern, a concentric pattern, or the like.
- the sub-pixel area and the relief pixel area as described above. That is, in the region for displaying the first image P1, from the region where a part of the region where the first image P1 is displayed and a part of the region where the second image P2 is displayed overlap, The proportion of the sub-pixel region can be increased along the direction toward the outer edge.
- the proportion of the relief pixel region can be increased along the direction toward the outer edge.
- the layer provided with the relief surface may have a quantization phase difference structure described below, and display a reflective layer formed by monochrome light with the structure.
- a quantization phase difference structure described below
- display a reflective layer formed by monochrome light with the structure With reference to FIGS. 26 to 28, the structure of the layer having the relief surface will be described.
- FIG. 26 shows a structure in plan view facing the relief surface.
- a plurality of quantization convex portions 52a having a constant size and a plurality of quantization concave portions 52b having a constant size are aligned.
- the bright part is the quantization convex part 52a
- the dark part is the quantization concave part 52b.
- the quantization convex part 52a and the quantization concave part 52b are arrange
- the quantization convex part 52a is adjacent to the quantization concave part 52b or the quantization convex part 52a at a constant interval.
- the quantized concave portions 52b are adjacent to the quantized convex portions 52a or the quantized concave portions 52b at regular intervals.
- the quantized convex portions 52a and the quantized concave portions 52b of the quantized phase difference structure 52 are alternately arranged one by one, or a plurality of quantized convex portions 52a and a plurality of quantized concave portions 52b are alternately arranged.
- the spatial frequency component with a coarse period and the spatial frequency component with a fine period are superimposed on the relief surface by the arrangement of the quantized convex part 52a and the quantized concave part 52b.
- the relief surface can be a cell containing the quantized phase difference structure 52.
- a rib-shaped convex portion in which the quantized convex portions 52a are aligned in one direction and a quantized concave portion that is a concave portion having a constant size as an element structure are parallel to the rib-shaped convex portion.
- the groove-like recesses aligned in a row may be arranged adjacent to each other and alternately.
- the size of the quantized convex portion 52a can be set to 1/20 or more of the center wavelength at the visible wavelength and to half or less of the center wavelength.
- the size of the quantization recess 52b can be set to 1/20 or more of the center wavelength at the visible wavelength and to half or less of the center wavelength.
- the size of the quantization convex part 52a can be 25 nm or more and 250 nm or less.
- the size of the quantization recess 52b can be 25 nm or more and 250 nm or less.
- the quantization convex part 52a can be made into a square in the plan view facing the relief surface.
- the quantization recess 52b can be a square in a plan view facing the relief surface. In a plan view facing the relief surface, the corners of the quantized convex portions 52a can be rounded. In a plan view facing the relief surface, the corners of the quantization recess 52b can be rounded.
- the quantization convex portion 52a and the quantization concave portion 52b may be aligned with the virtual grid.
- the height of the quantization convex part 52a can be made the same height as the reference height or an integral multiple of the reference height.
- the depth of the quantization recess 52b can be the same as the reference depth or an integral multiple of the reference depth.
- the reference height and the reference depth may be the same value.
- the integer multiple value can be 1 to 4 times.
- the integer multiple may be 1 to 8 times.
- the reference height and the reference depth can be 10 nm or more and 500 nm or less.
- FIG. 27 shows the peak of the spatial frequency component calculated along one direction D shown in FIG.
- a spatial frequency component is calculated along a predetermined direction D in the relief plane.
- the hologram reproduction image reproduced by the relief surface is a reproduction point group of five points, discrete five-point peaks are recognized in the spatial frequency components F1 to F5 corresponding to the reproduction points.
- the horizontal axis represents the spatial frequency (1 / mm), and the vertical axis represents the intensity of the spatial frequency component.
- the reconstructed image is a rainbow image, and when it is dense, it is a monochrome image. It is also possible to adjust the density of the spatial frequency component distribution so that the reproduced image at a certain observation angle is an iridescent image, and the reproduced image at other observation angles is monochrome.
- FIG. 28 is a cross-sectional view schematically showing the quantized phase difference structure 52.
- the relief surface formed by the quantized phase difference structure 52 is shown as the upper surface.
- the layer including the quantized retardation structure 52 has a substantially flat shape.
- the quantized phase difference structure 52 is located on one surface of the surfaces facing each other in the layer.
- the length L from the top surface 52c of the quantization convex portion 52a to the bottom surface 52d of the quantization concave portion 52b is constant regardless of the position on the relief surface.
- the top surface 52c of the quantization convex portion 52a and the bottom surface 52d of the quantization concave portion 52b may be substantially parallel to the surface of the carrier when the optical element 50 is formed.
- the color of the reflected light of the quantized phase difference structure 52 changes according to the length L.
- the uneven direction of the quantized phase difference structure 52 that is, the vertical direction in FIG. 28, is a rib-shaped recess and a groove-shaped recess formed by the top surface 52c of the quantized convex portion 52a and the bottom surface 52d of the quantized concave portion 52b. It is perpendicular to the extending direction. With such a structure, it is possible to control the emission distribution of reflected light and the color of reflected light without breaking the emission distribution of reflected light and without damaging the color of the light.
- each of the top surface 52c of the quantization convex portion 52a and the bottom surface 52d of the quantization concave portion 52b functions as a reflection surface.
- the quantized convex part 52a and the quantized concave part 52b have a width that is an integral multiple of the unit length and a vertical width that is an integral multiple of the unit length in a plan view facing the relief surface.
- the unit length may be not less than 1/20 of the center wavelength at the visible wavelength and not more than half of the center wavelength.
- the unit length may be 25 nm or more and 250 nm or less.
- the quantized phase difference structure 52 may be located on both of a pair of surfaces facing each other in the layer including the quantized phase difference structure 52.
- the relief surface includes a phase angle recording area.
- the quantized phase difference structure 52 described above is formed in the phase angle recording area.
- the extending direction of the groove-shaped concave portion or rib-shaped convex portion and the orientation of the sub-wavelength grating 11G are equal or orthogonal. In other words, the arrangement direction of the groove-shaped concave portions and rib-shaped convex portions and the azimuth angle of the sub-wavelength grating 11G can be orthogonal or equal.
- the average of the orientations can be set as the orientation of the sub-wavelength grating 11G.
- the average can be a weighted average weighted by the area of each region where a plurality of sub-wavelength gratings are formed. Accordingly, when the observer OB tilts the card 100 forward with respect to the reference plane Ph0, the card 100 displays the first image P1 and the second image P2 according to the position of the card 100.
- the card 100 displays the first image P1 and the second image P2 (see FIG. 40).
- the optical element 50 may include a reflective layer on the quantization phase difference structure 52.
- the reflective layer may be translucent or concealed.
- the reflective layer may be formed from a metal material. Examples of metal materials are Al, Ag, Sn, Cr, Ni, Cu, Au, and alloys thereof.
- the reflective layer formed from a metal material can be a concealable reflective layer.
- the reflective layer may be a dielectric layer having a refractive index different from that of the relief structure forming layer.
- the reflective layer may be a laminate of dielectric layers having different refractive indexes between adjacent layers, that is, a dielectric multilayer film.
- the refractive index of the layer in contact with the relief surface is preferably different from the refractive index of the layer including the relief surface.
- the material for forming the dielectric layer can be a metal compound or silicon oxide.
- the metal compound can be a metal oxide, a metal sulfide, and a metal fluoride.
- Examples of the material for forming the dielectric layer are TiO 2 , ZnO, Si 2 O 3 , SiO, Fe 2 O 3 , ZnS, CaF, and MgF.
- the reflective layer of the dielectric layer can be translucent.
- the reflective layer can be formed by a vapor deposition method.
- a vapor deposition method a vacuum deposition method, a sputtering method, or the like can be applied.
- the thickness of the reflective layer can be 10 nm or more and 1000 nm or less.
- the reflective layer may be formed using ink.
- the ink for forming the reflective layer may be offset ink, letterpress ink, gravure ink, or the like depending on the printing method.
- the ink which forms a reflection layer may be resin ink, oil-based ink, water-based ink, etc. according to the difference in composition.
- the ink for forming the reflective layer may be an oxidation polymerization type ink, a permeation drying type ink, an evaporation drying type ink, and an ultraviolet curable ink depending on the difference in the drying method.
- the ink for forming the reflective layer may be a functional ink whose color changes according to the illumination angle or the observation angle.
- the functionality may be optically variable ink (Optical Variable Ink), color shift ink, and pearl ink.
- the observation angle range in which the second image displayed on the relief surface is observed may be larger than the observation angle range in which the first image displayed on the sub-wavelength grating 11G is observed. That is, the optical element 50 is observed in a state where the first image is displayed at the observation angle in the first range, and is observed in a state where the second image is displayed in the observation angle in the second range.
- the range may be larger than the first range.
- the size of the observation angle range in which the first image is observed is equal to the size of the angle range in which the second image is observed.
- the uniformity in changing the image displayed by the optical element 50 is disturbed. This makes it easier for the image displayed by the optical element 50 to catch the eyes of the observer. That is, the attractiveness by the image displayed by the optical element 50 is enhanced.
- the first image displayed by the subwavelength grating 11G and the second image displayed by the relief surface may have a correlation with each other.
- the observer who observed the optical element 50 notices the correlation between the first image and the second image, thereby observing. It is possible to draw the attention of the person.
- examples of the first image and the second image in a case where the first image and the second image have a correlation will be described in more detail with reference to FIGS. 29 to 31. 29 to 31 show a state where both the first image and the second image are displayed for convenience of explanation.
- the second image P2 is positioned outside the first image P1 and has a shape that follows the contour of the first image P1.
- the outline of the first image P1 is bordered by the second image P2 having a contrasting color with the first image P1
- the outline of the first image P1 can be made to stand out. It is. Thereby, the attractiveness of the 1st image P1 and the 2nd image P2 can be improved.
- the relief surface forming the second image P2 includes a plurality of pixel regions Px and each pixel region Px includes a plurality of reflecting surfaces extending along one direction
- the relief surface is as follows. It may be the structure. That is, in a plurality of pixel regions Px, the azimuth angle of the reflecting surface may change along the direction from the contour of the first image P1 toward the contour of the second image P2. Thereby, it is possible to produce the brightness gradation in the 2nd image P2 according to the azimuth angle of a reflective surface. Thereby, the smooth texture and attractiveness by the 1st image P1 and the 2nd image P2 can be improved.
- one of the first image P1 and the second image P2 has a shape representing a predetermined symbol or a predetermined object.
- the other of the first image P1 and the second image P2 is a character representing the shape.
- the first image P1 has the shape of the symbol Euro (EURO)
- the second image P2 is a character representing the shape.
- the first image P1 may be a character representing the shape.
- the first image P1 and the second image P2 showing the same meaning may or may not be displayed depending on the observation angle. Therefore, it is possible to increase the degree of recognition of the contents meant by the first image P1 and the second image P2, and the attractiveness of the first image P1 and the second image P2.
- the first image P1 has a shape representing a set of objects together with the second image P2.
- each of the first image P1 and the second image P2 has a shape forming a pair of legs.
- the first image P1 has a left foot shape
- the second image P2 has a right foot shape.
- the first image P1 and the second image P2 only need to have a shape that represents a set of objects with each other.
- the first image P1 and the second image P2 may have a shape that forms a set of hands.
- first image P1 and the second image P2 may have shapes representing different objects, and may form one image that is complemented by each of the first image P1 and the second image P2. That is, the first image P1 and the second image P2 may form one trick picture. Also by this, the attractiveness of the first image P1 and the second image P2 can be enhanced.
- FIGS. 32 to 35 a sixth embodiment of the optical element will be described.
- the optical element according to the sixth embodiment of the present invention is different from the optical element 50 according to the fifth embodiment in that the layers other than the first layer 11, the second layer 12, and the third layer 13 are relief layers. Different. Therefore, in the following, such differences will be described in detail.
- components corresponding to the optical element 50 of the fifth embodiment are denoted by the same reference numerals as those in the fifth embodiment. Detailed description thereof is omitted.
- four examples will be described in order as the optical element of the sixth embodiment.
- the optical element 60 includes a first layer 11, a second layer 12, and a third layer 13.
- the optical element 60 further includes a relief layer 61 including a relief surface 61Re.
- the relief surface 61Re is a surface different from the back surface 11R and the front surface 12F described above.
- the relief surface 61Re includes a plurality of reflecting surfaces, and the pitch between the reflecting surfaces adjacent to each other is larger than the pitch of the sub-wavelength grating 11G.
- the relief surface 61Re is included in the back surface 61R of the relief layer 61.
- the optical element 60 further includes a reflective layer 62 and an adhesive layer 63.
- the reflective layer 62 is in contact with the relief surface 61Re and has a shape that follows the unevenness of the relief surface 61Re.
- the adhesive layer 63 is in contact with the reflective layer 62 on the side opposite to the relief layer 61 with respect to the reflective layer 62.
- the third layer 13 functions as an adhesive layer.
- the multilayer body formed of the first layer 11 and the second layer 12 is attached to the relief layer 61 by the third layer 13. Therefore, in the optical element 60, the sub-wavelength grating 11G and the relief surface 61Re overlap each other when viewed from the thickness direction of the optical element 60.
- the adhesive layer 63 may be located on the entire surface of the reflective layer 62 opposite to the surface in contact with the relief layer 61 or may be located on a part thereof.
- the second multilayer body composed of the above can be manufactured individually. Further, according to the optical element 60 of the first example, the optical element 60 can be attached to the adherend using the adhesive layer 63.
- the optical element 60 includes a relief layer 61, a reflective layer, in addition to the first layer 11, the second layer 12, and the third layer 13, in the same manner as the optical element 60 in the first example described above. 62 and an adhesive layer 63.
- the optical element 60 of the second example further includes a base material 64 between the third layer 13 and the relief layer 61. In the pair of surfaces facing each other in the base material 64, the third layer 13 is positioned on one surface and the relief layer 61 is positioned on the other surface.
- the base material 64 has optical transparency.
- the base material 64 can function as a support layer for the first layer 11 and the relief layer 61 formed with respect to the base material 64 when the optical element 60 is manufactured.
- the optical element 60 of the second example is observed from the base material 64 side with respect to the relief layer 61.
- the optical element of the third example will be described with reference to FIG. As shown in FIG. 34, in the optical element 60, in the same manner as the optical element 60 in the first example described above, in addition to the first layer 11, the second layer 12, and the third layer 13, a relief layer 61, a reflective layer 62 and an adhesive layer 63.
- the optical element 60 of the third example further includes a first base material 65 and a second base material 66.
- the first base material 65 is located between the third layer 13 and the relief layer 61.
- the third layer 13 functions as an adhesive layer, whereby the multilayer body composed of the first layer 11 and the second layer 12 is bonded to the first base material 65 by the third layer 13.
- the adhesive layer 63 is adhered to the second base material 66.
- the first base 65 has light transmittance.
- the 2nd base material 66 may have a light transmittance, and does not need to have a light transmittance.
- the first multilayer body composed of the first layer 11, the second layer 12, and the third layer 13 is located in a part of the first base material 65 in a plan view facing the sub-wavelength grating 11G. .
- the second multilayer body including the relief layer 61, the reflective layer 62, and the adhesive layer 63 is located at a part of the second base material 66 in a plan view facing the relief surface 61Re.
- the first layer 11 overlaps the relief layer 61 when viewed from the thickness direction of the optical element 60.
- the optical element of the fourth example will be described.
- the optical element 60 includes a relief layer 61, a reflective layer 62, An adhesive layer 63 is provided.
- the optical element 60 further includes a first base material 65 and a second base material 66.
- the third layer 13 functions as an adhesive layer, and the third layer 13 is bonded to the relief layer 61.
- the adhesive layer 63 is adhered to the second base material 66.
- the first multilayer body described above is located in a part of the first base material 65 in a plan view corresponding to the sub-wavelength grating 11G.
- the second multilayer body is located at a part of the second base material 66 in a plan view facing the relief surface 61Re.
- the first layer 11 overlaps the relief layer 61 when viewed from the thickness direction of the optical element 60.
- the optical element 60 is observed from the reflective layer 62 side with respect to the adhesive layer 63. Therefore, the 1st base material 65 has light transmittance. On the other hand, the 2nd base material 66 may have a light transmittance, and does not need to have a light transmittance.
- each substrate paper, plastic film, or the like can be used for each substrate.
- Each substrate may be printed.
- each base material is a multilayer body, and printing may be performed on at least some of the plurality of layers constituting the base material.
- the optical element of the sixth embodiment in addition to the above (10), the following effects can be obtained. (12) Since the layers other than the first layer 11, the second layer 12, and the third layer 13 are relief layers having a relief surface, the degree of freedom in designing the relief layer is increased.
- each base material may be smaller than at least one of the first multilayer body and the second multilayer body in a plan view facing the sub-wavelength grating 11G.
- the first multilayer body including the first layer 11 and the second multilayer body including the relief layer 61 may be included between the two base materials.
- each of the first multilayer body and the second multilayer body may be laminated while being sandwiched between two substrates.
- each substrate may be a laser coloring layer that develops color when irradiated with a laser beam.
- the base material 64 in a 1st example may also contain the information memorize
- At least one of the first base material 65 and the second base material 66 can include information stored by laser beam irradiation.
- the first base material 65 includes information
- the second image displayed by the relief surface 61Re and the information included in the first base material 65 are overlapped with each other when viewed from the thickness direction of the optical element 60. Only part of the two images is visible. Thereby, in the optical element 60, the tolerance with respect to forgery increases.
- the second substrate 66 includes information, the entire first image displayed by the sub-wavelength grating 11G and the second surface displayed by the relief surface are viewed from the thickness direction of the optical element 60. The entire image is visible.
- the optical element 60 of the third example when the first base material 65 includes information, the first image displayed by the sub-wavelength grating 11G and the relief surface 61Re are viewed from the thickness direction of the optical element 60.
- the tolerance with respect to forgery increases.
- the second substrate 66 when the second substrate 66 includes information, the entire first image displayed by the sub-wavelength grating 11G and the second surface displayed by the relief surface are viewed from the thickness direction of the optical element 60. The entire image is visible.
- a transfer foil provided with an optical element will be described with reference to FIG.
- the optical element included in the transfer foil is a first example of the optical element 50 of the fifth embodiment will be described as one form of the transfer foil.
- the transfer foil 70 includes an adhesive body including the optical element 50 and an adhesive layer 71 for bonding the optical element 50 to the transfer target body.
- the transfer foil 70 further includes a support layer 72 and a release layer 73.
- the support layer 72, the release layer 73, the optical element 50, and the adhesive layer 71 are stacked in the order described.
- the optical element 50 after being transferred to the transfer medium is observed from the side opposite to the optical element 50 with respect to the release layer 73. Therefore, the release layer 73 is light transmissive.
- the support layer 72 since the peeling layer 73 is peeled from the support layer 72 when the optical element 50 is transferred, the support layer 72 may or may not have light transmittance. .
- the transfer foil 70 includes a sub-wavelength grating 11G and a relief surface 13Re. Therefore, the optical element 50 that displays the first image P1 and the second image P2 can be transferred to the transfer target body only by transferring a part of the transfer foil 70.
- a hot stamp method can be used for the transfer of the optical element 50.
- [Modification of the seventh embodiment] [Transfer foil] It is possible to prepare a first transfer foil including the sub-wavelength grating 11G and a second transfer foil including the relief surface 13Re, and form an optical element using the two transfer foils. In this case, when viewed from the thickness direction of the optical element, the first sub-wavelength grating 11G included in the first transfer foil and the relief surface 13Re included in the second transfer foil overlap with each other on the first transfer object. A part of the transfer foil and a part of the second transfer foil may be transferred. In this case, when forming the optical element, it is necessary to align the position where a part of the first transfer foil is transferred and the position where a part of the second transfer foil is transferred. Therefore, the resistance against counterfeiting is enhanced in the optical element.
- the transfer foil is replaced with the optical element 50 described above, the optical element 10 of the first embodiment, the optical element 20 of the second embodiment, the optical element 30 of the third embodiment, and the optical element of the fourth embodiment. 40 may be included. Further, the transfer foil may include the optical element 50 of the second example in the fifth embodiment, and the optical element 60 of the first example and the second example in the sixth embodiment, instead of the optical element 50 described above.
- the card curd which is an example of an authentication body is demonstrated.
- the card according to the embodiment of the present invention are an ID card, a license, a license card, a member card, and a credit card.
- the card includes the third example of the optical element 60 of the sixth embodiment as a part of the card.
- the card 80 has a plate shape that spreads two-dimensionally in a plan view facing the surface 80F of the card 80.
- the card 80 displays the first image 81, the second image 82, and the third image 83 via the surface 80F. Further, the card 80 displays the first image P1 and the second image P2 via the surface 80F.
- the first image 81 includes a face image 81a and a background image 81b.
- the face image 81a is an image showing the face of the owner of the card 80.
- the background image 81b includes a face image 81a inside, and forms the background of the face image 81a.
- the second image 82 includes information regarding the owner of the card 80.
- the second image 82 includes information expressed by letters and numbers.
- the third image 83 includes information regarding the card 80.
- the information included in the third image 83 is the name of the card 80.
- the face image 81a and the second image 82 are identification information for identifying the card owner.
- the card 80 only needs to be able to display the first image P1 and the second image P2 via the surface 80F.
- the above-described image is an example of an image that can be displayed by the card 80.
- FIG. 38 shows a cross-sectional structure of the card 80 taken along line IV-IV in FIG.
- a card 80 that is an example of an authentication body includes an optical element 60.
- the optical element 60 may cover the identification information.
- the first multilayer body including the first layer 11, the second layer 12, and the third layer 13 further includes a release layer 68.
- the release layer 68 covers the first layer 11.
- the second multilayer body including the relief layer 61, the reflective layer 62, and the adhesive layer 63 further includes a release layer 69.
- the release layer 69 covers the relief layer 61.
- the second multilayer body is covered with the first base material 65.
- the whole or a part of the second base material 66 may have a characteristic of color development by laser beam irradiation before laser beam irradiation. Coloring by laser beam irradiation can be carbonized. That is, the whole or a part of the second base material 66 may have a characteristic of being carbonized by the laser beam irradiation before the laser beam irradiation.
- the second base material 66 included in the card 80 includes a first color development part 66a and a second color development part 66b, which are parts colored by irradiation with a laser beam.
- the first color developing unit 66a is a part that displays the face image 81a
- the second color developing unit 66b is a part that displays the second image 82.
- the card 80 includes a white layer 91, a lower protective layer 92, and an upper protective layer 93.
- the white layer 91 is a white layer and is in contact with the second base material 66.
- printing 94 is applied to a part of the surface in contact with the second base material 66.
- the print 94 is located in an area overlapping with the first color development portion 66a.
- the print 94 displays a background image 81b.
- the lower protective layer 92 is located on the surface of the white layer 91 opposite to the surface in contact with the second base material 66.
- the upper protective layer 93 covers the first base material 65 and encloses the first multilayer body with the first base material 65.
- the upper protective layer 93 is light transmissive.
- the lower protective layer 92 may have light transmittance or may not have light transmittance.
- the authentication body is not limited to a card, and may be embodied as another authentication body used for authenticating an owner such as a passport.
- the authentication body is replaced with the optical element 60 described above, the optical element 10 of the first embodiment, the optical element 20 of the second embodiment, the optical element 30 of the third embodiment, the optical element 40 of the fourth embodiment, And the optical element 50 of 5th Embodiment may be included. Further, the authentication body may include the optical element 60 in the first example, the second example, and the fourth example of the sixth embodiment instead of the optical element 60 described above.
- Card configuration The configuration of the card will be described with reference to FIG. As an example of the card, a card including the optical element 10 of the first embodiment will be described. However, the card is not limited to the optical element 10 of the first embodiment, and the optical element in each of the second to sixth embodiments. May be provided.
- the card 100 further includes a display layer 101 in addition to the first layer 11, the second layer 12, and the third layer 13.
- the display layer 101 can display predetermined information.
- the display layer 101 can display predetermined information using characters, numbers, figures, QR codes (registered trademark), and the like.
- the surface of the first layer 11 opposite to the surface in contact with the second layer 12 is the surface 100F.
- the display layer 101 can display predetermined information by printing performed on the display surface 101F in contact with the third layer 13.
- the display surface 101F can be printed by letterpress printing, gravure printing, offset printing, or screen printing.
- a functional ink can be used as the printing ink.
- the functional ink is ink that changes color according to the type or state of the light source that irradiates the card 100, and ink that changes color or gloss according to the observation angle of the observer.
- the ink whose color changes depending on the type or state of the light source can be phosphorescent ink, fluorescent ink, and photochromic ink.
- the ink whose color and gloss change according to the observation angle can be pearl ink, magnetic ink, and color shift ink.
- Phorochromic ink is ink that develops color in response to ultraviolet light.
- the photochromic ink has a function of exhibiting different colors such as red, blue, purple, and yellow according to the irradiation amount of ultraviolet rays to the photochromic ink.
- Pearl ink is ink to which a pearl pigment is added. The gloss of the pearl ink changes depending on the observation angle.
- the pearl ink contains a pearl pigment formed from a polarized pearl as a pearl pigment, so that the color tone changes depending on the observation angle. According to the functional ink, it can be easily confirmed whether or not the color of the printing formed on the display surface 101F changes. Therefore, the authenticity of the card 100 can be reliably verified based on the printing color.
- an ink jet method, a thermal printer method, a laser method, or the like may be used as a method for printing on the display surface 101F.
- the information to be formed on the display surface 101F can be set for each card 100. Therefore, a pattern or the like common to a plurality of cards 100 is printed at a relatively high speed by the above-described printing, and identification information for identifying each card 100 is an ink jet method, a thermal printer method, a laser method, or the like. It is preferable to print using.
- the optical element included in the card 100 is not limited to the optical element 10 of the first embodiment, and may be the optical element in each of the fifth embodiment and the sixth embodiment. That is, the card 100 may be capable of displaying the first image P1 displayed by the sub-wavelength grating 11G, the second image P2 displayed by the relief surface, and the third image displayed by the display layer 101. .
- the card 100 when the luminance of the first image P1 and the luminance of the second image P2 are sufficiently high, the observation angle at which the first image P1 is displayed and the observation at which the second image P2 is displayed. At each angle, the third image is hardly visible.
- the third image is visually recognized at an observation angle at which both the first image P1 and the second image P2 are not displayed. Therefore, the observer can visually recognize the third image.
- the observation angle at which each of the first image P1 and the second image P2 is visually recognized is arbitrary depending on the observation angle at which each of the first image P1 and the second image P2 appears, that is, the shape of the sub-wavelength grating 11G and the relief surface. Can be set.
- the multilayer body composed of the first layer 11, the second layer 12, and the third layer 13 preferably has a transmittance of 70% or more in the direction in which the three layers are stacked.
- the image displayed on the card 100 is easily visually recognized.
- an optical element that is a multilayer body composed of the first layer 11, the second layer 12, and the third layer 13 covers the identification information
- the ease of identification is improved.
- Article 195 in the safety standard for road transport vehicles requires that the transmittance of each of the front glass and side glass of an automobile is 70% or more. Even in view of these standards, it can be said that it is preferable that the transmittance of a transmission body through which light for displaying information is transmitted is 70% or more in order for a person to view information clearly and reliably.
- the transmittance of the transparent multilayer body can be measured using a spectrophotometer.
- the light source is sunlight or a fluorescent lamp. Therefore, it is preferable to measure the transmittance at a wavelength of 500 nm as the transmittance of the multilayer body used in the card 100.
- the transmittance of the multilayer body is preferably measured by a method in accordance with JIS K7375: 2008 “How to obtain total light transmittance and total light reflectance of plastic”.
- the operation of the card 100 will be described with reference to FIGS. Below, the effect
- curd 100 is a structure provided with the optical element containing the subwavelength grating 11G and a relief surface, and the authenticity of the card
- the second example of the card 100 is configured to include an optical element that includes the sub-wavelength grating 11G but does not include a relief surface, and the verifier verifies the authenticity of the card 100.
- FIG. 40 schematically shows a method in which the observer OB verifies the authenticity of the card 100 by visual observation.
- the reference plane Ph0 is a plane on which the card 100 is arranged when the observer OB starts observing the card 100.
- the reference plane Ph0 is a base plane used when verifying the authenticity of the card 100.
- the observer OB tilts the card 100 arranged on the reference plane Ph0 along each of the first plane Ph1, the second plane Ph2, and the third plane Ph3.
- the observer OB observes the card 100 when the card 100 is positioned on each of the planes Ph1, Ph2, and Ph3.
- the angle formed by the reference plane Ph0 and the first plane Ph1 is the first angle ⁇ 1
- the angle formed by the reference plane Ph0 and the second plane Ph2 is the second angle ⁇ 2
- the reference plane Ph0 and the third plane Ph3. Is the third angle ⁇ 3.
- the first angle ⁇ 1 is larger than the second angle ⁇ 2 and the third angle ⁇ 3, and the second angle ⁇ 2 is larger than the third angle ⁇ 3.
- the light source LS is located on the side opposite to the observer OB with respect to the card 100. In other words, the light source LS is located in front of the observer OB.
- the light source LS, the card 100, and the observer OB are arranged at relative positions such that the light of the light source LS incident on the card 100 is reflected toward the observer OB on the card 100.
- it is preferable that light from a point light source is incident on the card 100 from one direction.
- light from a fluorescent lamp or external light enters the card 100 from various directions.
- the light incident on the card 100 includes light reflected toward the observer OB in the card 100, the luminance of the light emitted from the card 100 is reduced, but the observation is performed.
- the person OB can visually recognize the information displayed on the card 100.
- FIG. 41 to 43 show images displayed on the card 100, respectively.
- FIG. 41 is an image that the card 100 shows when the card 100 is arranged on the first plane Ph1
- FIG. 42 is an image that the card 100 shows when the card 100 is arranged on the second plane Ph2.
- FIG. 43 is an image that the card 100 shows when the card 100 is arranged on the third plane Ph3.
- the card 100 is configured to be able to display the first image P1, the second image P2, and the third image P3.
- the third image P3 may include identification information for identifying the card 100.
- the identification information that can identify the owner included in the third image P3 includes the face image, name, and ID number of the owner.
- the card 100 displays the entire third image P3 to the outside through the surface 100F.
- the card 100 displays the second image P2.
- the second image P2 overlaps a part of the third image P3. Therefore, in the present embodiment, a part of the third image P3 is concealed by the second image P2.
- the luminance of the second image P2 may be a luminance that does not completely hide part of the third image P3.
- the card 100 displays the first image P1.
- the card 100 does not display the second image P2.
- the first image P1 overlaps a part of the third image P3. Therefore, in the present embodiment, a part of the third image P3 is hidden by the first image P1.
- the luminance of the first image P1 may be a luminance that does not completely hide a part of the third image P3.
- the card 100 displays the first image P1 and the second image P2 according to the position of the card 100.
- the card 100 displays the first image P1 and the second image P2.
- the observer OB visually recognizes the first image P1 and the second image P2 displayed on the card 100. Is possible. In other words, even when the observer OB tilts the card 100 without substantially changing the distance between the surface 100F of the card 100 and the observer OB in the observation space, the observer OB does not change the first image P1. It is possible to visually recognize the second image P2. However, the observer OB can easily view the second image P2, while the observer OB can observe the first image P1 only under limited observation conditions for the following reason.
- the first image P1 is viewed by the observer OB only when the light source LS and the observer OB are positioned at a target angle with respect to the plane including the ray with respect to the surface of the card 100. Therefore, when the card 100 is tilted left and right with respect to the second plane Ph2, the angle formed by the second plane Ph2 and the reference plane Ph0 needs to be the third angle ⁇ 3.
- the second plane Ph2 is a plane on which the card 100 is arranged when the observer OB unconsciously picks up the card 100. Therefore, the probability that the angle formed by the second plane Ph2 and the reference plane Ph0 matches the third angle ⁇ 3 is low.
- the observer OB tilts the card 100 back and forth with respect to the reference plane Ph0, the probability that the observer OB places the card 100 on the third plane Ph3 is high.
- the observer OB tilts the card 100 back and forth while the light source LS is positioned obliquely upward with respect to the plane including the line of sight of the observer OB. Can be determined. This increases the probability that the observer OB observes both the first image P1 and the second image P2. Therefore, the authentic verification of the card 100 by the observer OB is easily performed accurately.
- FIG. 44 schematically shows a method of verifying the authenticity of the card 100 by the verifier V.
- the card 100 is designed such that the light from the light source LS is incident on the surface 100F of the card 100 at the incident angle ⁇ and the reflected light reflected at the emission angle ⁇ is input to the verifier V.
- An environment for verifying the authenticity of 100 is set.
- the verifier V can be a camera capable of reading an image, a sensor capable of reading a luminance distribution, and the like.
- the verifier V may be any device that can process the first image P1 as an image or optical information such as luminance.
- FIG. 45 shows an image displayed by the genuine card 100.
- FIG. 46 shows an image displayed by the fake card 200.
- 45 and 46 show images displayed on the cards 100 and 200 under certain observation conditions.
- the genuine card 100 shows a QR code (registered trademark) P3a as a part of the third image P3.
- the fake card 200 displays the QR code P3a as a part of the third image P3 and at the same time displays the first image P1 through the surface 200F.
- the verifier V verifies that the card 100 is authentic when the QR code P3a displayed on the card 100 is read under the above-described observation conditions. In this case, since the card 100 displays the QR code P3a as a part of the third image P3 and the QR code P3a does not overlap with other images, the verifier V determines that the card 100 is a genuine card. It can be verified that it is 100.
- the card 200 displays the QR code P3a as a part of the third image P3, but displays the first image P1 so as to overlap the QR code P3a when viewed from the thickness direction of the card 100.
- the information read by the verifier V includes information other than the QR code. Therefore, the verifier V can verify that the card 200 is a fake.
- the QR code P3a is shown as the code displayed on the cards 100 and 200, but the code displayed on the cards 100 and 200 may be another code that can be read by the verifier V. Other codes can be bar codes.
- the first image P1 or the second image P2 may be used instead of the third image P3.
- the position of the verifier V is fixed at one place.
- the light emitted from the card 100 may be read even at an angle ⁇ that is different from the angle ⁇ .
- the authenticity of the card 100 can be verified in two stages by using two pieces of information obtained at different angles. Thereby, the accuracy of authenticity verification can be further increased.
- optical element forming material materials that can be used for forming the optical element will be described. Below, the material for forming each of the 1st layer 11, the 2nd layer 12, and the 3rd layer 13 in an optical element is demonstrated.
- Each material of the first layer 11 and the third layer 13 can essentially contain the following various resins.
- materials forming each layer are poly (meth) acrylic resin, polyurethane resin, fluorine resin, silicone resin, polyimide resin, epoxy resin, polyethylene resin, polypropylene resin, methacrylic resin, poly Methylpentene resin, cyclic polyolefin resin, polystyrene resin, polyvinyl chloride resin, polycarbonate resin, polyester resin, polyamide resin, polyamideimide resin, polyarylphthalate resin, polysulfone resin, polyphenylene sulfide Resins, polyethersulfone resins, polyethylene naphthalate resins, polyetherimide resins, acetal resins, and cellulose resins can be used.
- the material for forming the first layer and the third layer only one of these resins may be used, or two or more of them may be mixed or combined.
- the materials for forming the first layer 11 and the third layer 13 are a curing agent, a plasticizer, a dispersant, various leveling agents, an ultraviolet absorber, an antioxidant, a viscosity modifier, a lubricant, and a light stabilizer. It may contain at least one such as an agent.
- the method of forming each of the first layer 11 and the third layer 13 can be a heat embossing method, a casting method, and a photopolymer method.
- a radiation curable resin is poured between a flat substrate such as a plastic film and a metal stamper. Then, after the radiation curable resin is cured by irradiation with radiation, the cured resin film is peeled off from the metal stamper together with the base material.
- the photopolymer method compared with the press method and the cast method using a thermoplastic resin, the transfer accuracy of the fine concavo-convex structure is high, and the heat resistance and chemical resistance are also excellent.
- a light-transmitting dielectric can be used as the material of the second layer 12, as described above.
- a metal, a metal compound, a silicon compound, or a mixture thereof can be used.
- dielectrics can be ZnS, ZnO, ZnSe, SiN x , SiO x , Ti x O x , Ta 2 O 5 , Cr 2 O 3 , ZrO 2 , Nb 2 O 5 , and ITO.
- the method of forming the second layer 12 can be a physical vapor deposition method, a chemical vapor deposition method, or the like.
- the physical vapor deposition method can be a vacuum deposition method, a sputtering method, an ion plating method, and an ion cluster beam method.
- the chemical vapor deposition method can be a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, or a photochemical vapor deposition method.
- the vacuum deposition method is easy to improve productivity.
- the ion plating method makes it easy to obtain a reflective layer with good film quality. Note that film formation conditions in the physical vapor deposition method and the chemical vapor deposition method may be appropriately selected according to the material for forming the reflective layer.
- the second layer 12 can also be formed by various printing methods, casting methods, die coating methods, and the like.
- the second layer 12 can be formed of a resin in which at least one of the dielectrics described above is dispersed.
- Test Example 1 is a test example corresponding to the authentication body of the eighth embodiment described above.
- a first transfer foil including the first layer 11 and a second transfer foil including the relief layer 61 were prepared.
- a part of the first transfer foil was transferred to the first base material 65, and a part of the second transfer foil was transferred to the second base material 66.
- the second base material 66 a base material that develops color when irradiated with a laser beam was used.
- an ID card was obtained as an authentication body of Test Example 1.
- a PET film (Lumirror (registered trademark), Toray Industries, Inc.) having a thickness of 38 ⁇ m was prepared as a support layer.
- the release layer 68 was obtained by applying the release layer ink to one surface of the support layer and drying the release layer ink. The thickness of the release layer 68 was 1 ⁇ m.
- the first layer ink was applied onto the release layer 68 by a gravure printing method, and then the first layer ink was dried. The thickness of the first layer ink after drying was 2 ⁇ m.
- the subwavelength grating 11G was shape
- the press pressure was set to 2 kgf / cm 2
- the press temperature was set to 80 ° C.
- the first layer ink was irradiated with ultraviolet rays from the side opposite to the release layer 68 with respect to the support layer.
- a high pressure mercury lamp was used for ultraviolet irradiation, and the output of the high pressure mercury lamp was set to 300 mJ / cm 2 .
- the 1st layer 11 was obtained by hardening the ink for 1st layers.
- a TiO 2 film having a thickness of 50 nm was formed on the first layer 11 by vacuum deposition.
- the second layer 12 was obtained.
- the adhesive layer ink was applied, and the adhesive layer ink was dried to obtain a third layer 13 having a thickness of 2.5 ⁇ m to 4 ⁇ m and functioning as an adhesive layer.
- the drying temperature was set to 120 ° C., and the time was set to 45 seconds.
- the same method as the first transfer foil was used, except that the original used for forming the relief surface 61Re was different from the original used for forming the sub-wavelength grating 11G.
- the ink having the following composition was used as the above-described release layer ink, first layer ink, relief layer ink, third layer ink, and adhesive layer ink.
- UV curable acrylic acrylate resin 70.0 parts by weight Methyl ethyl ketone 30.0 parts by weight
- a transparent polycarbonate substrate (LEXAN SD8B14, manufactured by SABIC) (LEXAN is a registered trademark) having a thickness of 100 ⁇ m was prepared as the first substrate 65.
- a polycarbonate base material (LEXAN SD8B94, manufactured by SABIC) which has a thickness of 100 ⁇ m and develops color when irradiated with a laser beam was prepared.
- the support layer was removed. Further, after the second transfer foil was transferred to the second substrate 66, the support layer was removed.
- the temperature of the surface in contact with the transfer foil is set to 120 ° C.
- the pressure is set to 1.05 t / cm 2
- the pressurizing time is set to 1 second. did.
- a white resin film (LEXAN SD8B24, manufactured by SAVIC) having a thickness of 400 ⁇ m was prepared as the white layer 91.
- a transparent resin film (LEXAN SD8B14) having a thickness of 100 ⁇ m was prepared. And these layers were laminated in the state which accumulated the lower protective layer 92, the white layer 91, the 2nd base material 66, the 1st base material 65, and the upper protective layer 93 in order of description.
- the temperature was set to 200 ° C.
- the pressure was set to 80 N / cm 2
- the heating and pressurizing time was set to 25 minutes. Then, a part of the laminated multilayer body was cut out in a card shape.
- the multilayer body was irradiated with a laser beam having a wavelength of 1064 nm.
- the first coloring portion 66a and the second coloring portion 66b were formed on the second base material 66.
- the ID card of Test Example 1 was obtained.
- FIG. 47 is an image of a first image that is a colored image displayed on the ID card
- FIG. 48 is an image of a second image that is a monochrome image displayed on the ID card. As FIG. 47 and FIG. 48 show, it was recognized that the ID card can display both the first image and the second image.
- Test Example 2 The transfer foil of Test Example 2 is a test example corresponding to the transfer foil of the seventh embodiment described above.
- Test Example 2 first, the same support layer 72 as in Test Example 1 was prepared. A release layer 73 was formed on one surface of the support layer by the same method as in Test Example 1. Then, the first layer 11 was formed on the release layer 73 and the second layer 12 was formed on the first layer 11 by the same method as in Test Example 1.
- the third layer ink was applied and the third layer ink was dried in the same manner as when the first layer 11 was formed using the first layer ink.
- the relief surface 13Re was shape
- Various conditions at the time of molding were set to the same conditions as when the sub-wavelength grating 11G was molded.
- the fourth layer 51 was formed on the relief surface 13Re in the same manner as when the second layer 12 was formed.
- the adhesive layer 71 was formed on the fourth layer 51 in the same manner as when the third layer 13 was formed in Test Example 1. Thereby, the transfer foil of Test Example 2 was obtained.
- an ink having the same composition as that of the first layer ink in Test Example 1 was used as the third layer ink for forming the third layer 13.
- a physical entity can refer to a physical form or a spatial form surrounded by a substance.
- a physical entity can be a structure.
- the structure may have a specific function.
- a combination of structures having specific functions can exhibit a synergistic effect by a combination of functions of the structures.
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Credit Cards Or The Like (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
- Inspection Of Paper Currency And Valuable Securities (AREA)
Abstract
In the present invention, a subwavelength grating displays a colored image exhibiting a color corresponding to a grating period of the subwavelength grating in a direction of reflection, which includes a direction of regular reflection. A relief surface displays a reflected image from monochromatic reflected light in a direction of reflection, which includes a direction different from the direction of regular reflection. An optical element has a first state where the colored image and the reflected image are not displayed, a second state where primarily the colored image is displayed, and a third state where primarily the reflected image is displayed. An angle formed by a plane in which the optical element spreads and a plane that includes an observer's gaze is an observation angle. The optical element is observed in the first state, the second state, or the third state, depending on the observation angle.
Description
本発明の各実施形態は、光学素子、転写箔、認証体、および、認証体の検証方法に関する。本願は、2018年3月20日に日本に出願された特願2018-053545号、2019年1月30日に日本に出願された特願2019-014299号に基づき優先権を主張し、その内容をここに援用する。
Each embodiment of the present invention relates to an optical element, a transfer foil, an authentication body, and an authentication body verification method. This application claims priority based on Japanese Patent Application No. 2018-053545 filed in Japan on March 20, 2018 and Japanese Patent Application No. 2019-014299 filed in Japan on January 30, 2019, and the contents thereof. Is hereby incorporated by reference.
