KR102403987B1 - Transmissive type diffraction optical elements and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a transmissive diffractive optical element and a manufacturing method thereof. A diffraction pattern includes a plurality of layers. In addition, a minimum distance (Δh) between the plurality of layers in the thickness direction has a maximum light conversion efficiency in a specific section. An objective of the present invention is to provide a transmissive diffractive optical element with excellent productivity and the manufacturing method thereof.

Description

TRANSMISSIVE TYPE DIFFRACTION OPTICAL ELEMENTS AND MANUFACTURING METHOD FOR THE SAME

The present invention relates to a transmission type diffractive optical element and a method for manufacturing the same.

A hologram or a diffractive optical element has been used in the field of forgery prevention technology or depth measurement technology.

A hologram is a medium in which interference fringes that reproduce a three-dimensional image are recorded, and is manufactured using the principle of holography.

More specifically, the hologram reproduces (or implements) a specific image by incident (or irradiating) a reproduction light having the same frequency, wavelength, and phase as a reference light on the interference fringe at a specific angle.

However, the hologram has a fundamental limitation because the reproduced light must have the same phase, wavelength, and frequency as the reference light.

Furthermore, there is a limit to the information that can be recorded as a hologram, so there is a problem in that it is difficult to produce a sophisticated hologram.

Furthermore, there is a problem that the hologram can be easily removed because it is located only in a part of the product or part of the product packaging due to the difficulty in manufacturing.

In order to improve the problem of the hologram, a diffractive optical device to which a semiconductor process, particularly a fine pattern process, is applied has been developed.

The diffractive optical element may be generally classified into a transmissive diffractive optical element, a transflective diffractive optical element, a transmissive diffractive optical element, and the like.

Among these, transmission-type diffractive optical devices are gradually expanding their application fields to wearable smart glasses and AR/VR.

In particular, the transmissive diffractive optical element may be applied to a technology for providing necessary information or images to provide information to a user by irradiating light to a glass surface or helmet of a vehicle, such as an airplane, or the like.

Since the diffractive optical device uses a semiconductor process, in particular, as the number of fine pattern processes increases, productivity decreases.

More specifically, if the number of fine pattern processes increases, clearer and brighter information can be recorded, but the low productivity sharply increases the unit cost of the diffractive optical element or the film itself including the diffractive optical element.

As a result, for example, a problem arises in that the manufacturing cost of the diffractive optical element itself exceeds the price of a product to which the diffractive optical element is attached.

On the other hand, when the fine pattern process is reduced, the sharpness of recorded information is lowered and the light conversion efficiency is reduced.

In particular, since the transmissive diffractive optical element provides an image or information on the back side of the base or substrate, unlike the conventional hologram or reflective diffractive optical element, light absorption by the base or substrate is inevitable.

As a result, since the transmissive diffractive optical element has a high possibility of lowering the light conversion efficiency compared to a hologram or other diffractive optical element, the need to minimize the reduction in light conversion efficiency is further increased.

The present invention is an invention for solving the problems of the conventional transmission-type diffractive optical element described above, and a transmission-type diffractive optical element (hereinafter referred to as diffraction optical elements or DOE) having excellent productivity while securing maximum light conversion efficiency and manufacturing the same The purpose is to provide a method.

Another object of the present invention is to provide a transmission-type diffractive optical element in which the height of an information pattern part in which information is stored is controlled, and a method for manufacturing the same.

Another object of the present invention is to provide a transmission-type diffractive optical device capable of realizing information having a complex image more brightly and clearly, and a method for manufacturing the same.

Furthermore, an object of the present invention is to provide a transmissive diffractive optical device capable of having maximum light conversion efficiency even for input light having various wavelengths by using the characteristics of white light in which various wavelengths are mixed, and a method for manufacturing the same.