商品券などの有価証券、紙幣、および、クレジットカードの偽造の防止と、商品のブランドプロテクションとを目的として、それらの物品に対し、ホログラム、回折格子、および、多層干渉膜などを用いた光学素子が付される。こうした光学素子の製造は容易でないため、光学素子は、光学素子が付された物品の偽造を防止する効果を有する。
Optical elements that use holograms, diffraction gratings, multilayer interference films, etc., for the purpose of preventing counterfeiting of securities such as gift certificates, banknotes, and credit cards, and for the purpose of product brand protection Is attached. Since manufacturing of such an optical element is not easy, the optical element has an effect of preventing forgery of an article to which the optical element is attached.
上述した光学素子として、光学素子の真正を検証するときに、特別な検証器具を用いることなく目視のみによって検証が可能な光学素子が広く用いられている。なかでも、光学素子を観察する角度に応じて、光学素子が視認される色や、光学素子が表示する像が変化するものが広く用いられている。このうち、光学素子を観察する角度に応じて色が変化する光学素子には、上述した回折格子や多層干渉膜などを挙げることができる。
As optical elements described above, optical elements that can be verified only by visual inspection without using a special verification instrument when verifying the authenticity of the optical element are widely used. Among them, those in which the color in which the optical element is visually recognized or the image displayed by the optical element change according to the angle at which the optical element is observed are widely used. Among these, examples of the optical element whose color changes according to the angle at which the optical element is observed include the above-described diffraction grating and multilayer interference film.
回折格子および多層干渉膜は、これらの光学素子を観察する角度を変化させると、観察者によって視認される光学素子の色が連続的に変化する特徴を有する。このように複数の色が観察者によって観察されるため、真正検証において光学素子が真正の光学素子であると検証する上で視認するべき色を明文化しにくい。また、光学素子の真正を検証する上で、光学素子を観察する角度のなかで、適切な角度の範囲が観察者に分かりにくい。
The diffraction grating and the multilayer interference film have a feature that when the angle at which these optical elements are observed is changed, the color of the optical elements visually recognized by the observer changes continuously. As described above, since a plurality of colors are observed by the observer, it is difficult to clearly specify the color to be visually recognized when verifying that the optical element is an authentic optical element in authenticity verification. In addition, when verifying the authenticity of the optical element, it is difficult for the observer to find an appropriate angle range among the angles at which the optical element is observed.
こうした問題を解決するために、所定の色に発色する光学素子として、サブ波長格子が用いられている。サブ波長格子における微細な構造の周期は可視光の波長以下である。サブ波長格子は、サブ波長格子に入射した光のなかで、特定の波長の光のみを正反射方向に射出する特性を有する。そのため、サブ波長格子によれば、観察者は、正反射方向以外の方向から光学素子を観察したときには、光学素子において所定の色を有した光を視認することができない。そのため、サブ波長格子によれば、回折格子や多層干渉膜とは異なり、光学素子を観察するべき角度や、その角度において視認される色を規定することができる。それゆえに、光学素子の真正検証の方法を明文化することができる。こうしたサブ波長格子を用いた偽造防止用の光学素子には、例えば、特許文献1に記載の光学素子を挙げることができる。
In order to solve such a problem, a sub-wavelength grating is used as an optical element that develops a predetermined color. The period of the fine structure in the sub-wavelength grating is less than the wavelength of visible light. The sub-wavelength grating has a characteristic of emitting only light of a specific wavelength in the regular reflection direction among the light incident on the sub-wavelength grating. Therefore, according to the sub-wavelength grating, the observer cannot visually recognize light having a predetermined color in the optical element when observing the optical element from a direction other than the regular reflection direction. Therefore, according to the sub-wavelength grating, unlike the diffraction grating and the multilayer interference film, the angle at which the optical element should be observed and the color visually recognized at the angle can be defined. Therefore, a method for authenticating the optical element can be clearly described. Examples of the anti-counterfeit optical element using such a sub-wavelength grating include the optical element described in Patent Document 1.
ところで、特許文献1に記載の光学素子では、第1の色が視認される第1の角度において光学素子を視認した後に、光学素子が広がる平面に対する法線を回転軸として、光学素子を回転させる。そして、第2の色が視認される第2の角度において光学素子を視認することによって、光学素子の真正を検証する。
By the way, in the optical element described in Patent Document 1, after viewing the optical element at the first angle at which the first color is visually recognized, the optical element is rotated with the normal to the plane in which the optical element spreads as the rotation axis. . Then, the authenticity of the optical element is verified by visually recognizing the optical element at the second angle at which the second color is visually recognized.
ここで、光学素子を回転させるために観察者が行う手の動作は、光学素子を傾ける動作に比べて自然な動作ではない。そのため、観察者による検証作業の作業性が低くなりやすく、これによって、検証の効率も低くなりやすい。また、サブ波長格子は、上述したように、正反射方向にのみ所定の色を有した光を放出する。そのため、観察者が光学素子を手に取った瞬間、あるいは、観察者が光学素子を平面上に載置し、次いで光学素子を観察した瞬間に、観察者が、光学素子が呈する色を視認できる可能性は低い。すなわち、そうした瞬間に観察者が正反射方向において光学素子を観察する可能性は低い。それゆえに、観察者は、光学素子が呈する色が視認できる角度を見つけた後に、光学素子を回転させ、さらに、光学素子を回転させた後にも、光学素子が呈する別の色が視認できる角度を見つける必要がある。結果として、観察者が光学素子の真正を検証するまでに時間を要するため、より容易に真正を検証することが可能な光学素子が求められている。
Here, the hand movement performed by the observer to rotate the optical element is not a natural movement compared to the movement of tilting the optical element. Therefore, the workability of the verification work by the observer tends to be low, and the verification efficiency tends to be low. Further, as described above, the sub-wavelength grating emits light having a predetermined color only in the regular reflection direction. Therefore, at the moment when the observer picks up the optical element or when the observer places the optical element on a flat surface and then observes the optical element, the observer can visually recognize the color that the optical element exhibits. Unlikely. That is, it is unlikely that the observer will observe the optical element in the regular reflection direction at that moment. Therefore, the observer rotates the optical element after finding an angle at which the color exhibited by the optical element can be visually recognized, and further, the angle at which another color exhibited by the optical element can be visually recognized even after rotating the optical element. I need to find it. As a result, since it takes time for the observer to verify the authenticity of the optical element, an optical element that can verify the authenticity more easily is demanded.
本発明は、真正の検証を容易に行うことを可能とした光学素子、転写箔、認証体、および、認証体の検証方法を提供することを目的とする。
An object of the present invention is to provide an optical element, a transfer foil, an authentication body, and a verification method for the authentication body that can easily perform authentic verification.
上記課題を解決するための光学素子は、第1層と、前記第1層に接する第2層と、前記第2層に接する第3層とを備え、各層が光透過性を有する。前記第1層は第1の屈折率を有する樹脂製の層であり、前記第2層に接する第1面を有し、前記第1面の少なくとも一部にサブ波長格子を含み、前記第2層は前記第1の屈折率よりも高い第2の屈折率を有する誘電体製の層であり、前記第1層の前記第1面に接する第2面を有し、前記第1面は前記サブ波長格子に追従した凹凸状であり、前記第3層は、前記第2の屈折率よりも低い第3の屈折率を有する樹脂製の層である。前記第1層、前記第2層、および、前記第3層のいずれかがレリーフ層であり、前記レリーフ層は、複数の反射面を含むレリーフ面を含み、互いに隣り合う前記反射面間のピッチは、前記サブ波長格子のピッチよりも大きい。前記第2層に対して前記第3層とは反対側に位置する光源から前記光学素子に対し光が照射されている状態を前記光源の側から観察するとき、前記サブ波長格子は、正反射方向を含む反射方向に前記サブ波長格子の格子周期に応じた色を呈する有色像を表示し、前記レリーフ面は、前記正反射方向とは異なる方向を含む反射方向にモノクロームの反射光による反射像、すなわちモノクロームの像を表示し、前記光学素子は、前記有色像および前記反射像を表示しない第1状態、前記有色像を主として表示する第2状態、前記反射像を主として表示する第3状態を有し、前記光学素子が広がる平面と、観察者の視線を含む平面とが形成する角度が観察角度であり、前記光学素子は、前記観察角度に応じて前記第1状態、前記第2状態、および、前記第3状態のいずれかにより観察される。
An optical element for solving the above problems includes a first layer, a second layer in contact with the first layer, and a third layer in contact with the second layer, and each layer has light transmittance. The first layer is a resin layer having a first refractive index, has a first surface in contact with the second layer, includes a subwavelength grating in at least a part of the first surface, and The layer is a dielectric layer having a second refractive index higher than the first refractive index, and has a second surface in contact with the first surface of the first layer, and the first surface is The third layer is a resin layer having a third refractive index lower than the second refractive index. Any one of the first layer, the second layer, and the third layer is a relief layer, and the relief layer includes a relief surface including a plurality of reflection surfaces, and a pitch between the reflection surfaces adjacent to each other. Is larger than the pitch of the sub-wavelength grating. When observing from the light source side that the optical element is irradiated with light from a light source located on the opposite side of the third layer with respect to the second layer, the sub-wavelength grating is specularly reflected. A colored image having a color corresponding to a grating period of the sub-wavelength grating is displayed in a reflection direction including a direction, and the relief surface is a reflection image by monochrome reflected light in a reflection direction including a direction different from the regular reflection direction. That is, a monochrome image is displayed, and the optical element has a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, and a third state in which the reflected image is mainly displayed. And an angle formed by a plane in which the optical element spreads and a plane including the observer's line of sight is an observation angle, and the optical element has the first state, the second state, depending on the observation angle, and, Serial observed by any of the third state.
上記課題を解決するための光学素子は、第1層と、前記第1層に接する第2層と、前記第2層に接する第3層とを備え、各層が光透過性を有する。前記第1層は第1の屈折率を有する樹脂製の層であり、前記第2層に接する第1面を有し、前記第1面の少なくとも一部にサブ波長格子を含み、前記第2層は前記第1の屈折率よりも高い第2の屈折率を有する誘電体製の層であり、前記第1層の前記第1面に接する第2面を有し、前記第2面は前記サブ波長格子に追従した凹凸状であり、前記第3層は、前記第2の屈折率よりも低い第3の屈折率を有する樹脂製の層である。前記光学素子は、前記第1面および前記第2面とは異なるレリーフ面を含むレリーフ層をさらに備え、前記レリーフ面は、複数の反射面を含み、互いに隣り合う前記反射面間のピッチが、前記サブ波長格子のピッチよりも大きく、前記第2層に対して前記第3層とは反対側に位置する光源から前記光学素子に対し光が照射されている状態を前記光源の側から観察するとき、前記サブ波長格子は、前記サブ波長格子の格子周期に応じた色を呈する有色像を正反射方向に表示し、前記レリーフ面は、前記正反射方向とは異なる方向にモノクロームの反射光による反射像を表示し、前記光学素子は、前記有色像および前記反射像を表示しない第1状態、前記有色像を主として表示する第2状態、前記反射像を主として表示する第3状態を有し、前記光学素子が広がる平面と、観察者の視線を含む平面とが形成する角度が観察角度であり、前記光学素子は、前記観察角度に応じて前記第1状態、前記第2状態、および、前記だ3状態のいずれかにより観察される。
An optical element for solving the above problems includes a first layer, a second layer in contact with the first layer, and a third layer in contact with the second layer, and each layer has light transmittance. The first layer is a resin layer having a first refractive index, has a first surface in contact with the second layer, includes a subwavelength grating in at least a part of the first surface, and The layer is a dielectric layer having a second refractive index higher than the first refractive index, and has a second surface in contact with the first surface of the first layer, and the second surface is The third layer is a resin layer having a third refractive index lower than the second refractive index. The optical element further includes a relief layer including a relief surface different from the first surface and the second surface, the relief surface includes a plurality of reflection surfaces, and a pitch between the reflection surfaces adjacent to each other is A state in which light is applied to the optical element from a light source that is larger than the pitch of the sub-wavelength grating and located on the side opposite to the third layer with respect to the second layer is observed from the light source side. The sub-wavelength grating displays a colored image exhibiting a color corresponding to the grating period of the sub-wavelength grating in the regular reflection direction, and the relief surface is reflected by monochrome reflected light in a direction different from the regular reflection direction. Displaying a reflected image, and the optical element has a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, and a third state in which the reflected image is mainly displayed. Above The angle formed by the plane in which the scientific element spreads and the plane including the observer's line of sight is the observation angle, and the optical element is in the first state, the second state, and the plane according to the observation angle. Observed in any of three states.
上記課題を解決するための転写箔は、上記光学素子と、前記光学素子を被転写体に接着させるための接着層と、を含む接着体を備える。
上記課題を解決するための認証体は、上記光学素子を備える。 A transfer foil for solving the above problems includes an adhesive body including the optical element and an adhesive layer for bonding the optical element to a transfer target.
The authentication body for solving the said subject is provided with the said optical element.
上記課題を解決するための認証体は、上記光学素子を備える。 A transfer foil for solving the above problems includes an adhesive body including the optical element and an adhesive layer for bonding the optical element to a transfer target.
The authentication body for solving the said subject is provided with the said optical element.
上記各構成によれば、光学素子は、モノクロームの反射光によって形成される反射像、すなわちモノクロームの像と、特定の波長を有した光によって形成される有色像、すなわち有彩色の像とを表示する。ここで、モノクロームの像と有彩色の像との判別は、モノクロームの第1像とモノクロームの第2像とを判別したり、有彩色の第1像と有彩色の第2像とを判別したりする場合に比べて、2つの像の判別に個人差が生じにくい。それゆえに、光学素子では、2つの有彩色の像、または、2つのモノクロームの像に基づいて、光学素子の真正を検証させる場合と比べて、真正の検証に個人差が生じにくく、また、真正を検証する基準が明文化されやすい。これにより、光学素子によれば、真正の検証をより容易に行うことが可能である。
According to each of the above configurations, the optical element displays a reflected image formed by monochrome reflected light, that is, a monochrome image, and a colored image formed by light having a specific wavelength, that is, a chromatic image. To do. Here, the discrimination between the monochrome image and the chromatic image is performed by discriminating between the first monochrome image and the second monochrome image, or distinguishing the first chromatic color image and the second chromatic color image. Compared to the case where the difference between the two images is different, there is less individual difference between the two images. Therefore, in the optical element, compared with the case where the authenticity of the optical element is verified based on two chromatic color images or two monochrome images, individual differences are less likely to occur in the authenticity verification. Standards for verifying are easily written. Thereby, according to the optical element, authenticity verification can be performed more easily.
[第1実施形態]
図1から図11を参照して、本発明の光学素子の第1実施形態を説明する。なお、各図面において、同一または類似した機能を発揮する構成要素には全て同一の参照符号を付し、重複する説明は省略する。また、本開示の本発明の実施形態は、背景からの独自の単一の発明を元とする一群の実施形態である。また、本開示の各側面は、単一の発明を元とした一群の実施形態の側面である。本開示の各構成は、本開示の各側面を有しうる。本開示の各特徴(feature)は組合せ可能であり、各構成をなせる。したがって、本開示の各特徴(feature)、本開示の各構成、本開示の各側面、本開示の各実施形態は、組合せることが可能であり、その組合せは相乗的機能を有し、相乗的な効果を発揮しうる。 [First Embodiment]
A first embodiment of the optical element of the present invention will be described with reference to FIGS. Note that, in each drawing, the same reference numerals are assigned to the constituent elements that exhibit the same or similar functions, and redundant descriptions are omitted. Also, the embodiments of the present invention of the present disclosure are a group of embodiments based on a unique single invention from the background. In addition, each aspect of the present disclosure is an aspect of a group of embodiments based on a single invention. Each configuration of the present disclosure may have each aspect of the present disclosure. Each feature of the present disclosure is combinable and can be configured. Accordingly, each feature of the present disclosure, each configuration of the present disclosure, each aspect of the present disclosure, and each embodiment of the present disclosure can be combined, and the combination has a synergistic function, Can be effective.
図1から図11を参照して、本発明の光学素子の第1実施形態を説明する。なお、各図面において、同一または類似した機能を発揮する構成要素には全て同一の参照符号を付し、重複する説明は省略する。また、本開示の本発明の実施形態は、背景からの独自の単一の発明を元とする一群の実施形態である。また、本開示の各側面は、単一の発明を元とした一群の実施形態の側面である。本開示の各構成は、本開示の各側面を有しうる。本開示の各特徴(feature)は組合せ可能であり、各構成をなせる。したがって、本開示の各特徴(feature)、本開示の各構成、本開示の各側面、本開示の各実施形態は、組合せることが可能であり、その組合せは相乗的機能を有し、相乗的な効果を発揮しうる。 [First Embodiment]
A first embodiment of the optical element of the present invention will be described with reference to FIGS. Note that, in each drawing, the same reference numerals are assigned to the constituent elements that exhibit the same or similar functions, and redundant descriptions are omitted. Also, the embodiments of the present invention of the present disclosure are a group of embodiments based on a unique single invention from the background. In addition, each aspect of the present disclosure is an aspect of a group of embodiments based on a single invention. Each configuration of the present disclosure may have each aspect of the present disclosure. Each feature of the present disclosure is combinable and can be configured. Accordingly, each feature of the present disclosure, each configuration of the present disclosure, each aspect of the present disclosure, and each embodiment of the present disclosure can be combined, and the combination has a synergistic function, Can be effective.
図1が示すように、光学素子10は、第1層11と、第1層11に接する第2層12と、第2層12に接する第3層13とを備えている。各層は、光透過性を有している。光学素子10は、セキュリティシールの全体または一部とできる。言い換えれば、セキュリティシールは、光学素子10を含むことができる。また、光学素子10は、可視のモチーフとできる。セキュリティシールの形態はパッチ、ストライプ、オーバーレイ、ステッカーとできる。光学素子10では、第2層12に対して第3層13とは反対側に位置する光源から光が照射されている状態が、第2層12に対して第3層13とは反対側から観察される。光学素子10において、第1層11のなかで、第2層12に接する面とは反対側の面が、観察者によって観察される観察面10Sである。
As shown in FIG. 1, the optical element 10 includes a first layer 11, a second layer 12 in contact with the first layer 11, and a third layer 13 in contact with the second layer 12. Each layer has optical transparency. The optical element 10 can be all or part of a security seal. In other words, the security seal can include the optical element 10. The optical element 10 can be a visible motif. Security seals can be in the form of patches, stripes, overlays and stickers. In the optical element 10, the state in which light is irradiated from the light source located on the opposite side to the third layer 13 with respect to the second layer 12 is from the side opposite to the third layer 13 with respect to the second layer 12. Observed. In the optical element 10, the surface of the first layer 11 opposite to the surface in contact with the second layer 12 is an observation surface 10S that is observed by an observer.
第1層11は、第1の屈折率を有する樹脂製の層である。第1層11は、第2層12に接する表面11Sの少なくとも一部にサブ波長格子11Gを含む。第2層12は、第1の屈折率よりも高い第2の屈折率を有する誘電体製の層である。第2層12は、サブ波長格子11Gに追従した凹凸状を有している。第3層13は、第2の屈折率よりも低い第3の屈折率を有する樹脂製の層である。サブ波長格子11Gは、1つの方向に沿って並ぶ複数の格子パターンGPによって形成される。格子パターンGPは、1つの方向に沿って複数の凸面と凹面とが1つずつ交互に並んでいるものとできる。格子パターンGPは表面11Sに広がる。各凸面と各凹面は、並んでいる方向と直交する方向を長軸とする長細いものとできる。サブ波長格子11Gにおいて、格子パターンGPの周期は、可視波長未満とできる。実例として、格子パターンGPの周期は、680nm未満とできる。また、格子パターンGPの周期は、可視光の最短波長以下としてもよい。すなわち、格子パターンGPの周期は、400nm以下としてもよい。サブ波長格子11Gは、入射した光を回折できる。サブ波長格子11Gは、格子周期に応じた波長の回折した光を、第2層12中に導ける。第2層12中に導かれた光は、導波光である。導波光は、入射した光の正反射方向に回折する。つまり、サブ波長格子11Gは、入射した光を選択的に正反射方向に射出(emerge)する。
The first layer 11 is a resin layer having a first refractive index. The first layer 11 includes a sub-wavelength grating 11G on at least a part of the surface 11S in contact with the second layer 12. The second layer 12 is a dielectric layer having a second refractive index higher than the first refractive index. The second layer 12 has an uneven shape that follows the sub-wavelength grating 11G. The third layer 13 is a resin layer having a third refractive index lower than the second refractive index. The sub-wavelength grating 11G is formed by a plurality of grating patterns GP arranged along one direction. The lattice pattern GP can be one in which a plurality of convex surfaces and concave surfaces are alternately arranged along one direction. The lattice pattern GP extends over the surface 11S. Each convex surface and each concave surface can be long and thin with a major axis in a direction orthogonal to the direction in which they are arranged. In the sub-wavelength grating 11G, the period of the grating pattern GP can be less than the visible wavelength. As an illustration, the period of the grating pattern GP can be less than 680 nm. Further, the period of the lattice pattern GP may be equal to or shorter than the shortest wavelength of visible light. That is, the period of the lattice pattern GP may be 400 nm or less. The sub-wavelength grating 11G can diffract the incident light. The sub-wavelength grating 11G can guide the diffracted light having a wavelength corresponding to the grating period into the second layer 12. The light guided into the second layer 12 is guided light. The guided light is diffracted in the regular reflection direction of the incident light. That is, the sub-wavelength grating 11G selectively emits incident light in the regular reflection direction.
第1層11の屈折率は、第3層13の屈折率と互いに同じであってもよいし、互いに異なってもよい。第1層11の屈折率と第3層13の屈折率との差は、0.2以下であることが好ましく、0.1以下であることがより好ましい。第1層11の屈折率と第2層12の屈折率との差、および、第3層13の屈折率と第2層12の屈折率との差は、それぞれ0.3以上とでき、さらには0.5以上とできる。
The refractive index of the first layer 11 may be the same as or different from the refractive index of the third layer 13. The difference between the refractive index of the first layer 11 and the refractive index of the third layer 13 is preferably 0.2 or less, and more preferably 0.1 or less. The difference between the refractive index of the first layer 11 and the refractive index of the second layer 12 and the difference between the refractive index of the third layer 13 and the refractive index of the second layer 12 can be 0.3 or more, respectively. Can be 0.5 or more.
第1層11の表面11Sのなかで、サブ波長格子11Gが位置する領域が凹凸面である。本実施形態では、表面11Sの全体が凹凸面であるが、表面11Sの一部のみが凹凸面であってもよい。
In the surface 11S of the first layer 11, the region where the sub-wavelength grating 11G is located is an uneven surface. In the present embodiment, the entire surface 11S is an uneven surface, but only a part of the surface 11S may be an uneven surface.
図2は、観察面10Sと対向する平面視における光学素子10の構造を示している。なお、以下では、図示および説明の便宜上、観察面10Sと対向する平面視での構造を用いて、第1層11の表面11S、すなわち第1層11のなかで第2層12との界面を形成する面について説明する。また、図2では、図示の便宜上、サブ波長格子11Gが備える格子パターンGPの延びる方向を直線によって示している。
FIG. 2 shows the structure of the optical element 10 in plan view facing the observation surface 10S. In the following, for convenience of illustration and explanation, the surface 11S of the first layer 11, that is, the interface with the second layer 12 in the first layer 11 is used using a structure in plan view facing the observation surface 10S. The surface to be formed will be described. In FIG. 2, for the convenience of illustration, the extending direction of the grating pattern GP included in the sub-wavelength grating 11 </ b> G is indicated by a straight line.
図2が示すように、凹凸面の一実例である表面11Sは、第1領域11S1と、表面11Sと対向する平面視において第1領域11S1を取り囲む第2領域11S2とを含んでいる。本実施形態では、表面11Sは、第1領域11S1と第2領域11S2とから構成されているが、表面11Sは、第1領域11S1および第2領域11S2以外の領域を含んでもよい。
As shown in FIG. 2, the surface 11S, which is an example of the uneven surface, includes a first region 11S1 and a second region 11S2 that surrounds the first region 11S1 in a plan view facing the surface 11S. In the present embodiment, the surface 11S includes the first region 11S1 and the second region 11S2, but the surface 11S may include regions other than the first region 11S1 and the second region 11S2.
第1領域11S1に属するサブ波長格子が、第1サブ波長格子11G1である。第2領域11S2に属するサブ波長格子が、第2サブ波長格子11G2である。第1サブ波長格子11G1の方位角と、第2サブ波長格子11G2の方位角とが互いに等しくできる。第1サブ波長格子11G1の格子周期と、第2サブ波長格子11G2の格子周期とが互いに異なってもよい。サブ波長格子11Gにおける格子周期とは、上述した格子パターンGPの周期である。サブ波長格子11Gにおける方位角とは、第1層11が広がる平面において設定された基準線と、格子パターンGPとが形成する角度である。
The sub-wavelength grating belonging to the first region 11S1 is the first sub-wavelength grating 11G1. The sub-wavelength grating belonging to the second region 11S2 is the second sub-wavelength grating 11G2. The azimuth angle of the first sub-wavelength grating 11G1 and the azimuth angle of the second sub-wavelength grating 11G2 can be equal to each other. The grating period of the first sub-wavelength grating 11G1 and the grating period of the second sub-wavelength grating 11G2 may be different from each other. The grating period in the sub-wavelength grating 11G is the period of the grating pattern GP described above. The azimuth angle in the sub-wavelength grating 11G is an angle formed by the reference line set in the plane in which the first layer 11 extends and the grating pattern GP.
第1領域11S1および第2領域11S2において、複数の画素領域Pxが区画されている。各画素領域Pxの面積は、0.1mm2以下であることが好ましい。第1層11の表面11Sの全体において、複数の画素領域Pxが隙間なく並んでいる。本実施形態では、表面11Sと対向する平面視において、各画素領域Pxは正方形状を有しているが、画素領域Pxは、正三角形状および正六角形状などを有してもよい。また、各画素領域Pxは、多角形状であって、かつ、互いに異なる長さを有した辺を含む形状であってもよい。各画素領域Pxにおいて、一辺の長さは0.3mm以下であることが好ましい。なお、一辺の長さが0.08mm以下であることがより好ましい。この場合には、画素領域Pxの一辺の長さが人の目の分解能よりも小さい値であるため、各画素領域Pxが観察者によって視認されない。これにより、光学素子10が、高解像度の像を表示することが可能である。
In the first region 11S1 and the second region 11S2, a plurality of pixel regions Px are partitioned. The area of each pixel region Px is preferably 0.1 mm 2 or less. On the entire surface 11S of the first layer 11, the plurality of pixel regions Px are arranged without gaps. In the present embodiment, each pixel region Px has a square shape in a plan view facing the surface 11S, but the pixel region Px may have a regular triangular shape, a regular hexagonal shape, or the like. Each pixel region Px may have a polygonal shape and include sides having different lengths. In each pixel region Px, the length of one side is preferably 0.3 mm or less. In addition, it is more preferable that the length of one side is 0.08 mm or less. In this case, since the length of one side of the pixel region Px is smaller than the resolution of the human eye, each pixel region Px is not visually recognized by the observer. Thereby, the optical element 10 can display a high-resolution image.
図3は、図2におけるI‐I線に沿うサブ波長格子11Gの断面構造を示している。図3では、図示の便宜上、第1サブ波長格子11G1の断面構造と、第2サブ波長格子11G2の断面構造とを、紙面の上下方向において並べて示している。なお、各サブ波長格子の断面構造は、1つの画素領域Pxに位置するサブ波長格子の断面構造を模式的に示している。また、図3では、図示の便宜上、各サブ波長格子を、平坦面から離れる方向に突出する凸部を構成する面として示している。
FIG. 3 shows a cross-sectional structure of the sub-wavelength grating 11G along the line II in FIG. In FIG. 3, for the convenience of illustration, the cross-sectional structure of the first sub-wavelength grating 11G1 and the cross-sectional structure of the second sub-wavelength grating 11G2 are shown side by side in the vertical direction of the drawing. The cross-sectional structure of each sub-wavelength grating schematically shows the cross-sectional structure of the sub-wavelength grating located in one pixel region Px. In FIG. 3, for convenience of illustration, each sub-wavelength grating is shown as a surface constituting a convex portion protruding in a direction away from the flat surface.
図3が示すように、第1サブ波長格子11G1の格子周期と、第2サブ波長格子11G2の格子周期とは互いに異なっている。第1サブ波長格子11G1における格子周期が第1周期d1であり、第2サブ波長格子11G2における格子周期が第2周期d2である。本実施形態では、第1周期d1が第2周期d2よりも小さいが、第1周期d1が第2周期d2よりも大きくてもよい。本実施形態では、各サブ波長格子は、1つの方向において繰り返す波状を有し、各波がサブ波長格子を構成する格子パターンGPである。互いに隣り合う2つの格子パターンGP間の距離が、各サブ波長格子の格子周期である。
As shown in FIG. 3, the grating period of the first sub-wavelength grating 11G1 and the grating period of the second sub-wavelength grating 11G2 are different from each other. The grating period in the first subwavelength grating 11G1 is the first period d1, and the grating period in the second subwavelength grating 11G2 is the second period d2. In the present embodiment, the first period d1 is smaller than the second period d2, but the first period d1 may be larger than the second period d2. In this embodiment, each sub-wavelength grating is a grating pattern GP that has a wave shape that repeats in one direction, and each wave constitutes a sub-wavelength grating. The distance between two grating patterns GP adjacent to each other is the grating period of each sub-wavelength grating.
格子パターンGPが並ぶ方向に沿う断面において、第1サブ波長格子11G1が含む複数の格子パターンGPは、互いに同じ形状を有している。格子パターンGPが並ぶ方向に沿う断面において、第2サブ波長格子11G2が含む複数の格子パターンGPは、互いに同じ形状を有している。
In the cross section along the direction in which the grating patterns GP are arranged, the plurality of grating patterns GP included in the first sub-wavelength grating 11G1 have the same shape. In the cross section along the direction in which the grating patterns GP are arranged, the plurality of grating patterns GP included in the second sub-wavelength grating 11G2 have the same shape.
サブ波長格子において、サブ波長格子の格子周期に応じて、サブ波長格子から射出される光の波長が変わる。すなわち、サブ波長格子の格子周期に応じて、サブ波長格子を含む光学素子10が呈する色相、言い換えれば観察者が光学素子10の色相として視認する色が変わる。
In the sub-wavelength grating, the wavelength of light emitted from the sub-wavelength grating changes according to the grating period of the sub-wavelength grating. That is, according to the grating period of the sub-wavelength grating, the hue exhibited by the optical element 10 including the sub-wavelength grating, in other words, the color visually recognized by the observer as the hue of the optical element 10 changes.
図4が示すように、光学素子10では、光学素子10の観察面10Sに垂直な平面上において、光源LSと観察者OBとが、観察面10Sの法線に対して対象となるように位置するとき、観察者OBは、光学素子10が射出するゼロ次回折光を視認することができる。言い換えれば、光学素子10は、光源LSから入射した入射光に対する正反射の方向に、サブ波長格子11Gの格子周期に応じた波長の光を射出することができる。
As shown in FIG. 4, in the optical element 10, the light source LS and the observer OB are positioned on the plane perpendicular to the observation surface 10 </ b> S of the optical element 10 so that they are targets with respect to the normal line of the observation surface 10 </ b> S. When doing so, the observer OB can visually recognize the zero-order diffracted light emitted by the optical element 10. In other words, the optical element 10 can emit light having a wavelength corresponding to the grating period of the sub-wavelength grating 11G in the direction of regular reflection with respect to incident light incident from the light source LS.
上述したように、本実施形態において、サブ波長格子の格子周期は、可視光の最短波長以下、すなわち400nm以下に設定されている。しかしながら、ゼロ次回折光による特定の波長を有した光のみが特定の方向に射出されるための格子周期は、サブ波長格子の屈折率、および、サブ波長格子に入射する入射光の入射角などによって変わる。以下において、サブ波長格子がゼロ次回折光のみを射出するための条件、言い換えれば、サブ波長格子が1次回折光を射出しないための条件を説明する。
As described above, in this embodiment, the grating period of the sub-wavelength grating is set to be shorter than the shortest wavelength of visible light, that is, 400 nm or less. However, the grating period for emitting only light having a specific wavelength by the zero-order diffracted light in a specific direction depends on the refractive index of the sub-wavelength grating and the incident angle of the incident light incident on the sub-wavelength grating. change. Hereinafter, a condition for the sub-wavelength grating to emit only the zero-order diffracted light, in other words, a condition for the sub-wavelength grating not to emit the first-order diffracted light will be described.
反射型の回折格子において、以下の式(1)が成り立つことが知られている。
sinθ1+sinθ2 = mλ/nd … 式(1)
なお、式(1)において、θ1は回折格子に対する入射光の入射角であり、θ2は回折格子が射出する回折光の回折角であり、mは回折光の回折次数である。λは波長であり、nは回折格子の屈折率であり、dは回折格子の格子周期である。 It is known that the following expression (1) holds in a reflective diffraction grating.
sin θ1 + sin θ2 = mλ / nd (1)
In Equation (1), θ1 is an incident angle of incident light with respect to the diffraction grating, θ2 is a diffraction angle of diffracted light emitted from the diffraction grating, and m is a diffraction order of the diffracted light. λ is the wavelength, n is the refractive index of the diffraction grating, and d is the grating period of the diffraction grating.
sinθ1+sinθ2 = mλ/nd … 式(1)
なお、式(1)において、θ1は回折格子に対する入射光の入射角であり、θ2は回折格子が射出する回折光の回折角であり、mは回折光の回折次数である。λは波長であり、nは回折格子の屈折率であり、dは回折格子の格子周期である。 It is known that the following expression (1) holds in a reflective diffraction grating.
sin θ1 + sin θ2 = mλ / nd (1)
In Equation (1), θ1 is an incident angle of incident light with respect to the diffraction grating, θ2 is a diffraction angle of diffracted light emitted from the diffraction grating, and m is a diffraction order of the diffracted light. λ is the wavelength, n is the refractive index of the diffraction grating, and d is the grating period of the diffraction grating.
ここで、屈折率nが1であり、かつ、回折格子が配置された平面に対して垂直な光が入射したと仮定したときの1次回折光について考える。このとき、入射角θ1は0°であり、回折次数mは1である。そのため、これらの数値を式(1)に代入すると、以下の式(2)が導かれる。
Here, consider the first-order diffracted light when it is assumed that the refractive index n is 1 and light perpendicular to the plane on which the diffraction grating is arranged is incident. At this time, the incident angle θ1 is 0 °, and the diffraction order m is 1. Therefore, substituting these numerical values into equation (1) leads to the following equation (2).
sinθ2 = λ/d … 式(2)
sinθ2は-1以上1以下であるため、式(2)における右辺(λ/d)が1よりも大きいときには、式(2)は成り立たない。言い換えれば、右辺(λ/d)が1よりも大きいときには、1次回折光は回折格子から射出されない。したがって、上述した前提のもとでは、回折格子の格子周期が波長よりも小さいときに、回折格子はゼロ次回折光のみを射出する。 sin θ2 = λ / d Equation (2)
Since sin θ2 is not less than −1 and not more than 1, Equation (2) does not hold when the right side (λ / d) in Equation (2) is larger than 1. In other words, when the right side (λ / d) is larger than 1, the first-order diffracted light is not emitted from the diffraction grating. Therefore, under the above assumption, when the grating period of the diffraction grating is smaller than the wavelength, the diffraction grating emits only zero-order diffracted light.
sinθ2は-1以上1以下であるため、式(2)における右辺(λ/d)が1よりも大きいときには、式(2)は成り立たない。言い換えれば、右辺(λ/d)が1よりも大きいときには、1次回折光は回折格子から射出されない。したがって、上述した前提のもとでは、回折格子の格子周期が波長よりも小さいときに、回折格子はゼロ次回折光のみを射出する。 sin θ2 = λ / d Equation (2)
Since sin θ2 is not less than −1 and not more than 1, Equation (2) does not hold when the right side (λ / d) in Equation (2) is larger than 1. In other words, when the right side (λ / d) is larger than 1, the first-order diffracted light is not emitted from the diffraction grating. Therefore, under the above assumption, when the grating period of the diffraction grating is smaller than the wavelength, the diffraction grating emits only zero-order diffracted light.
一方で、屈折率が1ではなく、かつ、入射角θ1が0°でない場合には、回折格子がゼロ次以外の次数の回折光を射出する場合もある。例えば、入射角θ1が30°であり、かつ、波長λが600nmであると仮定したときの1次回折光について考える。このとき、入射角θ1は30°であり、波長λは600nmであり、回折次数mは1である。そのため、これらの数値を式(1)に代入すると、以下の式(3)が導かれる。
On the other hand, when the refractive index is not 1 and the incident angle θ1 is not 0 °, the diffraction grating may emit diffracted light of a non-zero order. For example, consider first-order diffracted light when it is assumed that the incident angle θ1 is 30 ° and the wavelength λ is 600 nm. At this time, the incident angle θ1 is 30 °, the wavelength λ is 600 nm, and the diffraction order m is 1. Therefore, substituting these numerical values into equation (1) leads to the following equation (3).
1/2 + sinθ2 =600/nd … 式(3)
sinθ2は-1以上1以下であるため、式(3)の左辺(1/2+sinθ2)は-0.5以上1.5以下であり、屈折率nと格子周期dとの積が0以上400以下を満たすとき、屈折率nと格子周期dとの組み合わせによって、回折格子が1次回折光を射出する。例えば、1次回折光が射出されるときの屈折率nと格子周期dとの組み合わせ(n,d)は、以下の通りである。 1/2 + sin θ2 = 600 / nd Formula (3)
Since sin θ2 is −1 or more and 1 or less, the left side (1/2 + sin θ2) of Equation (3) is −0.5 or more and 1.5 or less, and the product of the refractive index n and the grating period d is 0 or more and 400 or less. When satisfying the above, the diffraction grating emits the first-order diffracted light by the combination of the refractive index n and the grating period d. For example, the combination (n, d) of the refractive index n and the grating period d when the first-order diffracted light is emitted is as follows.
sinθ2は-1以上1以下であるため、式(3)の左辺(1/2+sinθ2)は-0.5以上1.5以下であり、屈折率nと格子周期dとの積が0以上400以下を満たすとき、屈折率nと格子周期dとの組み合わせによって、回折格子が1次回折光を射出する。例えば、1次回折光が射出されるときの屈折率nと格子周期dとの組み合わせ(n,d)は、以下の通りである。 1/2 + sin θ2 = 600 / nd Formula (3)
Since sin θ2 is −1 or more and 1 or less, the left side (1/2 + sin θ2) of Equation (3) is −0.5 or more and 1.5 or less, and the product of the refractive index n and the grating period d is 0 or more and 400 or less. When satisfying the above, the diffraction grating emits the first-order diffracted light by the combination of the refractive index n and the grating period d. For example, the combination (n, d) of the refractive index n and the grating period d when the first-order diffracted light is emitted is as follows.
(n,d) = (1,400)、(1.5,200)、(2,100)
このように、回折格子の屈折率nによっては、回折格子の格子周期dが波長λ以下であっても、1次回折光やより高次の回折光が射出されることがある。言い換えれば、回折格子の格子周期dと、回折格子の屈折率nとの調整によって、回折格子がゼロ次回折光を射出する一方で、ゼロ次回折光よりも高次の回折光を射出しないように回折格子を形成することが可能である。 (N, d) = (1,400), (1.5,200), (2,100)
Thus, depending on the refractive index n of the diffraction grating, even when the grating period d of the diffraction grating is less than or equal to the wavelength λ, the first-order diffracted light or higher-order diffracted light may be emitted. In other words, by adjusting the grating period d of the diffraction grating and the refractive index n of the diffraction grating, the diffraction grating emits zero-order diffracted light while diffracting so as not to emit higher-order diffracted light than zero-order diffracted light. It is possible to form a lattice.
このように、回折格子の屈折率nによっては、回折格子の格子周期dが波長λ以下であっても、1次回折光やより高次の回折光が射出されることがある。言い換えれば、回折格子の格子周期dと、回折格子の屈折率nとの調整によって、回折格子がゼロ次回折光を射出する一方で、ゼロ次回折光よりも高次の回折光を射出しないように回折格子を形成することが可能である。 (N, d) = (1,400), (1.5,200), (2,100)
Thus, depending on the refractive index n of the diffraction grating, even when the grating period d of the diffraction grating is less than or equal to the wavelength λ, the first-order diffracted light or higher-order diffracted light may be emitted. In other words, by adjusting the grating period d of the diffraction grating and the refractive index n of the diffraction grating, the diffraction grating emits zero-order diffracted light while diffracting so as not to emit higher-order diffracted light than zero-order diffracted light. It is possible to form a lattice.
一方で、1次回折光の回折角θ2がゼロ次回折光の回折角θ2よりも大幅に大きくなるように設計することで、観察者に対する回折格子の相対位置が固定された状態において、ゼロ次回折光が観察者によって視認される一方で、1次回折光が観察者によって視認されないように、回折格子を構成することも可能である。これにより、回折格子を形成する材料の選択における自由度や、回折格子の格子周期における自由度を高めることはできる。
On the other hand, by designing the diffraction angle θ2 of the first-order diffracted light to be significantly larger than the diffraction angle θ2 of the zero-order diffracted light, the zero-order diffracted light can be generated in a state where the relative position of the diffraction grating with respect to the observer is fixed. It is also possible to configure the diffraction grating so that the first-order diffracted light is not visually recognized by the observer while visually recognized by the observer. Thereby, the freedom degree in selection of the material which forms a diffraction grating, and the freedom degree in the grating period of a diffraction grating can be raised.
図5が示すように、光源LSと観察者OBの視点とを固定した状態で、上述した平面と光学素子10とが、垂直以外の角度で交差するように光学素子10を傾ける。この場合には、光学素子10は、観察者OBの視線の方向にはゼロ次回折光を射出しないため、観察者は光学素子10が射出するゼロ次回折光を視認することができない。言い換えれば、観察者は、光学素子10が呈する色を視認することができない。
As shown in FIG. 5, in a state where the light source LS and the viewpoint of the observer OB are fixed, the optical element 10 is tilted so that the above-described plane and the optical element 10 intersect at an angle other than vertical. In this case, since the optical element 10 does not emit zero-order diffracted light in the direction of the line of sight of the observer OB, the observer cannot visually recognize the zero-order diffracted light emitted by the optical element 10. In other words, the observer cannot visually recognize the color that the optical element 10 exhibits.
光学素子10では、第1サブ波長格子11G1および第2サブ波長格子11G2の両方において、各サブ波長格子に起因する色の発現と消失とが同期して起こる。そのため、光学素子10の全体において、色を呈する状態と、モノクロームの状態とが切り替わる。それゆえに、光学素子10の真正検証では、光学素子10が、第1サブ波長格子11G1に由来する色を呈する第1領域11S1と、第2サブ波長格子11G2に由来する色を呈する第2領域11S2とを備えるか否かを、一度に把握することができる。結果として、光学素子10を回転させることによって、光学素子10が2つの色を呈する状態を有するか否かを判定する場合に比べて、光学素子10の真正をより容易に検証することができる。
In the optical element 10, in both the first sub-wavelength grating 11G1 and the second sub-wavelength grating 11G2, the onset and disappearance of the color due to each sub-wavelength grating occurs in synchronization. For this reason, in the entire optical element 10, the color state and the monochrome state are switched. Therefore, in authenticity verification of the optical element 10, the optical element 10 has a first region 11S1 that exhibits a color derived from the first sub-wavelength grating 11G1 and a second region 11S2 that exhibits a color derived from the second sub-wavelength grating 11G2. Can be grasped at a time. As a result, the authenticity of the optical element 10 can be verified more easily by rotating the optical element 10 than when determining whether or not the optical element 10 has a state of two colors.
図6は、本実施形態の光学素子10における他の実例である。図6は、図2と同様、観察面10Sと対向する平面視における光学素子10の構造を示している。
図6が示すように、複数の画素領域Pxは、表面11Sと対向する平面視において、各画素領域Pxの一部に位置する第1サブ波長格子11G1を備える画素領域Pxを含んでもよい。図3を参照して先に説明した実例では、第1サブ波長格子11G1は、各画素領域Pxの全体に位置している。これに限らず、各画素領域Pxにおいて、その画素領域Pxの一部のみに第1サブ波長格子11G1が位置してもよい。各画素領域Pxにおいて、画素領域Pxの面積に対する第1サブ波長格子11G1の面積の比が面積率である。複数の画素領域Pxには、面積率が互いに異なる画素領域Pxが含まれてもよい。 FIG. 6 is another example of theoptical element 10 of the present embodiment. FIG. 6 shows the structure of the optical element 10 in plan view facing the observation surface 10S, as in FIG.
As shown in FIG. 6, the plurality of pixel regions Px may include a pixel region Px including a first sub-wavelength grating 11G1 located in a part of each pixel region Px in a plan view facing thesurface 11S. In the example described above with reference to FIG. 3, the first sub-wavelength grating 11G1 is located in the entire pixel region Px. Not limited to this, in each pixel region Px, the first sub-wavelength grating 11G1 may be located only in a part of the pixel region Px. In each pixel region Px, the ratio of the area of the first sub-wavelength grating 11G1 to the area of the pixel region Px is the area ratio. The plurality of pixel regions Px may include pixel regions Px having different area ratios.
図6が示すように、複数の画素領域Pxは、表面11Sと対向する平面視において、各画素領域Pxの一部に位置する第1サブ波長格子11G1を備える画素領域Pxを含んでもよい。図3を参照して先に説明した実例では、第1サブ波長格子11G1は、各画素領域Pxの全体に位置している。これに限らず、各画素領域Pxにおいて、その画素領域Pxの一部のみに第1サブ波長格子11G1が位置してもよい。各画素領域Pxにおいて、画素領域Pxの面積に対する第1サブ波長格子11G1の面積の比が面積率である。複数の画素領域Pxには、面積率が互いに異なる画素領域Pxが含まれてもよい。 FIG. 6 is another example of the
As shown in FIG. 6, the plurality of pixel regions Px may include a pixel region Px including a first sub-wavelength grating 11G1 located in a part of each pixel region Px in a plan view facing the
各画素領域Pxにおける面積率が高いほど、各画素領域Pxの輝度が高い。そのため、複数の画素領域Pxが、面積率が互いに異なる画素領域Pxを含むことによって、第1領域11S1が呈する色において、同一の色相において輝度による濃淡を形成することが可能である。濃淡は連続変化とできる。また濃淡はグラデーション的でもよい。これにより、第1領域11S1に擬似的な立体像を表示させることが可能でもある。この場合には、第1領域11S1が表示すべき立体像における輝度の高低、すなわち階調値に応じて、面積率を決定することができる。
The higher the area ratio in each pixel region Px, the higher the luminance of each pixel region Px. For this reason, the plurality of pixel regions Px include pixel regions Px having different area ratios, whereby in the colors exhibited by the first region 11S1, it is possible to form shades of brightness in the same hue. The shading can be a continuous change. The shade may be gradation. Thereby, it is also possible to display a pseudo stereoscopic image in the first region 11S1. In this case, the area ratio can be determined according to the level of brightness in the stereoscopic image to be displayed by the first region 11S1, that is, the gradation value.
本実施形態では、光学素子10は、第1領域11S1の中央から第1領域11S1の外縁に向かう方向に沿って、画素領域Pxにおける面積率が小さくなる部分を含み、かつ、第1領域11S1の外縁における面積率が最も小さい。
In the present embodiment, the optical element 10 includes a portion where the area ratio in the pixel region Px decreases along the direction from the center of the first region 11S1 toward the outer edge of the first region 11S1, and the optical region 10 of the first region 11S1. The area ratio at the outer edge is the smallest.
本実施形態の光学素子10は、図7から図11を参照して以下に説明する構成であってもよい。以下では、光学素子10における他の実例を説明する前に、上述したサブ波長格子における方位角をより詳しく説明する。
The optical element 10 of the present embodiment may have a configuration described below with reference to FIGS. Hereinafter, the azimuth angle in the sub-wavelength grating described above will be described in more detail before another example of the optical element 10 is described.
図7が示すように、光学素子10の観察面10Sに沿う任意の方向が、X方向であり、X方向に直交する方向がY方向である。本実施形態では、X方向が方位角において基準となる方向であり、X方向と格子パターンが延びる方向とが形成する角度が方位角θである。そのため、第1画素領域Px1における方位角θは0°であり、第2画素領域Px2における方位角θは45°である。また、第3画素領域Px3における方位角θは90°であり、第4画素領域Px4における方位角θは135°である。
As shown in FIG. 7, an arbitrary direction along the observation surface 10S of the optical element 10 is the X direction, and a direction orthogonal to the X direction is the Y direction. In the present embodiment, the X direction is a reference direction in the azimuth angle, and the angle formed by the X direction and the direction in which the lattice pattern extends is the azimuth angle θ. Therefore, the azimuth angle θ in the first pixel region Px1 is 0 °, and the azimuth angle θ in the second pixel region Px2 is 45 °. The azimuth angle θ in the third pixel region Px3 is 90 °, and the azimuth angle θ in the fourth pixel region Px4 is 135 °.
図8は、図2と同様、観察面10Sと対向する平面視における光学素子10の構造を示している。
図8が示すように、第1領域11S1は、第1要素S1Aと、第1要素S1Aと隣り合う第2要素S1Bとを含んでいる。各要素S1A,S1Bは、第1層11の表面11Sと対向する平面視において、第1領域11S1の輪郭に沿う形状を有している。本実施形態では、第1領域11S1は、第1要素S1Aと第2要素S1Bとから形成され、第1要素S1Aが第2要素S1Bよりも外側に位置している。第1要素S1Aの輪郭、および、第2要素S1Bの輪郭は、第1領域11S1の輪郭に相似な形状である。 FIG. 8 shows the structure of theoptical element 10 in plan view facing the observation surface 10S, as in FIG.
As shown in FIG. 8, the first region 11S1 includes a first element S1A and a second element S1B adjacent to the first element S1A. Each element S1A, S1B has a shape that follows the contour of the first region 11S1 in a plan view facing thesurface 11S of the first layer 11. In the present embodiment, the first region 11S1 is formed of a first element S1A and a second element S1B, and the first element S1A is located outside the second element S1B. The outline of the first element S1A and the outline of the second element S1B are similar in shape to the outline of the first region 11S1.
図8が示すように、第1領域11S1は、第1要素S1Aと、第1要素S1Aと隣り合う第2要素S1Bとを含んでいる。各要素S1A,S1Bは、第1層11の表面11Sと対向する平面視において、第1領域11S1の輪郭に沿う形状を有している。本実施形態では、第1領域11S1は、第1要素S1Aと第2要素S1Bとから形成され、第1要素S1Aが第2要素S1Bよりも外側に位置している。第1要素S1Aの輪郭、および、第2要素S1Bの輪郭は、第1領域11S1の輪郭に相似な形状である。 FIG. 8 shows the structure of the
As shown in FIG. 8, the first region 11S1 includes a first element S1A and a second element S1B adjacent to the first element S1A. Each element S1A, S1B has a shape that follows the contour of the first region 11S1 in a plan view facing the
第1サブ波長格子11G1のなかで、第1要素S1Aに属するサブ波長格子が第1格子G1Aである。第1サブ波長格子11G1のなかで、第2要素S1Bに属するサブ波長格子が第2格子G1Bである。第1格子G1Aの格子周期と、第2格子G1Bの格子周期とが互いに等しい。一方で、第1格子G1Aの方位角θと第2格子G1Bの方位角θとは互いに異なり、かつ、第1格子G1Aの方位角θと第2格子G1Bの方位角θとの差が、90°以下である。本実施形態では、第1格子G1Aにおける方位角θが0°であり、第2格子G1Bにおける方位角θが45°である。そのため、第1格子G1Aの方位角θと、第2格子G1Bの方位角θとの差は、45°である。
Among the first sub-wavelength gratings 11G1, the sub-wavelength grating belonging to the first element S1A is the first grating G1A. Of the first sub-wavelength grating 11G1, the sub-wavelength grating belonging to the second element S1B is the second grating G1B. The grating period of the first grating G1A and the grating period of the second grating G1B are equal to each other. On the other hand, the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B are different from each other, and the difference between the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B is 90 ° or less. In the present embodiment, the azimuth angle θ in the first grating G1A is 0 °, and the azimuth angle θ in the second grating G1B is 45 °. Therefore, the difference between the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B is 45 °.
図9は、図8におけるII‐II線に沿う第1格子G1Aの断面構造と、III‐III線に沿う第2格子G1Bの断面構造とを示している。図9では、図示の便宜上、第1格子G1Aの断面構造と、第2格子G1Bの断面構造とを、紙面の上下方向において並べて示している。なお、各格子の断面構造は、1つの画素領域Pxに位置するサブ波長格子の断面構造を模式的に示している。また、図9では、図3と同様、図示の便宜上、各サブ波長格子を、平坦面から離れる方向に突出する凸部を構成する面として示している。
FIG. 9 shows a cross-sectional structure of the first lattice G1A along the line II-II in FIG. 8 and a cross-sectional structure of the second lattice G1B along the line III-III. In FIG. 9, for the convenience of illustration, the cross-sectional structure of the first lattice G1A and the cross-sectional structure of the second lattice G1B are shown side by side in the vertical direction of the drawing. Note that the cross-sectional structure of each grating schematically shows the cross-sectional structure of a sub-wavelength grating located in one pixel region Px. Further, in FIG. 9, as in FIG. 3, for convenience of illustration, each sub-wavelength grating is shown as a surface constituting a convex portion protruding in a direction away from the flat surface.
図9が示すように、第1格子G1Aの格子周期と、第2格子G1Bの格子周期とは互いに等しい。すなわち、第1格子G1Aの格子周期は第1周期d1であり、第2格子G1Bの格子周期も第1周期d1である。なお、上述したように互いに隣り合う2つの格子パターンGP間の距離が、各格子の格子周期である。
As shown in FIG. 9, the grating period of the first grating G1A and the grating period of the second grating G1B are equal to each other. That is, the grating period of the first grating G1A is the first period d1, and the grating period of the second grating G1B is also the first period d1. As described above, the distance between two lattice patterns GP adjacent to each other is the lattice period of each lattice.
サブ波長格子において、サブ波長格子の格子周期、および、方位角θが互いに等しい2つのサブ波長格子間では、2つのサブ波長格子が呈する色は互いに同じである。一方で、サブ波長格子において、サブ波長格子の格子周期が互いに等しい一方で、方位角θが互いに異なる2つのサブ波長格子間では、2つのサブ波長格子が呈する色が互いに異なる。すなわち、ある観察条件における、第1格子G1Aが呈する色と、第2格子G1Bが呈する色とは互いに異なる。図10および図11を参照して、第1格子G1Aが呈する色と、第2格子G1Bが呈する色とが互いに異なる理由を説明する。
In the sub-wavelength grating, between the two sub-wavelength gratings having the same grating period and azimuth angle θ, the colors exhibited by the two sub-wavelength gratings are the same. On the other hand, in the sub-wavelength grating, while the grating periods of the sub-wavelength gratings are equal to each other, two sub-wavelength gratings having different azimuth angles θ have different colors. That is, the color exhibited by the first lattice G1A and the color exhibited by the second lattice G1B are different from each other under certain observation conditions. With reference to FIGS. 10 and 11, the reason why the color exhibited by the first lattice G1A and the color exhibited by the second lattice G1B are different from each other will be described.
図10は、方位角θが0°であるサブ波長格子11Gの斜視構造を示している。一方で、図11は、方位角θが90°であるサブ波長格子11Gの斜視構造を示している。サブ波長格子11Gへの入射光が含む偏光成分のうち、サブ波長格子11Gの入射面に対して電場が垂直に振動している偏光がs偏光である。これに対して、サブ波長格子11Gの入射面に対して電場が平行に振動している偏光がp偏光である。なお、入射面とは、サブ波長格子が広がる平面に対して垂直であり、かつ、入射光と反射光とを含む平面である。また、s偏光およびp偏光の各々は、サブ波長格子11Gの方位角θには依存しない。言い換えれば、図10が示すサブ波長格子11Gに入射する入射光であっても、図11が示すサブ波長格子11Gに入射する入射光であっても、s偏光およびp偏光を含む。
FIG. 10 shows a perspective structure of the sub-wavelength grating 11G having an azimuth angle θ of 0 °. On the other hand, FIG. 11 shows a perspective structure of the subwavelength grating 11G having an azimuth angle θ of 90 °. Of the polarization components included in the light incident on the sub-wavelength grating 11G, the polarization whose electric field oscillates perpendicularly to the incident surface of the sub-wavelength grating 11G is s-polarized light. On the other hand, the polarized light whose electric field is oscillating in parallel with the incident surface of the sub-wavelength grating 11G is p-polarized light. The incident surface is a plane that is perpendicular to the plane in which the sub-wavelength grating spreads and includes incident light and reflected light. Further, each of the s-polarized light and the p-polarized light does not depend on the azimuth angle θ of the sub-wavelength grating 11G. In other words, both incident light incident on the sub-wavelength grating 11G shown in FIG. 10 and incident light incident on the sub-wavelength grating 11G shown in FIG. 11 include s-polarized light and p-polarized light.
ここで、回折格子のように溝を有する構造では、溝が延びる方向すなわち方位角θと、電場の振動方向との関係によって、光の波長とその波長における回折効率との関係が変わる。回折格子に入射した光のなかで、電場の振動方向が回折格子の方位角θと平行な成分がTE波である。一方で、回折格子に入射した光のなかで、電場の振動方向が回折格子の方位角θと直交する成分がTM波である。図10を参照して先に説明したように、方位角θが0°である回折格子では、電場の振動方向が回折格子の方位角θと平行な成分であるp偏光は、TE波と等しい。これに対して、図11を参照して先に説明したように、方位角θが90°である回折格子では、電場の振動方向が回折格子の方位角θと直交する成分であるp偏光は、TM波と等しい。
Here, in a structure having a groove like a diffraction grating, the relationship between the wavelength of light and the diffraction efficiency at that wavelength varies depending on the relationship between the direction in which the groove extends, that is, the azimuth angle θ, and the vibration direction of the electric field. Among the light incident on the diffraction grating, a component in which the vibration direction of the electric field is parallel to the azimuth angle θ of the diffraction grating is a TE wave. On the other hand, among the light incident on the diffraction grating, a component in which the vibration direction of the electric field is orthogonal to the azimuth angle θ of the diffraction grating is a TM wave. As described above with reference to FIG. 10, in the diffraction grating having an azimuth angle θ of 0 °, the p-polarized light whose component is a component in which the vibration direction of the electric field is parallel to the azimuth angle θ of the diffraction grating is equal to the TE wave. . On the other hand, as described above with reference to FIG. 11, in the diffraction grating having the azimuth angle θ of 90 °, the p-polarized light that is a component in which the vibration direction of the electric field is orthogonal to the azimuth angle θ of the diffraction grating is , Equal to TM wave.
光が、回折格子と回折格子を取り囲む媒質との界面に入射するとき、入射面に対する入射光の偏光方向によって反射率が変わることが知られている。さらに、回折格子において、TE波とTM波との間では、入射光に含まれる各波長での回折効率が互いに異なることが知られている。そのため、s偏光およびp偏光の各々が、TE波およびTM波のいずれに対応するかによって、どのような波長分布を有した光がゼロ次回折光として回折格子から射出されるかが異なると言える。それゆえに、図10が示すサブ波長格子11Gが呈する色と、図11が示すサブ波長格子11Gが呈する色とは互いに異なる。図10が示すサブ波長格子11Gが呈する色が第1色であり、図11が示すサブ波長格子11Gが呈する色は第2色とできる。第2色は、第1色とは異なる色である。
It is known that when light is incident on the interface between the diffraction grating and the medium surrounding the diffraction grating, the reflectivity changes depending on the polarization direction of the incident light with respect to the incident surface. Furthermore, in the diffraction grating, it is known that the diffraction efficiency at each wavelength included in the incident light is different between the TE wave and the TM wave. For this reason, it can be said that the light having what wavelength distribution is emitted from the diffraction grating as zero-order diffracted light depends on whether each of the s-polarized light and the p-polarized light corresponds to the TE wave or the TM wave. Therefore, the color exhibited by the sub-wavelength grating 11G shown in FIG. 10 is different from the color exhibited by the sub-wavelength grating 11G shown in FIG. The color presented by the sub-wavelength grating 11G shown in FIG. 10 is the first color, and the color presented by the sub-wavelength grating 11G shown in FIG. 11 can be the second color. The second color is a color different from the first color.
図8を参照して先に説明した光学素子10は、第1格子G1Aとして図10が示すサブ波長格子11Gを備えることが可能であり、第2格子G1Bとして図11が示すサブ波長格子11Gを備えることが可能である。この場合において、第1格子G1Aを含む第1要素S1Aが第1色を呈し、かつ、第2格子G1Bを含む第2要素S1Bが第2色を呈する状態が、光学素子10、観察者、および、光源の相対位置における初期位置である。光学素子10の放線を回転軸として光学素子10を初期位置から90°回転させると、第1格子G1Aにおいて、s偏光がTE波に対応し、かつ、p偏光がTM波に対応する。これに対して、第2格子G1Bにおいて、s偏光がTM波に対応し、かつ、p偏光がTE波に対応する。これにより、第1要素S1Aが第2色を呈し、かつ、第2要素S1Bが第1色を呈する。それゆえに、観察者は、光学素子10の回転によって、第1要素S1Aが呈する色と第2要素S1Bが呈する色とが反転したと認識する。
The optical element 10 described above with reference to FIG. 8 can include the sub-wavelength grating 11G shown in FIG. 10 as the first grating G1A, and the sub-wavelength grating 11G shown in FIG. 11 as the second grating G1B. It is possible to provide. In this case, the state in which the first element S1A including the first grating G1A exhibits the first color and the second element S1B including the second grating G1B exhibits the second color is the optical element 10, the observer, and , The initial position in the relative position of the light source. When the optical element 10 is rotated 90 ° from the initial position with the ray of the optical element 10 as the rotation axis, the s-polarized light corresponds to the TE wave and the p-polarized light corresponds to the TM wave in the first grating G1A. On the other hand, in the second grating G1B, the s-polarized light corresponds to the TM wave, and the p-polarized light corresponds to the TE wave. Accordingly, the first element S1A exhibits the second color, and the second element S1B exhibits the first color. Therefore, the observer recognizes that the color of the first element S1A and the color of the second element S1B are reversed by the rotation of the optical element 10.
このように、サブ波長格子11Gによれば、サブ波長格子11Gの格子線が延びる方向からサブ波長格子11Gに入射した光と、格子線の延びる方向と直交する方向から入射した光とで、光から見て光学素子10の屈折率が変わるために、異なる波長の光を射出する。
As described above, according to the sub-wavelength grating 11G, the light incident on the sub-wavelength grating 11G from the direction in which the grating line of the sub-wavelength grating 11G extends and the light incident from the direction orthogonal to the direction in which the grating line extends Since the refractive index of the optical element 10 changes as viewed from the above, light of different wavelengths is emitted.
上述したように、第1格子G1Aの方位角θと、第2格子G1Bの方位角θとは、90°以下であることが以下の理由から好ましい。光学素子10の観察面10Sと、観察者の視線を含む平面とが形成する角度が、観察角度である。サブ波長格子が呈する色が視認される観察角度は、光源、観察者、および、光学素子10の相対的な位置の関係のみに影響される。そのため、第1格子G1Aの方位角θと、第2格子G1Bの方位角θとが互いに異なっても、第1格子G1Aが呈する色が視認される観察角度と、第2格子G1Bが呈する色とが視認される観察角度とは、互いに等しい。言い換えれば、各格子G1A,G1Bが呈する色が発現する観察角度と、各格子G1A,G1Bが呈する色が消失する観察角度とは、2つの格子間において互いに等しい。
As described above, the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B are preferably 90 ° or less for the following reason. The angle formed by the observation surface 10S of the optical element 10 and the plane including the observer's line of sight is the observation angle. The observation angle at which the color exhibited by the sub-wavelength grating is visually recognized is affected only by the relationship between the relative positions of the light source, the observer, and the optical element 10. Therefore, even if the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B are different from each other, the observation angle at which the color exhibited by the first grating G1A is visually recognized, and the color exhibited by the second grating G1B The viewing angles at which are visually recognized are equal to each other. In other words, the observation angle at which the color exhibited by each grating G1A, G1B appears and the observation angle at which the color exhibited by each grating G1A, G1B disappears are equal to each other between the two gratings.
第1格子G1Aの方位角θと、第2格子G1Bの方位角θとの差が90°である場合、第1格子G1Aから射出されるゼロ次回折光の波長と、第2格子G1Bから射出されるゼロ次回折光の波長とは互いに異なる。これにより、第1格子G1Aが呈する第1色と、第2格子G1Bが呈する第2色とが互いに異なる。第1格子G1Aの方位角θと第2格子G1Bの方位角θとの差を、0°よりも大きくかつ90°未満の範囲に含まれる角度に設定した場合には、第1格子G1Aおよび第2格子G1Bの少なくとも一方が、第1色と第2色との中間色を呈する。第1格子G1Aが呈する色と、第2格子G1Bが呈する色とは、方位角θの差に応じて変わる。そのため、第1格子G1Aの方位角θと第2格子G1Bの方位角θとの差によって、1つの方向に沿って並ぶ画素領域Pxにおいて、各画素領域Pxが呈する色を徐々に変化させたり、互いに隣り合う画素領域Px間において、各画素領域Pxが呈する色を急激に変えたりすることができる。
When the difference between the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B is 90 °, the wavelength of the zero-order diffracted light emitted from the first grating G1A and the second grating G1B are emitted. The wavelengths of the zero-order diffracted light are different from each other. Thereby, the first color exhibited by the first lattice G1A and the second color exhibited by the second lattice G1B are different from each other. When the difference between the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B is set to an angle that is greater than 0 ° and less than 90 °, the first grating G1A and the second grating G1A At least one of the two lattices G1B exhibits an intermediate color between the first color and the second color. The color exhibited by the first grating G1A and the color exhibited by the second grating G1B vary depending on the difference in azimuth angle θ. Therefore, depending on the difference between the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B, in the pixel area Px arranged along one direction, the color exhibited by each pixel area Px is gradually changed, The color exhibited by each pixel region Px can be changed abruptly between adjacent pixel regions Px.
なお、サブ波長格子11Gにおいて、第1格子G1Aにおける方位角θと、第2格子G1Bにおける方位角θとの差が90°に設定されたときに、第1格子G1Aが射出する光の波長と、第2格子G1Bが射出する光の波長との差が最も大きくなる。これに対して、第1格子G1Aにおける方位角θと、第2格子G1Bにおける方位角θとの差を90°よりも大きくしても、第1格子G1Aが射出する光の波長と、第2格子G1Bが射出する光の波長との差は、大きくはならない。
In the sub-wavelength grating 11G, when the difference between the azimuth angle θ in the first grating G1A and the azimuth angle θ in the second grating G1B is set to 90 °, the wavelength of light emitted by the first grating G1A The difference from the wavelength of the light emitted from the second grating G1B is the largest. On the other hand, even if the difference between the azimuth angle θ in the first grating G1A and the azimuth angle θ in the second grating G1B is larger than 90 °, the wavelength of the light emitted by the first grating G1A and the second The difference from the wavelength of light emitted by the grating G1B does not increase.
加えて、第1格子G1Aにおける方位角θと、第2格子G1Bにおける方位角θとの差が小さいほど、第1格子G1Aにおける形状の精度と、第2格子G1Bにおける形状の精度とに差が生じにくい。それゆえに、第1格子G1Aにおける方位角θと、第2格子G1Bにおける方位角θとの差の最大値は、90°であることが好ましい。
In addition, the smaller the difference between the azimuth angle θ in the first grating G1A and the azimuth angle θ in the second grating G1B, the difference between the shape accuracy in the first grating G1A and the shape accuracy in the second grating G1B. Hard to occur. Therefore, the maximum difference between the azimuth angle θ in the first grating G1A and the azimuth angle θ in the second grating G1B is preferably 90 °.
以上説明したように、光学素子の第1実施形態によれば、以下に列挙する効果を得ることができる。
(1)光学素子10の真正検証では、光学素子10が、第1サブ波長格子11G1に由来する色を呈する第1領域11S1と、第2サブ波長格子11G2に由来する色を呈する第2領域11S2とを備えるか否かを、一度に把握することができる。結果として、光学素子10を回転させることによって、光学素子10が2つの色を呈する状態を有するか否かを判定する場合に比べて、光学素子10の真正をより容易に検証することができる。 As described above, according to the first embodiment of the optical element, the effects listed below can be obtained.
(1) In authenticity verification of theoptical element 10, the optical element 10 has a first region 11S1 exhibiting a color derived from the first sub-wavelength grating 11G1 and a second region 11S2 exhibiting a color derived from the second sub-wavelength grating 11G2. Can be grasped at a time. As a result, the authenticity of the optical element 10 can be verified more easily by rotating the optical element 10 than when determining whether or not the optical element 10 has a state of two colors.
(1)光学素子10の真正検証では、光学素子10が、第1サブ波長格子11G1に由来する色を呈する第1領域11S1と、第2サブ波長格子11G2に由来する色を呈する第2領域11S2とを備えるか否かを、一度に把握することができる。結果として、光学素子10を回転させることによって、光学素子10が2つの色を呈する状態を有するか否かを判定する場合に比べて、光学素子10の真正をより容易に検証することができる。 As described above, according to the first embodiment of the optical element, the effects listed below can be obtained.
(1) In authenticity verification of the
(2)各画素領域Pxにおける面積率が高いほど、各画素領域Pxの輝度が高い。そのため、複数の画素領域Pxが、面積率が互いに異なる画素領域Pxを含むことによって、第1領域11S1が呈する色において、同一の色相において輝度による濃淡を形成することが可能である。
(2) The higher the area ratio in each pixel region Px, the higher the luminance of each pixel region Px. For this reason, the plurality of pixel regions Px include pixel regions Px having different area ratios, whereby in the colors exhibited by the first region 11S1, it is possible to form shades of brightness in the same hue.
(3)第1格子G1Aの方位角θと、第2格子G1Bの方位角θとが互いに異なるため、第1格子G1Aが呈する色と、第2格子G1Bが呈する色とが互いに異なる。
(3) Since the azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B are different from each other, the color exhibited by the first grating G1A and the color exhibited by the second grating G1B are different from each other.
[第1実施形態の変形]
なお、上述した本発明の第1実施形態は、以下のように適宜変更して実施することができる。
[格子周期]
・第1格子G1Aの方位角θと、第2格子G1Bの方位角θとが互いに等しく、かつ、第1格子G1Aの格子周期と、第2格子G1Bの格子周期とが互いに異なってもよい。この場合には、以下に記載の効果を得ることができる。 [Modification of First Embodiment]
The first embodiment of the present invention described above can be implemented with appropriate modifications as follows.
[Lattice period]
The azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B may be equal to each other, and the grating period of the first grating G1A may be different from the grating period of the second grating G1B. In this case, the following effects can be obtained.
なお、上述した本発明の第1実施形態は、以下のように適宜変更して実施することができる。
[格子周期]
・第1格子G1Aの方位角θと、第2格子G1Bの方位角θとが互いに等しく、かつ、第1格子G1Aの格子周期と、第2格子G1Bの格子周期とが互いに異なってもよい。この場合には、以下に記載の効果を得ることができる。 [Modification of First Embodiment]
The first embodiment of the present invention described above can be implemented with appropriate modifications as follows.
[Lattice period]
The azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B may be equal to each other, and the grating period of the first grating G1A may be different from the grating period of the second grating G1B. In this case, the following effects can be obtained.
(4)第1格子G1Aの格子周期と、第2格子G1Bの格子周期とが互いに異なることによって、第1格子G1Aが呈する色と、第2格子G1Bが呈する色とが互いに異なる。
(4) When the grating period of the first grating G1A and the grating period of the second grating G1B are different from each other, the color exhibited by the first grating G1A and the color exhibited by the second grating G1B are different from each other.
なお、第1格子G1Aと第2格子G1Bとの間において、方位角θを異ならせる場合に比べて、格子周期を異ならせることによって、第1格子G1Aが呈することが可能な色、および、第2格子G1Bが呈することが可能な色の種類を増やすことができる。これにより、光学素子10が呈する色の自由度が高まる。
Note that the colors that the first grating G1A can exhibit by changing the grating period compared to the case where the azimuth angle θ is different between the first grating G1A and the second grating G1B, and The types of colors that can be presented by the two-grating G1B can be increased. Thereby, the freedom degree of the color which the optical element 10 exhibits increases.
・第1格子G1Aの方位角θと、第2格子G1Bの方位角θとが互いに異なり、かつ、第1格子G1Aの格子周期と、第2格子G1Bの格子周期とが互いに異なってもよい。
The azimuth angle θ of the first grating G1A and the azimuth angle θ of the second grating G1B may be different from each other, and the grating period of the first grating G1A and the grating period of the second grating G1B may be different from each other.
[第2実施形態]
図12から図14を参照して、光学素子の第2実施形態を説明する。本発明の第2実施形態の光学素子は、第1実施形態の光学素子と比べて、サブ波長格子が備える格子パターンの形状が異なる。そのため以下では、こうした相違点について詳しく説明する一方で、第2実施形態の光学素子において第1実施形態の光学素子に対応する構成には、第1実施形態と同一の符号を付すことによって、その詳しい説明を省略する。なお、以下に参照する図12から図14では、図示の便宜上、サブ波長格子を平坦面から離れる方向に突出する凸部が並ぶ構造として示している。また、第2実施形態の光学素子では、観察者によって観察されるサブ波長格子の色が、ゼロ次回折光よりも高次の回折光に基づく場合もある。そのため以下では、サブ波長格子が発色する効果が最も高い効率で現れる角度をm次とし、m次における回折光をm次回折光とする。 [Second Embodiment]
A second embodiment of the optical element will be described with reference to FIGS. The optical element according to the second embodiment of the present invention differs from the optical element according to the first embodiment in the shape of the grating pattern included in the sub-wavelength grating. Therefore, in the following, such differences will be described in detail. On the other hand, in the optical element of the second embodiment, the components corresponding to the optical element of the first embodiment are denoted by the same reference numerals as those in the first embodiment. Detailed description is omitted. In FIGS. 12 to 14 referred to below, the sub-wavelength grating is shown as a structure in which convex portions protruding in a direction away from the flat surface are arranged for convenience of illustration. In the optical element of the second embodiment, the color of the sub-wavelength grating observed by the observer may be based on higher-order diffracted light than zero-order diffracted light. Therefore, in the following, the angle at which the sub-wavelength grating has the highest color development efficiency is the mth order, and the diffracted light at the mth order is the mth order diffracted light.
図12から図14を参照して、光学素子の第2実施形態を説明する。本発明の第2実施形態の光学素子は、第1実施形態の光学素子と比べて、サブ波長格子が備える格子パターンの形状が異なる。そのため以下では、こうした相違点について詳しく説明する一方で、第2実施形態の光学素子において第1実施形態の光学素子に対応する構成には、第1実施形態と同一の符号を付すことによって、その詳しい説明を省略する。なお、以下に参照する図12から図14では、図示の便宜上、サブ波長格子を平坦面から離れる方向に突出する凸部が並ぶ構造として示している。また、第2実施形態の光学素子では、観察者によって観察されるサブ波長格子の色が、ゼロ次回折光よりも高次の回折光に基づく場合もある。そのため以下では、サブ波長格子が発色する効果が最も高い効率で現れる角度をm次とし、m次における回折光をm次回折光とする。 [Second Embodiment]
A second embodiment of the optical element will be described with reference to FIGS. The optical element according to the second embodiment of the present invention differs from the optical element according to the first embodiment in the shape of the grating pattern included in the sub-wavelength grating. Therefore, in the following, such differences will be described in detail. On the other hand, in the optical element of the second embodiment, the components corresponding to the optical element of the first embodiment are denoted by the same reference numerals as those in the first embodiment. Detailed description is omitted. In FIGS. 12 to 14 referred to below, the sub-wavelength grating is shown as a structure in which convex portions protruding in a direction away from the flat surface are arranged for convenience of illustration. In the optical element of the second embodiment, the color of the sub-wavelength grating observed by the observer may be based on higher-order diffracted light than zero-order diffracted light. Therefore, in the following, the angle at which the sub-wavelength grating has the highest color development efficiency is the mth order, and the diffracted light at the mth order is the mth order diffracted light.
サブ波長格子11Gは、上述したように、複数の格子パターンを含んでいる。複数の格子パターンが繰り返される方向が第1方向D1であり、第1方向D1と直交する方向が第2方向D2である。各格子パターンにおいて、第1方向D1に沿い、かつ、第1層11が広がる平面に垂直な断面における形状が、断面形状である。各格子パターンは、断面形状が第2方向D2に沿って連なる形状を有している。複数の格子パターンは、断面形状が互いに異なる格子パターンを含んでいる。以下、本実施形態の光学素子について、より詳しく説明する。
As described above, the sub-wavelength grating 11G includes a plurality of grating patterns. The direction in which the plurality of lattice patterns are repeated is the first direction D1, and the direction orthogonal to the first direction D1 is the second direction D2. In each lattice pattern, the shape in a cross section perpendicular to the plane in which the first layer 11 extends along the first direction D1 is a cross-sectional shape. Each lattice pattern has a shape in which the cross-sectional shape continues along the second direction D2. The plurality of lattice patterns include lattice patterns having different cross-sectional shapes. Hereinafter, the optical element of this embodiment will be described in more detail.
図12が示すように、第1実施形態の光学素子10と同様、光学素子20は、第1層11、第2層12、および、第3層13を備えている。光学素子20は、第1方向D1において、3つの部分を含んでいる。すなわち、光学素子20は、第1部分20A、第2部分20B、および、第3部分20Cを含んでいる。第1部分20A、第2部分20B、および、第3部分20Cは、格子パターンが繰り返される方向において、記載の順に並んでいる。
As shown in FIG. 12, the optical element 20 includes a first layer 11, a second layer 12, and a third layer 13, similar to the optical element 10 of the first embodiment. The optical element 20 includes three portions in the first direction D1. That is, the optical element 20 includes a first portion 20A, a second portion 20B, and a third portion 20C. The first portion 20A, the second portion 20B, and the third portion 20C are arranged in the order described in the direction in which the lattice pattern is repeated.
サブ波長格子11Gにおいて、各部分に属する複数の格子パターンは、互いに同じ断面形状を有する。一方で、各部分間において、各部分に属する格子パターンの断面形状は、互いに異なっている。サブ波長格子11Gにおいて、第1部分20Aに属する部分が第1格子20AGであり、第2部分20Bに属する部分が第2格子20BGであり、第3部分20Cに属する部分が第3格子20CGである。
In the sub-wavelength grating 11G, the plurality of grating patterns belonging to each part have the same cross-sectional shape. On the other hand, the cross-sectional shapes of the lattice patterns belonging to each part are different from each other. In the subwavelength grating 11G, the portion belonging to the first portion 20A is the first grating 20AG, the portion belonging to the second portion 20B is the second grating 20BG, and the portion belonging to the third portion 20C is the third grating 20CG. .
第1格子20AGは、複数の第1格子パターンAGPを含んでいる。複数の第1格子パターンAGPは、第1方向D1に沿って繰り返されている。第1格子20AGの断面形状は、波状である。第1格子20AGの格子周期は、第1周期d1である。第1格子パターンAGPは、第1方向D1に沿う断面において、1つの山部が2つの谷部によって挟まれた形状を有している。第1格子パターンAGPは、一方の谷部と山部とを結ぶ斜面と、山部と他方の谷部とを結ぶ斜面とを有している。各斜面は、第1層11が広がる平面に対して傾きを有している。
The first lattice 20AG includes a plurality of first lattice patterns AGP. The plurality of first lattice patterns AGP are repeated along the first direction D1. The cross-sectional shape of the first lattice 20AG is wavy. The grating period of the first grating 20AG is the first period d1. The first lattice pattern AGP has a shape in which one peak is sandwiched between two valleys in the cross section along the first direction D1. The first lattice pattern AGP has a slope connecting one valley and the mountain and a slope connecting the mountain and the other valley. Each slope has an inclination with respect to the plane in which the first layer 11 extends.
第1方向D1に沿う断面において、一方の斜面に対する接線と、複数の谷部を結ぶ直線とが形成する角度が第1接線角度θ1である。なお、複数の谷部を結ぶ直線は、第1層11の表面にほぼ平行な直線である。また、第1接線角度θ1は、第1層11が広がる平面と斜面とが形成する角度に等しい。
In the cross section along the first direction D1, an angle formed by a tangent to one slope and a straight line connecting a plurality of valleys is a first tangent angle θ1. A straight line connecting the plurality of valleys is a straight line substantially parallel to the surface of the first layer 11. In addition, the first tangent angle θ1 is equal to the angle formed by the plane on which the first layer 11 extends and the slope.
第2格子20BGは、複数の第2格子パターンBGPを含んでいる。複数の第2格子パターンBGPは、第1方向D1に沿って繰り返されている。第2格子20BGの断面形状は、波状である。第2格子20BGの格子周期は、第2周期d2である。第2周期d2は、第1周期d1に等しい。第2格子パターンBGPは、第1格子パターンAGPと同様、第1方向D1に沿う断面において、1つの山部が2つの谷部によって挟まれた形状を有している。第2格子パターンBGPは、一方の谷部と山部とを結ぶ斜面と、山部と他方の谷部とを結ぶ斜面とを有している。各斜面は、第1層11が広がる平面に対して傾きを有している。
The second grid 20BG includes a plurality of second grid patterns BGP. The plurality of second lattice patterns BGP are repeated along the first direction D1. The cross-sectional shape of the second grating 20BG is wavy. The grating period of the second grating 20BG is the second period d2. The second period d2 is equal to the first period d1. Similarly to the first lattice pattern AGP, the second lattice pattern BGP has a shape in which one peak is sandwiched between two valleys in the cross section along the first direction D1. The second lattice pattern BGP has a slope connecting one valley and the mountain and a slope connecting the mountain and the other valley. Each slope has an inclination with respect to the plane in which the first layer 11 extends.
第1方向D1に沿う断面において、一方の斜面に対する接線と、複数の谷部を結ぶ直線とが形成する角度が第2接線角度θ2である。第2接線角度θ2は、第1接線角度θ1とは異なる角度である。なお、第2接線角度θ2は、第1層11が広がる平面と斜面とが形成する角度に等しい。本実施形態において、第2接線角度θ2は、第1接線角度θ1よりも小さい。一方で、上述したように、第2格子20BGの第2周期d2は、第1格子20AGの第1格子周期d1に等しい。そのため、第1方向D1に沿う断面において、第2格子パターンBGPの断面形状と、第1格子パターンAGPの断面形状とは互いに異なっている。
In the cross section along the first direction D1, the angle formed by the tangent to one slope and the straight line connecting the plurality of valleys is the second tangent angle θ2. The second tangent angle θ2 is an angle different from the first tangent angle θ1. The second tangent angle θ2 is equal to the angle formed by the plane on which the first layer 11 extends and the slope. In the present embodiment, the second tangent angle θ2 is smaller than the first tangent angle θ1. On the other hand, as described above, the second period d2 of the second grating 20BG is equal to the first grating period d1 of the first grating 20AG. Therefore, in the cross section along the first direction D1, the cross sectional shape of the second lattice pattern BGP and the cross sectional shape of the first lattice pattern AGP are different from each other.
第3格子20CGは、複数の第3格子パターンCGPを含んでいる。複数の第3格子パターンCGPは、第1方向D1に沿って繰り返されている。第3格子20CGの断面形状は、波状である。第3格子20CGの格子周期は、第3周期d3である。第3周期d3は、第1周期d1および第2周期d2に等しい。第3格子パターンCGPは、第1格子パターンAGPと同様、第1方向D1に沿う断面において、1つの山部が2つの谷部によって挟まれた形状を有している。第3格子パターンCGPは、一方の谷部と山部とを結ぶ斜面と、山部と他方の谷部とを結ぶ斜面とを有している。各斜面は、第1層11が広がる平面に対して傾きを有している。
The third grid 20CG includes a plurality of third grid patterns CGP. The plurality of third lattice patterns CGP are repeated along the first direction D1. The cross-sectional shape of the third lattice 20CG is wavy. The grating period of the third grating 20CG is the third period d3. The third period d3 is equal to the first period d1 and the second period d2. Similar to the first lattice pattern AGP, the third lattice pattern CGP has a shape in which one peak is sandwiched between two valleys in the cross section along the first direction D1. The third lattice pattern CGP has a slope connecting one valley and the mountain and a slope connecting the mountain and the other valley. Each slope has an inclination with respect to the plane in which the first layer 11 extends.
第1方向D1に沿う断面において、一方の斜面に対する接線と、複数の谷部を結ぶ直線とが形成する角度が第3接線角度θ3である。第3接線角度θ3は、第1接線角度θ1とは異なる角度であり、かつ、第2接線角度θ2とも異なる角度である。なお、第3接線角度θ3は、第1層11が広がる平面と斜面とが形成する角度に等しい。本実施形態において、第3接線角度θ3は、第1接線角度θ1よりも小さく、かつ、第2接線角度θ2よりも小さい。一方で、上述したように、第3格子20CGの第3周期d3は、第1周期d1および第2周期d2に等しい。そのため、第1方向D1に沿う断面において、第3格子パターンCGPの断面形状は、第1格子パターンAGPの断面形状、および、第2格子パターンBGPの断面形状の両方と異なっている。
In the cross section along the first direction D1, the angle formed by the tangent to one slope and the straight line connecting the plurality of valleys is the third tangent angle θ3. The third tangent angle θ3 is an angle different from the first tangent angle θ1 and also an angle different from the second tangent angle θ2. Note that the third tangent angle θ3 is equal to the angle formed by the plane on which the first layer 11 extends and the inclined surface. In the present embodiment, the third tangent angle θ3 is smaller than the first tangent angle θ1 and smaller than the second tangent angle θ2. On the other hand, as described above, the third period d3 of the third grating 20CG is equal to the first period d1 and the second period d2. Therefore, in the cross section along the first direction D1, the cross sectional shape of the third lattice pattern CGP is different from both the cross sectional shape of the first lattice pattern AGP and the cross sectional shape of the second lattice pattern BGP.