A film including a diffractive optical element layer for transmission according to an embodiment of the present invention for achieving the above object, the base; a transmissive diffractive optical element layer positioned on the base and including a diffraction pattern, wherein the diffraction pattern includes a plurality of layers, and the minimum distance (Δh) in the thickness direction between the plurality of layers is 60 to 200 nm, the light conversion efficiency of the diffractive optical element is 63% or more, the value calculated by Equation 1 below, and the total height (H) of the diffraction pattern is 800 to 1350 nm; characterized in that It may be a film with

A film including a diffractive optical element layer for transmission according to another embodiment of the present invention for achieving the above object is a base; a reflective diffractive optical element layer disposed on the base and including a diffraction pattern, wherein the diffraction pattern 122 includes a plurality of layers, the diffraction pattern includes a plurality of layers, the plurality of layers The minimum distance (Δh) in the thickness direction between the layers is 45 to 190 nm, the light conversion efficiency of the diffractive optical element is 51% or more, the value calculated by Equation 1 below, and the diffraction pattern The total height (H) of 800 to 1350 nm may be an anti-counterfeiting film.

(Equation 1)

(In Equation 1 above, {Usig(x')} ² means the intensity of the desired output field, {Uin(ξ)} ² below means the intensity of the input field, and the alpha value is the scaling factor. As , it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated Intensity of the Output Field, x' means the position value of the Desired Output Field (on the xy plane), and ξ is the input It means the position value in the field, and W _sig means the Optimization Region.)

In this case, it is preferable to include a residue positioned between the diffraction pattern and the base.

In this case, the base is preferably transparent PET.

In this case, the diffractive optical element layer is preferably a urethane-based or acrylic-based resin.

Meanwhile, an adhesive layer, an adhesive layer, or a double-sided tape may be additionally included under the base.

Meanwhile, a printed layer may be additionally included on the upper and/or lower portion of the base.

A method of manufacturing a film including a transmission type diffractive optical element layer according to an embodiment of the present invention for achieving the above object, (a) converting an original image image into a DOE (diffraction optical elements) mask to do; (b) separating the DOE mask into 4 or 5 DOE unit masks; (c) manufacturing each of the four or five DOE unit masks; (d) manufacturing a master stamp including a diffraction pattern on the silicon substrate by sequentially exposing and etching each of the DOE unit masks; (e) imprinting the transmissive diffractive optical element using the master stamp; may include.

A transmissive diffractive optical element according to an embodiment of the present invention for achieving the above object includes a diffraction pattern, the diffraction pattern includes a plurality of layers, and a minimum interval in a thickness direction between the plurality of layers (Δh) is 60 to 200 nm, the light conversion efficiency of the diffractive optical element has a value calculated by Equation 1 above 63%, and the total height H of the diffraction pattern is 800 to 1350 nm It may be a phosphorus reflection type diffractive optical element.

A transmissive diffractive optical element according to an embodiment of the present invention for achieving the above object includes a diffraction pattern, the diffraction pattern includes a plurality of layers, and a minimum interval in a thickness direction between the plurality of layers (Δh) is 45 to 190 nm, the light conversion efficiency of the diffractive optical element has a value calculated by Equation 1 above 51%, and the total height H of the diffraction pattern is 800 to 1350 nm It may be a phosphorus reflection type diffractive optical element.

A method for manufacturing a transmission diffractive optical element according to an embodiment of the present invention for achieving the above object, (a) DOE (diffraction optical elements) through Fourier transform and inverse Fourier transform on an original image image converting to a mask; (b) separating the DOE mask into 4 or 5 DOE unit masks; (c) manufacturing each of the four or five DOE unit masks; (d) manufacturing a master stamp including a diffraction pattern on a silicon substrate by sequentially exposing and etching each of the DOE unit masks.

Advantageous Effects of Invention According to the present invention, it is possible to provide a transmission type diffractive optical device having excellent light conversion efficiency characteristics and providing clear information while having high productivity, and a method for manufacturing the same.

Specifically, the transmissive diffractive optical device according to the present invention can provide a transmissive diffractive optical device capable of providing clear information with high light conversion efficiency.

More specifically, the transmissive diffractive optical device according to the present invention has the effect of realizing maximum light conversion efficiency for each of red (R), green (G), and blue (B) components of white light (visible light). can

In addition, according to the method for manufacturing a transmission type diffractive optical element according to the present invention, a method for manufacturing a transmission type diffractive optical element excellent in both productivity and light conversion efficiency characteristics can be manufactured at low cost.

In addition to the above-described effects, the specific effects of the present invention will be described together while describing specific details for carrying out the invention below.

1 is a cross-sectional view of a film including a transmissive diffractive optical element according to an embodiment of the present invention.
2 is a cross-sectional view for explaining a phase difference of light transmitted through a diffraction pattern of a transmission type diffractive optical element (Diffractive Optical Element, hereinafter referred to as an optical diffractive element or DOE).
3 is a photograph of a conventional hologram and a photograph of a transmission type diffractive optical element of the present invention.
4 shows a wafer fabrication process, which is part of a method for manufacturing a transmission type diffractive optical device of the present invention.
5 shows the steps of converting an original image image into a DOE mask.
6 illustrates a step of separately designing the DOE mask into a plurality of unit masks.
7 shows an example of arranging each unit mask of the DOE mask on a reticle.
8 shows the steps of exposing on a silicon substrate.
9 shows the etching step.
10 shows an example in which the DOE pattern substrate is manufactured.
11 shows a flowchart of an imprinting process for manufacturing a DOE from a substrate having a DOE pattern.
12 shows a film as an example of a final product including a transmission diffractive optical element manufactured through the imprinting process.
13 shows a simulation result of light conversion efficiency according to the number of steps of the DOE unit mask and the red light (R), green light (G), and blue light (B) light sources.
14 shows a simulation result of light conversion efficiency according to the minimum distance (Δh) and the red light (R), green light (G), and blue light (B) light sources in the thickness direction between each layer of the DOE diffraction pattern.
15 shows images (images) of transmitted light according to stages of the DOE unit mask when incident light is red light (R), green light (G), and blue light (B), and when the incident light is white light (W).
16 shows an image realized when two DOE unit masks are used and an image of a diffraction slit.
FIG. 17 shows an image realized when using three DOE unit masks and an image of a diffraction slit.
18 shows an image realized when using five DOE unit masks and an image of a diffraction slit.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. Further, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In the accompanying drawings, the size and amount of objects are enlarged or reduced than the actual size for clarity of the present invention. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the nature, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It should be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "comprises" or "comprising" are intended to designate that a feature, step, function, element or a combination thereof described in the specification exists, and other features, steps, functions, or elements It should be understood that it does not preclude the possibility of the existence or addition of those or combinations thereof.

Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

An object of the present invention is to invent a film including a transmissive diffractive optical element and a transmissive diffractive optical element having a diffraction pattern that can satisfy both the light conversion efficiency and productivity, which are difficult to coexist.

1 is a cross-sectional view of a film including a transmissive diffractive optical element according to an embodiment of the present invention.

Referring to FIG. 1 , a film 100 including a transmissive diffractive optical element according to an embodiment of the present invention includes a base 110 and a diffractive optical element layer 120 .

The diffractive optical element layer 120 refers to a layer in which the diffraction pattern 122 forming the diffractive optical element DOE is located.

Visible light, LED light, or laser light incident from the outside is mostly transmitted from the diffractive optical element layer 120 of the film 100 including the transmissive diffractive optical element, and a small portion is reflected.

Accordingly, the upper portion of the base 110 can be implemented as a specific image.

In particular, the film 100 including the transmissive diffractive optical element may have a greater loss of light compared to the film including the reflective or semi-transmissive diffractive optical element, so the design of the transmissive diffractive optical element is very important.

This is because, in the case of a film comprising a transmissive diffractive optical element, light loss occurs in the transmitted light passing through the diffractive optical element layer by the base film or other laminated films.

In this case, the specific image may correspond to an image for authenticity determination or an image to be provided to a user. For example, the image may include a trademark or logo of a manufacturing company of a product (object) requiring authenticity determination, or information to be provided to a user.

As a non-limiting and specific example, the base 110 may be made of a polymer material.

For example, the base 110 may be made of a PET material, but is not limited thereto.

As a non-limiting and specific example, synthetic resins such as PP, OPP, and PVC may also be used as the base.