すなわち、本実施形態では、各格子パターンにおける上述した断面形状は、第1層11が広がる平面に対して傾きを有した斜面を含んでいる。そして、複数の格子パターンは、第1層11に対する斜面の傾斜角が互いに異なる格子パターンを含んでいる。
That is, in the present embodiment, the above-described cross-sectional shape in each lattice pattern includes a slope having an inclination with respect to the plane in which the first layer 11 extends. The plurality of lattice patterns include lattice patterns having different slope angles with respect to the first layer 11.
こうしたサブ波長格子11Gによれば、各斜面における接線角度θ1,θ2,θ3を変えることによって、光学素子20に入射した光が回折する角度を変えることができる。すなわち、第1格子20AG、第2格子20BG、および、第3格子20CGの間において、接線角度θ1,θ2,θ3を互いに異ならせることで、各格子20AG,20BG,20CGにおいてm次回折光が射出される角度を互いに異ならせることができる。これにより、サブ波長格子11Gの全体において接線角度が等しい場合と比べて、m次回折光が射出される角度の範囲を広げることができる。言い換えれば、観察者がm次回折光を観察することが可能な観察角度の範囲を広げることができる。なお、各格子20AG,20BG,20CGにおいて、断面形状が異なる一方で格子周期は等しいため、各格子20AG,20BG,20CGが呈する色はほぼ同じである。それゆえに、各格子20AG,20BG,20CGから射出されたm次回折光の集合はモノクロームな光を生成しない。
According to the sub-wavelength grating 11G, the angle at which the light incident on the optical element 20 is diffracted can be changed by changing the tangent angles θ1, θ2, and θ3 on each slope. That is, by changing the tangent angles θ1, θ2, and θ3 between the first grating 20AG, the second grating 20BG, and the third grating 20CG, m-order diffracted light is emitted from the gratings 20AG, 20BG, and 20CG. The angles can be different from each other. Thereby, compared with the case where the tangent angle is equal in the whole sub-wavelength grating 11G, the range of the angle at which m-order diffracted light is emitted can be expanded. In other words, it is possible to widen the range of observation angles at which the observer can observe the mth order diffracted light. In addition, in each grating | lattice 20AG, 20BG, and 20CG, since cross-sectional shapes differ, a grating | lattice period is equal, Therefore The color which each grating | lattice 20AG, 20BG, and 20CG exhibits is substantially the same. Therefore, a set of m-th order diffracted lights emitted from the gratings 20AG, 20BG, and 20CG does not generate monochrome light.
第1方向D1において、各格子20AG,20BG,20CGの幅は300μm以下であることが好ましく、85μm以下であることがより好ましい。各格子20AG,20BG,20CGの幅が300μm以下であることによって、人の目の分解能では、各格子20AG,20BG,20CGを分離することができない。それゆえに、観察者は、各格子20AG,20BG,20CGが、互いに異なる角度で光を回折していると認識することはできない。
In the first direction D1, the width of each of the gratings 20AG, 20BG, and 20CG is preferably 300 μm or less, and more preferably 85 μm or less. Since the widths of the respective gratings 20AG, 20BG, and 20CG are 300 μm or less, the respective gratings 20AG, 20BG, and 20CG cannot be separated with human eye resolution. Therefore, the observer cannot recognize that the gratings 20AG, 20BG, and 20CG are diffracting light at different angles.
なお、各格子20AG,20BG,20CGの幅は、以下の理由から85μm以下であることがより好ましい。一般に、視力が1.0である人が、観察対象から5m離れた位置から視覚1分で分離することが可能な間隔は、1.454mmであることが知られている。こうした事項は、ランドルト環を用いて説明されている。なお、1分は、1°の60分の1である。観察者が光学素子20から30cm離れた位置から光学素子20を観察すると仮定した場合、観察者の目によって分離することが可能な間隔、すなわち分解能Rは、以下の式(4)から導出することができる。
Note that the width of each of the gratings 20AG, 20BG, and 20CG is more preferably 85 μm or less for the following reason. In general, it is known that a distance at which a person whose visual acuity is 1.0 can be separated in 1 minute from a position 5 m away from an observation target is 1.454 mm. These matters are explained using the Landolt ring. One minute is 1 / 60th of 1 °. When it is assumed that the observer observes the optical element 20 from a position 30 cm away from the optical element 20, the interval that can be separated by the observer's eyes, that is, the resolution R, is derived from the following equation (4). Can do.
R = 1454 × (30/500) (μm) … 式(4)
なお、式(4)の右辺において、第1項の単位がμmであり、第2項の単位がcmである。式(4)より、分解能Rは87.24μmである。そのため、各格子20AG,20BG,20CGの幅が85μm以下であれば、人の目の分解能では、各格子20AG,20BG,20CGを分解することができない確実性を高めることができる。 R = 1454 × (30/500) (μm) Formula (4)
In the right side of Equation (4), the unit of the first term is μm and the unit of the second term is cm. From equation (4), the resolution R is 87.24 μm. Therefore, if the width of each of the gratings 20AG, 20BG, and 20CG is 85 μm or less, it is possible to increase the certainty that the gratings 20AG, 20BG, and 20CG cannot be decomposed with human eye resolution.
なお、式(4)の右辺において、第1項の単位がμmであり、第2項の単位がcmである。式(4)より、分解能Rは87.24μmである。そのため、各格子20AG,20BG,20CGの幅が85μm以下であれば、人の目の分解能では、各格子20AG,20BG,20CGを分解することができない確実性を高めることができる。 R = 1454 × (30/500) (μm) Formula (4)
In the right side of Equation (4), the unit of the first term is μm and the unit of the second term is cm. From equation (4), the resolution R is 87.24 μm. Therefore, if the width of each of the gratings 20AG, 20BG, and 20CG is 85 μm or less, it is possible to increase the certainty that the gratings 20AG, 20BG, and 20CG cannot be decomposed with human eye resolution.
各格子パターンAGP,BGP,CGPの断面形状が、互いに異なる接線角度を有した波形状であることは、m次回折光が射出される方向を、接線角度によって制御することが可能である点で好ましい。これに対して、格子パターンの断面形状が、光学素子20の表面に対して平行な面と、表面に対して直交する面とから形成される矩形状である場合、m次回折光、すなわちゼロ次回折光は、入射光に対する正反射の方向に射出される。例えば、光学素子20の表面に対する入射光の入射角度が45°である場合には、正反射光の射出角度も45°である。そのため、観察者は、観察角度が45°である方向から光学素子20を観察しなければ、光学素子20が射出する光を観察することができない。
It is preferable that the cross-sectional shapes of the respective grating patterns AGP, BGP, and CGP have wave shapes having different tangent angles from the viewpoint that the direction in which the m-th order diffracted light is emitted can be controlled by the tangential angles. . On the other hand, when the cross-sectional shape of the grating pattern is a rectangular shape formed from a surface parallel to the surface of the optical element 20 and a surface orthogonal to the surface, m-order diffracted light, that is, zero next time The folded light is emitted in the direction of regular reflection with respect to the incident light. For example, when the incident angle of the incident light with respect to the surface of the optical element 20 is 45 °, the emission angle of the regular reflection light is also 45 °. Therefore, the observer cannot observe the light emitted from the optical element 20 unless the observer observes the optical element 20 from the direction where the observation angle is 45 °.
正反射光の射出角度で光学素子20を観察した場合には、光源から光学素子20に向けて射出された光の正反射光も観察者によって観察される。そのため、観察者が、サブ波長格子によって射出された光を視認しにくい場合がある。さらに、光学素子20に対する光源の相対位置によって、光学素子20を正反射の角度から観察することが難しい場合もある。この点で、m次回折光が射出される方向を、接線角度によって制御することが可能であることで、光学素子20がm次回折光を射出する角度の自由度が高くなる。そのため、上述した問題を解決することが可能にもなる。
When the optical element 20 is observed at the emission angle of the regular reflection light, the regular reflection light of the light emitted from the light source toward the optical element 20 is also observed by the observer. Therefore, it may be difficult for an observer to visually recognize the light emitted by the sub-wavelength grating. Further, depending on the relative position of the light source with respect to the optical element 20, it may be difficult to observe the optical element 20 from the regular reflection angle. In this respect, since the direction in which the m-th order diffracted light is emitted can be controlled by the tangential angle, the degree of freedom in the angle at which the optical element 20 emits the m-th order diffracted light is increased. Therefore, it becomes possible to solve the above-described problem.
3つの格子パターンを含むサブ波長格子11Gは、以下の構造を有してもよい。
図13が示すように、サブ波長格子11Gは、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPを含んでいる。サブ波長格子11Gにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPが、1つのパターン群GPGを構成している。1つのパターン群GPGにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPが、第1方向D1に沿って記載の順に並んでいる。サブ波長格子11Gにおいて、複数のパターン群GPGが、第1方向D1に沿って繰り返されている。 The sub-wavelength grating 11G including the three grating patterns may have the following structure.
As shown in FIG. 13, the sub-wavelength grating 11G includes a first grating pattern AGP, a second grating pattern BGP, and a third grating pattern CGP. In the sub-wavelength grating 11G, the first grating pattern AGP, the second grating pattern BGP, and the third grating pattern CGP constitute one pattern group GPG. In one pattern group GPG, the first lattice pattern AGP, the second lattice pattern BGP, and the third lattice pattern CGP are arranged in the order described in the first direction D1. In the sub-wavelength grating 11G, a plurality of pattern groups GPG are repeated along the first direction D1.
図13が示すように、サブ波長格子11Gは、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPを含んでいる。サブ波長格子11Gにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPが、1つのパターン群GPGを構成している。1つのパターン群GPGにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPが、第1方向D1に沿って記載の順に並んでいる。サブ波長格子11Gにおいて、複数のパターン群GPGが、第1方向D1に沿って繰り返されている。 The sub-wavelength grating 11G including the three grating patterns may have the following structure.
As shown in FIG. 13, the sub-wavelength grating 11G includes a first grating pattern AGP, a second grating pattern BGP, and a third grating pattern CGP. In the sub-wavelength grating 11G, the first grating pattern AGP, the second grating pattern BGP, and the third grating pattern CGP constitute one pattern group GPG. In one pattern group GPG, the first lattice pattern AGP, the second lattice pattern BGP, and the third lattice pattern CGP are arranged in the order described in the first direction D1. In the sub-wavelength grating 11G, a plurality of pattern groups GPG are repeated along the first direction D1.
第1方向D1において、第1格子パターンAGPの格子周期が第1周期d1であり、第2格子パターンBGPの格子周期が第2周期d2であり、第3格子パターンCGPの格子周期が第3周期d3である。第1周期d1、第2周期d2、および、第3周期d3は、互いに等しい。
In the first direction D1, the grating period of the first grating pattern AGP is the first period d1, the grating period of the second grating pattern BGP is the second period d2, and the grating period of the third grating pattern CGP is the third period. d3. The first period d1, the second period d2, and the third period d3 are equal to each other.
第1方向D1において、パターン群GPGの周期Dは、20μm以上であることが好ましい。パターン群GPGの周期Dが大きいほど、より高次の回折光が同一の観察角度内に含まれる。言い換えれば、パターン群GPGの周期Dが大きいほど、同一の次数の回折光が含まれる観察角度の範囲が狭くなる。これにより、m次回折光の観察角度と他の回折光の観察角度との差を小さくすることで、観察者は、m次回折光と同時に複数の回折光を視認することができる。これにより、観察者が光学素子20から射出された光を視認することができる観察角度の範囲が広がる。
In the first direction D1, the period D of the pattern group GPG is preferably 20 μm or more. As the period D of the pattern group GPG is larger, higher-order diffracted light is included in the same observation angle. In other words, the larger the period D of the pattern group GPG, the narrower the range of observation angles including the same order of diffracted light. Thus, by reducing the difference between the observation angle of the mth-order diffracted light and the observation angle of other diffracted light, the observer can visually recognize a plurality of diffracted lights simultaneously with the mth-order diffracted light. Thereby, the range of the observation angle in which the observer can visually recognize the light emitted from the optical element 20 is expanded.
例えば、上述したように、断面形状が矩形状の回折格子では、入射光と回折格子の放線とが形成する角度を角度αとし、かつ、回折光と回折格子の放線とが形成する角度を角度βとするとき、以下の式(5)が成り立つ。なお、角度αは入射角であり、角度βは回折角である。
For example, in the case of a diffraction grating having a rectangular cross-sectional shape as described above, the angle formed by the incident light and the ray of the diffraction grating is the angle α, and the angle formed by the diffraction light and the ray of the diffraction grating is the angle. When β is set, the following equation (5) is established. Note that the angle α is an incident angle, and the angle β is a diffraction angle.
d(sinα+sinβ) = mλ … 式(5)
なお、式(5)において、dは回折格子の周期であり、mは回折次数であり、λは光の波長である。周期および波長の単位は、nmである。また、図13に示されるサブ波長格子11Gでは、周期dが上述したパターン群GPGの周期Dに相当する。式(5)において、角度αを45°に設定し、波長λを500nmに設定するとき、周期dを5000nmに設定すると、以下のように回折次数mと角度βとが決まる。
(m,β) = (1,-37.4)、(2,-30.5)、(3,-24.0)… d (sin α + sin β) = mλ (5)
In equation (5), d is the period of the diffraction grating, m is the diffraction order, and λ is the wavelength of light. The unit of period and wavelength is nm. In thesub-wavelength grating 11G shown in FIG. 13, the period d corresponds to the period D of the pattern group GPG described above. In equation (5), when the angle α is set to 45 ° and the wavelength λ is set to 500 nm, the diffraction order m and the angle β are determined as follows when the period d is set to 5000 nm.
(M, β) = (1, −37.4), (2, −30.5), (3−24.0)...
なお、式(5)において、dは回折格子の周期であり、mは回折次数であり、λは光の波長である。周期および波長の単位は、nmである。また、図13に示されるサブ波長格子11Gでは、周期dが上述したパターン群GPGの周期Dに相当する。式(5)において、角度αを45°に設定し、波長λを500nmに設定するとき、周期dを5000nmに設定すると、以下のように回折次数mと角度βとが決まる。
(m,β) = (1,-37.4)、(2,-30.5)、(3,-24.0)… d (sin α + sin β) = mλ (5)
In equation (5), d is the period of the diffraction grating, m is the diffraction order, and λ is the wavelength of light. The unit of period and wavelength is nm. In the
(M, β) = (1, −37.4), (2, −30.5), (3−24.0)...
また、周期dを10000nmに変更すると、以下のように回折次数mと角度βとが決まる。
(m,β) = (1,-41.1)、(2,-37.4)、(3,-33.9)… When the period d is changed to 10000 nm, the diffraction order m and the angle β are determined as follows.
(M, β) = (1, -41.1), (2, -37.4), (3, -33.9) ...
(m,β) = (1,-41.1)、(2,-37.4)、(3,-33.9)… When the period d is changed to 10000 nm, the diffraction order m and the angle β are determined as follows.
(M, β) = (1, -41.1), (2, -37.4), (3, -33.9) ...
また、周期dを20000nmに変更すると、以下のように回折次数mと角度βとが決まる。
(m,β) = (1,-43.0)、(2,-41.1)、(3,-39.2)… When the period d is changed to 20000 nm, the diffraction order m and the angle β are determined as follows.
(M, β) = (1, -43.0), (2, -41.1), (3, -39.2) ...
(m,β) = (1,-43.0)、(2,-41.1)、(3,-39.2)… When the period d is changed to 20000 nm, the diffraction order m and the angle β are determined as follows.
(M, β) = (1, -43.0), (2, -41.1), (3, -39.2) ...
このように、周期dが大きくなるほど、回折次数の異なる回折光間において、角度βの差が小さくなる。
Thus, as the period d increases, the difference in the angle β decreases between diffracted lights having different diffraction orders.
ここで、人の目における瞳孔径が5mmであり、かつ、観察者が光学素子20を観察する距離を30cmであると仮定する。この場合、光学素子20におけるある点から射出される光のうち、約1°の観察角度内に含まれる光が、観察者の目に入る。すなわち、観察者は約1°の観察角度内の光を積算した結果を視認している。つまり、約1°の観察角度の範囲内にある波長の回折光が含まれていると、この観察角度の範囲内において回折効率が高くなる。また、観察者が、観察角度が変わるように光学素子20を傾けながら観察する場合、観察者が観察角度を2°以上変える間にわたって、光学素子20の呈する色が特定の色に保持されていることによって、観察者は光学素子20が呈する色を認識しやすい。そのため、光学素子20は、観察角度における2°の範囲内に次数の異なる回折光を少なくとも2つ射出するように構成されることが好ましい。この点で、光学素子20における周期Dは、20μm以上であることが好ましい。
Here, it is assumed that the pupil diameter in the human eye is 5 mm and the distance that the observer observes the optical element 20 is 30 cm. In this case, of the light emitted from a certain point in the optical element 20, light included within an observation angle of about 1 ° enters the eyes of the observer. That is, the observer visually recognizes the result of integrating the light within the observation angle of about 1 °. That is, when diffracted light having a wavelength within the range of the observation angle of about 1 ° is included, the diffraction efficiency is increased within the range of the observation angle. In addition, when the observer observes the optical element 20 while tilting it so that the observation angle changes, the color exhibited by the optical element 20 is held at a specific color while the observer changes the observation angle by 2 ° or more. Thus, the observer can easily recognize the color exhibited by the optical element 20. Therefore, the optical element 20 is preferably configured to emit at least two diffracted lights having different orders within a range of 2 ° in the observation angle. In this respect, the period D in the optical element 20 is preferably 20 μm or more.
3つの格子パターンを含むサブ波長格子11Gは、以下の構造を有してもよい。
図14が示すように、サブ波長格子11Gは、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPを含んでいる。サブ波長格子11Gにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPが、1つのパターン群GPGを構成している。1つのパターン群GPGにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPは、第1方向D1に沿って記載の順に並んでいる。サブ波長格子11Gにおいて、複数のパターン群GPGが、第1方向D1に沿って繰り返されている。 The sub-wavelength grating 11G including the three grating patterns may have the following structure.
As shown in FIG. 14, the sub-wavelength grating 11G includes a first grating pattern AGP, a second grating pattern BGP, and a third grating pattern CGP. In the sub-wavelength grating 11G, the first grating pattern AGP, the second grating pattern BGP, and the third grating pattern CGP constitute one pattern group GPG. In one pattern group GPG, the first lattice pattern AGP, the second lattice pattern BGP, and the third lattice pattern CGP are arranged in the order described in the first direction D1. In the sub-wavelength grating 11G, a plurality of pattern groups GPG are repeated along the first direction D1.
図14が示すように、サブ波長格子11Gは、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPを含んでいる。サブ波長格子11Gにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPが、1つのパターン群GPGを構成している。1つのパターン群GPGにおいて、第1格子パターンAGP、第2格子パターンBGP、および、第3格子パターンCGPは、第1方向D1に沿って記載の順に並んでいる。サブ波長格子11Gにおいて、複数のパターン群GPGが、第1方向D1に沿って繰り返されている。 The sub-wavelength grating 11G including the three grating patterns may have the following structure.
As shown in FIG. 14, the sub-wavelength grating 11G includes a first grating pattern AGP, a second grating pattern BGP, and a third grating pattern CGP. In the sub-wavelength grating 11G, the first grating pattern AGP, the second grating pattern BGP, and the third grating pattern CGP constitute one pattern group GPG. In one pattern group GPG, the first lattice pattern AGP, the second lattice pattern BGP, and the third lattice pattern CGP are arranged in the order described in the first direction D1. In the sub-wavelength grating 11G, a plurality of pattern groups GPG are repeated along the first direction D1.
第1格子パターンAGPの格子周期が第1周期d1であり、第2格子パターンBGPの格子周期が第2周期d2であり、第3格子パターンCGPの格子周期が第3周期d3である。第1周期d1、第2周期d2、および、第3周期d3は、互いに異なる。第1方向D1において互いに隣り合う格子パターン間では、格子周期の差が20nm以下であることが好ましい。例えば、第1周期d1を300nmに設定し、第2周期d2を310nmに設定し、かつ、第3周期d3を290nmに設定することが可能である。
The grating period of the first grating pattern AGP is the first period d1, the grating period of the second grating pattern BGP is the second period d2, and the grating period of the third grating pattern CGP is the third period d3. The first period d1, the second period d2, and the third period d3 are different from each other. It is preferable that the difference in the grating period is 20 nm or less between the grating patterns adjacent to each other in the first direction D1. For example, the first period d1 can be set to 300 nm, the second period d2 can be set to 310 nm, and the third period d3 can be set to 290 nm.
格子パターン間において格子周期が互いに異なるため、格子パターン間において回折角が互いに異なる。格子パターン間において、格子周期の差が小さいほど、回折角の差が小さくなる。上述したように、第1方向D1において互いに隣り合う格子パターン間での格子周期の差が20nm以下であれば、各格子パターンから射出されるm次回折光の回折角が互いにほぼ等しくなる。これにより、観察者は、各格子パターンから射出されるm次回折光を分離することができない。そのため、観察者が光学素子20から射出される光を観察することが可能な観察角度を広げることができる。
Since the grating periods are different between the grating patterns, the diffraction angles are different between the grating patterns. The smaller the difference in grating period between grating patterns, the smaller the difference in diffraction angle. As described above, when the difference in the grating period between the grating patterns adjacent to each other in the first direction D1 is 20 nm or less, the diffraction angles of the m-th order diffracted lights emitted from the grating patterns are substantially equal to each other. Thereby, the observer cannot separate the m-th order diffracted light emitted from each grating pattern. Therefore, the observation angle at which the observer can observe the light emitted from the optical element 20 can be widened.
以上説明したように、光学素子の第2実施形態によれば、以下に記載の効果を得ることができる。
(5)複数の格子パターンにおいて、第1方向D1に沿う断面形状が互いに同一である場合と比べて、サブ波長格子11Gから射出される光を観察者が視認することが可能な観察角度を広げることができる。 As described above, according to the second embodiment of the optical element, the following effects can be obtained.
(5) In a plurality of grating patterns, as compared with the case where the cross-sectional shapes along the first direction D1 are the same, the observation angle at which the observer can visually recognize the light emitted from the sub-wavelength grating 11G is widened. be able to.
(5)複数の格子パターンにおいて、第1方向D1に沿う断面形状が互いに同一である場合と比べて、サブ波長格子11Gから射出される光を観察者が視認することが可能な観察角度を広げることができる。 As described above, according to the second embodiment of the optical element, the following effects can be obtained.
(5) In a plurality of grating patterns, as compared with the case where the cross-sectional shapes along the first direction D1 are the same, the observation angle at which the observer can visually recognize the light emitted from the sub-wavelength grating 11G is widened. be able to.
(6)複数の格子パターンにおいて、第1方向D1に沿う断面形状に含まれる斜面の傾斜角が互いに同一である場合と比べて、格子パターン間における傾斜角の差に応じて、サブ波長格子11Gから射出される光を観察者が視認することが可能な観察角度を広げることができる。
(6) In the plurality of grating patterns, the sub-wavelength grating 11G corresponds to the difference in the inclination angle between the grating patterns as compared with the case where the inclination angles of the slopes included in the cross-sectional shape along the first direction D1 are the same. The observation angle at which the observer can visually recognize the light emitted from the projector can be expanded.
[第2実施形態の変形]
なお、上述した第2実施形態は、以下のように適宜変更して実施することができる。
[断面形状]
・サブ波長格子11Gは、上述した断面形状が互いに異なる4種以上の格子パターンを含んでもよい。また、複数種の格子パターンは、サブ波長格子11G内においてランダムに位置してもよい。また、複数種の格子パターンは、規則的に位置してもよい。 [Modification of Second Embodiment]
The second embodiment described above can be implemented with appropriate modifications as follows.
[Cross-sectional shape]
Thesub-wavelength grating 11G may include four or more types of grating patterns having different cross-sectional shapes as described above. Further, the plurality of types of grating patterns may be randomly positioned in the sub-wavelength grating 11G. Further, the plurality of types of lattice patterns may be regularly arranged.
なお、上述した第2実施形態は、以下のように適宜変更して実施することができる。
[断面形状]
・サブ波長格子11Gは、上述した断面形状が互いに異なる4種以上の格子パターンを含んでもよい。また、複数種の格子パターンは、サブ波長格子11G内においてランダムに位置してもよい。また、複数種の格子パターンは、規則的に位置してもよい。 [Modification of Second Embodiment]
The second embodiment described above can be implemented with appropriate modifications as follows.
[Cross-sectional shape]
The
・サブ波長格子11Gの断面形状は、上述した波状に限らない。サブ波長格子11Gが波形状以外の形状を有する場合であっても、サブ波長格子11Gが、断面形状が互いに異なる格子パターンを含んでいることによって、上述した(5)に準じた効果を得ることはできる。
· The cross-sectional shape of the sub-wavelength grating 11G is not limited to the wave shape described above. Even when the sub-wavelength grating 11G has a shape other than the wave shape, the sub-wavelength grating 11G includes the grating patterns having different cross-sectional shapes, thereby obtaining the effect according to the above (5). I can.
[第3実施形態]
図15を参照して、光学素子の第3実施形態を説明する。本発明の第3実施形態の光学素子は、第1実施形態の光学素子10と比べて、第1層がフィラーを含む点が異なっている。そのため、以下では、こうした相違点を詳しく説明する一方で、第3実施形態の光学素子において、第1実施形態の光学素子に対応する構成には、第1実施形態と同一の符号を付すことによって、その詳しい説明を省略する。 [Third Embodiment]
A third embodiment of the optical element will be described with reference to FIG. The optical element according to the third embodiment of the present invention is different from theoptical element 10 according to the first embodiment in that the first layer includes a filler. Therefore, in the following, such differences will be described in detail. On the other hand, in the optical element of the third embodiment, the components corresponding to the optical element of the first embodiment are denoted by the same reference numerals as in the first embodiment. Detailed description thereof will be omitted.
図15を参照して、光学素子の第3実施形態を説明する。本発明の第3実施形態の光学素子は、第1実施形態の光学素子10と比べて、第1層がフィラーを含む点が異なっている。そのため、以下では、こうした相違点を詳しく説明する一方で、第3実施形態の光学素子において、第1実施形態の光学素子に対応する構成には、第1実施形態と同一の符号を付すことによって、その詳しい説明を省略する。 [Third Embodiment]
A third embodiment of the optical element will be described with reference to FIG. The optical element according to the third embodiment of the present invention is different from the
図15が示すように、光学素子30が備える第1層11は、第1層11を形成する樹脂中に分散したフィラー31を含んでいる。フィラー31の平均粒径は、400nm以下である。第1層11に入射した光の少なくとも一部は、第1層11内に分散したフィラーによって散乱される。そのため、サブ波長格子11Gに入射する光には、互いに異なる入射角を有した光が含まれる。これにより、サブ波長格子11Gが含む各格子パターンGPは、その格子パターンGPに入射した光の入射角に応じた正反射の方向に光を反射する。格子パターンGPが反射した光は、フィラー31によって散乱されることなく、または、フィラー31によって散乱された後に、光学素子30の外部に射出される。そのため、第1層11がフィラーを含まない場合と比べて、光学素子30から射出される光の射出角の範囲が広がる。結果として、光学素子30が呈する色を観察者が観察することが可能な観察角度の範囲が広がる。
As shown in FIG. 15, the first layer 11 included in the optical element 30 includes a filler 31 dispersed in the resin forming the first layer 11. The average particle diameter of the filler 31 is 400 nm or less. At least a part of the light incident on the first layer 11 is scattered by the filler dispersed in the first layer 11. Therefore, the light incident on the sub-wavelength grating 11G includes light having different incident angles. Thereby, each grating pattern GP included in the sub-wavelength grating 11G reflects light in the regular reflection direction according to the incident angle of the light incident on the grating pattern GP. The light reflected by the lattice pattern GP is emitted to the outside of the optical element 30 without being scattered by the filler 31 or after being scattered by the filler 31. Therefore, compared with the case where the 1st layer 11 does not contain a filler, the range of the emission angle of the light inject | emitted from the optical element 30 spreads. As a result, the range of observation angles at which the observer can observe the colors exhibited by the optical element 30 is expanded.
上述したように、フィラー31の平均粒径は、400nm以下であることが好ましい。これにより、ミー散乱が生じることが抑えられるため、第1層11の透明性が少なからず高められる。フィラー31の形状は、球状に限らない。そのため、本実施形態では、各フィラー31において規定することが可能な複数の直径における平均値が、各フィラー31の平均粒径である。ここで、フィラー31などの散乱体の大きさと散乱現象との関係について、以下のことが知られている。散乱体の平均粒径が400nm以上700nm以下の範囲に含まれる場合には、散乱体によってミー散乱が生じる。ミー散乱では、可視域に含まれる光は、光の波長に関わらず同程度に散乱されるため、ミー散乱によって散乱された光は白色の光として視認される。なお、ミー散乱では、散乱体の粒径によって光の散乱角度が影響される。ミー散乱では、散乱体の粒径が大きいほど、光の進行方向における前方に対する散乱が強くなる。
As described above, the average particle diameter of the filler 31 is preferably 400 nm or less. Thereby, since Mie scattering is suppressed, the transparency of the first layer 11 is improved to some extent. The shape of the filler 31 is not limited to a spherical shape. Therefore, in this embodiment, the average value in a plurality of diameters that can be defined in each filler 31 is the average particle diameter of each filler 31. Here, the following is known about the relationship between the size of the scatterer such as the filler 31 and the scattering phenomenon. When the average particle size of the scatterer is included in the range of 400 nm or more and 700 nm or less, Mie scattering is generated by the scatterer. In Mie scattering, the light included in the visible range is scattered to the same extent regardless of the wavelength of the light, so that the light scattered by the Mie scattering is visually recognized as white light. In Mie scattering, the light scattering angle is affected by the particle size of the scatterer. In Mie scattering, the larger the particle size of the scatterer, the stronger the scattering toward the front in the light traveling direction.
これに対して、散乱体が光の波長に対して1/10よりも小さい場合には、レイリー散乱が生じる。レイリー散乱では、光が散乱される方向は、散乱体の粒径に依存しない。レイリー散乱では、散乱体の粒径に関わらず、光の進行方向に対して8の字を描くような分布で、光が散乱される。また、レイリー散乱では、光の波長が短いほど、光の散乱が強くなる。
On the other hand, when the scatterer is smaller than 1/10 with respect to the wavelength of light, Rayleigh scattering occurs. In Rayleigh scattering, the direction in which light is scattered does not depend on the particle size of the scatterer. In Rayleigh scattering, light is scattered with a distribution that draws a figure of 8 in the traveling direction of light regardless of the particle size of the scatterer. In Rayleigh scattering, the shorter the light wavelength, the stronger the light scattering.
本実施形態のように、散乱体であるフィラー31が分散した第1層11に透明性が必要とされる場合には、フィラー31の平均粒径は、少なくとも光の波長以下であり、かつ、フィラー31によってレイリー散乱が生じることが必要である。それゆえに、フィラー31の平均粒径は、400nm以下であることが好ましい。フィラー31の平均粒径をDとし、光の波長をλとするとき、散乱断面積αは以下の式(6)によって算出することができる。
When transparency is required for the first layer 11 in which the filler 31 as a scatterer is dispersed as in the present embodiment, the average particle size of the filler 31 is at least equal to or less than the wavelength of light, and It is necessary for the filler 31 to cause Rayleigh scattering. Therefore, the average particle diameter of the filler 31 is preferably 400 nm or less. When the average particle diameter of the filler 31 is D and the wavelength of light is λ, the scattering cross section α can be calculated by the following equation (6).
α =πD/λ … 式(6)
式(6)を用いることによって、フィラー31によって生じる散乱現象が、レイリー散乱であるか、あるいは、ミー散乱であるかを簡易的に判断することができる。散乱断面積αが0.4以下である場合には、主にレイリー散乱が生じる一方で、散乱断面積αが、0.4よりも大きく、かつ、3未満である場合には、主にミー散乱が生じることが知られている。それゆえに、フィラー31に入射する光が可視域の光であって、光の波長が400nmである場合には、フィラー31の平均粒径が50nm以下であれば、フィラー31によって主にレイリー散乱を生じさせることができる。これにより、第1層11における透明性が高い状態で、第1層11に入射した光をフィラー31によって散乱させることができる。 α = πD / λ Formula (6)
By using Expression (6), it is possible to easily determine whether the scattering phenomenon caused by thefiller 31 is Rayleigh scattering or Mie scattering. When the scattering cross section α is 0.4 or less, Rayleigh scattering mainly occurs. On the other hand, when the scattering cross section α is greater than 0.4 and less than 3, the M It is known that scattering occurs. Therefore, when the light incident on the filler 31 is light in the visible range and the wavelength of the light is 400 nm, if the average particle size of the filler 31 is 50 nm or less, the filler 31 mainly causes Rayleigh scattering. Can be generated. Thereby, the light incident on the first layer 11 can be scattered by the filler 31 in a state where the transparency in the first layer 11 is high.
式(6)を用いることによって、フィラー31によって生じる散乱現象が、レイリー散乱であるか、あるいは、ミー散乱であるかを簡易的に判断することができる。散乱断面積αが0.4以下である場合には、主にレイリー散乱が生じる一方で、散乱断面積αが、0.4よりも大きく、かつ、3未満である場合には、主にミー散乱が生じることが知られている。それゆえに、フィラー31に入射する光が可視域の光であって、光の波長が400nmである場合には、フィラー31の平均粒径が50nm以下であれば、フィラー31によって主にレイリー散乱を生じさせることができる。これにより、第1層11における透明性が高い状態で、第1層11に入射した光をフィラー31によって散乱させることができる。 α = πD / λ Formula (6)
By using Expression (6), it is possible to easily determine whether the scattering phenomenon caused by the
以上説明したように、第3実施形態の光学素子によれば、以下に記載の効果を得ることができる。
(7)第1層11がフィラーを含まない場合と比べて、光学素子30から射出される光の射出角の範囲が広がる。そのため、光学素子30が呈する色を観察者が観察することが可能な観察角度の範囲が広がる。 As described above, according to the optical element of the third embodiment, the following effects can be obtained.
(7) Compared to the case where thefirst layer 11 does not include a filler, the range of the emission angle of light emitted from the optical element 30 is widened. Therefore, the range of observation angles at which the observer can observe the colors exhibited by the optical element 30 is expanded.
(7)第1層11がフィラーを含まない場合と比べて、光学素子30から射出される光の射出角の範囲が広がる。そのため、光学素子30が呈する色を観察者が観察することが可能な観察角度の範囲が広がる。 As described above, according to the optical element of the third embodiment, the following effects can be obtained.
(7) Compared to the case where the
[第4実施形態]
図16および図17を参照して、光学素子の第4実施形態を説明する。本発明の第4実施形態の光学素子は、第1実施形態の光学素子10と比べて、第3層13において、第2層12に接する面とは反対側の面の状態が異なっている。そのため以下では、こうした相違点を詳しく説明する一方で、第3実施形態の光学素子において第1実施形態の光学素子10と対応する構成には同一の符号を付すことによって、その詳しい説明を省略する。また、以下では、第4実施形態における第1実例と第2実例とを順に説明する。 [Fourth Embodiment]
A fourth embodiment of the optical element will be described with reference to FIGS. 16 and 17. The optical element according to the fourth embodiment of the present invention differs from theoptical element 10 according to the first embodiment in the state of the surface of the third layer 13 opposite to the surface in contact with the second layer 12. Therefore, in the following, such differences will be described in detail, and in the optical element of the third embodiment, the same reference numerals are given to the components corresponding to those of the optical element 10 of the first embodiment, and detailed description thereof will be omitted. . Hereinafter, the first example and the second example in the fourth embodiment will be described in order.
図16および図17を参照して、光学素子の第4実施形態を説明する。本発明の第4実施形態の光学素子は、第1実施形態の光学素子10と比べて、第3層13において、第2層12に接する面とは反対側の面の状態が異なっている。そのため以下では、こうした相違点を詳しく説明する一方で、第3実施形態の光学素子において第1実施形態の光学素子10と対応する構成には同一の符号を付すことによって、その詳しい説明を省略する。また、以下では、第4実施形態における第1実例と第2実例とを順に説明する。 [Fourth Embodiment]
A fourth embodiment of the optical element will be described with reference to FIGS. 16 and 17. The optical element according to the fourth embodiment of the present invention differs from the
[第1実例]
図16が示すように、光学素子40において、第3層13は、熱可塑性を有した接着層である。第3層13は、第3層13の厚さ方向における中央よりも第2層12に接する面とは反対側の面寄りの部分に分散したフィラー41を含んでいる。第3層13において、第2層12に接する面が表面13Fであり、表面13Fとは反対側の面が裏面13Rである。第3層13において、フィラー41は、上述したように、第3層13の厚さ方向における中央よりも裏面13R寄りに位置することが好ましく、裏面13Rの近傍に位置することが好ましい。 [First example]
As shown in FIG. 16, in theoptical element 40, the third layer 13 is an adhesive layer having thermoplasticity. The third layer 13 includes a filler 41 dispersed in a portion closer to the surface opposite to the surface in contact with the second layer 12 than the center in the thickness direction of the third layer 13. In the third layer 13, the surface in contact with the second layer 12 is the front surface 13F, and the surface opposite to the front surface 13F is the back surface 13R. In the third layer 13, as described above, the filler 41 is preferably located closer to the back surface 13R than the center in the thickness direction of the third layer 13, and is preferably located in the vicinity of the back surface 13R.
図16が示すように、光学素子40において、第3層13は、熱可塑性を有した接着層である。第3層13は、第3層13の厚さ方向における中央よりも第2層12に接する面とは反対側の面寄りの部分に分散したフィラー41を含んでいる。第3層13において、第2層12に接する面が表面13Fであり、表面13Fとは反対側の面が裏面13Rである。第3層13において、フィラー41は、上述したように、第3層13の厚さ方向における中央よりも裏面13R寄りに位置することが好ましく、裏面13Rの近傍に位置することが好ましい。 [First example]
As shown in FIG. 16, in the
上述したように、第3層13は、熱可塑性を有した接着層である。第3層13を形成する材料には、熱可塑性を有した接着剤を用いることができる。第3層13が熱可塑性を有した接着層であるため、第3層13が被転写体に接する状態で光学素子40に熱および圧力を加えることにより、光学素子40を被転写体に転写することができる。このとき、第3層13に加えられた熱および圧力によって、第3層13の裏面13Rにフィラー41に起因する凹凸が生じ、これによって、第3層13の表面13Fにも凹凸が生じる。結果として、第1層11および第2層12のなかで、光学素子40の厚さ方向から見て、第3層13に形成された凹凸と重なる部分にも、凹凸が生じる。これにより、第1層11と第2層12との界面において、サブ波長格子11Gに対してフィラー41に起因する凹凸が付加される。被転写体の実例は、紙幣、パスポート、および、カードなどとできる。
As described above, the third layer 13 is an adhesive layer having thermoplasticity. As a material for forming the third layer 13, an adhesive having thermoplasticity can be used. Since the third layer 13 is an adhesive layer having thermoplasticity, heat and pressure are applied to the optical element 40 in a state where the third layer 13 is in contact with the transfer target, thereby transferring the optical element 40 to the transfer target. be able to. At this time, the heat and pressure applied to the third layer 13 cause unevenness due to the filler 41 on the back surface 13 </ b> R of the third layer 13, thereby causing unevenness on the surface 13 </ b> F of the third layer 13. As a result, in the first layer 11 and the second layer 12, unevenness also occurs in a portion overlapping with the unevenness formed in the third layer 13 when viewed from the thickness direction of the optical element 40. Thereby, the unevenness | corrugation resulting from the filler 41 is added with respect to the subwavelength grating 11G in the interface of the 1st layer 11 and the 2nd layer 12. FIG. Examples of the transfer object can be bills, passports, cards, and the like.
第1層11と第2層12との界面における凹凸は、フィラー41の大きさ、各層11,12,13の厚さ、および、光学素子40を転写するときの熱および圧力の条件によって、調節することができる。
The unevenness at the interface between the first layer 11 and the second layer 12 is adjusted by the size of the filler 41, the thickness of each layer 11, 12, 13 and the conditions of heat and pressure when transferring the optical element 40. can do.
サブ波長格子11Gには、フィラー41に起因する凹凸が付加されるため、サブ波長格子11Gを形成する複数の格子パターンGPには、格子パターンGPに対する光の入射角が違いに異なる格子パターンGPが含まれる。そして、各格子パターンGPは、その格子パターンGPにおける光の入射角に応じた射出角で、m次回折光を反射する。各格子パターンがm次回折光を射出する射出角の範囲は、各格子パターンGPに付与された凹凸が有する曲率によって変わる。言い換えれば、観察者が、サブ波長格子11Gが呈する色を観察することが可能な観察角度は、各格子パターンGPに付与された凹凸の曲率によって変わる。
Since the unevenness due to the filler 41 is added to the sub-wavelength grating 11G, the plurality of grating patterns GP forming the sub-wavelength grating 11G have different grating patterns GP with different incident angles of light with respect to the grating pattern GP. included. Each grating pattern GP reflects m-th order diffracted light at an exit angle corresponding to the incident angle of light in the grating pattern GP. The range of the emission angle at which each grating pattern emits m-th order diffracted light varies depending on the curvature of the unevenness imparted to each grating pattern GP. In other words, the observation angle at which the observer can observe the color exhibited by the sub-wavelength grating 11G varies depending on the curvature of the unevenness imparted to each grating pattern GP.
上述したように、光学素子40が呈する色は、観察角度における2°以上の範囲において保たれることが好ましい。一方で、光学素子40が呈する色を観察することができる観察角度の範囲が広すぎると、各観察角度において光学素子40が射出する光の強度が低くなる。そのため、光学素子40が呈する色を観察することができる観察角度の範囲は、2°以上10°以下であることが好ましく、2°以上5°以下であることがより好ましい。こうした観察角度の範囲に、全ての格子パターンGPが射出するm次回折光の射出角が含まれることが好ましい。
As described above, the color exhibited by the optical element 40 is preferably maintained in a range of 2 ° or more in the observation angle. On the other hand, if the observation angle range in which the color exhibited by the optical element 40 can be observed is too wide, the intensity of light emitted from the optical element 40 at each observation angle is lowered. Therefore, the range of the observation angle in which the color exhibited by the optical element 40 can be observed is preferably 2 ° or more and 10 ° or less, and more preferably 2 ° or more and 5 ° or less. It is preferable that the range of the observation angle includes the emission angle of the m-th order diffracted light emitted by all the grating patterns GP.
そのため、フィラー41に起因する凹凸の曲率は、過度に大きくないことが好ましい。フィラー41に起因する凹凸の曲率が過度に大きくなることを抑える方法として、以下の2つの方法とできる。第1の方法では、フィラー41を第3層13において一様に分散させ、かつ、凹凸の曲率が過度に大きくならないように、転写における熱および圧力の条件を調節する。第2の方法では、フィラー41として、球状を有するフィラーではなく、扁平な形状を有するフィラーを用い、かつ、第3層13の厚さ方向において、フィラー41の直径が小さくなるように、第3層13にフィラー41を分散させる。
Therefore, it is preferable that the curvature of the unevenness caused by the filler 41 is not excessively large. The following two methods can be used as a method for suppressing the uneven curvature due to the filler 41 from becoming excessively large. In the first method, the heat and pressure conditions in the transfer are adjusted so that the filler 41 is uniformly dispersed in the third layer 13 and the curvature of the irregularities does not become excessively large. In the second method, a filler having a flat shape is used as the filler 41 instead of a spherical filler, and the diameter of the filler 41 decreases in the thickness direction of the third layer 13. Filler 41 is dispersed in layer 13.