In addition, an adhesive layer, an adhesive layer, or a double-sided adhesive tape (not shown) may be positioned on the lower surface of the base 110 as non-limiting examples.

The adhesive layer, the adhesive layer, or the adhesive tape may perform a function of attaching the base 110 to a specific product such as wrapping paper.

The transmissive diffractive optical element layer 120 may be positioned on the upper surface of the base 110 (eg, the outer surface of the wrapping paper in the case of wrapping paper).

The transmissive diffractive optical element layer 120 includes a diffraction pattern 122 on its upper surface. The diffraction pattern 122 may have various sizes and shapes. For example, the shape of the diffraction pattern 122 may include a stripe shape, a mosaic shape, a pyramid shape, or the like. The diffraction pattern 122 may be defined as a pattern for using a diffraction characteristic to implement a specific image through a design algorithm including Fourier transform and inverse Fourier transform processes.

The diffraction pattern 122 formed on the diffractive optical element layer 120 has a profile in the height (or thickness based on the film) direction.

The diffraction pattern 122 may implement a specific image by the profile.

FIG. 2 is a cross-sectional view for explaining the retardation of light transmitted through the diffraction pattern 122 of the transmissive diffractive optical element layer 120 included in the film including the transmissive diffractive optical element.

In general, when visible light (not a single wavelength) or light of a single wavelength, such as a laser, is incident on a structure having a profile in the height direction as shown in FIG. 2 as incident light and is transmitted, the transmitted light is the profile A path difference of light is generated as much as the height difference (h) in the inside, and the path difference again generates a phase difference of transmitted light.

In this case, the phase difference causes constructive or destructive interference of transmitted light to form an image.

Therefore, when the diffraction pattern 122 is designed to finally obtain a desired image image, the diffraction pattern 122 transmits incident light such as natural light or light of a single wavelength to generate transmitted light having a desired image. can

In this case, the quality of the transmitted light having the desired image is determined by the light conversion efficiency of the transmitted light.

The light conversion efficiency may be defined as a ratio of the intensity of the incident light to the intensity of the transmitted light of the diffraction pattern image other than the light source point, similar to other general efficiencies.

Equation 1 below represents the light conversion efficiency in the transmission type diffractive optical element.

(Equation 1)

(In Equation 1 above, {Usig(x')} ² means the intensity of the desired output field, {Uin(ξ)} ² below means the intensity of the input field, and the alpha value is the scaling factor. As , it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated Intensity of the Output Field, x' means the position value of the Desired Output Field (on the xy plane), and ξ is the input It means the position value in the field, and W _sig means the Optimization Region.)

3 is a photograph (a) of a conventional hologram and a photograph (b) of a film including a transmission-type diffractive optical element (layer) of the present invention.

It can be seen that, unlike the conventional hologram, the film including the transmissive diffractive optical element of the present invention has a profile in the height direction.

1 and 3, the film including the transmission type diffractive optical element of the present invention includes the diffraction pattern 122 constituting the profile. The diffraction pattern 122 again includes a plurality of layers (corresponding to the diffraction pattern) having different heights.

Each layer in the plurality of layers constituting the diffraction pattern 122 has a thickness (h) lower than the total thickness (H) of the transmission type diffractive optical element, and the thickness (h) of each of the layers is The differences constitute the profile.

Meanwhile, the transmissive diffractive optical device may include a residue 121 on the lower surface of the diffraction pattern as shown in FIG. 1 due to characteristics such as an imprinting process, which will be described later. The residue 121 refers to a lower portion of the film on which a pattern is not formed by imprinting when a film including a transmissive diffractive optical element is manufactured using an imprinting process.

The thickness of the residue 121 may be optimized according to process conditions and the like. Although the residue 121 does not directly affect the optical characteristics of the transmissive diffractive optical element, the residue 121 may indirectly affect the optical characteristics of the transmissive diffractive optical element.

For example, if the transmission-type diffractive optical element is attached to an uneven surface, the residue 121 functions like a mirror due to the material properties of the residue 121, which is usually formed of resin. can be performed. Therefore, a portion of the incident light incident on the uneven material is reflected due to the mirror effect of the residue 121 and is incident on the diffractive optical element, thereby negatively contributing to the improvement of the intensity of the finally observed diffracted light.

However, since the residue 121 does not directly affect the optical properties of the transmissive diffractive optical element, the overall thickness H and the diffraction pattern 122 of the transmissive diffractive optical element described in this specification below. The thickness of the residue 121 is not included in the thickness h of each layer. In other words, the total thickness (H) of the transmission type diffractive optical element layer (120) and the thickness (h) of each layer constituting the diffraction pattern (122) described herein are all residues (h) as shown in FIG. 121) means the thickness excluding the thickness. In other words, the total thickness (H, or height) of the diffractive optical element layer 120 is the height from the top of the residue 121 to the top of the diffractive optical element layer 120 based on FIG. 1 . it means.

At this time, in the film including the transmissive diffractive optical element of the present invention, the total thickness (or height, H) of the transmissive diffractive optical element layer 120 may be 800 to 1,350 nm depending on the color of the designed incident light. .

If the thickness (H) is thinner than 800 nm, the mechanical stability of the transmissive diffractive optical element becomes weak, and further, some light is reflected due to the too thin thickness to become a transflective type instead of a transmissive type or a problem that the light conversion efficiency is lowered there is

On the other hand, if the thickness H is thicker than 1350 nm, there is a problem in that the amount of incident light absorbed by the diffractive optical element itself increases, so that the light conversion efficiency is lowered.

Meanwhile, as shown in FIG. 2 , in order for the transmitted light to form an image (image), the transmission type diffractive optical element must have the above profile.

In addition, as described above, in order to form the profile, a minimum spacing Δh between each layer of the diffraction pattern in the thickness direction should be provided.

At this time, it is preferable that the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern is 45 to 200 nm.

If the minimum interval (Δh) is thinner than 45 nm, there is a problem in that productivity decreases because the number of semiconductor processing steps for manufacturing the master stamp increases.

On the other hand, if the minimum interval Δh is thicker than 200 nm, diffraction of transmitted light is not sufficient, so that there is a problem in that light conversion efficiency is lowered.

The minimum distance ?h varies depending on the wavelength (that is, color) of the light source at the time of designing the optical diffractive element. This is because, in the case of R, G, and B constituting visible light, the wavelengths are different from each other, and thus the difference in the paths of R, G, and B is different from each other. The minimum interval Δh according to each of the R, G, and B light sources will be described in more detail in the following examples.

In particular, the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern directly affects the light conversion efficiency and productivity (yield).

In general, as the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern is smaller, the light conversion efficiency increases and the transmitted light image becomes finer and clearer.

On the other hand, as for the minimum spacing Δh in the thickness direction between the respective layers in the diffraction pattern actually implemented by a process such as imprinting, the smaller the minimum spacing Δh, the more difficult it is to implement, and accordingly, the productivity this will be lowered

As a result, light conversion efficiency and productivity have a trade-off relationship with each other according to a change in the minimum distance Δh in the thickness direction between the respective layers of the diffraction pattern.

In other words, the light conversion efficiency and productivity are in a characteristic relationship that is difficult to coexist with each other.

Meanwhile, the film including the transmission-type diffractive optical element of the present invention may further include a light-transmitting layer, an adhesive layer, an adhesive layer, and a protective layer in addition to the base and the diffractive optical element layer.

4 shows a wafer manufacturing process for manufacturing the transmission type diffractive optical element of the present invention.

5 to 10 show each step constituting the wafer manufacturing process.

First, as shown in FIG. 4, a method for manufacturing a transmission type diffractive optical element and a film including the same of the present invention comprises the steps of (a) converting an original image image into a DOE (diffraction optical elements) mask; (b) separating the DOE mask into a plurality of unit masks; (c) fabricating each layer of the DOE unit mask; (d) exposing on the substrate; (e) etching; (f) manufacturing the DOE pattern substrate; includes.

5 shows the steps of converting an original image image into a DOE mask.