[第2実例]
図17が示すように、光学素子40は、第3層13に接する第4層42をさらに備えている。第4層42は、第3層13に接する表面42Fを含んでいる。表面42Fは、凹凸を含んでいる。 [Second example]
As shown in FIG. 17, theoptical element 40 further includes a fourth layer 42 in contact with the third layer 13. The fourth layer 42 includes a surface 42 </ b> F that contacts the third layer 13. The surface 42F includes irregularities.
図17が示すように、光学素子40は、第3層13に接する第4層42をさらに備えている。第4層42は、第3層13に接する表面42Fを含んでいる。表面42Fは、凹凸を含んでいる。 [Second example]
As shown in FIG. 17, the
第4層42の表面42Fにおける凹凸は、種々の方法によって形成することができる。第3層13を被転写体である第4層42に転写するときに、熱および圧力によって変形した第3層13に追従するように、第4層42の表面42Fに凹凸を形成することができる。この場合には、第3層13には、熱可塑性を有した接着層を用いることができる。また、第4層42には、紙や樹脂フィルムを用いることができる。あるいは、第4層42に微粒子や繊維を分散させることによって、第4層42の表面42Fに凹凸を形成することができる。また、第4層42の表面42Fには、第4層42を成膜するときに生じる脱泡やむらによっても凹凸を生じさせることができる。第2実例においても、第1実例と同様、第4層42の表面42Fに起因する凹凸をサブ波長格子11Gに付加することができる。そのため、第2実例の光学素子40によっても、第1実例の光学素子40と同様の効果を得ることができる。
The unevenness on the surface 42F of the fourth layer 42 can be formed by various methods. When transferring the third layer 13 to the fourth layer 42 as the transfer target, unevenness may be formed on the surface 42F of the fourth layer 42 so as to follow the third layer 13 deformed by heat and pressure. it can. In this case, an adhesive layer having thermoplasticity can be used for the third layer 13. The fourth layer 42 can be made of paper or a resin film. Alternatively, irregularities can be formed on the surface 42F of the fourth layer 42 by dispersing fine particles and fibers in the fourth layer 42. Further, the surface 42F of the fourth layer 42 can be made uneven by defoaming or unevenness generated when the fourth layer 42 is formed. Also in the second example, as in the first example, the unevenness caused by the surface 42F of the fourth layer 42 can be added to the sub-wavelength grating 11G. Therefore, the same effect as the optical element 40 of the first example can be obtained by the optical element 40 of the second example.
なお、第4層42が被転写体であり、かつ、第4層42が微粒子を含む場合には、微粒子の平均粒径が、接着層である第3層13の厚さと同程度であることが好ましい。また、第4層42に対する転写において、熱および圧力の条件を調節することによって、サブ波長格子11Gに付与される凹凸が過度に大きくなることが抑えられる。
When the fourth layer 42 is a transfer target and the fourth layer 42 includes fine particles, the average particle diameter of the fine particles is approximately the same as the thickness of the third layer 13 that is an adhesive layer. Is preferred. Further, in the transfer to the fourth layer 42, by adjusting the conditions of heat and pressure, it is possible to suppress the unevenness imparted to the sub-wavelength grating 11G from becoming excessively large.
また、繊維が分散した第4層42として、紙製の第4層42を用いることができる。この場合、第4層42を形成する繊維は、第4層42の表面42Fに平行に並んでいる。パルプ繊維は、直径が20μm以上50μm以下であり、かつ、長さが1mm以上5mm以下程度の大きさを有する。そのため、サブ波長格子11Gに付与される凹凸が過度に大きくなる場合がある。これに対して、セルロースナノファイバーは、直径が4nm以上100nm以下であり、かつ、長さが5μm以上程度の大きさを有する。そのため、サブ波長格子11Gに付与される凹凸が過度に大きくなることが抑えられる。なお、セルロースナノファイバーは、パルプ繊維を分解することによって得られる繊維である。
Also, the paper-made fourth layer 42 can be used as the fourth layer 42 in which the fibers are dispersed. In this case, the fibers forming the fourth layer 42 are arranged in parallel to the surface 42F of the fourth layer 42. The pulp fiber has a diameter of 20 μm or more and 50 μm or less and a length of about 1 mm or more and 5 mm or less. Therefore, the unevenness imparted to the sub-wavelength grating 11G may become excessively large. On the other hand, the cellulose nanofiber has a diameter of 4 nm or more and 100 nm or less and a length of about 5 μm or more. Therefore, it is possible to suppress the unevenness imparted to the sub-wavelength grating 11G from becoming excessively large. Cellulose nanofibers are fibers obtained by decomposing pulp fibers.
以上説明したように、第4実施形態の光学素子によれば、以下に記載の効果を得ることができる。
(8)フィラー41に起因する凹凸がサブ波長格子11Gに付与されるため、複数の格子パターンGPが、格子パターンGPに対する光の入射角が互いに異なる格子パターンGPを含むことができる。これにより、格子パターンGPにおける射出角も異なるため、サブ波長格子11Gから射出される光が観察される観察角度を広げることができる。 As described above, according to the optical element of the fourth embodiment, the following effects can be obtained.
(8) Since the unevenness caused by thefiller 41 is imparted to the sub-wavelength grating 11G, the plurality of grating patterns GP can include grating patterns GP having different incident angles of light with respect to the grating pattern GP. Thereby, since the emission angle in the grating pattern GP is also different, the observation angle at which the light emitted from the sub-wavelength grating 11G is observed can be widened.
(8)フィラー41に起因する凹凸がサブ波長格子11Gに付与されるため、複数の格子パターンGPが、格子パターンGPに対する光の入射角が互いに異なる格子パターンGPを含むことができる。これにより、格子パターンGPにおける射出角も異なるため、サブ波長格子11Gから射出される光が観察される観察角度を広げることができる。 As described above, according to the optical element of the fourth embodiment, the following effects can be obtained.
(8) Since the unevenness caused by the
(9)第4層42の表面42Fに起因する凹凸がサブ波長格子11Gに付与されるため、複数の格子パターンGPが、格子パターンGPに対する光の入射角度が互いに異なる格子パターンGPを含むことができる。これにより、格子パターンGPにおける射出角も異なるため、サブ波長格子11Gから射出される光が観察される観察角度を広げることができる。
(9) Since the unevenness due to the surface 42F of the fourth layer 42 is imparted to the sub-wavelength grating 11G, the plurality of grating patterns GP include grating patterns GP having different incident angles of light with respect to the grating pattern GP. it can. Thereby, since the emission angle in the grating pattern GP is also different, the observation angle at which the light emitted from the sub-wavelength grating 11G is observed can be widened.
[第5実施形態]
図18から図24を参照して、光学素子の第5実施形態を説明する。本発明の第5実施形態の光学素子は、第1実施形態の光学素子と比べて、レリーフ面を備えるレリーフ層を備える点が異なっている。そのため以下では、こうした相違点を詳しく説明する一方で、第5実施形態の光学素子において第1実施形態の光学素子10と対応する構成には、第1実施形態の光学素子10と同じ符号を付すことによって、その詳しい説明を省略する。また以下では、第5実施形態の光学素子における2つの例を順に説明する。 [Fifth Embodiment]
A fifth embodiment of the optical element will be described with reference to FIGS. The optical element of the fifth embodiment of the present invention is different from the optical element of the first embodiment in that it includes a relief layer having a relief surface. Therefore, in the following, such differences will be described in detail. On the other hand, in the optical element of the fifth embodiment, the components corresponding to those of theoptical element 10 of the first embodiment are denoted by the same reference numerals as those of the optical element 10 of the first embodiment. Therefore, the detailed description is omitted. Hereinafter, two examples of the optical element of the fifth embodiment will be described in order.
図18から図24を参照して、光学素子の第5実施形態を説明する。本発明の第5実施形態の光学素子は、第1実施形態の光学素子と比べて、レリーフ面を備えるレリーフ層を備える点が異なっている。そのため以下では、こうした相違点を詳しく説明する一方で、第5実施形態の光学素子において第1実施形態の光学素子10と対応する構成には、第1実施形態の光学素子10と同じ符号を付すことによって、その詳しい説明を省略する。また以下では、第5実施形態の光学素子における2つの例を順に説明する。 [Fifth Embodiment]
A fifth embodiment of the optical element will be described with reference to FIGS. The optical element of the fifth embodiment of the present invention is different from the optical element of the first embodiment in that it includes a relief layer having a relief surface. Therefore, in the following, such differences will be described in detail. On the other hand, in the optical element of the fifth embodiment, the components corresponding to those of the
[第1実例]
[光学素子の構成]
図18を参照して、第1実例の光学素子における構成を説明する。 [First example]
[Configuration of optical element]
With reference to FIG. 18, the structure in the optical element of a 1st example is demonstrated.
[光学素子の構成]
図18を参照して、第1実例の光学素子における構成を説明する。 [First example]
[Configuration of optical element]
With reference to FIG. 18, the structure in the optical element of a 1st example is demonstrated.
図18が示すように、光学素子50は、上述した第1実施形態の光学素子10と同様、第1層11と、第1層11に接する第2層12と、第2層12に接する第3層13とを備えている。第1層11は、第2層12に接する裏面11Rの少なくとも一部にサブ波長格子11Gを含む樹脂製の層である。裏面11Rは、第1面の実例である。図18では、図示の便宜上、裏面11Rの全体にサブ波長格子11Gが位置するような断面形状が示されているが、本実施形態の光学素子50では、裏面11Rの一部にサブ波長格子11Gが形成されている。
As shown in FIG. 18, the optical element 50 includes the first layer 11, the second layer 12 in contact with the first layer 11, and the second layer 12 in contact with the second layer 12, as in the optical element 10 in the first embodiment described above. And three layers 13. The first layer 11 is a resin layer including the sub-wavelength grating 11G on at least a part of the back surface 11R in contact with the second layer 12. The back surface 11R is an example of the first surface. In FIG. 18, for convenience of illustration, a cross-sectional shape in which the sub-wavelength grating 11G is located on the entire back surface 11R is shown. Is formed.
第2層12において、第1層11の裏面11Rに接する表面12Fには、サブ波長格子11Gに追従した凹凸状がある。表面12Fは、第2面の実例である。第2層12は、第1の屈折率よりも高い第2の屈折率を有した誘電体製の層である。第3層13は、第2の屈折率よりも低い第3の屈折率を有した樹脂製の層である。
In the second layer 12, the surface 12F in contact with the back surface 11R of the first layer 11 has an uneven shape following the sub-wavelength grating 11G. The surface 12F is an example of the second surface. The second layer 12 is a dielectric layer having a second refractive index higher than the first refractive index. The third layer 13 is a resin layer having a third refractive index lower than the second refractive index.
光学素子50は、裏面11Rおよび表面12Fとは異なるレリーフ面13Reを含むレリーフ層を含んでいる。レリーフ面13Reは、複数の反射面を含み、互いに隣り合う反射面間のピッチは、サブ波長格子11Gのピッチよりも大きい。本実施形態では、レリーフ層は、上述した第3層13である。より詳しくは、第3層13のなかで、第2層12に接する面とは反対側の面である裏面13Rが、レリーフ面13Reである。
The optical element 50 includes a relief layer including a relief surface 13Re different from the back surface 11R and the front surface 12F. The relief surface 13Re includes a plurality of reflecting surfaces, and the pitch between the reflecting surfaces adjacent to each other is larger than the pitch of the sub-wavelength grating 11G. In the present embodiment, the relief layer is the third layer 13 described above. More specifically, the back surface 13R which is the surface opposite to the surface in contact with the second layer 12 in the third layer 13 is the relief surface 13Re.
なお、図18では、図示の便宜上、表面13Fの全体にレリーフ面13Reが位置しているが、本実施形態の光学素子50では、表面13Fの一部にレリーフ面13Reが位置している。また、レリーフ面13Reは、光学素子50の厚さ方向から見て、表面13Fのなかでサブ波長格子11Gと重なる位置に形成されてもよい。
In FIG. 18, for convenience of illustration, the relief surface 13Re is located on the entire surface 13F, but in the optical element 50 of the present embodiment, the relief surface 13Re is located on a part of the surface 13F. Further, the relief surface 13Re may be formed at a position overlapping the sub-wavelength grating 11G in the surface 13F when viewed from the thickness direction of the optical element 50.
サブ波長格子11Gは、正反射方向を含む反射方向に、サブ波長格子11Gの格子周期に応じた色を呈する有色像を表示する。レリーフ面13Reは、正反射方向とは異なる方向を含む反射方向にモノクロームの反射光による反射像を表示する。モノクロームの反射光の色の実例は、白色、銀白色、銀色、セミホワイト、パールホワイト、シルキーホワイト、ミルキーホワイト、灰色、セピアである。光学素子50は、有色像および反射像を表示しない第1状態、有色像を主として表示する第2状態、反射像を主として表示する第3状態、および、有色像および反射像を主として表示する第4状態を有する。光学素子50が広がる平面と、観察者の視線を含む平面とが形成する角度が観察角度である。光学素子50は、観察角度に応じて各状態のいずれかを有する。すなわち、光学素子50は、観察角度に応じて第1状態、第2状態、および、第3状態のいずれかにより観察される。また、サブ波長格子11Gは、観察角度における正反射方向を含む所定の範囲に、サブ波長格子の格子周期に応じた色を呈する有色像を表示する。レリーフ面13Reは、観察角度における正反射方向とは異なる方向を含む所定の範囲に、モノクロームの反射光による反射像を表示する。
The sub-wavelength grating 11G displays a colored image exhibiting a color corresponding to the grating period of the sub-wavelength grating 11G in the reflection direction including the regular reflection direction. The relief surface 13Re displays a reflected image by monochrome reflected light in a reflection direction including a direction different from the regular reflection direction. Examples of monochrome reflected light colors are white, silvery white, silvery, semi-white, pearl white, silky white, milky white, gray, sepia. The optical element 50 includes a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, a third state in which the reflected image is mainly displayed, and a fourth state in which the colored image and the reflected image are mainly displayed. Have a state. The angle formed by the plane on which the optical element 50 spreads and the plane including the observer's line of sight is the observation angle. The optical element 50 has one of the states depending on the observation angle. That is, the optical element 50 is observed in any one of the first state, the second state, and the third state according to the observation angle. The sub-wavelength grating 11G displays a colored image exhibiting a color corresponding to the grating period of the sub-wavelength grating in a predetermined range including the regular reflection direction at the observation angle. The relief surface 13Re displays a reflected image of monochrome reflected light in a predetermined range including a direction different from the regular reflection direction at the observation angle.
光学素子50は、さらに第4層51を備えている。第4層51は、反射層であってもよいし、屈折層であってもよい。第4層51が屈折層である場合、第4層51の屈折率は、第3層13の屈折率と異なっている。第4層51の屈折率が、第3層13の屈折率と異なることによって、第4層51は、レリーフ面13Reにおける反射率を高めることができる。互いに隣接する2つの層において、界面における反射率は、2つの層の間における屈折率の差によって決まる。そのため、第4層51の屈折率が第3層13の屈折率とは異なることによって、第4層51が反射層である場合と同様の効果が得られる。
The optical element 50 further includes a fourth layer 51. The fourth layer 51 may be a reflective layer or a refractive layer. When the fourth layer 51 is a refractive layer, the refractive index of the fourth layer 51 is different from the refractive index of the third layer 13. Since the refractive index of the fourth layer 51 is different from the refractive index of the third layer 13, the fourth layer 51 can increase the reflectance at the relief surface 13Re. In two layers adjacent to each other, the reflectivity at the interface is determined by the difference in refractive index between the two layers. Therefore, when the refractive index of the fourth layer 51 is different from the refractive index of the third layer 13, the same effect as when the fourth layer 51 is a reflective layer can be obtained.
上述したように、光学素子50は、第2層12に対して第3層13とは反対側から観察される。そのため、第4層51は、光透過性を有してもよいし、光透過性を有しなくてもよい。第4層51は、単一の層から構成されてもよいし、複数の層から構成されてもよい。第4層51が屈折層であり、かつ、複数の層から構成される場合には、第4層51は、相対的に屈折率の低い層と、相対的に屈折率の高い層とを備えることができる。
As described above, the optical element 50 is observed from the side opposite to the third layer 13 with respect to the second layer 12. Therefore, the fourth layer 51 may have light transmittance or may not have light transmittance. The fourth layer 51 may be composed of a single layer or a plurality of layers. When the fourth layer 51 is a refractive layer and includes a plurality of layers, the fourth layer 51 includes a layer having a relatively low refractive index and a layer having a relatively high refractive index. be able to.
レリーフ面13Reは、上述したように複数の反射面を含んでいる。レリーフ面13Reは、回折、散乱および反射の少なくとも一方によって、モノクローム光によって形成される反射像を表示する。レリーフ面13Reは、上述したように複数の反射面を含み、複数の反射面は、レリーフ面13Re内において所定の規則で並んでもよいし、不規則に並んでもよい。レリーフ面13Reでは、各反射面の向きや角度によって、レリーフ面13Reが射出する光の射出方向を制御することができる。
The relief surface 13Re includes a plurality of reflecting surfaces as described above. The relief surface 13Re displays a reflected image formed by monochrome light by at least one of diffraction, scattering, and reflection. As described above, the relief surface 13Re includes a plurality of reflection surfaces, and the plurality of reflection surfaces may be arranged in a predetermined rule or irregularly in the relief surface 13Re. In the relief surface 13Re, the emission direction of light emitted from the relief surface 13Re can be controlled by the direction and angle of each reflection surface.
反射面の向きは、第1層11が広がる平面に投影された反射面の法線ベクトルの向きとできる。また、反射面の角度は、第1層11が広がる平面の法線ベクトルと反射面の法線ベクトルのなす角とできる。この反射面の向きは、サブ波長格子11Gの方位と等しいか、直交するものとできる。また、サブ波長格子11Gの方位が複数ある場合その方位の平均を、そのサブ波長格子11Gの方位とできる。平均は、複数あるサブ波長格子が形成された領域のそれぞれの面積で重み付けした加重平均とできる。これにより、観察者OBがカード100を基準平面Ph0に対して前方に傾けた場合に、カード100は、カード100の位置に応じて、第1像P1および第2像P2を表示する。言い換えれば、観察者OBが、観察空間において、カード100のなかで観察者OBが把持した部分の位置をほぼ固定した状態で、カード100の表面100Fを観察者OBに近づけた場合に、カード100の位置に応じて、カード100は、第1像P1および第2像P2を表示する(図40参照)。
The direction of the reflecting surface can be the direction of the normal vector of the reflecting surface projected on the plane in which the first layer 11 spreads. The angle of the reflection surface can be an angle formed by the normal vector of the plane in which the first layer 11 extends and the normal vector of the reflection surface. The direction of the reflecting surface can be the same as or perpendicular to the orientation of the sub-wavelength grating 11G. Further, when there are a plurality of orientations of the sub-wavelength grating 11G, the average of the orientations can be set as the orientation of the sub-wavelength grating 11G. The average can be a weighted average weighted by the area of each region where a plurality of sub-wavelength gratings are formed. Accordingly, when the observer OB tilts the card 100 forward with respect to the reference plane Ph0, the card 100 displays the first image P1 and the second image P2 according to the position of the card 100. In other words, when the observer OB brings the surface 100F of the card 100 close to the observer OB in a state where the position of the portion held by the observer OB in the card 100 is substantially fixed in the observation space, the card 100 Depending on the position, the card 100 displays the first image P1 and the second image P2 (see FIG. 40).
サブ波長格子11Gは、上述した正反射方向を含む射出方向の範囲に光を射出する。サブ波長格子11Gが射出する光のなかで、正反射方向に射出される光の強度が最も大きい。これに対して、レリーフ面13Reは、正反射方向とは異なる方向を含む射出方向の範囲に光を射出する。レリーフ面13Reが射出する光のなかで、正反射方向とは異なる方向に射出される光の強度が最も大きい。言い換えれば、レリーフ面13Reでは、レリーフ面13Reが射出する光のなかで、正反射方向とは異なる方向に射出される光の強度が最も大きくなるように、反射面の向きや角度が設定されている。
The sub-wavelength grating 11G emits light in the range of the emission direction including the above-described regular reflection direction. Of the light emitted from the sub-wavelength grating 11G, the intensity of the light emitted in the regular reflection direction is the highest. On the other hand, the relief surface 13Re emits light in an emission direction range including a direction different from the regular reflection direction. Of the light emitted from the relief surface 13Re, the intensity of the light emitted in a direction different from the regular reflection direction is the highest. In other words, on the relief surface 13Re, the direction and angle of the reflection surface are set so that the intensity of the light emitted in the direction different from the regular reflection direction is the largest among the light emitted from the relief surface 13Re. Yes.
レリーフ面13Reにおいて、反射面の周期は400nmよりも大きく1000nm以下であってもよいし、1000nmよりも大きくてもよい。レリーフ面13Reが回折光を射出することを抑える上では、反射面の周期は1000nmよりも大きいことが好ましい。レリーフ面13Reにおいて、反射面が延びる方向と直交する断面における形状は、鋸歯状でもよい。
In the relief surface 13Re, the period of the reflection surface may be greater than 400 nm and 1000 nm or less, or may be greater than 1000 nm. In order to prevent the relief surface 13Re from emitting diffracted light, it is preferable that the period of the reflection surface is larger than 1000 nm. In the relief surface 13Re, the shape in a cross section orthogonal to the direction in which the reflecting surface extends may be a sawtooth shape.
サブ波長格子11Gが表示する有色像とは、可視光の波長に含まれる特定の波長の光によって形成される像である。有色像には、実例として、赤色の像、緑色の像、および、青色の像などの有彩色の像が含まれる。サブ波長格子11Gが赤色の像を表示する場合、サブ波長格子11Gが射出する光には、実例として、620nm以上750nm以下の波長の光が含まれる。サブ波長格子11Gが緑色の像を表示する場合、サブ波長格子11Gが射出する光には、実例として、495nm以上570nm以下の波長の光が含まれる。サブ波長格子11Gが青色の像を表示する場合、サブ波長格子11Gが射出する光には、実例として、450nm以上495nm以下の波長の光が含まれる。なお、サブ波長格子11Gが有色像を表示するとは、サブ波長格子11Gが、有彩色を呈することと同義である。
The colored image displayed by the sub-wavelength grating 11G is an image formed by light having a specific wavelength included in the wavelength of visible light. Illustrative examples of chromatic images include chromatic images such as red, green, and blue images. When the sub-wavelength grating 11G displays a red image, the light emitted from the sub-wavelength grating 11G includes, for example, light having a wavelength of 620 nm or more and 750 nm or less. When the sub-wavelength grating 11G displays a green image, the light emitted from the sub-wavelength grating 11G includes light having a wavelength of 495 nm or more and 570 nm or less as an example. When the sub-wavelength grating 11G displays a blue image, the light emitted from the sub-wavelength grating 11G includes light having a wavelength of 450 nm or more and 495 nm or less as an example. Note that the sub-wavelength grating 11G displaying a colored image is synonymous with the sub-wavelength grating 11G exhibiting a chromatic color.
レリーフ面13Reが表示する反射像とは、レリーフ面13Reでの反射、散乱、回折によって生じるモノクローム光によって形成される像である。言い換えれば、レリーフ面13Reが表示する反射像はモノクロームの像であり、色相を有しない像である。レリーフ面13Reは、各位置から射出されるモノクローム光の強度が互いに異なるように構成されてもよい。これにより、レリーフ面13Reは、光の強度の差によって、言い換えれば明度の差によって、画像を表示することができる。なお、レリーフ面13Reがモノクロームな反射像を表示するとは、レリーフ面13Reが、モノクロームを呈することと同義である。
The reflection image displayed on the relief surface 13Re is an image formed by monochrome light generated by reflection, scattering, and diffraction on the relief surface 13Re. In other words, the reflected image displayed by the relief surface 13Re is a monochrome image and an image having no hue. The relief surface 13Re may be configured such that the intensity of the monochrome light emitted from each position is different from each other. Thereby, the relief surface 13Re can display an image by a difference in light intensity, in other words, by a difference in brightness. In addition, that the relief surface 13Re displays a monochrome reflected image is synonymous with the relief surface 13Re exhibiting monochrome.
[光学素子の作用]
図19から図23を参照して、光学素子50の作用を説明する。
図19が示すように、光源LSが放出した入射光ILが光学素子50に入射する角度が入射角αであり、光学素子50が射出する射出光ELが射出される角度が射出角βである。観察者OBの視線方向を含む平面と、光学素子50が広がる平面とが形成する角度が、観察角度θOBである。上述した正反射方向とは、入射角αと同一の大きさを有した射出角βで、射出光ELが射出される方向である。光学素子50において、サブ波長格子11Gは、正反射方向を含む反射方向に有色像を表示する一方で、レリーフ面13Reは、正反射方向とは異なる方向を含む反射方向にモノクローム光による反射像を表示する。光学素子50は、観察角度θOBに応じて、以下の4つの状態のいずれかを有する。 [Operation of optical element]
The operation of theoptical element 50 will be described with reference to FIGS.
As shown in FIG. 19, the angle at which the incident light IL emitted from the light source LS enters theoptical element 50 is the incident angle α, and the angle at which the emitted light EL emitted from the optical element 50 is emitted is the emission angle β. . An angle formed by a plane including the viewing direction of the observer OB and a plane on which the optical element 50 spreads is an observation angle θOB. The above-described regular reflection direction is the direction in which the emitted light EL is emitted at an emission angle β having the same magnitude as the incident angle α. In the optical element 50, the sub-wavelength grating 11G displays a colored image in the reflection direction including the regular reflection direction, while the relief surface 13Re displays the reflected image by the monochrome light in the reflection direction including a direction different from the regular reflection direction. indicate. The optical element 50 has one of the following four states according to the observation angle θOB.
図19から図23を参照して、光学素子50の作用を説明する。
図19が示すように、光源LSが放出した入射光ILが光学素子50に入射する角度が入射角αであり、光学素子50が射出する射出光ELが射出される角度が射出角βである。観察者OBの視線方向を含む平面と、光学素子50が広がる平面とが形成する角度が、観察角度θOBである。上述した正反射方向とは、入射角αと同一の大きさを有した射出角βで、射出光ELが射出される方向である。光学素子50において、サブ波長格子11Gは、正反射方向を含む反射方向に有色像を表示する一方で、レリーフ面13Reは、正反射方向とは異なる方向を含む反射方向にモノクローム光による反射像を表示する。光学素子50は、観察角度θOBに応じて、以下の4つの状態のいずれかを有する。 [Operation of optical element]
The operation of the
As shown in FIG. 19, the angle at which the incident light IL emitted from the light source LS enters the
なお、本実施形態では、サブ波長格子11Gが表示する有色像が月形状を有し、レリーフ面13Reが表示する反射像が星形状を有する実例を説明する。ただし、サブ波長格子11Gが表示する有色像の形状、および、レリーフ面13Reが表示する反射像の形状は、任意の形状とすることが可能である。また、サブ波長格子11Gが表示する像が第1像であり、レリーフ面13Reが表示する像が第2像である。
In the present embodiment, an example will be described in which the colored image displayed by the sub-wavelength grating 11G has a moon shape, and the reflected image displayed by the relief surface 13Re has a star shape. However, the shape of the colored image displayed by the sub-wavelength grating 11G and the shape of the reflected image displayed by the relief surface 13Re can be any shape. The image displayed by the sub-wavelength grating 11G is the first image, and the image displayed by the relief surface 13Re is the second image.
図20は、光学素子50の第1状態を示している。
図20が示すように、光学素子50の第1状態では、光学素子50において、第1像P1および第2像P2の両方が消失する。第1状態において、第1像P1を形成するための光における輝度、および、第2像P2を形成するための光における輝度が、観察者OBによって第1像P1および第2像P2が識別されない程度に低い。言い換えれば、観察者OBが光学素子50を観察する観察角度θOBでは、サブ波長格子11Gが反射した光、および、レリーフ面13Reが反射した光の輝度は、いずれも光学素子50が貼られた媒体の反射光と比べて低いため、観察者OBによって第1像P1および第2像P2が識別されない。 FIG. 20 shows a first state of theoptical element 50.
As shown in FIG. 20, in the first state of theoptical element 50, both the first image P1 and the second image P2 disappear in the optical element 50. In the first state, the first image P1 and the second image P2 are not identified by the observer OB because of the luminance in the light for forming the first image P1 and the luminance in the light for forming the second image P2. To a low degree. In other words, at the observation angle θOB where the observer OB observes the optical element 50, the brightness of the light reflected by the sub-wavelength grating 11G and the light reflected by the relief surface 13Re are both media on which the optical element 50 is affixed. Therefore, the first image P1 and the second image P2 are not identified by the observer OB.
図20が示すように、光学素子50の第1状態では、光学素子50において、第1像P1および第2像P2の両方が消失する。第1状態において、第1像P1を形成するための光における輝度、および、第2像P2を形成するための光における輝度が、観察者OBによって第1像P1および第2像P2が識別されない程度に低い。言い換えれば、観察者OBが光学素子50を観察する観察角度θOBでは、サブ波長格子11Gが反射した光、および、レリーフ面13Reが反射した光の輝度は、いずれも光学素子50が貼られた媒体の反射光と比べて低いため、観察者OBによって第1像P1および第2像P2が識別されない。 FIG. 20 shows a first state of the
As shown in FIG. 20, in the first state of the
図21は、光学素子50の第2状態を示している。
図21が示すように、光学素子50の第2状態では、光学素子50において、第1像P1が出現し、第2像P2は消失する。第1像P1が出現するとは、第1像P1における光の輝度が、第2像P2における光の輝度よりも高い状態で、光学素子50が、第1像P1を表示することである。そのため、第2状態には、第1像P1が識別される一方で、第2像P2は識別されない状態が含まれる。また、第2状態には、光学素子50において第1像P1および第2像P2が出現し、かつ、第1像P1における光の輝度が、第2像P2における光の輝度よりも高い状態が含まれる。 FIG. 21 shows a second state of theoptical element 50.
As shown in FIG. 21, in the second state of theoptical element 50, the first image P1 appears and the second image P2 disappears in the optical element 50. The appearance of the first image P1 means that the optical element 50 displays the first image P1 in a state where the luminance of light in the first image P1 is higher than the luminance of light in the second image P2. Therefore, the second state includes a state in which the first image P1 is identified while the second image P2 is not identified. In the second state, the first image P1 and the second image P2 appear in the optical element 50, and the luminance of light in the first image P1 is higher than the luminance of light in the second image P2. included.
図21が示すように、光学素子50の第2状態では、光学素子50において、第1像P1が出現し、第2像P2は消失する。第1像P1が出現するとは、第1像P1における光の輝度が、第2像P2における光の輝度よりも高い状態で、光学素子50が、第1像P1を表示することである。そのため、第2状態には、第1像P1が識別される一方で、第2像P2は識別されない状態が含まれる。また、第2状態には、光学素子50において第1像P1および第2像P2が出現し、かつ、第1像P1における光の輝度が、第2像P2における光の輝度よりも高い状態が含まれる。 FIG. 21 shows a second state of the
As shown in FIG. 21, in the second state of the
言い換えれば、観察者OBが光学素子50を観察する観察角度θOBでは、サブ波長格子11Gが反射した光を観察者が知覚しやすい一方で、レリーフ面13Reが反射した光を観察者が知覚しにくい。
In other words, at the observation angle θOB where the observer OB observes the optical element 50, the observer can easily perceive the light reflected by the sub-wavelength grating 11G, while the observer does not easily perceive the light reflected by the relief surface 13Re. .
図22は、光学素子50の第3状態を示している。
図22が示すように、光学素子50の第3状態では、光学素子50において、第2像P2が出現する。第2像P2が出現するとは、第2像P2における光の輝度が、第1像P1における光の輝度よりも高く、光学素子50が、少なくとも第2像P2を表示することである。そのため、第3状態には、第2像P2が識別される一方で、第1像P1が識別されない状態が含まれる。また、第3状態には、光学素子50が第2像P2および第1像P1を表示し、かつ、第2像P2における光の輝度が、第1像P1における光の輝度よりも高い状態が含まれる。 FIG. 22 shows a third state of theoptical element 50.
As shown in FIG. 22, in the third state of theoptical element 50, the second image P <b> 2 appears in the optical element 50. The appearance of the second image P2 means that the luminance of light in the second image P2 is higher than the luminance of light in the first image P1, and the optical element 50 displays at least the second image P2. Therefore, the third state includes a state in which the second image P2 is identified while the first image P1 is not identified. In the third state, the optical element 50 displays the second image P2 and the first image P1, and the light intensity in the second image P2 is higher than the light intensity in the first image P1. included.
図22が示すように、光学素子50の第3状態では、光学素子50において、第2像P2が出現する。第2像P2が出現するとは、第2像P2における光の輝度が、第1像P1における光の輝度よりも高く、光学素子50が、少なくとも第2像P2を表示することである。そのため、第3状態には、第2像P2が識別される一方で、第1像P1が識別されない状態が含まれる。また、第3状態には、光学素子50が第2像P2および第1像P1を表示し、かつ、第2像P2における光の輝度が、第1像P1における光の輝度よりも高い状態が含まれる。 FIG. 22 shows a third state of the
As shown in FIG. 22, in the third state of the
言い換えれば、観察者OBが光学素子50を観察する観察角度θOBでは、レリーフ面13Reが反射した光の輝度は観察者が像を識別できる程度であり、サブ波長格子11Gが反射した光の輝度は観察者が識別できる程度ではない。
In other words, at the observation angle θOB at which the observer OB observes the optical element 50, the brightness of the light reflected by the relief surface 13Re is such that the observer can identify the image, and the brightness of the light reflected by the sub-wavelength grating 11G is Not enough for an observer to identify.
図23は、光学素子50の第4状態を示している。
図23が示すように、光学素子50の第4状態では、光学素子50において、第1像P1および第2像P2の両方が出現する。第1像P1および第2像P2の両方が出現するとは、光学素子50が第1像P1および第2像P2の両方が観察者に識別される。この状態では、第1像P1における光の輝度が、第2像P2における光の輝度とほぼ等しくてもよい。言い換えれば、観察者OBが光学素子50を観察する観察角度θOBでは、サブ波長格子11Gが反射した光と、レリーフ面13Reが反射した光の強度は、観察者OBが識別できる程度である。なお、光学素子50は第1状態から第3状態を有していればよい。光学素子50において、第4状態は必須ではない。 FIG. 23 shows a fourth state of theoptical element 50.
As shown in FIG. 23, in the fourth state of theoptical element 50, both the first image P1 and the second image P2 appear in the optical element 50. When both the first image P1 and the second image P2 appear, the optical element 50 identifies both the first image P1 and the second image P2 to the observer. In this state, the luminance of light in the first image P1 may be substantially equal to the luminance of light in the second image P2. In other words, at the observation angle θOB where the observer OB observes the optical element 50, the intensity of the light reflected by the sub-wavelength grating 11G and the light reflected by the relief surface 13Re is such that the observer OB can distinguish. In addition, the optical element 50 should just have a 3rd state from a 1st state. In the optical element 50, the fourth state is not essential.
図23が示すように、光学素子50の第4状態では、光学素子50において、第1像P1および第2像P2の両方が出現する。第1像P1および第2像P2の両方が出現するとは、光学素子50が第1像P1および第2像P2の両方が観察者に識別される。この状態では、第1像P1における光の輝度が、第2像P2における光の輝度とほぼ等しくてもよい。言い換えれば、観察者OBが光学素子50を観察する観察角度θOBでは、サブ波長格子11Gが反射した光と、レリーフ面13Reが反射した光の強度は、観察者OBが識別できる程度である。なお、光学素子50は第1状態から第3状態を有していればよい。光学素子50において、第4状態は必須ではない。 FIG. 23 shows a fourth state of the
As shown in FIG. 23, in the fourth state of the
このように、光学素子50は、モノクロームの反射光によって形成される反射像、すなわちモノクローム像と、ある波長範囲を有した光によって形成される有色像、すなわち有彩色の像とを表示する。ここで、モノクローム像と有彩色の像との判別は、モノクロームの第1像とモノクロームの第2像とを判別したり、有彩色の第1像と有彩色の第2像とを判別したりする場合に比べて、2つの像の判別に個人差が生じにくい。それゆえに、光学素子50では、2つの有彩色の像、または、2つのモノクロームの像に基づいて、光学素子50の真正を検証させる場合と比べて、真正の検証に個人差が生じにくく、また、真正を検証する基準が、簡単に記述できる。
As described above, the optical element 50 displays a reflected image formed by monochrome reflected light, that is, a monochrome image, and a colored image formed by light having a certain wavelength range, that is, a chromatic image. Here, the discrimination between the monochrome image and the chromatic color image is performed by discriminating between the first monochrome image and the second monochrome image, or discriminating between the first chromatic color image and the second chromatic color image. Compared with the case where it does, an individual difference does not arise easily in discrimination | determination of two images. Therefore, in the optical element 50, compared with the case where the authenticity of the optical element 50 is verified based on two chromatic images or two monochrome images, individual differences are less likely to occur. Standards for verifying authenticity can be easily described.
また、光学素子50は、第1像P1が主として表示される第2状態と、第2像P2が主として表示される第3状態と、第1像P1と第2像P2との両方が表示されない第1状態とを含む。ここで、第2状態あるいは第3状態と第1状態とは、互いに対照的な状態であるため、第2状態あるいは第3状態と第1状態との判別に個人差が生じにくい。それゆえに、真正の検証に個人差が生じにくく、また、真正を検証する基準が、簡単に記述できる。
The optical element 50 does not display both the second state in which the first image P1 is mainly displayed, the third state in which the second image P2 is mainly displayed, and the first image P1 and the second image P2. Including the first state. Here, since the second state or the third state and the first state are in contrast with each other, individual differences are unlikely to occur in the discrimination between the second state or the third state and the first state. Therefore, individual differences are less likely to occur in authenticity verification, and the criteria for verifying authenticity can be easily described.
[第2実例]
図24を参照して、光学素子50の第2実例を説明する。
図24が示すように、第2実例の光学素子50は、第1実例の光学素子50と同様、第1層11、第2層12、および、第3層13を備えている。一方で、第2実例の光学素子50では、第2層12がレリーフ層である。第2層12において、レリーフ面12Reは、第2層12の表面12Fとは反対側の面、すなわち裏面12Rにあってもよい。なお、図24では、裏面12Rの全体にレリーフ面12Reが位置しているが、レリーフ面12Reは、裏面12Rの全体に位置してもよいし、裏面12Rの一部のみであってもよい。 [Second example]
A second example of theoptical element 50 will be described with reference to FIG.
As shown in FIG. 24, theoptical element 50 in the second example includes the first layer 11, the second layer 12, and the third layer 13, as in the optical element 50 in the first example. On the other hand, in the optical element 50 of the second example, the second layer 12 is a relief layer. In the second layer 12, the relief surface 12Re may be on the surface opposite to the surface 12F of the second layer 12, that is, on the back surface 12R. In FIG. 24, the relief surface 12Re is positioned on the entire back surface 12R, but the relief surface 12Re may be positioned on the entire back surface 12R or only a part of the back surface 12R.
図24を参照して、光学素子50の第2実例を説明する。
図24が示すように、第2実例の光学素子50は、第1実例の光学素子50と同様、第1層11、第2層12、および、第3層13を備えている。一方で、第2実例の光学素子50では、第2層12がレリーフ層である。第2層12において、レリーフ面12Reは、第2層12の表面12Fとは反対側の面、すなわち裏面12Rにあってもよい。なお、図24では、裏面12Rの全体にレリーフ面12Reが位置しているが、レリーフ面12Reは、裏面12Rの全体に位置してもよいし、裏面12Rの一部のみであってもよい。 [Second example]
A second example of the
As shown in FIG. 24, the
第2実例の光学素子50では、第1層11の屈折率と第2層12の屈折率との差によって、サブ波長格子11Gにより反射された光による有色像を表示することができる。また、第2実例の光学素子50では、第2層12の屈折率と第3層13の屈折率との差によって、レリーフ面12Reにより反射された光による反射像を表示することができる。
In the optical element 50 of the second example, a colored image by the light reflected by the sub-wavelength grating 11G can be displayed by the difference between the refractive index of the first layer 11 and the refractive index of the second layer 12. Further, in the optical element 50 of the second example, a reflection image by the light reflected by the relief surface 12Re can be displayed by the difference between the refractive index of the second layer 12 and the refractive index of the third layer 13.
なお、第2実例の光学素子50において、第3層13における第2層12に接する面とは反対側の面は平坦面であってもよいし、第2層12のレリーフ面12Reにおける凹凸に追従する形状を有してもよい。
In the optical element 50 of the second example, the surface of the third layer 13 opposite to the surface in contact with the second layer 12 may be a flat surface, or uneven in the relief surface 12Re of the second layer 12. You may have the shape to follow.
以上説明したように、光学素子の第5実施形態によれば、以下に記載の効果を得ることができる。
(10)光学素子50が有色像と、モノクローム光による反射像とを表示するため、2つの像の判別に個人差が生じにくい。それゆえに、光学素子50では、真正の検証に個人差が生じにくく、また、真正を検証する基準が、簡単に記述できる。 As described above, according to the fifth embodiment of the optical element, the following effects can be obtained.
(10) Since theoptical element 50 displays a colored image and a reflected image by monochrome light, individual differences are unlikely to occur between the two images. Therefore, in the optical element 50, individual differences are less likely to occur in authenticity verification, and the criteria for verifying authenticity can be easily described.
(10)光学素子50が有色像と、モノクローム光による反射像とを表示するため、2つの像の判別に個人差が生じにくい。それゆえに、光学素子50では、真正の検証に個人差が生じにくく、また、真正を検証する基準が、簡単に記述できる。 As described above, according to the fifth embodiment of the optical element, the following effects can be obtained.
(10) Since the
(11)第2層12がサブ波長格子11Gとレリーフ面12Reとを含むため、第1層11の屈折率と第2層12との屈折率との差によりサブ波長格子11Gでの反射率を高め、かつ、第2層12の屈折率と第3層13の屈折率との差によりレリーフ面12Reでの反射率を高めることができる。
(11) Since the second layer 12 includes the sub-wavelength grating 11G and the relief surface 12Re, the reflectance at the sub-wavelength grating 11G is determined by the difference between the refractive index of the first layer 11 and the refractive index of the second layer 12. The reflectance at the relief surface 12Re can be increased by the difference between the refractive index of the second layer 12 and the refractive index of the third layer 13.
[第5実施形態の変形]
なお、上述した第5実施形態は、以下のように適宜変更して実施することができる。
[サブ波長格子]
・第1実施形態の光学素子10において、サブ波長格子11Gは、第1領域11S1と第2領域11S2とを含むが、光学素子50が備えるサブ波長格子11Gは、1つの領域のみから構成されてもよい。 [Modification of Fifth Embodiment]
The fifth embodiment described above can be implemented with appropriate modifications as follows.
[Subwavelength grating]
In theoptical element 10 of the first embodiment, the sub-wavelength grating 11G includes the first region 11S1 and the second region 11S2, but the sub-wavelength grating 11G included in the optical element 50 is configured by only one region. Also good.