First, the original image to be displayed by the transmissive diffractive optical element simulates whether the target efficiency and intensity are obtained by the actual light source (visible light or laser light) through Fourier transformation. As a non-limiting and specific example of the light source, the light source may be short-wavelength green light (G), red light (R), or blue light (B). However, in the case of green light (G), it is most visible to the human eye as an observer among natural light, and is preferable because the intensity of light is greater than that of other wavelengths.

The simulation process may be omitted if necessary.

Next, after setting the target intensity of the original image as a target, the DOE mask is designed through Inverse Fourier transformation in order to obtain a DOE mask for realizing it.

6 illustrates a step of separately designing the DOE mask into a plurality of unit masks.

The DOE mask may be designed as a single mask or a plurality of unit masks.

If a single DOE mask is designed, the diffraction pattern 122 in the transmissive optical element included in the film including the transmissive optical element, which is the final product, cannot accurately represent the final image. see level)

On the other hand, if the DOE mask is designed with an excessively large number (steps), the improvement in light efficiency or sharpness perceived by the observer cannot be achieved, and the final product is a transmissive diffractive optical element or a film containing a transmissive diffractive optical element. Since the diffraction pattern 122 becomes too precise and complicated, productivity is reduced as well as a problem in yield occurs.

7 shows an example of arranging each unit mask of the DOE mask on a reticle.

8 shows the steps of exposing on a silicon substrate.

9 shows the etching step.

7 to 9 , the plurality of unit masks implement a diffraction pattern 122 on a silicon wafer through conventional photo lithography.

Specifically, the diffraction pattern 122 may be formed on the wafer coated with the photoresist by exposing a light source (UV or EUV-based light source) on the reticle original plate.

More specifically, as shown in FIG. 9 , when the photolithography process is performed a plurality of times using each unit mask, a diffraction pattern 122 including layers having different thicknesses is formed on the final wafer.

10 shows an example in which the DOE pattern substrate is manufactured.

As shown in FIG. 10 , a diffraction pattern 122 including respective layers having different thicknesses as in the schematic diagram shown by the etching step in FIG. 9 is formed on the silicon wafer manufactured by the DOE mask. can be known

Meanwhile, a single or a plurality of identical master stamps having the same diffraction pattern 122 may be formed on one silicon substrate by the above method.

Hereinafter, as a non-limiting and specific example, a method of manufacturing a film including a transmissive diffractive optical element through an imprinting process using the master stamp will be described in more detail.

11 shows a flowchart of an imprinting process for manufacturing a DOE from a substrate having a DOE pattern.

12 illustrates a film including a transmissive diffractive optical element as an example of a final product manufactured through the imprinting process.

First, a fabric tiling process may be performed using a single or a plurality of master stamps positioned on the wafer.

The tiling process is a process for manufacturing a copper plate that can be used to imprint a diffraction pattern 122 of a diffractive optical element on a film including a transmissive diffractive optical element using a replica.

Specifically, in the tiling process, the master stamp is copied on a tiling-only film by machine or manually, and then tiled according to the size of the film including the transmissive diffractive optical element. As a non-limiting and specific example, the tiling may be performed in a size of about 1,200 mm in width, but may be adjusted according to the size of the final product and/or copper plate.

The tiled exclusive film is used for manufacturing a roll-type master mold used in a subsequent molding process, and the manufactured master mold is implanted on a copper plate.

In the copper plate manufactured by the tiling process, a transmission-type diffractive optical element may be implanted on a film including the transmission-type diffractive optical element through a subsequent molding process.

As a non-limiting and specific example, the forming process may be a roll to roll process or a roll to plate process.

The transmissive diffractive optical element manufactured through the molding process and positioned in the film including the transmissive diffractive optical element is positioned on the base as shown in FIGS. 1 and 12 .

Therefore, in order to manufacture the transmissive diffractive optical element, first, a base and a laminate of resin positioned on the base and capable of forming a transmissive diffractive optical element must be performed prior to the molding process.

In this case, since the diffractive optical element of the present invention is a transmissive type, a film having high transparency to transmit light is preferable.