なお、上述した第5実施形態は、以下のように適宜変更して実施することができる。
[サブ波長格子]
・第1実施形態の光学素子10において、サブ波長格子11Gは、第1領域11S1と第2領域11S2とを含むが、光学素子50が備えるサブ波長格子11Gは、1つの領域のみから構成されてもよい。 [Modification of Fifth Embodiment]
The fifth embodiment described above can be implemented with appropriate modifications as follows.
[Subwavelength grating]
In the
[レリーフ層]
・光学素子50において、第1層11がレリーフ層であってもよい。すなわち、第1層11のなかで、サブ波長格子11Gを含む面とは反対側の面が、レリーフ面を含んでもよい。こうした場合にも、上述した(10)に準じた効果を得ることができる。 [Relief layer]
In theoptical element 50, the first layer 11 may be a relief layer. That is, in the first layer 11, the surface opposite to the surface including the sub-wavelength grating 11G may include a relief surface. Even in such a case, the effect according to the above (10) can be obtained.
・光学素子50において、第1層11がレリーフ層であってもよい。すなわち、第1層11のなかで、サブ波長格子11Gを含む面とは反対側の面が、レリーフ面を含んでもよい。こうした場合にも、上述した(10)に準じた効果を得ることができる。 [Relief layer]
In the
・第2実例の光学素子50において、第3層13のなかでレリーフ面12Reに接する面である表面は、レリーフ面12Reに追従する形状を有している。そのため、第3層13の表面もレリーフ面として機能することができる。
In the optical element 50 of the second example, the surface that is in contact with the relief surface 12Re in the third layer 13 has a shape that follows the relief surface 12Re. Therefore, the surface of the third layer 13 can also function as a relief surface.
[レリーフ面]
・図25が示すように、光学素子50において、第1層11の裏面11Rが、サブ波長格子11Gとレリーフ面11Reとを含んでもよい。この場合には、サブ波長格子11Gとレリーフ面11Reとを1つの原板を用いて同時に形成することが可能であるため、サブ波長格子11Gの位置に対するレリーフ面11Reの位置の精度を高めることができる。 [Relief surface]
As shown in FIG. 25, in theoptical element 50, the back surface 11R of the first layer 11 may include a sub-wavelength grating 11G and a relief surface 11Re. In this case, since the sub-wavelength grating 11G and the relief surface 11Re can be formed simultaneously using one original plate, the accuracy of the position of the relief surface 11Re with respect to the position of the sub-wavelength grating 11G can be improved. .
・図25が示すように、光学素子50において、第1層11の裏面11Rが、サブ波長格子11Gとレリーフ面11Reとを含んでもよい。この場合には、サブ波長格子11Gとレリーフ面11Reとを1つの原板を用いて同時に形成することが可能であるため、サブ波長格子11Gの位置に対するレリーフ面11Reの位置の精度を高めることができる。 [Relief surface]
As shown in FIG. 25, in the
・図25が示すように、サブ波長格子11Gとレリーフ面11Reとが同一面に位置し、かつ、第1層11の裏面11Rと対向する方向から見て、第1像P1が表示される領域の一部と第2像P2が表示される領域の一部とを重ねることができる。また、第1像P1が表示される領域と第2像P2が表示される領域が重なってもよい。さらに、第1像P1が表示される領域の輪郭の一部または全部と第2像P2が表示される領域の輪郭の一部または全部が重なってもよい。第1像P1と第2像P2の輪郭が重なることで、双方の絵柄の対比が容易となる。この場合には、各領域の一部が重なる領域において、サブ波長格子11Gが位置する画素領域Pxであるサブ画素領域と、レリーフ面11Reが位置するレリーフ画素領域とを以下のように配置することができる。実例として、サブ画素領域とレリーフ画素領域との配置は、市松状、ストライブ状、ハニカム状、および、同心円状などであってよい。
As shown in FIG. 25, the sub-wavelength grating 11G and the relief surface 11Re are located on the same plane, and the region where the first image P1 is displayed when viewed from the direction facing the back surface 11R of the first layer 11 And a part of the area where the second image P2 is displayed can be overlapped. Further, the area where the first image P1 is displayed and the area where the second image P2 is displayed may overlap. Furthermore, a part or all of the outline of the area where the first image P1 is displayed may overlap with a part or all of the outline of the area where the second image P2 is displayed. Since the outlines of the first image P1 and the second image P2 overlap, it is easy to compare the two patterns. In this case, in a region where a part of each region overlaps, the sub-pixel region that is the pixel region Px where the sub-wavelength grating 11G is located and the relief pixel region where the relief surface 11Re is located are arranged as follows. Can do. As an example, the arrangement of the sub-pixel area and the relief pixel area may be a checkered pattern, a stripe pattern, a honeycomb pattern, a concentric pattern, or the like.
なお、第1層11の裏面11Rと対向する方向から見て、第1像P1が表示される領域の一部と第2像P2が表示される領域の一部とを重ねる場合には、以下のようにサブ画素領域とレリーフ画素領域とを配置することも可能である。すなわち、第1像P1を表示するための領域において、第1像P1が表示される領域の一部と第2像P2が表示される領域の一部とが重なる領域から、第1像P1の外縁に向かう方向に沿って、サブ画素領域が占める割合を大きくすることができる。また、第2像P2を表示するための領域において、第1像P1が表示される領域の一部と第2像P2が表示される領域の一部とが重なる領域から、第2像P2の外縁に向かう方向に沿って、レリーフ画素領域が占める割合を大きくすることができる。これにより、第1像P1が表示される領域の一部と第2像P2が表示される領域の一部とが重なる領域において、サブ画素領域およびレリーフ画素領域の各々が占める割合が他の領域に比べて小さいことによる輝度の低下が、第1像P1および第2像P2の各々におけるデザインとして把握される。
When a part of the area where the first image P1 is displayed and a part of the area where the second image P2 is displayed are overlapped when viewed from the direction facing the back surface 11R of the first layer 11, the following is performed. It is also possible to arrange the sub-pixel area and the relief pixel area as described above. That is, in the region for displaying the first image P1, from the region where a part of the region where the first image P1 is displayed and a part of the region where the second image P2 is displayed overlap, The proportion of the sub-pixel region can be increased along the direction toward the outer edge. In addition, in the region for displaying the second image P2, from the region where a part of the region where the first image P1 is displayed and a part of the region where the second image P2 is displayed overlap, The proportion of the relief pixel region can be increased along the direction toward the outer edge. Thereby, in the area where a part of the area where the first image P1 is displayed and a part of the area where the second image P2 is displayed, the ratio of each of the sub pixel area and the relief pixel area is another area. A decrease in luminance due to being smaller than the first is recognized as a design in each of the first image P1 and the second image P2.
・レリーフ面を備える層は、以下に説明する量子化位相差構造を備え、当該構造によりモノクローム光によって形成される反射層を表示してもよい。図26から図28を参照して、レリーフ面を備える層の構造を説明する。
The layer provided with the relief surface may have a quantization phase difference structure described below, and display a reflective layer formed by monochrome light with the structure. With reference to FIGS. 26 to 28, the structure of the layer having the relief surface will be described.
図26は、レリーフ面と対向する平面視における構造を示している。図26が示すように、量子化位相差構造52において、サイズが一定である複数の量子化凸部52aと、サイズが一定である複数の量子化凹部52bとが整列している。図26において、明るい部分が量子化凸部52aであり、暗い部分が量子化凹部52bである。量子化凸部52aと量子化凹部52bとは、一定の間隔で配置されている。量子化凸部52aには、量子化凹部52bまたは量子化凸部52aが一定の間隔で隣接している。また、量子化凹部52bには、量子化凸部52aまたは量子化凹部52bが一定の間隔で隣接している。実例として、量子化位相差構造52の量子化凸部52aと量子化凹部52bは、一つずつ交互に配置されたり、複数の量子化凸部52aと複数の量子化凹部52bとが交互に配置されたりする。
FIG. 26 shows a structure in plan view facing the relief surface. As shown in FIG. 26, in the quantization phase difference structure 52, a plurality of quantization convex portions 52a having a constant size and a plurality of quantization concave portions 52b having a constant size are aligned. In FIG. 26, the bright part is the quantization convex part 52a, and the dark part is the quantization concave part 52b. The quantization convex part 52a and the quantization concave part 52b are arrange | positioned by the fixed space | interval. The quantization convex part 52a is adjacent to the quantization concave part 52b or the quantization convex part 52a at a constant interval. In addition, the quantized concave portions 52b are adjacent to the quantized convex portions 52a or the quantized concave portions 52b at regular intervals. As an actual example, the quantized convex portions 52a and the quantized concave portions 52b of the quantized phase difference structure 52 are alternately arranged one by one, or a plurality of quantized convex portions 52a and a plurality of quantized concave portions 52b are alternately arranged. Or
量子化位相差構造52において、量子化凸部52aおよび量子化凹部52bの配列により、レリーフ面上に粗い周期の空間周波数成分と細かい周期の空間周波数成分とが重ね合わせられる。レリーフ面は、量子化位相差構造52を内包したセルとすることができる。レリーフ面の量子化位相差構造52において、量子化凸部52aが一方向に整列されたリブ状凸部と、要素構造としてサイズが一定の凹部である量子化凹部がリブ状凸部と並行して整列された溝状凹部とが、互いに隣接し、かつ、交互に配置されてよい。
In the quantized phase difference structure 52, the spatial frequency component with a coarse period and the spatial frequency component with a fine period are superimposed on the relief surface by the arrangement of the quantized convex part 52a and the quantized concave part 52b. The relief surface can be a cell containing the quantized phase difference structure 52. In the quantized phase difference structure 52 on the relief surface, a rib-shaped convex portion in which the quantized convex portions 52a are aligned in one direction and a quantized concave portion that is a concave portion having a constant size as an element structure are parallel to the rib-shaped convex portion. The groove-like recesses aligned in a row may be arranged adjacent to each other and alternately.
量子化凸部52aのサイズは、可視波長における中心波長の1/20以上、かつ、中心波長の半分以下とできる。量子化凹部52bのサイズは、可視波長における中心波長の1/20以上、かつ、中心波長の半分以下とできる。具体的には、量子化凸部52aのサイズは、25nm以上250nm以下とできる。量子化凹部52bのサイズは、25nm以上250nm以下とできる。量子化凸部52aは、レリーフ面と対向する平面視において、正方形とできる。
The size of the quantized convex portion 52a can be set to 1/20 or more of the center wavelength at the visible wavelength and to half or less of the center wavelength. The size of the quantization recess 52b can be set to 1/20 or more of the center wavelength at the visible wavelength and to half or less of the center wavelength. Specifically, the size of the quantization convex part 52a can be 25 nm or more and 250 nm or less. The size of the quantization recess 52b can be 25 nm or more and 250 nm or less. The quantization convex part 52a can be made into a square in the plan view facing the relief surface.
量子化凹部52bは、レリーフ面と対向する平面視において、正方形とできる。レリーフ面と対向する平面視において、量子化凸部52aの角は、丸くできる。レリーフ面と対向する平面視において、量子化凹部52bの角は、丸くできる。
The quantization recess 52b can be a square in a plan view facing the relief surface. In a plan view facing the relief surface, the corners of the quantized convex portions 52a can be rounded. In a plan view facing the relief surface, the corners of the quantization recess 52b can be rounded.
量子化凸部52aおよび量子化凹部52bは、仮想グリットに整列してもよい。また、量子化凸部52aの高さは、基準高さと同じ高さ、または、基準高さの整数倍とできる。量子化凹部52bの深さは、基準深さと同じ深さ、または、基準深さの整数倍とできる。基準高さと基準深さは、同じ値であってよい。基準高さと基準深さとが同じ値である場合には、整数倍の値は、1倍以上4倍以下とできる。また、整数倍は、1倍以上8倍以下としてもよい。基準高さおよび基準深さは、10nm以上500nm以下とできる。
The quantization convex portion 52a and the quantization concave portion 52b may be aligned with the virtual grid. Moreover, the height of the quantization convex part 52a can be made the same height as the reference height or an integral multiple of the reference height. The depth of the quantization recess 52b can be the same as the reference depth or an integral multiple of the reference depth. The reference height and the reference depth may be the same value. When the reference height and the reference depth are the same value, the integer multiple value can be 1 to 4 times. The integer multiple may be 1 to 8 times. The reference height and the reference depth can be 10 nm or more and 500 nm or less.
図27は、図26が示す1方向Dに沿って計算された空間周波数成分のピークを示している。レリーフ面内において予め決定された1方向Dに沿って空間周波数成分を計算する。レリーフ面によって再現されるホログラムの再生像が、5点の再生点群である場合には、再生点に対応する空間周波数成分F1からF5において、離散的な5点のピークが認められる。なお、図27における横軸は空間周波数(1/mm)であり、縦軸は空間周波数成分の強度である。
FIG. 27 shows the peak of the spatial frequency component calculated along one direction D shown in FIG. A spatial frequency component is calculated along a predetermined direction D in the relief plane. When the hologram reproduction image reproduced by the relief surface is a reproduction point group of five points, discrete five-point peaks are recognized in the spatial frequency components F1 to F5 corresponding to the reproduction points. In FIG. 27, the horizontal axis represents the spatial frequency (1 / mm), and the vertical axis represents the intensity of the spatial frequency component.
離散的な空間周波数成分が疎な場合、再生像は虹色の像であり、密な場合はモノクローム像である。また、空間周波数成分の分布の粗密を調整することにより、ある観察角度における再生像が虹色の像であり、それ以外の観察角度における再生像がモノクロームであることも可能である。
When the discrete spatial frequency components are sparse, the reconstructed image is a rainbow image, and when it is dense, it is a monochrome image. It is also possible to adjust the density of the spatial frequency component distribution so that the reproduced image at a certain observation angle is an iridescent image, and the reproduced image at other observation angles is monochrome.
図28は、量子化位相差構造52を模式的に示す断面図である。なお、図28では、量子化位相差構造52が形成するレリーフ面を上面として示している。
量子化位相差構造52を備える層は、略平坦な形状を有する。量子化位相差構造52は、層において互いに対向する面における一方の面に位置している。量子化位相差構造52において、量子化凸部52aの頂面52cから量子化凹部52bの底面52dまでの長さLは、レリーフ面における位置によらず一定である。量子化凸部52aの頂面52cおよび量子化凹部52bの底面52dは、光学素子50が形成される際のキャリアが有する表面に対して略平行であってよい。こうした量子化位相差構造52を備える層では、長さLに応じて、量子化位相差構造52の反射光における色が変わる。また、量子化位相差構造52の凹凸方向、すなわち図28における上下方向は、量子化凸部52aの頂面52cと量子化凹部52bの底面52dとによって形成されるリブ状凹部と溝状凹部の延在方向に対して垂直である。こうした構造によって、反射光の射出分布をブロードとし、かつ、光の色味を崩さずに、反射光の射出分布および反射光の色を制御することが可能である。なお、量子化位相差構造52では、量子化凸部52aの頂面52cおよび量子化凹部52bの底面52dの各々が、反射面として機能する。 FIG. 28 is a cross-sectional view schematically showing the quantizedphase difference structure 52. In FIG. 28, the relief surface formed by the quantized phase difference structure 52 is shown as the upper surface.
The layer including the quantizedretardation structure 52 has a substantially flat shape. The quantized phase difference structure 52 is located on one surface of the surfaces facing each other in the layer. In the quantization phase difference structure 52, the length L from the top surface 52c of the quantization convex portion 52a to the bottom surface 52d of the quantization concave portion 52b is constant regardless of the position on the relief surface. The top surface 52c of the quantization convex portion 52a and the bottom surface 52d of the quantization concave portion 52b may be substantially parallel to the surface of the carrier when the optical element 50 is formed. In the layer including the quantized phase difference structure 52, the color of the reflected light of the quantized phase difference structure 52 changes according to the length L. In addition, the uneven direction of the quantized phase difference structure 52, that is, the vertical direction in FIG. 28, is a rib-shaped recess and a groove-shaped recess formed by the top surface 52c of the quantized convex portion 52a and the bottom surface 52d of the quantized concave portion 52b. It is perpendicular to the extending direction. With such a structure, it is possible to control the emission distribution of reflected light and the color of reflected light without breaking the emission distribution of reflected light and without damaging the color of the light. In the quantization phase difference structure 52, each of the top surface 52c of the quantization convex portion 52a and the bottom surface 52d of the quantization concave portion 52b functions as a reflection surface.
量子化位相差構造52を備える層は、略平坦な形状を有する。量子化位相差構造52は、層において互いに対向する面における一方の面に位置している。量子化位相差構造52において、量子化凸部52aの頂面52cから量子化凹部52bの底面52dまでの長さLは、レリーフ面における位置によらず一定である。量子化凸部52aの頂面52cおよび量子化凹部52bの底面52dは、光学素子50が形成される際のキャリアが有する表面に対して略平行であってよい。こうした量子化位相差構造52を備える層では、長さLに応じて、量子化位相差構造52の反射光における色が変わる。また、量子化位相差構造52の凹凸方向、すなわち図28における上下方向は、量子化凸部52aの頂面52cと量子化凹部52bの底面52dとによって形成されるリブ状凹部と溝状凹部の延在方向に対して垂直である。こうした構造によって、反射光の射出分布をブロードとし、かつ、光の色味を崩さずに、反射光の射出分布および反射光の色を制御することが可能である。なお、量子化位相差構造52では、量子化凸部52aの頂面52cおよび量子化凹部52bの底面52dの各々が、反射面として機能する。 FIG. 28 is a cross-sectional view schematically showing the quantized
The layer including the quantized
量子化凸部52aおよび量子化凹部52bは、レリーフ面と対向する平面視において、単位長さに対して整数倍の横幅と、単位長さに対して整数倍の縦幅を有する。単位長さは、可視波長における中心波長の1/20以上、かつ、中心波長の半分以下であってよい。単位長さは、25nm以上250nm以下であってよい。
The quantized convex part 52a and the quantized concave part 52b have a width that is an integral multiple of the unit length and a vertical width that is an integral multiple of the unit length in a plan view facing the relief surface. The unit length may be not less than 1/20 of the center wavelength at the visible wavelength and not more than half of the center wavelength. The unit length may be 25 nm or more and 250 nm or less.
なお、量子化位相差構造52は、量子化位相差構造52を備える層において、互いに対向する一対の面の両方に位置してもよい。レリーフ面は、位相角記録領域を含む。位相角記録領域には、上述した量子化位相差構造52が形成される。溝状凹部やリブ状凸部の延在方向と、サブ波長格子11Gの方位は等しいまたは直交する。言い換えれば、溝状凹部やリブ状凸部の配列方向と、サブ波長格子11Gの方位角は、直交するか等しくできる。また、サブ波長格子11Gの方位が複数ある場合その方位の平均を、そのサブ波長格子11Gの方位とできる。平均は、複数あるサブ波長格子が形成された領域のそれぞれの面積で重み付けした加重平均とできる。これにより、観察者OBがカード100を基準平面Ph0に対して前方に傾けた場合に、カード100は、カード100の位置に応じて、第1像P1および第2像P2を表示する。言い換えれば、観察者OBが、観察空間において、カード100のなかで観察者OBが把持した部分の位置をほぼ固定した状態で、カード100の表面100Fを観察者OBに近づけた場合に、カード100の位置に応じて、カード100は、第1像P1および第2像P2を表示する(図40参照)。
Note that the quantized phase difference structure 52 may be located on both of a pair of surfaces facing each other in the layer including the quantized phase difference structure 52. The relief surface includes a phase angle recording area. The quantized phase difference structure 52 described above is formed in the phase angle recording area. The extending direction of the groove-shaped concave portion or rib-shaped convex portion and the orientation of the sub-wavelength grating 11G are equal or orthogonal. In other words, the arrangement direction of the groove-shaped concave portions and rib-shaped convex portions and the azimuth angle of the sub-wavelength grating 11G can be orthogonal or equal. Further, when there are a plurality of orientations of the sub-wavelength grating 11G, the average of the orientations can be set as the orientation of the sub-wavelength grating 11G. The average can be a weighted average weighted by the area of each region where a plurality of sub-wavelength gratings are formed. Accordingly, when the observer OB tilts the card 100 forward with respect to the reference plane Ph0, the card 100 displays the first image P1 and the second image P2 according to the position of the card 100. In other words, when the observer OB brings the surface 100F of the card 100 close to the observer OB in a state where the position of the portion held by the observer OB in the card 100 is substantially fixed in the observation space, the card 100 Depending on the position, the card 100 displays the first image P1 and the second image P2 (see FIG. 40).
光学素子50は、量子化位相差構造52上に、反射層を備えていてもよい。反射層は、透光性であってもよいし、隠蔽性であってもよい。反射層は、金属材料から形成されてもよい。金属材料の実例は、Al、Ag、Sn、Cr、Ni、Cu、Au、および、これらの合金である。金属材料から形成される反射層は、隠蔽性の反射層とできる。
The optical element 50 may include a reflective layer on the quantization phase difference structure 52. The reflective layer may be translucent or concealed. The reflective layer may be formed from a metal material. Examples of metal materials are Al, Ag, Sn, Cr, Ni, Cu, Au, and alloys thereof. The reflective layer formed from a metal material can be a concealable reflective layer.
あるいは、反射層は、レリーフ構造形成層とは屈折率が異なる誘電体層でもよい。あるいは、反射層は、互いに隣り合う層同士の屈折率が異なる誘電体層の積層体、すなわち、誘電体多層膜でもよい。なお、誘電体多層膜が含む誘電体層のうち、レリーフ面と接触している層の屈折率は、レリーフ面を含む層の屈折率とは異なることが望ましい。
Alternatively, the reflective layer may be a dielectric layer having a refractive index different from that of the relief structure forming layer. Alternatively, the reflective layer may be a laminate of dielectric layers having different refractive indexes between adjacent layers, that is, a dielectric multilayer film. Of the dielectric layers included in the dielectric multilayer film, the refractive index of the layer in contact with the relief surface is preferably different from the refractive index of the layer including the relief surface.
誘電体層の形成材料は、金属化合物、または、酸化ケイ素とできる。金属化合物は、金属酸化物、金属硫化物、および、フッ化金属とできる。誘電体層の形成材料の実例は、TiO2、ZnO、Si2O3、SiO、Fe2O3、ZnS、CaF、および、MgFである。誘電体層の反射層は、透光性とできる。
The material for forming the dielectric layer can be a metal compound or silicon oxide. The metal compound can be a metal oxide, a metal sulfide, and a metal fluoride. Examples of the material for forming the dielectric layer are TiO 2 , ZnO, Si 2 O 3 , SiO, Fe 2 O 3 , ZnS, CaF, and MgF. The reflective layer of the dielectric layer can be translucent.
反射層は、気相堆積法により形成することができる。気相堆積法としては、真空蒸着法およびスパッタリング法などを適用することができる。反射層の厚さは、10nm以上1000nm以下とすることができる。
The reflective layer can be formed by a vapor deposition method. As the vapor deposition method, a vacuum deposition method, a sputtering method, or the like can be applied. The thickness of the reflective layer can be 10 nm or more and 1000 nm or less.
反射層は、インキを用いて形成されてもよい。反射層を形成するインキは、印刷方式に応じて、オフセットインキ、活版インキ、および、グラビアインキなどであってよい。また、反射層を形成するインキは、組成の違いに応じて、樹脂インキ、油性インキ、および、水性インキなどであってよい。また、反射層を形成するインキは、乾燥方式の違いに応じて、酸化重合型インキ、浸透乾燥型インキ、蒸発乾燥型インキ、および、紫外線硬化型インキであってよい。
The reflective layer may be formed using ink. The ink for forming the reflective layer may be offset ink, letterpress ink, gravure ink, or the like depending on the printing method. Moreover, the ink which forms a reflection layer may be resin ink, oil-based ink, water-based ink, etc. according to the difference in composition. Further, the ink for forming the reflective layer may be an oxidation polymerization type ink, a permeation drying type ink, an evaporation drying type ink, and an ultraviolet curable ink depending on the difference in the drying method.
また、反射層を形成するインキは、照明角度、または、観察角度に応じて色が変化する機能性インキであってもよい。機能性は、光学的変化インキ(Optical Variable Ink)、カラーシフトインキ、および、パールインキであってよい。
The ink for forming the reflective layer may be a functional ink whose color changes according to the illumination angle or the observation angle. The functionality may be optically variable ink (Optical Variable Ink), color shift ink, and pearl ink.
[第1像および第2像]
・レリーフ面が表示する第2像が観察される観察角度の範囲は、サブ波長格子11Gが表示する第1像が観察される観察角度の範囲よりも大きくてもよい。すなわち、光学素子50は、第1の範囲の観察角度において第1像が表示される状態で観察され、第2の範囲の観察角度において第2像が表示される状態で観察され、第2の範囲が第1の範囲よりも大きくてもよい。この場合には、第1像が観察される観察角度の範囲の大きさと、第2像が観察される角度の範囲の大きさとが同じである場合に比べて、光学素子50を傾けたときにおいて光学素子50が表示する像の変化における画一性が乱される。これにより、光学素子50が表示する像が、観察者の目をより引きやすくなる。すなわち、光学素子50が表示する像による誘目性が高まる。 [First image and second image]
The observation angle range in which the second image displayed on the relief surface is observed may be larger than the observation angle range in which the first image displayed on the sub-wavelength grating 11G is observed. That is, theoptical element 50 is observed in a state where the first image is displayed at the observation angle in the first range, and is observed in a state where the second image is displayed in the observation angle in the second range. The range may be larger than the first range. In this case, when the optical element 50 is tilted, the size of the observation angle range in which the first image is observed is equal to the size of the angle range in which the second image is observed. The uniformity in changing the image displayed by the optical element 50 is disturbed. This makes it easier for the image displayed by the optical element 50 to catch the eyes of the observer. That is, the attractiveness by the image displayed by the optical element 50 is enhanced.
・レリーフ面が表示する第2像が観察される観察角度の範囲は、サブ波長格子11Gが表示する第1像が観察される観察角度の範囲よりも大きくてもよい。すなわち、光学素子50は、第1の範囲の観察角度において第1像が表示される状態で観察され、第2の範囲の観察角度において第2像が表示される状態で観察され、第2の範囲が第1の範囲よりも大きくてもよい。この場合には、第1像が観察される観察角度の範囲の大きさと、第2像が観察される角度の範囲の大きさとが同じである場合に比べて、光学素子50を傾けたときにおいて光学素子50が表示する像の変化における画一性が乱される。これにより、光学素子50が表示する像が、観察者の目をより引きやすくなる。すなわち、光学素子50が表示する像による誘目性が高まる。 [First image and second image]
The observation angle range in which the second image displayed on the relief surface is observed may be larger than the observation angle range in which the first image displayed on the sub-wavelength grating 11G is observed. That is, the
・サブ波長格子11Gが表示する第1像と、レリーフ面が表示する第2像とは、互いに相関性を有してもよい。これにより、第1像と第2像とが互いに相関性を有しない場合に比べて、光学素子50を観察した観察者に第1像と第2像との相関性を気付かせることによって、観察者の注意を引くことが可能である。以下、図29から図31を参照して、第1像と第2像とが相関性を有する場合の第1像および第2像の実例をより詳しく説明する。なお、図29から図31では、説明の便宜上、第1像と第2像との両方が表示された状態が示されている。
The first image displayed by the subwavelength grating 11G and the second image displayed by the relief surface may have a correlation with each other. As a result, compared with the case where the first image and the second image have no correlation with each other, the observer who observed the optical element 50 notices the correlation between the first image and the second image, thereby observing. It is possible to draw the attention of the person. Hereinafter, examples of the first image and the second image in a case where the first image and the second image have a correlation will be described in more detail with reference to FIGS. 29 to 31. 29 to 31 show a state where both the first image and the second image are displayed for convenience of explanation.
図29が示すように、第1像P1および第2像P2の第1実例では、第2像P2が第1像P1よりも外側に位置し、かつ、第1像P1の輪郭に沿う形状を有している。第1実例によれば、第1像P1の輪郭を第1像P1とは対照的な色彩を有した第2像P2によって縁取っているため、第1像P1の輪郭を際立たせることが可能である。これにより、第1像P1および第2像P2の誘目性を高めることができる。
As shown in FIG. 29, in the first example of the first image P1 and the second image P2, the second image P2 is positioned outside the first image P1 and has a shape that follows the contour of the first image P1. Have. According to the first example, since the outline of the first image P1 is bordered by the second image P2 having a contrasting color with the first image P1, the outline of the first image P1 can be made to stand out. It is. Thereby, the attractiveness of the 1st image P1 and the 2nd image P2 can be improved.
なお、第2像P2を形成するレリーフ面が、複数の画素領域Pxを含み、かつ、各画素領域Pxが、1つの方向に沿って延びる複数の反射面を備える場合には、レリーフ面は以下の構造であってもよい。すなわち、複数の画素領域Pxにおいて、反射面の方位角が、第1像P1の輪郭から第2像P2の輪郭に向かう方向に沿って変化してもよい。これにより、反射面の方位角に応じて、第2像P2内において輝度の濃淡を生じさせることが可能である。これにより、第1像P1および第2像P2による滑らかな質感、および、誘目性を高めることができる。
When the relief surface forming the second image P2 includes a plurality of pixel regions Px and each pixel region Px includes a plurality of reflecting surfaces extending along one direction, the relief surface is as follows. It may be the structure. That is, in a plurality of pixel regions Px, the azimuth angle of the reflecting surface may change along the direction from the contour of the first image P1 toward the contour of the second image P2. Thereby, it is possible to produce the brightness gradation in the 2nd image P2 according to the azimuth angle of a reflective surface. Thereby, the smooth texture and attractiveness by the 1st image P1 and the 2nd image P2 can be improved.
図30が示すように、第1像P1および第2像P2の第2実例では、第1像P1および第2像P2のうちの一方が、所定の記号または所定の物体を表す形状を有し、第1像P1および第2像P2のうちの他方が、当該形状を表す文字である。図30が示す実例では、第1像P1が記号であるユーロ(EURO)の形状を有し、かつ、第2像P2が、形状を表す文字である。なお、第2像P2が所定の記号または所定の物体を表す形状を有する一方で、第1像P1が、当該形状を表す文字であってもよい。
As shown in FIG. 30, in the second example of the first image P1 and the second image P2, one of the first image P1 and the second image P2 has a shape representing a predetermined symbol or a predetermined object. The other of the first image P1 and the second image P2 is a character representing the shape. In the actual example shown in FIG. 30, the first image P1 has the shape of the symbol Euro (EURO), and the second image P2 is a character representing the shape. In addition, while the second image P2 has a shape representing a predetermined symbol or a predetermined object, the first image P1 may be a character representing the shape.
これにより、同一の意味を示す第1像P1と第2像P2とが、観察角度によって表示されたり表示されなかったりする。そのため、第1像P1および第2像P2が意味する内容の認知度、および、第1像P1および第2像P2の誘目性を高めることが可能である。
Thereby, the first image P1 and the second image P2 showing the same meaning may or may not be displayed depending on the observation angle. Therefore, it is possible to increase the degree of recognition of the contents meant by the first image P1 and the second image P2, and the attractiveness of the first image P1 and the second image P2.
図31が示すように、第1像P1および第2像P2の第3実例では、第1像P1が、第2像P2とともに一組の物体を表す形状を有している。図31が示す実例では、第1像P1および第2像P2の各々が、一組の足を形成する形状を有している。第1像P1が左足の形状を有し、第2像P2が右足の形状を有している。これにより、第1像P1および第2像P2の誘目性を高めることが可能である。なお、第1像P1および第2像P2は、互いに一組の物体を表す形状を有していればよく、実例として、一組の手を形成する形状を有してもよい。
As shown in FIG. 31, in the third example of the first image P1 and the second image P2, the first image P1 has a shape representing a set of objects together with the second image P2. In the example shown in FIG. 31, each of the first image P1 and the second image P2 has a shape forming a pair of legs. The first image P1 has a left foot shape, and the second image P2 has a right foot shape. Thereby, it is possible to improve the attractiveness of the first image P1 and the second image P2. Note that the first image P1 and the second image P2 only need to have a shape that represents a set of objects with each other. For example, the first image P1 and the second image P2 may have a shape that forms a set of hands.
なお、第1像P1および第2像P2は、互いに異なる物体を表す形状を有し、かつ、第1像P1および第2像P2の各々によって補完される1つの像を形成してもよい。すなわち、第1像P1および第2像P2は、1つのだまし絵を形成してもよい。これによっても、第1像P1および第2像P2の誘目性を高めることができる。
Note that the first image P1 and the second image P2 may have shapes representing different objects, and may form one image that is complemented by each of the first image P1 and the second image P2. That is, the first image P1 and the second image P2 may form one trick picture. Also by this, the attractiveness of the first image P1 and the second image P2 can be enhanced.
[第6実施形態]
図32から図35を参照して、光学素子の第6実施形態を説明する。本発明の第6実施形態の光学素子は、第5実施形態の光学素子50と比べて、第1層11、第2層12、および、第3層13以外の層がレリーフ層である点が異なる。そのため以下では、こうした相違点を詳しく説明する一方で、第6実施形態の光学素子において、第5実施形態の光学素子50と対応する構成には、第5実施形態と同じ符号を付すことによって、その詳しい説明を省略する。また以下では、第6実施形態の光学素子として4つの実例を順に説明する。 [Sixth Embodiment]
With reference to FIGS. 32 to 35, a sixth embodiment of the optical element will be described. The optical element according to the sixth embodiment of the present invention is different from theoptical element 50 according to the fifth embodiment in that the layers other than the first layer 11, the second layer 12, and the third layer 13 are relief layers. Different. Therefore, in the following, such differences will be described in detail. On the other hand, in the optical element of the sixth embodiment, components corresponding to the optical element 50 of the fifth embodiment are denoted by the same reference numerals as those in the fifth embodiment. Detailed description thereof is omitted. Hereinafter, four examples will be described in order as the optical element of the sixth embodiment.
図32から図35を参照して、光学素子の第6実施形態を説明する。本発明の第6実施形態の光学素子は、第5実施形態の光学素子50と比べて、第1層11、第2層12、および、第3層13以外の層がレリーフ層である点が異なる。そのため以下では、こうした相違点を詳しく説明する一方で、第6実施形態の光学素子において、第5実施形態の光学素子50と対応する構成には、第5実施形態と同じ符号を付すことによって、その詳しい説明を省略する。また以下では、第6実施形態の光学素子として4つの実例を順に説明する。 [Sixth Embodiment]
With reference to FIGS. 32 to 35, a sixth embodiment of the optical element will be described. The optical element according to the sixth embodiment of the present invention is different from the
[第1実例]
図32を参照して、第1実例の光学素子を説明する。
図32が示すように、光学素子60は、第1層11、第2層12、および、第3層13を備えている。光学素子60は、レリーフ面61Reを含むレリーフ層61をさらに備えている。レリーフ面61Reは、上述した裏面11Rおよび表面12Fとは異なる面である。レリーフ面61Reは複数の反射面を含み、互いに隣り合う反射面間のピッチが、サブ波長格子11Gのピッチよりも大きい。レリーフ面61Reは、レリーフ層61の裏面61Rに含まれる。 [First example]
The optical element of the first example will be described with reference to FIG.
As shown in FIG. 32, theoptical element 60 includes a first layer 11, a second layer 12, and a third layer 13. The optical element 60 further includes a relief layer 61 including a relief surface 61Re. The relief surface 61Re is a surface different from the back surface 11R and the front surface 12F described above. The relief surface 61Re includes a plurality of reflecting surfaces, and the pitch between the reflecting surfaces adjacent to each other is larger than the pitch of the sub-wavelength grating 11G. The relief surface 61Re is included in the back surface 61R of the relief layer 61.
図32を参照して、第1実例の光学素子を説明する。
図32が示すように、光学素子60は、第1層11、第2層12、および、第3層13を備えている。光学素子60は、レリーフ面61Reを含むレリーフ層61をさらに備えている。レリーフ面61Reは、上述した裏面11Rおよび表面12Fとは異なる面である。レリーフ面61Reは複数の反射面を含み、互いに隣り合う反射面間のピッチが、サブ波長格子11Gのピッチよりも大きい。レリーフ面61Reは、レリーフ層61の裏面61Rに含まれる。 [First example]
The optical element of the first example will be described with reference to FIG.
As shown in FIG. 32, the
光学素子60は、反射層62と、接着層63とをさらに備えている。反射層62は、レリーフ面61Reに接し、かつ、レリーフ面61Reの凹凸に追従する形状を有している。接着層63は、反射層62に対してレリーフ層61とは反対側において反射層62に接している。光学素子60において、第3層13が接着層として機能している。これにより、第1層11および第2層12から形成される多層体が、第3層13によってレリーフ層61に貼り付けられている。そのため、光学素子60では、光学素子60の厚さ方向から見て、サブ波長格子11Gとレリーフ面61Reとが重なっている。
The optical element 60 further includes a reflective layer 62 and an adhesive layer 63. The reflective layer 62 is in contact with the relief surface 61Re and has a shape that follows the unevenness of the relief surface 61Re. The adhesive layer 63 is in contact with the reflective layer 62 on the side opposite to the relief layer 61 with respect to the reflective layer 62. In the optical element 60, the third layer 13 functions as an adhesive layer. Thereby, the multilayer body formed of the first layer 11 and the second layer 12 is attached to the relief layer 61 by the third layer 13. Therefore, in the optical element 60, the sub-wavelength grating 11G and the relief surface 61Re overlap each other when viewed from the thickness direction of the optical element 60.
接着層63は、反射層62においてレリーフ層61に接する面とは反対側の面の全体に位置してもよいし、一部に位置してもよい。
第1実例の光学素子60によれば、第1層11、第2層12、および、第3層13から構成される第1多層体と、レリーフ層61、反射層62、および、接着層63から構成される第2多層体とを個別に製造することができる。また、第1実例の光学素子60によれば、接着層63を用いて光学素子60を被接着体に貼り付けることができる。 Theadhesive layer 63 may be located on the entire surface of the reflective layer 62 opposite to the surface in contact with the relief layer 61 or may be located on a part thereof.
According to theoptical element 60 of the first example, the first multilayer body composed of the first layer 11, the second layer 12, and the third layer 13, the relief layer 61, the reflective layer 62, and the adhesive layer 63. The second multilayer body composed of the above can be manufactured individually. Further, according to the optical element 60 of the first example, the optical element 60 can be attached to the adherend using the adhesive layer 63.
第1実例の光学素子60によれば、第1層11、第2層12、および、第3層13から構成される第1多層体と、レリーフ層61、反射層62、および、接着層63から構成される第2多層体とを個別に製造することができる。また、第1実例の光学素子60によれば、接着層63を用いて光学素子60を被接着体に貼り付けることができる。 The
According to the
[第2実例]
図33を参照して、第2実例の光学素子を説明する。
図33が示すように、光学素子60は、上述した第1実例の光学素子60と同様、第1層11、第2層12、および、第3層13に加えて、レリーフ層61、反射層62、および、接着層63を備えている。第2実例の光学素子60は、さらに、第3層13とレリーフ層61との間に基材64を備えている。基材64において互いに対向する一対の面では、第3層13が一方の面に位置し、レリーフ層61が他方の面に位置している。基材64は光透過性を有している。基材64は、光学素子60の製造時に、基材64に対して形成される第1層11およびレリーフ層61の支持層として機能することができる。第2実例の光学素子60は、レリーフ層61に対して基材64側から観察される。 [Second example]
The optical element of the second example will be described with reference to FIG.
As shown in FIG. 33, theoptical element 60 includes a relief layer 61, a reflective layer, in addition to the first layer 11, the second layer 12, and the third layer 13, in the same manner as the optical element 60 in the first example described above. 62 and an adhesive layer 63. The optical element 60 of the second example further includes a base material 64 between the third layer 13 and the relief layer 61. In the pair of surfaces facing each other in the base material 64, the third layer 13 is positioned on one surface and the relief layer 61 is positioned on the other surface. The base material 64 has optical transparency. The base material 64 can function as a support layer for the first layer 11 and the relief layer 61 formed with respect to the base material 64 when the optical element 60 is manufactured. The optical element 60 of the second example is observed from the base material 64 side with respect to the relief layer 61.
図33を参照して、第2実例の光学素子を説明する。
図33が示すように、光学素子60は、上述した第1実例の光学素子60と同様、第1層11、第2層12、および、第3層13に加えて、レリーフ層61、反射層62、および、接着層63を備えている。第2実例の光学素子60は、さらに、第3層13とレリーフ層61との間に基材64を備えている。基材64において互いに対向する一対の面では、第3層13が一方の面に位置し、レリーフ層61が他方の面に位置している。基材64は光透過性を有している。基材64は、光学素子60の製造時に、基材64に対して形成される第1層11およびレリーフ層61の支持層として機能することができる。第2実例の光学素子60は、レリーフ層61に対して基材64側から観察される。 [Second example]
The optical element of the second example will be described with reference to FIG.
As shown in FIG. 33, the
[第3実例]
図34を参照して、第3実例の光学素子を説明する。
図34が示すように、光学素子60では、上述した第1実例の光学素子60と同様、第1層11、第2層12、および、第3層13に加えて、レリーフ層61、反射層62、および、接着層63を備えている。第3実例の光学素子60は、さらに、第1基材65と第2基材66とを備えている。第1基材65は、第3層13とレリーフ層61との間に位置している。第3層13は接着層として機能し、これにより、第1層11および第2層12から構成される多層体が第3層13によって第1基材65に接着されている。接着層63は、第2基材66に接着されている。第1基材65は、光透過性を有する。一方で、第2基材66は、光透過性を有してもよいし、光透過性を有しなくてもよい。 [Third example]
The optical element of the third example will be described with reference to FIG.
As shown in FIG. 34, in theoptical element 60, in the same manner as the optical element 60 in the first example described above, in addition to the first layer 11, the second layer 12, and the third layer 13, a relief layer 61, a reflective layer 62 and an adhesive layer 63. The optical element 60 of the third example further includes a first base material 65 and a second base material 66. The first base material 65 is located between the third layer 13 and the relief layer 61. The third layer 13 functions as an adhesive layer, whereby the multilayer body composed of the first layer 11 and the second layer 12 is bonded to the first base material 65 by the third layer 13. The adhesive layer 63 is adhered to the second base material 66. The first base 65 has light transmittance. On the other hand, the 2nd base material 66 may have a light transmittance, and does not need to have a light transmittance.
図34を参照して、第3実例の光学素子を説明する。
図34が示すように、光学素子60では、上述した第1実例の光学素子60と同様、第1層11、第2層12、および、第3層13に加えて、レリーフ層61、反射層62、および、接着層63を備えている。第3実例の光学素子60は、さらに、第1基材65と第2基材66とを備えている。第1基材65は、第3層13とレリーフ層61との間に位置している。第3層13は接着層として機能し、これにより、第1層11および第2層12から構成される多層体が第3層13によって第1基材65に接着されている。接着層63は、第2基材66に接着されている。第1基材65は、光透過性を有する。一方で、第2基材66は、光透過性を有してもよいし、光透過性を有しなくてもよい。 [Third example]
The optical element of the third example will be described with reference to FIG.
As shown in FIG. 34, in the
第1層11、第2層12、および、第3層13から構成される第1多層体は、サブ波長格子11Gと対向する平面視において、第1基材65の一部に位置している。レリーフ層61、反射層62、および、接着層63を備える第2多層体は、レリーフ面61Reと対向する平面視において、第2基材66の一部に位置している。光学素子60の厚さ方向から見て、第1層11はレリーフ層61に重なっている。
The first multilayer body composed of the first layer 11, the second layer 12, and the third layer 13 is located in a part of the first base material 65 in a plan view facing the sub-wavelength grating 11G. . The second multilayer body including the relief layer 61, the reflective layer 62, and the adhesive layer 63 is located at a part of the second base material 66 in a plan view facing the relief surface 61Re. The first layer 11 overlaps the relief layer 61 when viewed from the thickness direction of the optical element 60.
[第4実例]
図35を参照して、第4実例の光学素子を説明する。
図35が示すように、光学素子60は、第1実例の光学素子60と同様、第1層11、第2層12、および、第3層13に加えて、レリーフ層61、反射層62、および、接着層63を備えている。光学素子60は、さらに、第1基材65、および、第2基材66を備えている。第3層13は接着層として機能し、第3層13はレリーフ層61に接着している。接着層63は、第2基材66に接着している。 [Fourth example]
With reference to FIG. 35, the optical element of the fourth example will be described.
As FIG. 35 shows, in addition to thefirst layer 11, the second layer 12, and the third layer 13, the optical element 60 includes a relief layer 61, a reflective layer 62, An adhesive layer 63 is provided. The optical element 60 further includes a first base material 65 and a second base material 66. The third layer 13 functions as an adhesive layer, and the third layer 13 is bonded to the relief layer 61. The adhesive layer 63 is adhered to the second base material 66.
図35を参照して、第4実例の光学素子を説明する。
図35が示すように、光学素子60は、第1実例の光学素子60と同様、第1層11、第2層12、および、第3層13に加えて、レリーフ層61、反射層62、および、接着層63を備えている。光学素子60は、さらに、第1基材65、および、第2基材66を備えている。第3層13は接着層として機能し、第3層13はレリーフ層61に接着している。接着層63は、第2基材66に接着している。 [Fourth example]
With reference to FIG. 35, the optical element of the fourth example will be described.
As FIG. 35 shows, in addition to the
上述した第1多層体は、サブ波長格子11Gと対応する平面視において、第1基材65の一部に位置している。第2多層体は、レリーフ面61Reと対向する平面視において、第2基材66の一部に位置している。光学素子60の厚さ方向から見て、第1層11はレリーフ層61に重なっている。
The first multilayer body described above is located in a part of the first base material 65 in a plan view corresponding to the sub-wavelength grating 11G. The second multilayer body is located at a part of the second base material 66 in a plan view facing the relief surface 61Re. The first layer 11 overlaps the relief layer 61 when viewed from the thickness direction of the optical element 60.
光学素子60は、接着層63に対して反射層62側から観察される。そのため、第1基材65は、光透過性を有する。一方で、第2基材66は、光透過性を有してもよいし、光透過性を有しなくてもよい。
The optical element 60 is observed from the reflective layer 62 side with respect to the adhesive layer 63. Therefore, the 1st base material 65 has light transmittance. On the other hand, the 2nd base material 66 may have a light transmittance, and does not need to have a light transmittance.
なお、光学素子60の第1実例から第3実例において、各基材には、紙およびプラスチックフィルムなどを用いることができる。各基材には印刷が施されていてもよい。または、各基材は多層体であり、基材を構成する複数の層において、少なくとも一部の層に印刷が施されてもよい。
In the first to third examples of the optical element 60, paper, plastic film, or the like can be used for each substrate. Each substrate may be printed. Alternatively, each base material is a multilayer body, and printing may be performed on at least some of the plurality of layers constituting the base material.
以上説明したように、第6実施形態の光学素子によれば、上述した(10)に加えて、以下に記載の効果を得ることができる。
(12)第1層11、第2層12、および、第3層13以外の層がレリーフ面を備えるレリーフ層であるため、レリーフ層における設計の自由度が高まる。 As described above, according to the optical element of the sixth embodiment, in addition to the above (10), the following effects can be obtained.
(12) Since the layers other than thefirst layer 11, the second layer 12, and the third layer 13 are relief layers having a relief surface, the degree of freedom in designing the relief layer is increased.
(12)第1層11、第2層12、および、第3層13以外の層がレリーフ面を備えるレリーフ層であるため、レリーフ層における設計の自由度が高まる。 As described above, according to the optical element of the sixth embodiment, in addition to the above (10), the following effects can be obtained.
(12) Since the layers other than the
[第6実施形態の変形]
なお、上述した第6実施形態は、以下のように適宜変更して実施することができる。
[基材]
・第1実例から第3実例の光学素子60において、サブ波長格子11Gと対向する平面視において、各基材は、第1多層体および第2多層体の少なくとも一方よりも小さくてもよい。 [Modification of Sixth Embodiment]
The sixth embodiment described above can be implemented with appropriate modifications as follows.
[Base material]
In theoptical element 60 of the first example to the third example, each base material may be smaller than at least one of the first multilayer body and the second multilayer body in a plan view facing the sub-wavelength grating 11G.
なお、上述した第6実施形態は、以下のように適宜変更して実施することができる。
[基材]
・第1実例から第3実例の光学素子60において、サブ波長格子11Gと対向する平面視において、各基材は、第1多層体および第2多層体の少なくとも一方よりも小さくてもよい。 [Modification of Sixth Embodiment]
The sixth embodiment described above can be implemented with appropriate modifications as follows.
[Base material]
In the
・第1層11を含む第1多層体、および、レリーフ層61を含む第2多層体は、2つの基材の間に内包されてもよい。言い換えれば、第1多層体および第2多層体の各々は、2つの基材によって挟まれた状態で、ラミネートされてもよい。
The first multilayer body including the first layer 11 and the second multilayer body including the relief layer 61 may be included between the two base materials. In other words, each of the first multilayer body and the second multilayer body may be laminated while being sandwiched between two substrates.
・各基材は、レーザー光線の照射によって発色するレーザー発色層であってもよい。そして、第1実例における基材64は、レーザー光線の照射によって基材64に記憶された情報を含んでもよい。
-Each substrate may be a laser coloring layer that develops color when irradiated with a laser beam. And the base material 64 in a 1st example may also contain the information memorize | stored in the base material 64 by irradiation of the laser beam.
また、第2実例の光学素子60において、第1基材65および第2基材66の少なくとも一方が、レーザー光線の照射によって記憶された情報を含むことができる。第1基材65が情報を含む場合には、光学素子60の厚さ方向から見て、レリーフ面61Reが表示する第2像と、第1基材65が含む情報とを重ねることによって、第2像の一部のみが視認される。これにより、光学素子60において、偽造に対する耐性が高まる。これに対して、第2基材66が情報を含む場合には、光学素子60の厚さ方向から見て、サブ波長格子11Gが表示する第1像の全体と、レリーフ面が表示する第2像の全体とが視認される。
Further, in the optical element 60 of the second example, at least one of the first base material 65 and the second base material 66 can include information stored by laser beam irradiation. When the first base material 65 includes information, the second image displayed by the relief surface 61Re and the information included in the first base material 65 are overlapped with each other when viewed from the thickness direction of the optical element 60. Only part of the two images is visible. Thereby, in the optical element 60, the tolerance with respect to forgery increases. On the other hand, when the second substrate 66 includes information, the entire first image displayed by the sub-wavelength grating 11G and the second surface displayed by the relief surface are viewed from the thickness direction of the optical element 60. The entire image is visible.
第3実例の光学素子60において、第1基材65が情報を含む場合には、光学素子60の厚さ方向から見て、サブ波長格子11Gが表示する第1像、および、レリーフ面61Reが表示する第2像と、第1基材65が含む情報とを重ねることによって、第1像の一部、および、第2像の一部のみが視認される。これにより、光学素子60において、偽造に対する耐性が高まる。これに対して、第2基材66が情報を含む場合には、光学素子60の厚さ方向から見て、サブ波長格子11Gが表示する第1像の全体と、レリーフ面が表示する第2像の全体とが視認される。
In the optical element 60 of the third example, when the first base material 65 includes information, the first image displayed by the sub-wavelength grating 11G and the relief surface 61Re are viewed from the thickness direction of the optical element 60. By overlapping the second image to be displayed and the information included in the first base material 65, only a part of the first image and a part of the second image are visually recognized. Thereby, in the optical element 60, the tolerance with respect to forgery increases. On the other hand, when the second substrate 66 includes information, the entire first image displayed by the sub-wavelength grating 11G and the second surface displayed by the relief surface are viewed from the thickness direction of the optical element 60. The entire image is visible.
[第7実施形態]
図36を参照して、光学素子を備える転写箔を説明する。本発明の第7実施形態では、転写箔が備える光学素子が、第5実施形態の光学素子50における第1実例である場合を、転写箔の一形態として説明する。 [Seventh Embodiment]
A transfer foil provided with an optical element will be described with reference to FIG. In the seventh embodiment of the present invention, a case where the optical element included in the transfer foil is a first example of theoptical element 50 of the fifth embodiment will be described as one form of the transfer foil.
図36を参照して、光学素子を備える転写箔を説明する。本発明の第7実施形態では、転写箔が備える光学素子が、第5実施形態の光学素子50における第1実例である場合を、転写箔の一形態として説明する。 [Seventh Embodiment]
A transfer foil provided with an optical element will be described with reference to FIG. In the seventh embodiment of the present invention, a case where the optical element included in the transfer foil is a first example of the
図36が示すように、転写箔70は、光学素子50と、光学素子50を被転写体に接着させるための接着層71と、を含む接着体を備えている。転写箔70は、さらに、支持層72と剥離層73とを備えている。転写箔70において、支持層72、剥離層73、光学素子50、および、接着層71が、記載の順に積み重なっている。被転写体に転写された後の光学素子50は、剥離層73に対して光学素子50とは反対側から観察される。そのため、剥離層73は光透過性を有する。一方で、光学素子50が転写されるとき、剥離層73は支持層72から剥離されるため、支持層72は光透過性を有してもよいし、光透過性を有しなくてもよい。
As shown in FIG. 36, the transfer foil 70 includes an adhesive body including the optical element 50 and an adhesive layer 71 for bonding the optical element 50 to the transfer target body. The transfer foil 70 further includes a support layer 72 and a release layer 73. In the transfer foil 70, the support layer 72, the release layer 73, the optical element 50, and the adhesive layer 71 are stacked in the order described. The optical element 50 after being transferred to the transfer medium is observed from the side opposite to the optical element 50 with respect to the release layer 73. Therefore, the release layer 73 is light transmissive. On the other hand, since the peeling layer 73 is peeled from the support layer 72 when the optical element 50 is transferred, the support layer 72 may or may not have light transmittance. .
転写箔70は、サブ波長格子11Gとレリーフ面13Reとを含む。そのため、被転写体には、転写箔70の一部を転写するのみによって、第1像P1と第2像P2とを表示する光学素子50を転写することができる。光学素子50の転写には、ホットスタンプ方式を用いることができる。
The transfer foil 70 includes a sub-wavelength grating 11G and a relief surface 13Re. Therefore, the optical element 50 that displays the first image P1 and the second image P2 can be transferred to the transfer target body only by transferring a part of the transfer foil 70. For the transfer of the optical element 50, a hot stamp method can be used.
[第7実施形態の変形]
[転写箔]
・サブ波長格子11Gを含む第1転写箔と、レリーフ面13Reを含む第2転写箔とを準備し、2つの転写箔を用いて光学素子を形成することが可能である。この場合には、光学素子の厚さ方向から見て、第1転写箔が含むサブ波長格子11Gと、第2転写箔が含むレリーフ面13Reとが重なるように、被転写体に対して第1転写箔の一部と第2転写箔の一部とを転写すればよい。この場合には、光学素子を形成するときに、第1転写箔の一部が転写される位置と、第2転写箔の一部が転写される位置との位置合わせが必要である。そのため、光学素子において、偽造に対する耐性が高められる。 [Modification of the seventh embodiment]
[Transfer foil]
It is possible to prepare a first transfer foil including the sub-wavelength grating 11G and a second transfer foil including the relief surface 13Re, and form an optical element using the two transfer foils. In this case, when viewed from the thickness direction of the optical element, the first sub-wavelength grating 11G included in the first transfer foil and the relief surface 13Re included in the second transfer foil overlap with each other on the first transfer object. A part of the transfer foil and a part of the second transfer foil may be transferred. In this case, when forming the optical element, it is necessary to align the position where a part of the first transfer foil is transferred and the position where a part of the second transfer foil is transferred. Therefore, the resistance against counterfeiting is enhanced in the optical element.
[転写箔]
・サブ波長格子11Gを含む第1転写箔と、レリーフ面13Reを含む第2転写箔とを準備し、2つの転写箔を用いて光学素子を形成することが可能である。この場合には、光学素子の厚さ方向から見て、第1転写箔が含むサブ波長格子11Gと、第2転写箔が含むレリーフ面13Reとが重なるように、被転写体に対して第1転写箔の一部と第2転写箔の一部とを転写すればよい。この場合には、光学素子を形成するときに、第1転写箔の一部が転写される位置と、第2転写箔の一部が転写される位置との位置合わせが必要である。そのため、光学素子において、偽造に対する耐性が高められる。 [Modification of the seventh embodiment]
[Transfer foil]
It is possible to prepare a first transfer foil including the sub-wavelength grating 11G and a second transfer foil including the relief surface 13Re, and form an optical element using the two transfer foils. In this case, when viewed from the thickness direction of the optical element, the first sub-wavelength grating 11G included in the first transfer foil and the relief surface 13Re included in the second transfer foil overlap with each other on the first transfer object. A part of the transfer foil and a part of the second transfer foil may be transferred. In this case, when forming the optical element, it is necessary to align the position where a part of the first transfer foil is transferred and the position where a part of the second transfer foil is transferred. Therefore, the resistance against counterfeiting is enhanced in the optical element.
[光学素子]
・転写箔は、上述した光学素子50に代えて、第1実施形態の光学素子10、第2実施形態の光学素子20、第3実施形態の光学素子30、および、第4実施形態の光学素子40を含んでもよい。また、転写箔は、上述した光学素子50に代えて、第5実施形態における第2実例の光学素子50、第6実施形態における第1実例および第2実例の光学素子60を含んでもよい。 [Optical element]
The transfer foil is replaced with theoptical element 50 described above, the optical element 10 of the first embodiment, the optical element 20 of the second embodiment, the optical element 30 of the third embodiment, and the optical element of the fourth embodiment. 40 may be included. Further, the transfer foil may include the optical element 50 of the second example in the fifth embodiment, and the optical element 60 of the first example and the second example in the sixth embodiment, instead of the optical element 50 described above.
・転写箔は、上述した光学素子50に代えて、第1実施形態の光学素子10、第2実施形態の光学素子20、第3実施形態の光学素子30、および、第4実施形態の光学素子40を含んでもよい。また、転写箔は、上述した光学素子50に代えて、第5実施形態における第2実例の光学素子50、第6実施形態における第1実例および第2実例の光学素子60を含んでもよい。 [Optical element]
The transfer foil is replaced with the
[第8実施形態]
図37および図38を参照して、本発明の第8実施形態の認証体を説明する。以下では、認証体の実例である、カードを説明する。本発明の実施形態のカードの実例は、IDカードや免許証、ライセンスカード、メンバーカード、クレジットカードである。なお、カードは、第6実施形態の光学素子60における第3実例をカードの一部として含んでいる。 [Eighth Embodiment]
With reference to FIGS. 37 and 38, an authenticator according to an eighth embodiment of the present invention will be described. Below, the card | curd which is an example of an authentication body is demonstrated. Examples of the card according to the embodiment of the present invention are an ID card, a license, a license card, a member card, and a credit card. The card includes the third example of theoptical element 60 of the sixth embodiment as a part of the card.
図37および図38を参照して、本発明の第8実施形態の認証体を説明する。以下では、認証体の実例である、カードを説明する。本発明の実施形態のカードの実例は、IDカードや免許証、ライセンスカード、メンバーカード、クレジットカードである。なお、カードは、第6実施形態の光学素子60における第3実例をカードの一部として含んでいる。 [Eighth Embodiment]
With reference to FIGS. 37 and 38, an authenticator according to an eighth embodiment of the present invention will be described. Below, the card | curd which is an example of an authentication body is demonstrated. Examples of the card according to the embodiment of the present invention are an ID card, a license, a license card, a member card, and a credit card. The card includes the third example of the
[カードの構成]
図37が示すように、カード80は、カード80の表面80Fと対向する平面視において、2次元的に広がる板状を有している。カード80は、表面80Fを介して、第1画像81、第2画像82、および、第3画像83を表示する。また、カード80は、表面80Fを介して第1像P1および第2像P2を表示する。 [Card configuration]
As shown in FIG. 37, thecard 80 has a plate shape that spreads two-dimensionally in a plan view facing the surface 80F of the card 80. The card 80 displays the first image 81, the second image 82, and the third image 83 via the surface 80F. Further, the card 80 displays the first image P1 and the second image P2 via the surface 80F.
図37が示すように、カード80は、カード80の表面80Fと対向する平面視において、2次元的に広がる板状を有している。カード80は、表面80Fを介して、第1画像81、第2画像82、および、第3画像83を表示する。また、カード80は、表面80Fを介して第1像P1および第2像P2を表示する。 [Card configuration]
As shown in FIG. 37, the
本実施形態では、第1画像81は、顔画像81aと背景画像81bとを含んでいる。顔画像81aは、カード80の所有者の顔を示す画像である。背景画像81bは、顔画像81aを内部に含み、顔画像81aの背景を形成している。第2画像82は、カード80の所有者に関する情報を含んでいる。第2画像82は、文字および数字によって表現される情報を含んでいる。第3画像83は、カード80に関する情報を含んでいる。第3画像83が含む情報は、カード80の名称である。顔画像81aと第2画像82はカードの所有者を識別する識別情報である。なお、カード80は、表面80Fを介して第1像P1および第2像P2を表示することが可能であればよい。上述した画像は、カード80が表示することが可能な画像の実例である。
In the present embodiment, the first image 81 includes a face image 81a and a background image 81b. The face image 81a is an image showing the face of the owner of the card 80. The background image 81b includes a face image 81a inside, and forms the background of the face image 81a. The second image 82 includes information regarding the owner of the card 80. The second image 82 includes information expressed by letters and numbers. The third image 83 includes information regarding the card 80. The information included in the third image 83 is the name of the card 80. The face image 81a and the second image 82 are identification information for identifying the card owner. The card 80 only needs to be able to display the first image P1 and the second image P2 via the surface 80F. The above-described image is an example of an image that can be displayed by the card 80.
図38は、図37におけるIV‐IV線に沿うカード80の断面構造を示している。
図38が示すように、認証体の実例であるカード80は、光学素子60を備えている。光学素子60は、識別情報を覆っていてもよい。カード80が備える光学素子60では、第1層11、第2層12、および、第3層13を備える第1多層体が、剥離層68をさらに備えている。剥離層68は、第1層11を覆っている。レリーフ層61、反射層62、および、接着層63を備える第2多層体は、剥離層69をさらに備えている。剥離層69は、レリーフ層61を覆っている。光学素子60において、第2多層体は、第1基材65によって覆われている。 FIG. 38 shows a cross-sectional structure of thecard 80 taken along line IV-IV in FIG.
As shown in FIG. 38, acard 80 that is an example of an authentication body includes an optical element 60. The optical element 60 may cover the identification information. In the optical element 60 included in the card 80, the first multilayer body including the first layer 11, the second layer 12, and the third layer 13 further includes a release layer 68. The release layer 68 covers the first layer 11. The second multilayer body including the relief layer 61, the reflective layer 62, and the adhesive layer 63 further includes a release layer 69. The release layer 69 covers the relief layer 61. In the optical element 60, the second multilayer body is covered with the first base material 65.
図38が示すように、認証体の実例であるカード80は、光学素子60を備えている。光学素子60は、識別情報を覆っていてもよい。カード80が備える光学素子60では、第1層11、第2層12、および、第3層13を備える第1多層体が、剥離層68をさらに備えている。剥離層68は、第1層11を覆っている。レリーフ層61、反射層62、および、接着層63を備える第2多層体は、剥離層69をさらに備えている。剥離層69は、レリーフ層61を覆っている。光学素子60において、第2多層体は、第1基材65によって覆われている。 FIG. 38 shows a cross-sectional structure of the
As shown in FIG. 38, a
第2基材66の全体または一部が、レーザー光線の照射前において、レーザー光線の照射によって発色する特性を有してもよい。レーザー光線の照射による発色は、炭化とできる。すなわち、第2基材66の全体または一部が、レーザー光線の照射前において、レーザー光線の照射によって炭化する特性を有してもよい。カード80が備える第2基材66は、レーザー光線の照射によって発色した部分である第1発色部66aと、第2発色部66bとを含んでいる。第1発色部66aは、顔画像81aを表示する部分であり、第2発色部66bは、第2画像82を表示する部分である。
The whole or a part of the second base material 66 may have a characteristic of color development by laser beam irradiation before laser beam irradiation. Coloring by laser beam irradiation can be carbonized. That is, the whole or a part of the second base material 66 may have a characteristic of being carbonized by the laser beam irradiation before the laser beam irradiation. The second base material 66 included in the card 80 includes a first color development part 66a and a second color development part 66b, which are parts colored by irradiation with a laser beam. The first color developing unit 66a is a part that displays the face image 81a, and the second color developing unit 66b is a part that displays the second image 82.
カード80は、白色層91、下部保護層92、および、上部保護層93を備えている。白色層91は、白色の層であり、第2基材66に接している。白色層91のなかで、第2基材66に接する面の一部には、印刷94が施されている。カード80の厚さ方向から見て、印刷94は、第1発色部66aと重なる領域に位置している。印刷94は、背景画像81bを表示する。
The card 80 includes a white layer 91, a lower protective layer 92, and an upper protective layer 93. The white layer 91 is a white layer and is in contact with the second base material 66. In the white layer 91, printing 94 is applied to a part of the surface in contact with the second base material 66. When viewed from the thickness direction of the card 80, the print 94 is located in an area overlapping with the first color development portion 66a. The print 94 displays a background image 81b.
下部保護層92は、白色層91のなかで、第2基材66に接する面とは反対側の面に位置している。上部保護層93は、第1基材65を覆い、かつ、第1基材65との間に第1多層体を内包している。上部保護層93は、光透過性を有している。一方で、下部保護層92は、光透過性を有してもよいし、光透過性を有しなくてもよい。
The lower protective layer 92 is located on the surface of the white layer 91 opposite to the surface in contact with the second base material 66. The upper protective layer 93 covers the first base material 65 and encloses the first multilayer body with the first base material 65. The upper protective layer 93 is light transmissive. On the other hand, the lower protective layer 92 may have light transmittance or may not have light transmittance.
[第8実施形態の変形]
[認証体]
・認証体は、カードに限らず、パスポートなどの所有者を認証するために用いられる他の認証体として具体化されてもよい。 [Modification of Eighth Embodiment]
[Authentication body]
The authentication body is not limited to a card, and may be embodied as another authentication body used for authenticating an owner such as a passport.
[認証体]
・認証体は、カードに限らず、パスポートなどの所有者を認証するために用いられる他の認証体として具体化されてもよい。 [Modification of Eighth Embodiment]
[Authentication body]
The authentication body is not limited to a card, and may be embodied as another authentication body used for authenticating an owner such as a passport.
[光学素子]
・認証体は、上述した光学素子60に代えて、第1実施形態の光学素子10、第2実施形態の光学素子20、第3実施形態の光学素子30、第4実施形態の光学素子40、および、第5実施形態の光学素子50を含んでもよい。また、認証体は、上述した光学素子60に代えて、第6実施形態の第1実例、第2実例、および、第4実例における光学素子60を備えてもよい。 [Optical element]
The authentication body is replaced with theoptical element 60 described above, the optical element 10 of the first embodiment, the optical element 20 of the second embodiment, the optical element 30 of the third embodiment, the optical element 40 of the fourth embodiment, And the optical element 50 of 5th Embodiment may be included. Further, the authentication body may include the optical element 60 in the first example, the second example, and the fourth example of the sixth embodiment instead of the optical element 60 described above.
・認証体は、上述した光学素子60に代えて、第1実施形態の光学素子10、第2実施形態の光学素子20、第3実施形態の光学素子30、第4実施形態の光学素子40、および、第5実施形態の光学素子50を含んでもよい。また、認証体は、上述した光学素子60に代えて、第6実施形態の第1実例、第2実例、および、第4実例における光学素子60を備えてもよい。 [Optical element]
The authentication body is replaced with the
[第9実施形態]
図39から図46を参照して、本発明の第9実施形態の認証体を説明する。以下では、認証体の実例としてカードの他の実例を説明する。 [Ninth Embodiment]
With reference to FIGS. 39 to 46, an authentication body according to a ninth embodiment of the present invention will be described. Hereinafter, another example of the card will be described as an example of the authentication body.
図39から図46を参照して、本発明の第9実施形態の認証体を説明する。以下では、認証体の実例としてカードの他の実例を説明する。 [Ninth Embodiment]
With reference to FIGS. 39 to 46, an authentication body according to a ninth embodiment of the present invention will be described. Hereinafter, another example of the card will be described as an example of the authentication body.
[カードの構成]
図39を参照して、カードの構成を説明する。カードの実例として、第1実施形態の光学素子10を備えるカードについて説明するが、カードは、第1実施形態の光学素子10に限らず、第2実施形態から第6実施形態の各々における光学素子を備えてもよい。 [Card configuration]
The configuration of the card will be described with reference to FIG. As an example of the card, a card including theoptical element 10 of the first embodiment will be described. However, the card is not limited to the optical element 10 of the first embodiment, and the optical element in each of the second to sixth embodiments. May be provided.
図39を参照して、カードの構成を説明する。カードの実例として、第1実施形態の光学素子10を備えるカードについて説明するが、カードは、第1実施形態の光学素子10に限らず、第2実施形態から第6実施形態の各々における光学素子を備えてもよい。 [Card configuration]
The configuration of the card will be described with reference to FIG. As an example of the card, a card including the
カード100は、第1層11、第2層12、および、第3層13に加えて、表示層101をさらに備えている。表示層101は、所定の情報を表示することができる。表示層101は、文字、数字、図形、および、QRコード(登録商標)などで所定の情報を表示することができる。カード100において、第1層11において第2層12に接する面とは反対側の面が、表面100Fである。
The card 100 further includes a display layer 101 in addition to the first layer 11, the second layer 12, and the third layer 13. The display layer 101 can display predetermined information. The display layer 101 can display predetermined information using characters, numbers, figures, QR codes (registered trademark), and the like. In the card 100, the surface of the first layer 11 opposite to the surface in contact with the second layer 12 is the surface 100F.
表示層101は、第3層13に接する表示面101F上に施された印刷によって、所定の情報を表示することができる。表示面101Fの印刷は、活版印刷、グラビア印刷、オフセット印刷、スクリーン印刷で形成できる。印刷のインキには、機能性インキを用いることができる。機能性インキは、カード100に光を照射する光源の種類あるいは状態に応じて色が変わるインキ、および、観察者の観察角度に応じて色や光沢が変わるインキなどである。光源の種類あるいは状態に応じて色が変化するインキは、蓄光インキ、蛍光インキ、および、フォトクロミックインキとできる。観察角度に応じて色や光沢が変わるインキは、パールインキ、磁性インキ、および、カラーシフトインキとできる。
The display layer 101 can display predetermined information by printing performed on the display surface 101F in contact with the third layer 13. The display surface 101F can be printed by letterpress printing, gravure printing, offset printing, or screen printing. A functional ink can be used as the printing ink. The functional ink is ink that changes color according to the type or state of the light source that irradiates the card 100, and ink that changes color or gloss according to the observation angle of the observer. The ink whose color changes depending on the type or state of the light source can be phosphorescent ink, fluorescent ink, and photochromic ink. The ink whose color and gloss change according to the observation angle can be pearl ink, magnetic ink, and color shift ink.
蓄光インキは、太陽光や蛍光灯などから放出された光エネルギーを吸収し、かつ、蓄積し、暗闇において徐々に発光する機能を有している。フォロクロミックインキは、紫外線に反応して発色するインキである。フォトクロミックインキは、フォトクロミックインキに対する紫外線の照射量に応じて、レッド、ブルー、パープル、および、イエローなどの互いに異なる色を呈する機能を有している。パールインキは、パール顔料が添加されたインキである。パールインキの光沢は、観察角度に応じて変わる。パールインキは、パール顔料として偏光パールから形成されたパール顔料を含むことによって、観察角度に応じて色調も変わる。機能性インキによれば、表示面101Fに形成された印刷の色が変わるか否かを容易に確認することができる。そのため、カード100の真正を、印刷の色に基づいて確実に検証することができる。
Storing ink absorbs and stores light energy emitted from sunlight, fluorescent lamps, etc., and has a function of gradually emitting light in the dark. Phorochromic ink is ink that develops color in response to ultraviolet light. The photochromic ink has a function of exhibiting different colors such as red, blue, purple, and yellow according to the irradiation amount of ultraviolet rays to the photochromic ink. Pearl ink is ink to which a pearl pigment is added. The gloss of the pearl ink changes depending on the observation angle. The pearl ink contains a pearl pigment formed from a polarized pearl as a pearl pigment, so that the color tone changes depending on the observation angle. According to the functional ink, it can be easily confirmed whether or not the color of the printing formed on the display surface 101F changes. Therefore, the authenticity of the card 100 can be reliably verified based on the printing color.
なお、表示面101Fに印刷を施す方法には、インクジェット方式、サーマルプリンタ方式、および、レーザー方式などを用いてもよい。これらの方式によれば、表示面101Fに形成する情報をカード100ごとに設定することが可能である。そのため、複数のカード100に共通する柄などは、上述した印刷によって相対的に高い速度で印刷し、かつ、各カード100を識別する識別情報は、インクジェット方式、サーマルプリンタ方式、および、レーザー方式などを用いて印刷することが好ましい。
In addition, as a method for printing on the display surface 101F, an ink jet method, a thermal printer method, a laser method, or the like may be used. According to these methods, the information to be formed on the display surface 101F can be set for each card 100. Therefore, a pattern or the like common to a plurality of cards 100 is printed at a relatively high speed by the above-described printing, and identification information for identifying each card 100 is an ink jet method, a thermal printer method, a laser method, or the like. It is preferable to print using.
なお、上述したように、カード100が備える光学素子は、第1実施形態の光学素子10に限らず、第5実施形態および第6実施形態の各々における光学素子であってもよい。すなわち、カード100は、サブ波長格子11Gが表示する第1像P1、レリーフ面が表示する第2像P2、および、表示層101が表示する第3像を表示することが可能であってもよい。こうしたカード100では、第1像P1の輝度、および、第2像P2の輝度が十分に高い場合には、第1像P1が表示される観察角度、および、第2像P2が表示される観察角度の各々では、第3像が視認されにくい。一方で、第1像P1および第2像P2の両方が表示されない観察角度では、第3像が視認される。それゆえに、観察者は、第3像を視認することができる。
As described above, the optical element included in the card 100 is not limited to the optical element 10 of the first embodiment, and may be the optical element in each of the fifth embodiment and the sixth embodiment. That is, the card 100 may be capable of displaying the first image P1 displayed by the sub-wavelength grating 11G, the second image P2 displayed by the relief surface, and the third image displayed by the display layer 101. . In such a card 100, when the luminance of the first image P1 and the luminance of the second image P2 are sufficiently high, the observation angle at which the first image P1 is displayed and the observation at which the second image P2 is displayed. At each angle, the third image is hardly visible. On the other hand, the third image is visually recognized at an observation angle at which both the first image P1 and the second image P2 are not displayed. Therefore, the observer can visually recognize the third image.
第1像P1および第2像P2の各々が視認される観察角度は、第1像P1および第2像P2の各々が発現する観察角度、すなわち、サブ波長格子11Gおよびレリーフ面の形状によって、任意に設定することが可能である。
The observation angle at which each of the first image P1 and the second image P2 is visually recognized is arbitrary depending on the observation angle at which each of the first image P1 and the second image P2 appears, that is, the shape of the sub-wavelength grating 11G and the relief surface. Can be set.
カード100において、第1層11、第2層12、および、第3層13から構成される多層体は、3つの層が積み重なる方向において、70%以上の透過率を有することが好ましい。これにより、カード100が表示する像が視認されやすい。この場合特に、第1層11、第2層12、および、第3層13から構成される多層体である光学素子が、識別情報を覆う場合、その識別のしやすさが向上する。例えば、道路運送車両の保安基準における第195条では、自動車の前面ガラスおよび側面ガラスの各々における透過率が70%以上であることが義務づけられている。こうした基準に鑑みても、人が情報を明瞭かつ確実に視認する上では、情報を表示するための光が透過する透過体の透過率が70%以上であることが好ましいと言える。
In the card 100, the multilayer body composed of the first layer 11, the second layer 12, and the third layer 13 preferably has a transmittance of 70% or more in the direction in which the three layers are stacked. Thereby, the image displayed on the card 100 is easily visually recognized. In this case, in particular, when an optical element that is a multilayer body composed of the first layer 11, the second layer 12, and the third layer 13 covers the identification information, the ease of identification is improved. For example, Article 195 in the safety standard for road transport vehicles requires that the transmittance of each of the front glass and side glass of an automobile is 70% or more. Even in view of these standards, it can be said that it is preferable that the transmittance of a transmission body through which light for displaying information is transmitted is 70% or more in order for a person to view information clearly and reliably.
透明な多層体の透過率は、分光光度計を用いて測定することができる。カード100が観察される環境では、光源が太陽光または蛍光灯であることが想定される。そのため、カード100に用いられる多層体の透過率として、500nmの波長における透過率を測定することが好ましい。多層体の透過率は、JIS K7375:2008「プラスチックの全光線透過率及び全光線反射率の求め方」に準拠する方法で測定することが好ましい。
The transmittance of the transparent multilayer body can be measured using a spectrophotometer. In an environment where the card 100 is observed, it is assumed that the light source is sunlight or a fluorescent lamp. Therefore, it is preferable to measure the transmittance at a wavelength of 500 nm as the transmittance of the multilayer body used in the card 100. The transmittance of the multilayer body is preferably measured by a method in accordance with JIS K7375: 2008 “How to obtain total light transmittance and total light reflectance of plastic”.
[カードの作用]
図40から図46を参照して、カード100の作用を説明する。以下では、カード100の第1実例における作用と、カード100の第2実例における作用とを順に説明する。なお、カード100の第1実例は、サブ波長格子11Gとレリーフ面とを含む光学素子を備え、かつ、観察者の目視によってカード100の真正が検証される構成である。これに対して、カード100の第2実例は、サブ波長格子11Gを含む一方で、レリーフ面を含まない光学素子を備え、かつ、検証器によってカード100の真正が検証される構成である。 [Card effects]
The operation of thecard 100 will be described with reference to FIGS. Below, the effect | action in the 1st example of the card | curd 100 and the effect | action in the 2nd example of the card | curd 100 are demonstrated in order. In addition, the 1st example of the card | curd 100 is a structure provided with the optical element containing the subwavelength grating 11G and a relief surface, and the authenticity of the card | curd 100 is verified by an observer's visual observation. On the other hand, the second example of the card 100 is configured to include an optical element that includes the sub-wavelength grating 11G but does not include a relief surface, and the verifier verifies the authenticity of the card 100.
図40から図46を参照して、カード100の作用を説明する。以下では、カード100の第1実例における作用と、カード100の第2実例における作用とを順に説明する。なお、カード100の第1実例は、サブ波長格子11Gとレリーフ面とを含む光学素子を備え、かつ、観察者の目視によってカード100の真正が検証される構成である。これに対して、カード100の第2実例は、サブ波長格子11Gを含む一方で、レリーフ面を含まない光学素子を備え、かつ、検証器によってカード100の真正が検証される構成である。 [Card effects]
The operation of the
[第1実例]
図40から図43を参照して、カード100の第1実例における作用を説明する。
図40は、観察者OBが目視によってカード100の真正を検証する方法を模式的に示している。 [First example]
The operation of thecard 100 in the first example will be described with reference to FIGS.
FIG. 40 schematically shows a method in which the observer OB verifies the authenticity of thecard 100 by visual observation.
図40から図43を参照して、カード100の第1実例における作用を説明する。
図40は、観察者OBが目視によってカード100の真正を検証する方法を模式的に示している。 [First example]
The operation of the
FIG. 40 schematically shows a method in which the observer OB verifies the authenticity of the
図40が示すように、観察者OBは、カード100を手に持った状態でカード100を視認する。基準平面Ph0は、観察者OBがカード100の観察を開始するときにカード100が配置される平面である。基準平面Ph0は、カード100の真正を検証するときのベース面である。観察者OBは、基準平面Ph0に配置したカード100を、第1平面Ph1、第2平面Ph2、および、第3平面Ph3の各々に沿うように傾ける。観察者OBは、カード100が各平面Ph1,Ph2,Ph3の各々に位置するときに、カード100を観察する。基準平面Ph0と第1平面Ph1とが形成する角度が第1角度θ1であり、基準平面Ph0と第2平面Ph2とが形成する角度が第2角度θ2であり、基準平面Ph0と第3平面Ph3とが形成する角度が第3角度θ3である。第1角度θ1は、第2角度θ2および第3角度θ3よりも大きく、かつ、第2角度θ2は、第3角度θ3よりも大きい。
40, the observer OB visually recognizes the card 100 while holding the card 100 in his / her hand. The reference plane Ph0 is a plane on which the card 100 is arranged when the observer OB starts observing the card 100. The reference plane Ph0 is a base plane used when verifying the authenticity of the card 100. The observer OB tilts the card 100 arranged on the reference plane Ph0 along each of the first plane Ph1, the second plane Ph2, and the third plane Ph3. The observer OB observes the card 100 when the card 100 is positioned on each of the planes Ph1, Ph2, and Ph3. The angle formed by the reference plane Ph0 and the first plane Ph1 is the first angle θ1, the angle formed by the reference plane Ph0 and the second plane Ph2 is the second angle θ2, and the reference plane Ph0 and the third plane Ph3. Is the third angle θ3. The first angle θ1 is larger than the second angle θ2 and the third angle θ3, and the second angle θ2 is larger than the third angle θ3.
光源LSは、カード100に対して観察者OBとは反対側に位置している。言い換えれば、光源LSは、観察者OBの前方に位置している。光源LS、カード100、および、観察者OBは、カード100に入射した光源LSの光が、カード100において、観察者OBに向けて反射されるような相対位置で配置されている。カード100を観察するときには、点光源からの光が一方向からカード100に入射することが好ましい。しかしながら、実際には、カード100の観察時には、蛍光灯からの光や外光が、様々な方向からカード100に入射する。この場合であっても、カード100に入射した光に、カード100において観察者OBに向けて反射される光が含まれていれば、カード100から射出される光の輝度が低くなるものの、観察者OBは、カード100が表示する情報を視認することができる。
The light source LS is located on the side opposite to the observer OB with respect to the card 100. In other words, the light source LS is located in front of the observer OB. The light source LS, the card 100, and the observer OB are arranged at relative positions such that the light of the light source LS incident on the card 100 is reflected toward the observer OB on the card 100. When observing the card 100, it is preferable that light from a point light source is incident on the card 100 from one direction. However, in actuality, when the card 100 is observed, light from a fluorescent lamp or external light enters the card 100 from various directions. Even in this case, if the light incident on the card 100 includes light reflected toward the observer OB in the card 100, the luminance of the light emitted from the card 100 is reduced, but the observation is performed. The person OB can visually recognize the information displayed on the card 100.
図41から図43は、それぞれカード100が表示する像を示している。図41は、カード100が第1平面Ph1に配置されたときにカード100が示す像であり、図42は、カード100が第2平面Ph2に配置されたときにカード100が示す像である。図43は、カード100が第3平面Ph3に配置されたときにカード100が示す像である。なお、カード100は、第1像P1、第2像P2、および、第3像P3を表示することが可能に構成されている。
41 to 43 show images displayed on the card 100, respectively. FIG. 41 is an image that the card 100 shows when the card 100 is arranged on the first plane Ph1, and FIG. 42 is an image that the card 100 shows when the card 100 is arranged on the second plane Ph2. FIG. 43 is an image that the card 100 shows when the card 100 is arranged on the third plane Ph3. The card 100 is configured to be able to display the first image P1, the second image P2, and the third image P3.
図41が示すように、観察者OBがカード100を第1平面Ph1に配置したときには、カード100は、第3像P3のみを表示している。なお、第3像P3は、カード100を識別する識別情報を含んでもよい。第3像P3が含む所有者を識別できる識別情報は、所有者の顔画像、氏名、および、ID番号などである。観察者OBがカード100を第1平面Ph1に配置したときには、カード100は、第3像P3の全てを、表面100Fを介して外部に表示する。
41, when the observer OB places the card 100 on the first plane Ph1, the card 100 displays only the third image P3. The third image P3 may include identification information for identifying the card 100. The identification information that can identify the owner included in the third image P3 includes the face image, name, and ID number of the owner. When the observer OB places the card 100 on the first plane Ph1, the card 100 displays the entire third image P3 to the outside through the surface 100F.
図42が示すように、観察者OBがカード100を第2平面Ph2に配置したときには、カード100は、第2像P2を表示する。カード100の表面100Fと対向する平面視において、第2像P2は第3像P3の一部に重なる。そのため、本実施形態では、第3像P3の一部は、第2像P2によって隠蔽される。なお、第2像P2の輝度は、第3像P3の一部を完全に隠蔽しない程度の輝度であってもよい。
42, when the observer OB places the card 100 on the second plane Ph2, the card 100 displays the second image P2. In a plan view facing the surface 100F of the card 100, the second image P2 overlaps a part of the third image P3. Therefore, in the present embodiment, a part of the third image P3 is concealed by the second image P2. The luminance of the second image P2 may be a luminance that does not completely hide part of the third image P3.
図43が示すように、観察者OBがカード100を第3平面Ph3に配置したときには、カード100は、第1像P1を表示する。一方で、カード100は、第2像P2を表示しない。カード100の表面100Fと対向する平面視において、第1像P1は第3像P3の一部に重なる。そのため、本実施形態では、第3像P3の一部は、第1像P1によって隠蔽される。なお、第1像P1の輝度は、第3像P3の一部を完全には隠蔽しない程度の輝度であってもよい。
43, when the observer OB places the card 100 on the third plane Ph3, the card 100 displays the first image P1. On the other hand, the card 100 does not display the second image P2. In a plan view facing the surface 100F of the card 100, the first image P1 overlaps a part of the third image P3. Therefore, in the present embodiment, a part of the third image P3 is hidden by the first image P1. Note that the luminance of the first image P1 may be a luminance that does not completely hide a part of the third image P3.
このように、観察者OBがカード100を基準平面Ph0に対して前方に傾けた場合に、カード100は、カード100の位置に応じて、第1像P1および第2像P2を表示する。言い換えれば、観察者OBが、観察空間において、カード100のなかで観察者OBが把持した部分の位置をほぼ固定した状態で、カード100の表面100Fを観察者OBに近づけた場合に、カード100の位置に応じて、カード100は、第1像P1および第2像P2を表示する。
Thus, when the observer OB tilts the card 100 forward with respect to the reference plane Ph0, the card 100 displays the first image P1 and the second image P2 according to the position of the card 100. In other words, when the observer OB brings the surface 100F of the card 100 close to the observer OB in a state where the position of the portion held by the observer OB in the card 100 is substantially fixed in the observation space, the card 100 Depending on the position, the card 100 displays the first image P1 and the second image P2.