As a non-limiting and specific example, PET or the like may be used.

As a non-limiting and specific example, synthetic resins such as PP, OPP, and PVC may also be used as the base.

However, in the case of PET, it is suitable for a base because it has high transparency as well as high mechanical rigidity compared to other olefin-based polymers.

The transmissive diffractive optical element positioned on the base may be made of a polymer resin.

In this case, the polymer resin may be formed of a urethane-based or an acrylic-based resin.

At this time, the polymer resin may be cured through thermal curing or UV curing.

The laminate of the base and the resin is provided to the roll-type master mold through a supply roller, and during the forming process, a constant force is applied to the laminate under a condition similar to rolling, and the master mold is applied to the laminate to be worked. can be engraved with the opposite pattern of Through this, the diffraction pattern 122 constituting the transmissive diffractive optical element may be formed on the laminate.

Furthermore, the lower and/or upper portion of the base may include a printed layer on which a trademark or the like is printed so as to increase the identification of the product if necessary.

In addition, an adhesive layer and/or an adhesive layer and/or a double-sided tape may be laminated to adhere or adhere the film including the transmissive diffractive optical element to the part to which the transmissive optical element is attached.

Hereinafter, a film including the transmission-type diffractive optical element of the present invention and a method of manufacturing the same will be described through Examples.

Example

13 shows a simulation result of light conversion efficiency according to the number of steps of a DOE unit mask and R (red), G (green), and B (blue) light sources.

14 shows the results of simulating the light conversion efficiency according to the minimum distance (Δh) and R (red), G (green) and B (blue) light sources in the thickness direction between the respective layers of the DOE diffraction pattern.

Table 1 below shows the results of calculating the light conversion efficiency according to the steps of the DOE mask when the light sources are R (red), G (green), and B (blue), respectively.

The light conversion efficiency is a simulation result using the Virtual Lab Fusion (2nd Generation Technology Update) program of Luen Soft based on Equation 1 above.

[Table 1]

First, as shown in FIG. 13 and Table 1, it can be seen that the light conversion efficiency increases as the step of the DOE mask for implementing the diffraction pattern increases.

At this time, as the level of the DOE mask increases from 1 to 3, the light conversion efficiency increases rapidly.

On the other hand, as the step of the DOE mask increased from 3 to 6, the light conversion efficiency showed little change or slightly increased.

The results of FIG. 13 and Table 1 mean that the light conversion efficiency is almost saturated at the stage 3 or 4 of the DOE mask.

Meanwhile, as shown in FIG. 14 , it can be seen that the light conversion efficiency increases as the minimum distance Δh between the respective layers of the diffraction pattern in the thickness direction becomes thinner (smaller).

In this case, the minimum interval Δh is related to the number of steps of the DOE mask in FIG. 13 and Table 1. FIG.

If the DOE mask has one step, two height steps are formed on the diffractive optical element layer 120 as shown in FIG. 9 . Furthermore, if the DOE mask has two steps, a step of four heights is formed on the diffractive optical element layer 120 . In other words, if the number of steps of the DOE mask is n, 2 ⁿ steps are formed on the diffractive optical element layer 120 .

However, as shown in FIG. 1 , the DOE pattern 122 is positioned on the residue 121 , and the uppermost surface of the residue 121 corresponds to the lowermost surface of the DOE pattern 122 . Therefore, if the step of the DOE mask is one, two height steps are formed on the diffractive optical element layer, which means that the formed DOE pattern 122 becomes one. As a result, when the number of steps of the DOE mask is n, 2 ⁿ steps are formed on the diffractive optical element layer 120 and the number of the formed DOE patterns 122 is (2 ⁿ - 1).

On the other hand, the result of FIG. 14 shows that the light conversion efficiency according to the change of the height of one layer of the DOE pattern 122 (that is, the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern) depends on the wavelength of the incident light. It shows the change directly.

When the incident light is green light (G), it was found that the light conversion efficiency was almost constant or slightly decreased until the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern was approximately 50 nm.

On the other hand, when the incident light is green light (G), when the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern exceeds approximately 195 nm, the light conversion efficiency is significantly reduced.