なお、観察者OBが、第2平面Ph2をベース面として、カード100を左右に傾けた場合にも、観察者OBは、カード100が表示する第1像P1および第2像P2を視認することは可能である。言い換えれば、観察者OBが、観察空間において、カード100の表面100Fと観察者OBとの間の距離をほぼ変えずに、カード100を傾けたときにも、観察者OBは、第1像P1および第2像P2を視認することは可能である。しかしながら、観察者OBは、第2像P2を容易に視認することができる一方で、観察者OBは、以下の理由から、限られた観察条件においてのみ第1像P1を観察することができる。
Even when the observer OB tilts the card 100 left and right with the second plane Ph2 as the base surface, the observer OB visually recognizes the first image P1 and the second image P2 displayed on the card 100. Is possible. In other words, even when the observer OB tilts the card 100 without substantially changing the distance between the surface 100F of the card 100 and the observer OB in the observation space, the observer OB does not change the first image P1. It is possible to visually recognize the second image P2. However, the observer OB can easily view the second image P2, while the observer OB can observe the first image P1 only under limited observation conditions for the following reason.
上述したように、第1像P1は、カード100の表面に対する放線を含む平面に対して、光源LSと観察者OBとが対象な角度に位置する場合にのみ観察者OBによって視認される。そのため、第2平面Ph2を基準としてカード100を左右に傾けた場合には、第2平面Ph2が基準平面Ph0と形成する角度が第3角度θ3である必要がある。ここで、第2平面Ph2は、観察者OBが無意識にカード100を手に取ったときにカード100を配置する平面である。そのため、第2平面Ph2と基準平面Ph0とが形成する角度が第3角度θ3に一致する確率は低い。これに対して、観察者OBが基準平面Ph0に対してカード100を前後に傾けたときに、観察者OBが第3平面Ph3にカード100を配置する確率が高い。
As described above, the first image P1 is viewed by the observer OB only when the light source LS and the observer OB are positioned at a target angle with respect to the plane including the ray with respect to the surface of the card 100. Therefore, when the card 100 is tilted left and right with respect to the second plane Ph2, the angle formed by the second plane Ph2 and the reference plane Ph0 needs to be the third angle θ3. Here, the second plane Ph2 is a plane on which the card 100 is arranged when the observer OB unconsciously picks up the card 100. Therefore, the probability that the angle formed by the second plane Ph2 and the reference plane Ph0 matches the third angle θ3 is low. In contrast, when the observer OB tilts the card 100 back and forth with respect to the reference plane Ph0, the probability that the observer OB places the card 100 on the third plane Ph3 is high.
それゆえに、認証体であるカード100を観察するときには、観察者OBの視線を含む平面に対して斜め上方に光源LSが位置する状態で、観察者OBがカード100を前後に傾けることで、真正の判定をできる。これにより、観察者OBが、第1像P1および第2像P2の両方を観察する確率が高まる。そのため、観察者OBによるカード100の真正の検証が、正確に行われやすい。
Therefore, when observing the card 100 as the authentication body, the observer OB tilts the card 100 back and forth while the light source LS is positioned obliquely upward with respect to the plane including the line of sight of the observer OB. Can be determined. This increases the probability that the observer OB observes both the first image P1 and the second image P2. Therefore, the authentic verification of the card 100 by the observer OB is easily performed accurately.
[第2実例]
図44から図46を参照して、カード100の第2実例における作用を説明する。
図44は、検証器Vによってカード100の真正を検証する方法を模式的に示している。 [Second example]
The operation of thecard 100 in the second example will be described with reference to FIGS.
FIG. 44 schematically shows a method of verifying the authenticity of thecard 100 by the verifier V.
図44から図46を参照して、カード100の第2実例における作用を説明する。
図44は、検証器Vによってカード100の真正を検証する方法を模式的に示している。 [Second example]
The operation of the
FIG. 44 schematically shows a method of verifying the authenticity of the
図44が示すように、カード100の表面100Fに、光源LSからの光を入射角αで入射させ、かつ、射出角βで反射される反射光が検証器Vに入力されるように、カード100の真正を検証するための環境を設定する。検証器Vは、画像を読み取ることが可能なカメラ、および、輝度の分布を読み取ることが可能なセンサーなどとできる。検証器Vは、第1像P1を画像、もしくは、輝度などの光学的な情報として処理することが可能な機器であればよい。
As shown in FIG. 44, the card 100 is designed such that the light from the light source LS is incident on the surface 100F of the card 100 at the incident angle α and the reflected light reflected at the emission angle β is input to the verifier V. An environment for verifying the authenticity of 100 is set. The verifier V can be a camera capable of reading an image, a sensor capable of reading a luminance distribution, and the like. The verifier V may be any device that can process the first image P1 as an image or optical information such as luminance.
図45は、真正のカード100が表示する像を示している。一方で、図46は、偽のカード200が表示する像を示している。なお、図45および図46は、ある観察条件において、各カード100,200が表示する像を示している。
FIG. 45 shows an image displayed by the genuine card 100. On the other hand, FIG. 46 shows an image displayed by the fake card 200. 45 and 46 show images displayed on the cards 100 and 200 under certain observation conditions.
図45が示すように、真正のカード100は、第3像P3の一部としてQRコード(登録商標)P3aを示している。
これに対して、図46が示すように、偽のカード200は、第3像P3の一部としてQRコードP3aを示すと同時に、第1像P1も表面200Fを介して表示している。ここで、検証器Vは、上述した観察条件において、カード100が表示するQRコードP3aを読み取った場合に、カード100が真正であると検証する。この場合には、カード100は、第3像P3の一部としてQRコードP3aを表示し、かつ、QRコードP3aが他の像とは重ならないため、検証器Vは、カード100を真正のカード100であると検証できる。これに対して、カード200は、第3像P3の一部としてQRコードP3aを表示するものの、カード100の厚さ方向から見て、QRコードP3aに重なるように第1像P1を表示する。言い換えれば、検証器Vが読み取った情報には、QRコード以外の情報も含まれる。そのため、検証器Vは、カード200が偽物であると検証できる。 As shown in FIG. 45, thegenuine card 100 shows a QR code (registered trademark) P3a as a part of the third image P3.
On the other hand, as shown in FIG. 46, thefake card 200 displays the QR code P3a as a part of the third image P3 and at the same time displays the first image P1 through the surface 200F. Here, the verifier V verifies that the card 100 is authentic when the QR code P3a displayed on the card 100 is read under the above-described observation conditions. In this case, since the card 100 displays the QR code P3a as a part of the third image P3 and the QR code P3a does not overlap with other images, the verifier V determines that the card 100 is a genuine card. It can be verified that it is 100. In contrast, the card 200 displays the QR code P3a as a part of the third image P3, but displays the first image P1 so as to overlap the QR code P3a when viewed from the thickness direction of the card 100. In other words, the information read by the verifier V includes information other than the QR code. Therefore, the verifier V can verify that the card 200 is a fake.
これに対して、図46が示すように、偽のカード200は、第3像P3の一部としてQRコードP3aを示すと同時に、第1像P1も表面200Fを介して表示している。ここで、検証器Vは、上述した観察条件において、カード100が表示するQRコードP3aを読み取った場合に、カード100が真正であると検証する。この場合には、カード100は、第3像P3の一部としてQRコードP3aを表示し、かつ、QRコードP3aが他の像とは重ならないため、検証器Vは、カード100を真正のカード100であると検証できる。これに対して、カード200は、第3像P3の一部としてQRコードP3aを表示するものの、カード100の厚さ方向から見て、QRコードP3aに重なるように第1像P1を表示する。言い換えれば、検証器Vが読み取った情報には、QRコード以外の情報も含まれる。そのため、検証器Vは、カード200が偽物であると検証できる。 As shown in FIG. 45, the
On the other hand, as shown in FIG. 46, the
本実施形態では、カード100,200が表示するコードとしてQRコードP3aを示したが、カード100,200が表示するコードは検証器Vによる読み取りが可能な他のコードでもよい。他のコードは、バーコードとできる。なお、検証器Vによる検証には、第3像P3ではなく、第1像P1を用いてもよいし、第2像P2を用いてもよい。
In the present embodiment, the QR code P3a is shown as the code displayed on the cards 100 and 200, but the code displayed on the cards 100 and 200 may be another code that can be read by the verifier V. Other codes can be bar codes. For verification by the verifier V, the first image P1 or the second image P2 may be used instead of the third image P3.
また、上述した実例では、検証器Vの位置が一カ所に固定されているが、検証器Vが可動式であり、かつ、検証器Vが、上述した射出角βに加えて、射出角βとは異なる角度である角度γでもカード100から射出された光を読み取ってもよい。この場合には、互いに異なる角度において得られた2つの情報を用いることによって、カード100の真正を二段階で検証することができる。これにより、真正検証の確度をより高めることができる。
Further, in the above-described example, the position of the verifier V is fixed at one place. The light emitted from the card 100 may be read even at an angle γ that is different from the angle γ. In this case, the authenticity of the card 100 can be verified in two stages by using two pieces of information obtained at different angles. Thereby, the accuracy of authenticity verification can be further increased.
[光学素子の形成材料]
以下、光学素子の形成に用いることが可能な材料を説明する。以下では、光学素子のなかで、第1層11、第2層12、および、第3層13の各々を形成するための材料を説明する。 [Optical element forming material]
Hereinafter, materials that can be used for forming the optical element will be described. Below, the material for forming each of the1st layer 11, the 2nd layer 12, and the 3rd layer 13 in an optical element is demonstrated.
以下、光学素子の形成に用いることが可能な材料を説明する。以下では、光学素子のなかで、第1層11、第2層12、および、第3層13の各々を形成するための材料を説明する。 [Optical element forming material]
Hereinafter, materials that can be used for forming the optical element will be described. Below, the material for forming each of the
[第1層および第3層]
第1層11および第3層13の各々の材料は、以下の各種の樹脂を本質的に含有できる。各層を形成する材料の実例は、ポリ(メタ)アクリル系樹脂、ポリウレタン系樹脂、フッ素系樹脂、シリコーン系樹脂、ポリイミド系樹脂、エポキシ系樹脂、ポリエチレン系樹脂、ポリプロピレン系樹脂、メタクリル系樹脂、ポリメチルペンテン系樹脂、環状ポリオレフィン系樹脂、ポリスチレン系樹脂、ポリ塩化ビニル系樹脂、ポリカーボネート系樹脂、ポリエステル系樹脂、ポリアミド系樹脂、ポリアミドイミド系樹脂、ポリアリールフタレート系樹脂、ポリスルホン系樹脂、ポリフェニレンスルフィド系樹脂、ポリエーテルスルホン系樹脂、ポリエチレンナフタレート系樹脂、ポリエーテルイミド系樹脂、アセタール系樹脂、および、セルロース系樹脂とできる。第1層および第3層の形成材料には、これらの樹脂のうちの1つのみを用いてもよいし、2つ以上の混合または複合としてもよい。第1層11および第3層13を形成するための材料は、硬化剤、可塑剤、分散剤、各種レベリング剤、紫外線吸収剤、抗酸化剤、粘性改質剤、潤滑剤、および、光安定化剤などの少なくとも1つを含んでもよい。 [First and third layers]
Each material of thefirst layer 11 and the third layer 13 can essentially contain the following various resins. Examples of materials forming each layer are poly (meth) acrylic resin, polyurethane resin, fluorine resin, silicone resin, polyimide resin, epoxy resin, polyethylene resin, polypropylene resin, methacrylic resin, poly Methylpentene resin, cyclic polyolefin resin, polystyrene resin, polyvinyl chloride resin, polycarbonate resin, polyester resin, polyamide resin, polyamideimide resin, polyarylphthalate resin, polysulfone resin, polyphenylene sulfide Resins, polyethersulfone resins, polyethylene naphthalate resins, polyetherimide resins, acetal resins, and cellulose resins can be used. As the material for forming the first layer and the third layer, only one of these resins may be used, or two or more of them may be mixed or combined. The materials for forming the first layer 11 and the third layer 13 are a curing agent, a plasticizer, a dispersant, various leveling agents, an ultraviolet absorber, an antioxidant, a viscosity modifier, a lubricant, and a light stabilizer. It may contain at least one such as an agent.
第1層11および第3層13の各々の材料は、以下の各種の樹脂を本質的に含有できる。各層を形成する材料の実例は、ポリ(メタ)アクリル系樹脂、ポリウレタン系樹脂、フッ素系樹脂、シリコーン系樹脂、ポリイミド系樹脂、エポキシ系樹脂、ポリエチレン系樹脂、ポリプロピレン系樹脂、メタクリル系樹脂、ポリメチルペンテン系樹脂、環状ポリオレフィン系樹脂、ポリスチレン系樹脂、ポリ塩化ビニル系樹脂、ポリカーボネート系樹脂、ポリエステル系樹脂、ポリアミド系樹脂、ポリアミドイミド系樹脂、ポリアリールフタレート系樹脂、ポリスルホン系樹脂、ポリフェニレンスルフィド系樹脂、ポリエーテルスルホン系樹脂、ポリエチレンナフタレート系樹脂、ポリエーテルイミド系樹脂、アセタール系樹脂、および、セルロース系樹脂とできる。第1層および第3層の形成材料には、これらの樹脂のうちの1つのみを用いてもよいし、2つ以上の混合または複合としてもよい。第1層11および第3層13を形成するための材料は、硬化剤、可塑剤、分散剤、各種レベリング剤、紫外線吸収剤、抗酸化剤、粘性改質剤、潤滑剤、および、光安定化剤などの少なくとも1つを含んでもよい。 [First and third layers]
Each material of the
第1層11および第3層13の各々を形成する方法は、熱エンボス法、キャスト法、および、フォトポリマー法とできる。フォトポリマー法では、プラスチックフィルムなどの平坦な基材と、金属製のスタンパとの間に、放射線硬化樹脂を流し込む。そして、放射線の照射によって放射線硬化樹脂を硬化させた後、硬化された樹脂膜を基材ごと金属製のスタンパから剥離する。フォトポリマー法では、熱可塑性樹脂を利用するプレス法やキャスト法に比べて、微細凹凸構造の転写精度が高く、耐熱性や耐薬品性にも優れている。
The method of forming each of the first layer 11 and the third layer 13 can be a heat embossing method, a casting method, and a photopolymer method. In the photopolymer method, a radiation curable resin is poured between a flat substrate such as a plastic film and a metal stamper. Then, after the radiation curable resin is cured by irradiation with radiation, the cured resin film is peeled off from the metal stamper together with the base material. In the photopolymer method, compared with the press method and the cast method using a thermoplastic resin, the transfer accuracy of the fine concavo-convex structure is high, and the heat resistance and chemical resistance are also excellent.
[第2層]
第2層12の材料には、上述したように、光透過性を有した誘電体を用いることができる。誘電体には、金属、金属化合物、ケイ素化合物、または、これらの混合物を用いることができる。誘電体の実例は、ZnS、ZnO、ZnSe、SiNx、SiOx、TixOx、Ta2O5、Cr2O3、ZrO2、Nb2O5、および、ITOとできる。 [Second layer]
As the material of thesecond layer 12, as described above, a light-transmitting dielectric can be used. As the dielectric, a metal, a metal compound, a silicon compound, or a mixture thereof can be used. Examples of dielectrics can be ZnS, ZnO, ZnSe, SiN x , SiO x , Ti x O x , Ta 2 O 5 , Cr 2 O 3 , ZrO 2 , Nb 2 O 5 , and ITO.
第2層12の材料には、上述したように、光透過性を有した誘電体を用いることができる。誘電体には、金属、金属化合物、ケイ素化合物、または、これらの混合物を用いることができる。誘電体の実例は、ZnS、ZnO、ZnSe、SiNx、SiOx、TixOx、Ta2O5、Cr2O3、ZrO2、Nb2O5、および、ITOとできる。 [Second layer]
As the material of the
第2層12を形成する方法は、物理気相成長法、および、化学気相成長法などとできる。物理気相成長法は、真空蒸着法、スパッタリング法、イオンプレーティング法、および、イオンクラスタービーム法とできる。化学気相成長法は、プラズマ化学気相成長法、熱化学気相成長法、および、光化学気相成長法とできる。真空蒸着法は生産性が向上しやすい。イオンプレーティング法は、良い膜質の反射層を得やすい。なお、物理気相成長法および化学気相成長法における成膜条件は、反射層の形成材料に応じて適宜選択されればよい。
The method of forming the second layer 12 can be a physical vapor deposition method, a chemical vapor deposition method, or the like. The physical vapor deposition method can be a vacuum deposition method, a sputtering method, an ion plating method, and an ion cluster beam method. The chemical vapor deposition method can be a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, or a photochemical vapor deposition method. The vacuum deposition method is easy to improve productivity. The ion plating method makes it easy to obtain a reflective layer with good film quality. Note that film formation conditions in the physical vapor deposition method and the chemical vapor deposition method may be appropriately selected according to the material for forming the reflective layer.
第2層12は、各種の印刷方式、キャスト方式、および、ダイコート方式などで形成することもできる。この場合には、上述した誘電体の少なくとも1つが分散した樹脂で、第2層12を形成することができる。
The second layer 12 can also be formed by various printing methods, casting methods, die coating methods, and the like. In this case, the second layer 12 can be formed of a resin in which at least one of the dielectrics described above is dispersed.
[試験例]
[試験例1]
以下、試験例1を説明する。試験例1は、上述した第8実施形態の認証体に対応する試験例である。試験例1では、第1層11を含む第1転写箔と、レリーフ層61を含む第2転写箔とを準備した。そして、第1転写箔の一部を第1基材65に転写し、かつ、第2転写箔の一部を第2基材66に転写した。第2基材66としてレーザー光線の照射によって発色する基材を用いた。第1基材65と第2基材66とをラミネートすることによって、試験例1の認証体としてIDカードを得た。 [Test example]
[Test Example 1]
Hereinafter, Test Example 1 will be described. Test Example 1 is a test example corresponding to the authentication body of the eighth embodiment described above. In Test Example 1, a first transfer foil including thefirst layer 11 and a second transfer foil including the relief layer 61 were prepared. A part of the first transfer foil was transferred to the first base material 65, and a part of the second transfer foil was transferred to the second base material 66. As the second base material 66, a base material that develops color when irradiated with a laser beam was used. By laminating the first base material 65 and the second base material 66, an ID card was obtained as an authentication body of Test Example 1.
[試験例1]
以下、試験例1を説明する。試験例1は、上述した第8実施形態の認証体に対応する試験例である。試験例1では、第1層11を含む第1転写箔と、レリーフ層61を含む第2転写箔とを準備した。そして、第1転写箔の一部を第1基材65に転写し、かつ、第2転写箔の一部を第2基材66に転写した。第2基材66としてレーザー光線の照射によって発色する基材を用いた。第1基材65と第2基材66とをラミネートすることによって、試験例1の認証体としてIDカードを得た。 [Test example]
[Test Example 1]
Hereinafter, Test Example 1 will be described. Test Example 1 is a test example corresponding to the authentication body of the eighth embodiment described above. In Test Example 1, a first transfer foil including the
より詳しくは、第1転写箔を製造するときに、まず、厚さが38μmであるPETフィルム(ルミラー(登録商標)、東レ(株))を支持層として準備した。支持層が備える1つの面に、剥離層用インキを塗布し、剥離層用インキを乾燥させることによって、剥離層68を得た。剥離層68の厚さは1μmであった。次いで、剥離層68上に第1層用インキをグラビア印刷法によって塗工した後、第1層用インキを乾燥させた。乾燥後の第1層用インキの厚さは2μmであった。そして、乾燥後の第1層用インキに、サブ波長格子11Gを形成するための原版を押し当てることによって、サブ波長格子11Gを成形した。なお、成形時において、プレス圧力を2kgf/cm2に設定し、プレス温度を80℃に設定し、プレススピードを10m/minに設定した。
More specifically, when manufacturing the first transfer foil, first, a PET film (Lumirror (registered trademark), Toray Industries, Inc.) having a thickness of 38 μm was prepared as a support layer. The release layer 68 was obtained by applying the release layer ink to one surface of the support layer and drying the release layer ink. The thickness of the release layer 68 was 1 μm. Next, the first layer ink was applied onto the release layer 68 by a gravure printing method, and then the first layer ink was dried. The thickness of the first layer ink after drying was 2 μm. And the subwavelength grating 11G was shape | molded by pressing the original for forming the subwavelength grating 11G to the ink for 1st layers after drying. At the time of molding, the press pressure was set to 2 kgf / cm 2 , the press temperature was set to 80 ° C., and the press speed was set to 10 m / min.
成型と同時に、支持層に対して剥離層68とは反対側から、第1層用インキに紫外線を照射した。紫外線の照射には、高圧水銀灯を用い、かつ、高圧水銀灯の出力を300mJ/cm2に設定した。これにより、第1層用インキを硬化させることによって、第1層11を得た。そして、第1層11上に、50nmの厚さを有するTiO2膜を真空蒸着によって形成した。これにより、第2層12が得られた。次いで、接着層用インキを塗工し、接着層用インキを乾燥させることによって、2.5μm以上4μm以下の厚さを有し、接着層として機能する第3層13を得た。なお、乾燥時の温度を120℃に設定し、時間を45秒に設定した。なお、第2転写箔を形成するときには、レリーフ面61Reの成形に用いる原版をサブ波長格子11Gの成形に用いる原版と異ならせる以外は、第1転写箔と同じ方法を用いた。
Simultaneously with the molding, the first layer ink was irradiated with ultraviolet rays from the side opposite to the release layer 68 with respect to the support layer. A high pressure mercury lamp was used for ultraviolet irradiation, and the output of the high pressure mercury lamp was set to 300 mJ / cm 2 . Thereby, the 1st layer 11 was obtained by hardening the ink for 1st layers. Then, a TiO 2 film having a thickness of 50 nm was formed on the first layer 11 by vacuum deposition. Thereby, the second layer 12 was obtained. Next, the adhesive layer ink was applied, and the adhesive layer ink was dried to obtain a third layer 13 having a thickness of 2.5 μm to 4 μm and functioning as an adhesive layer. The drying temperature was set to 120 ° C., and the time was set to 45 seconds. When forming the second transfer foil, the same method as the first transfer foil was used, except that the original used for forming the relief surface 61Re was different from the original used for forming the sub-wavelength grating 11G.
上述した剥離層用インキ、第1層用インキ、レリーフ層用インキ、第3層用インキ、および、接着層用インキとして、以下の組成を有するインキを用いた。
The ink having the following composition was used as the above-described release layer ink, first layer ink, relief layer ink, third layer ink, and adhesive layer ink.
[剥離層用インキ]
アクリル樹脂 70.0質量部
メチルエチルケトン 30.0質量部 [Ink for release layer]
Acrylic resin 70.0 parts by mass Methyl ethyl ketone 30.0 parts by mass
アクリル樹脂 70.0質量部
メチルエチルケトン 30.0質量部 [Ink for release layer]
Acrylic resin 70.0 parts by mass Methyl ethyl ketone 30.0 parts by mass
[第1層用インキ/レリーフ層用インキ]
紫外線硬化型アクリルアクリレート樹脂 70.0質量部
メチルエチルケトン 30.0質量部 [Ink for first layer / ink for relief layer]
UV curable acrylic acrylate resin 70.0 parts by weight Methyl ethyl ketone 30.0 parts by weight
紫外線硬化型アクリルアクリレート樹脂 70.0質量部
メチルエチルケトン 30.0質量部 [Ink for first layer / ink for relief layer]
UV curable acrylic acrylate resin 70.0 parts by weight Methyl ethyl ketone 30.0 parts by weight
[第3層用インキ/接着層用インキ]
ウレタン樹脂 50.0質量部
シリカフィラー 10.0質量部
メチルエチルケトン 40.0質量部 [3rd layer ink / adhesive layer ink]
Urethane resin 50.0 parts by mass Silica filler 10.0 parts by mass Methyl ethyl ketone 40.0 parts by mass
ウレタン樹脂 50.0質量部
シリカフィラー 10.0質量部
メチルエチルケトン 40.0質量部 [3rd layer ink / adhesive layer ink]
Urethane resin 50.0 parts by mass Silica filler 10.0 parts by mass Methyl ethyl ketone 40.0 parts by mass
第1基材65として、100μmの厚さを有し、かつ、透明なポリカーボネート基材(LEXAN SD8B14、SABIC社製)(LEXANは登録商標)を準備した。第2基材66として、100μmの厚さを有し、かつ、レーザー光線の照射によって発色するポリカーボネート基材(LEXAN SD8B94、SABIC社製)を準備した。第1転写箔を第1基材65に転写した後、支持層を取り除いた。また、第2転写箔を第2基材66に転写した後、支持層を取り除いた。転写時には、電気式のホットスタンプ機を用い、かつ、転写箔に接する面の温度を120℃に設定し、圧力を1.05t/cm2に設定し、かつ、加圧する時間を1秒に設定した。
A transparent polycarbonate substrate (LEXAN SD8B14, manufactured by SABIC) (LEXAN is a registered trademark) having a thickness of 100 μm was prepared as the first substrate 65. As the second base material 66, a polycarbonate base material (LEXAN SD8B94, manufactured by SABIC) which has a thickness of 100 μm and develops color when irradiated with a laser beam was prepared. After the first transfer foil was transferred to the first substrate 65, the support layer was removed. Further, after the second transfer foil was transferred to the second substrate 66, the support layer was removed. At the time of transfer, an electric hot stamping machine is used, the temperature of the surface in contact with the transfer foil is set to 120 ° C., the pressure is set to 1.05 t / cm 2 , and the pressurizing time is set to 1 second. did.
次いで、白色層91として、400μmの厚さを有し、かつ、白色の樹脂フィルム(LEXAN SD8B24、SAVIC社製)を準備した。下部保護層92および上部保護層93として、100μmの厚さを有し、かつ、透明な樹脂フィルム(LEXAN SD8B14)を準備した。そして、下部保護層92、白色層91、第2基材66、第1基材65、および、上部保護層93を記載の順に積み重ねた状態で、これらの層をラミネートした。ラミネート時には、温度を200℃に設定し、圧力を80N/cm2に設定し、加熱および加圧をする時間を25分に設定した。そして、ラミネート後の多層体の一部をカード状に切り出した。
Next, a white resin film (LEXAN SD8B24, manufactured by SAVIC) having a thickness of 400 μm was prepared as the white layer 91. As the lower protective layer 92 and the upper protective layer 93, a transparent resin film (LEXAN SD8B14) having a thickness of 100 μm was prepared. And these layers were laminated in the state which accumulated the lower protective layer 92, the white layer 91, the 2nd base material 66, the 1st base material 65, and the upper protective layer 93 in order of description. At the time of lamination, the temperature was set to 200 ° C., the pressure was set to 80 N / cm 2 , and the heating and pressurizing time was set to 25 minutes. Then, a part of the laminated multilayer body was cut out in a card shape.
レーザー印字機を用いて、多層体に1064nmの波長のレーザー光線を多層体に照射した。これにより、第2基材66に、第1発色部66aと第2発色部66bとを形成した。結果として、試験例1のIDカードを得た。
Using a laser printer, the multilayer body was irradiated with a laser beam having a wavelength of 1064 nm. As a result, the first coloring portion 66a and the second coloring portion 66b were formed on the second base material 66. As a result, the ID card of Test Example 1 was obtained.
なお、図47は、IDカードが表示する有色像である第1像を撮影した画像であり、図48は、IDカードが表示するモノクローム像である第2像を撮影した画像である。図47および図48が示すように、IDカードは、第1像と第2像との両方を表示することが可能であることが認められた。
47 is an image of a first image that is a colored image displayed on the ID card, and FIG. 48 is an image of a second image that is a monochrome image displayed on the ID card. As FIG. 47 and FIG. 48 show, it was recognized that the ID card can display both the first image and the second image.
[試験例2]
以下、試験例2を説明する。試験例2の転写箔は、上述した第7実施形態の転写箔に対応する試験例である。試験例2では、まず、試験例1と同じ支持層72を準備した。支持層が備える1つの面に、試験例1と同様の方法で、剥離層73を形成した。そして、試験例1と同様の方法で、剥離層73上に第1層11を形成し、かつ、第1層11上に第2層12を形成した。 [Test Example 2]
Hereinafter, Test Example 2 will be described. The transfer foil of Test Example 2 is a test example corresponding to the transfer foil of the seventh embodiment described above. In Test Example 2, first, thesame support layer 72 as in Test Example 1 was prepared. A release layer 73 was formed on one surface of the support layer by the same method as in Test Example 1. Then, the first layer 11 was formed on the release layer 73 and the second layer 12 was formed on the first layer 11 by the same method as in Test Example 1.
以下、試験例2を説明する。試験例2の転写箔は、上述した第7実施形態の転写箔に対応する試験例である。試験例2では、まず、試験例1と同じ支持層72を準備した。支持層が備える1つの面に、試験例1と同様の方法で、剥離層73を形成した。そして、試験例1と同様の方法で、剥離層73上に第1層11を形成し、かつ、第1層11上に第2層12を形成した。 [Test Example 2]
Hereinafter, Test Example 2 will be described. The transfer foil of Test Example 2 is a test example corresponding to the transfer foil of the seventh embodiment described above. In Test Example 2, first, the
次いで、第1層用インキを用いて第1層11を形成したときと同様の方法で、第3層用インキを塗工し、かつ、第3層用インキを乾燥させた。そして、乾燥後の第3層用インキに、レリーフ面13Reを形成するための原版を押し当てることによって、レリーフ面13Reを成形した。なお、成形時における各種の条件を、サブ波長格子11Gを成形したときと同様の条件に設定した。
Next, the third layer ink was applied and the third layer ink was dried in the same manner as when the first layer 11 was formed using the first layer ink. And the relief surface 13Re was shape | molded by pressing the original plate for forming the relief surface 13Re to the ink for 3rd layers after drying. Various conditions at the time of molding were set to the same conditions as when the sub-wavelength grating 11G was molded.
続いて、第2層12を形成したときと同様の方法で、レリーフ面13Re上に第4層51を形成した。また、試験例1において第3層13を形成したときと同様の方法で、第4層51上に接着層71を形成した。これにより、試験例2の転写箔を得た。なお、試験例2において第3層13を形成するための第3層用インキには、試験例1における第1層用インキと同様の組成を有するインキを用いた。
Subsequently, the fourth layer 51 was formed on the relief surface 13Re in the same manner as when the second layer 12 was formed. In addition, the adhesive layer 71 was formed on the fourth layer 51 in the same manner as when the third layer 13 was formed in Test Example 1. Thereby, the transfer foil of Test Example 2 was obtained. In Test Example 2, an ink having the same composition as that of the first layer ink in Test Example 1 was used as the third layer ink for forming the third layer 13.
以上、本発明の実施形態を、図面を参照して詳述してきたが、具体的な構成は本実施形態に限られるものではなく、本発明の要旨を逸脱しない範囲の設計,本発明が目的とするものと均等な効果をもたらす全ての実施形態をも含むことができる。更に、本開示の範囲は、請求項により画される発明の特徴(feature)に限定されるものではなく、全ての開示されたそれぞれの特徴(feature)、その特徴(feature)のあらゆる組み合わせも含む。
The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and the design and scope of the present invention are within the scope of the present invention. It is possible to include all embodiments that provide an effect equivalent to the above. Further, the scope of the present disclosure is not limited to the features of the invention defined by the claims, but also includes all the disclosed individual features, any combination of the features. .
本開示で用いられる「部分」、「要素」、「画素」、「セグメント」「単位」「印刷体」、「物品」という用語は、物理的存在である。物理的存在は、物質的形態または、物質に囲まれた空間的形態を指すことができる。物理的存在は、構造体とできる。構造体は、特定の機能を有するものとできる。特定の機能を有した構造体の組合せは、各構造体の各機能の組合せにより相乗的効果を発現できる。
The terms “part”, “element”, “pixel”, “segment”, “unit”, “printed body”, and “article” used in the present disclosure are physical entities. A physical entity can refer to a physical form or a spatial form surrounded by a substance. A physical entity can be a structure. The structure may have a specific function. A combination of structures having specific functions can exhibit a synergistic effect by a combination of functions of the structures.
本開示および特に添付の特許請求の範囲内で使用される用語(例えば、添付の特許請求の範囲の本文)は、一般的に、「オープンな」用語として意図される(例えば、「有する」という用語は、「少なくとも有する」と解釈すべきであり、「含む」という用語は「含むがそれに限定されない」などと解釈されるべきである。
Terms used in this disclosure and specifically the appended claims (eg, the body of the appended claims) are generally intended as “open” terms (eg, “have”). The term should be construed as “at least”, the term “including” should be construed as “including but not limited to” and the like.
また、用語、構成、特徴(feature)、側面、実施形態を解釈する場合、必要に応じて図面を参照すべきである。図面により、直接的かつ一義的に導き出せる事項は、テキストと同等に、補正の根拠となるべきである。
Also, when interpreting terms, configurations, features, aspects, and embodiments, drawings should be referenced as necessary. Matters that can be derived directly and unambiguously from the drawings should be the basis for amendment, equivalent to the text.
さらに、特定の数の導入された請求項の記載が意図される場合、そのような意図は、請求項に明示的に記載され、そのような記載がない場合、そのような意図は存在しない。例えば、理解を助けるために、以下の添付の特許請求の範囲は、「少なくとも1つ」および「1つまたは複数」の導入句の使用を含み、請求の列挙を導入することができる。しかしながら、そのような語句の使用は、不定冠詞「a」または「an」によるクレーム記載の導入が、そのようなクレームを含む特定のクレームを、そのような記載を1つだけ含む実施形態に限定することを意味すると解釈されるべきではない。 「1つ以上」または「少なくとも1つ」の冒頭の語句および「a」または「an」などの不定冠詞(例えば、「a」および/または「an」)は、少なくとも「少なくとも」を意味すると解釈されるべきである。「1つ」または「1つ以上」)。請求項の記述を導入するために使用される明確な記事の使用についても同様である。
Furthermore, if a specific number of introduced claims are intended to be stated, such intention is explicitly stated in the claims, and if there is no such description, such intention does not exist. For example, to assist in understanding, the following appended claims can use the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases constrains the introduction of claim descriptions by the indefinite article “a” or “an” to limit specific claims that contain such claims to embodiments that contain only one such description. Should not be construed to mean to do. The opening phrase of “one or more” or “at least one” and an indefinite article such as “a” or “an” (eg, “a” and / or “an”) are interpreted to mean at least “at least”. It should be. “One” or “one or more”). The same is true for the use of clear articles used to introduce claim statements.
Claims (12)
- 第1層と、前記第1層に接する第2層と、前記第2層に接する第3層とを備え、各層が光透過性を有する光学素子であって、
前記第1層は第1の屈折率を有する樹脂製の層であり、前記第2層に接する第1面を有し、前記第1面の少なくとも一部にサブ波長格子を含み、
前記第2層は前記第1の屈折率よりも高い第2の屈折率を有する誘電体製の層であり、前記第1層の前記第1面に接する第2面を有し、前記第2面は前記サブ波長格子に追従した凹凸状であり、
前記第3層は、前記第2の屈折率よりも低い第3の屈折率を有する樹脂製の層であり、
前記第1層、前記第2層、および、前記第3層のいずれかがレリーフ層であり、前記レリーフ層は、複数の反射面を含むレリーフ面を含み、互いに隣り合う前記反射面間のピッチは、前記サブ波長格子のピッチよりも大きく、
前記第2層に対して前記第3層とは反対側に位置する光源から前記光学素子に対し光が照射されている状態を前記光源の側から観察するとき、
前記サブ波長格子は、正反射方向を含む反射方向に前記サブ波長格子の格子周期に応じた色を呈する有色像を表示し、
前記レリーフ面は、前記正反射方向とは異なる方向を含む反射方向にモノクロームの反射光による反射像を表示し、
前記光学素子は、前記有色像および前記反射像を表示しない第1状態、前記有色像を主として表示する第2状態、前記反射像を主として表示する第3状態を有し、
前記光学素子が広がる平面と、観察者の視線を含む平面とが形成する角度が観察角度であり、
前記光学素子は、前記観察角度に応じて前記第1状態、前記第2状態、および、前記第3状態のいずれかにより観察される
光学素子。 An optical element comprising a first layer, a second layer in contact with the first layer, and a third layer in contact with the second layer, each layer having light transparency,
The first layer is a resin layer having a first refractive index, has a first surface in contact with the second layer, and includes a sub-wavelength grating in at least a part of the first surface;
The second layer is a dielectric layer having a second refractive index higher than the first refractive index, and has a second surface in contact with the first surface of the first layer, and the second layer The surface is an uneven shape following the sub-wavelength grating,
The third layer is a resin layer having a third refractive index lower than the second refractive index,
Any one of the first layer, the second layer, and the third layer is a relief layer, and the relief layer includes a relief surface including a plurality of reflection surfaces, and a pitch between the reflection surfaces adjacent to each other. Is larger than the pitch of the sub-wavelength grating,
When observing a state in which light is applied to the optical element from a light source located on the side opposite to the third layer with respect to the second layer,
The sub-wavelength grating displays a colored image exhibiting a color corresponding to a grating period of the sub-wavelength grating in a reflection direction including a regular reflection direction;
The relief surface displays a reflected image by monochrome reflected light in a reflection direction including a direction different from the regular reflection direction,
The optical element has a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, and a third state in which the reflected image is mainly displayed.
The angle formed by the plane in which the optical element spreads and the plane including the observer's line of sight is the observation angle,
The optical element is observed in any one of the first state, the second state, and the third state according to the observation angle. - 第1層と、前記第1層に接する第2層と、前記第2層に接する第3層とを備え、各層が光透過性を有する光学素子であって、
前記第1層は第1の屈折率を有する樹脂製の層であり、前記第2層に接する第1面を有し、前記第1面の少なくとも一部にサブ波長格子を含み、
前記第2層は前記第1の屈折率よりも高い第2の屈折率を有する誘電体製の層であり、前記第1層の前記第1面に接する第2面を有し、前記第2面は前記サブ波長格子に追従した凹凸状であり、
前記第3層は、前記第2の屈折率よりも低い第3の屈折率を有する樹脂製の層であり、
前記光学素子は、前記第1面および前記第2面とは異なるレリーフ面を含むレリーフ層をさらに備え、前記レリーフ面は、複数の反射面を含み、互いに隣り合う前記反射面間のピッチが、前記サブ波長格子のピッチよりも大きく、
前記第2層に対して前記第3層とは反対側に位置する光源から前記光学素子に対し光が照射されている状態を前記光源の側から観察するとき、
前記サブ波長格子は、前記サブ波長格子の格子周期に応じた色を呈する有色像を正反射方向に表示し、
前記レリーフ面は、前記正反射方向とは異なる方向にモノクロームの反射光による反射像を表示し、
前記光学素子は、前記有色像および前記反射像を表示しない第1状態、前記有色像を主として表示する第2状態、前記反射像を主として表示する第3状態を有し、
前記光学素子が広がる平面と、観察者の視線を含む平面とが形成する角度が観察角度であり、
前記光学素子は、前記観察角度に応じて前記第1状態、前記第2状態、および、前記第3状態のいずれかにより観察される
光学素子。 An optical element comprising a first layer, a second layer in contact with the first layer, and a third layer in contact with the second layer, each layer having light transparency,
The first layer is a resin layer having a first refractive index, has a first surface in contact with the second layer, and includes a sub-wavelength grating in at least a part of the first surface;
The second layer is a dielectric layer having a second refractive index higher than the first refractive index, and has a second surface in contact with the first surface of the first layer, and the second layer The surface is an uneven shape following the sub-wavelength grating,
The third layer is a resin layer having a third refractive index lower than the second refractive index,
The optical element further includes a relief layer including a relief surface different from the first surface and the second surface, the relief surface includes a plurality of reflection surfaces, and a pitch between the reflection surfaces adjacent to each other is Larger than the pitch of the sub-wavelength grating,
When observing a state in which light is applied to the optical element from a light source located on the side opposite to the third layer with respect to the second layer,
The sub-wavelength grating displays a colored image exhibiting a color according to the grating period of the sub-wavelength grating in the regular reflection direction,
The relief surface displays a reflected image by monochrome reflected light in a direction different from the regular reflection direction,
The optical element has a first state in which the colored image and the reflected image are not displayed, a second state in which the colored image is mainly displayed, and a third state in which the reflected image is mainly displayed.
The angle formed by the plane in which the optical element spreads and the plane including the observer's line of sight is the observation angle,
The optical element is observed in any one of the first state, the second state, and the third state according to the observation angle. - 前記光学素子は、第1の範囲の観察角度において前記有色像が表示される状態で観察され、第2の範囲の観察角度において前記反射像が表示される状態で観察され、
前記第2の範囲が、前記第1の範囲よりも大きい
請求項1または2に記載の光学素子。 The optical element is observed in a state where the colored image is displayed at an observation angle in a first range, and is observed in a state where the reflected image is displayed at an observation angle in a second range;
The optical element according to claim 1, wherein the second range is larger than the first range. - 前記有色像と前記反射像とは、互いに相関性を有する
請求項1から3のいずれか一項に記載の光学素子。 The optical element according to any one of claims 1 to 3, wherein the colored image and the reflected image have a correlation with each other. - 前記反射像は、前記有色像よりも外側に位置し、かつ、前記有色像の輪郭に沿う形状を有する
請求項4に記載の光学素子。 The optical element according to claim 4, wherein the reflected image has a shape that is located outside the colored image and that follows a contour of the colored image. - 前記有色像および前記反射像のうちの一方が、所定の記号または所定の物体を表す形状を有し、
前記有色像および前記反射像のうちの他方が、当該形状を表す文字である
請求項4に記載の光学素子。 One of the colored image and the reflected image has a shape representing a predetermined symbol or a predetermined object,
The optical element according to claim 4, wherein the other of the colored image and the reflected image is a character representing the shape. - 前記有色像は、前記反射像とともに一組の物体を表す形状を有する
請求項4に記載の光学素子。 The optical element according to claim 4, wherein the colored image has a shape representing a set of objects together with the reflected image. - 前記第2層が、前記レリーフ層であり、
前記レリーフ面は、前記第2層において前記第2面とは反対側の面である
請求項1に記載の光学素子。 The second layer is the relief layer;
The optical element according to claim 1, wherein the relief surface is a surface opposite to the second surface in the second layer. - 請求項1から8のいずれか一項に記載の光学素子と、
前記光学素子を被転写体に接着させるための接着層と、を含む接着体を備える転写箔。 An optical element according to any one of claims 1 to 8,
A transfer foil comprising an adhesive including an adhesive layer for adhering the optical element to a transfer target. - 請求項1から8のいずれか一項に記載の光学素子を備え、前記光学素子が識別情報を覆う
認証体。 An authentication body comprising the optical element according to any one of claims 1 to 8, wherein the optical element covers identification information. - 所定の情報を表示する表示層をさらに備える
請求項10に記載の認証体。 The authentication body according to claim 10, further comprising a display layer that displays predetermined information. - 請求項11に記載の認証体を、観察者の視線を含む平面に対して斜め上方に光源が位置する状態で、前記観察者が前記認証体を前後に傾ける観察することで、前記認証体の真正を検証する
認証体の検証方法。 The authentication body according to claim 11 is observed by tilting the authentication body back and forth by the observer in a state where the light source is positioned obliquely upward with respect to a plane including the line of sight of the observer. Authenticator verification method that verifies authenticity.
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US17/021,769 US11511558B2 (en) | 2018-03-20 | 2020-09-15 | Optical element, transfer foil, authentication medium, and method of verifying authentication medium |
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