On the other hand, when the incident light is red light (R), it was found that the light conversion efficiency was almost constant or slightly decreased until the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern was approximately 60 nm.

On the other hand, when the incident light is red light (R), when the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern exceeds approximately 200 nm, the light conversion efficiency is significantly reduced.

In addition, when the incident light is blue light (B), it was found that the light conversion efficiency was almost constant or slightly decreased until the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern was approximately 45 nm.

On the other hand, when the incident light is blue light (B), when the minimum distance (Δh) in the thickness direction between the respective layers of the diffraction pattern exceeds approximately 190 nm, the light conversion efficiency is significantly reduced.

Furthermore, as shown in FIG. 14 and Table 1, the maximum efficiency was found to decrease in the order of when the incident light is red light (R) > green light (G) > blue light (B) (maximum efficiency of blue light) this is the lowest). In addition, the minimum interval (Δh), at which the maximum efficiency appears, also decreased in the following order: when the incident light is red light (R) > green light (G) > blue light (B) (the minimum interval of blue light is the smallest)

Since the wavelengths of the green light (G), the red light (R), and the blue light (B) are different from each other, it could be predicted that the minimum interval Δh at which the maximum efficiency appears becomes smaller as the wavelength of the incident light is shorter.

However, when the incident light is green light (G) and red light (R), the difference in maximum efficiency is expected to vary depending on the pattern design.

The results of FIGS. 13 and 14 mean that the light conversion efficiency does not simply change linearly with respect to the minimum distance ?h in the thickness direction between the respective layers of the diffraction pattern.

Further, the results of FIGS. 13 and 14 show that the minimum spacing Δh between the respective layers of the diffraction pattern in the thickness direction is 50 to 195 nm (incident light is green light (G)), and 60 to 200 nm (incident light is red light ( R)), or 45 to 190 nm (incident light is blue light (B)), without significant change in light conversion efficiency (approximately, in the case of red light, the light conversion efficiency is 63% or more, and in the case of green light, the light conversion efficiency is 55% Above, in the case of blue light, the light conversion efficiency is 51% or more), which means that a diffraction pattern with excellent productivity can be obtained.

15 shows an image (image) of transmitted light according to stages of a DOE unit mask when incident light is red light (R), green light (G), blue light (B), and white light (W), respectively.

15 intuitively shows an image of transmitted light that an observer actually observes.

As shown in FIG. 15, as the layers constituting the diffraction pattern increase with respect to the total height (H) of the constant diffraction pattern (in other words, the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern) It can be seen that the image of transmitted light becomes clearer as this decreases).

More specifically, it can be seen that, as the layers constituting the diffraction pattern increase from level 2 to level 8, the clarity of the transmitted light is rapidly improved, and then there is little change until level 32.

The results of Fig. 15 agree very well with the results of Figs. 13 and 14 above.

On the other hand, it can be seen that when the incident light is monochromatic light (that is, red light, green light, or blue light), the image of transmitted light is clearer than when the incident light is white light. This is because, in the case of white light, several wavelengths are mixed instead of a single wavelength, which causes light of various wavelengths to interfere with each other.

16 to 18 show examples of actually implemented images and diffraction slits according to the number of DOE unit masks.

As shown in FIG. 16 , when an image is implemented using two DOE unit masks (in the case of the diffraction patterns 122 having four different heights), the desired lightning image and the actual image are not the same can be known

On the other hand, as shown in FIGS. 17 and 18, 3 DOE unit masks (FIG. 17, 8 diffraction patterns 122 having different heights) and 5 (FIG. 18, 32 diffraction patterns 122 having different heights) )), it can be confirmed that the desired lightning image is actually implemented in all cases, and further, the diffraction slit is similar to the extent that the difference is difficult to be clearly distinguished with the naked eye.

The results of FIGS. 16 to 18 can be said to intuitively (visually) verify the results of FIG. 15 described above.

As described above, the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and a variety of It is obvious that variations can be made. In addition, although the effects according to the configuration of the present invention are not explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the configuration should also be recognized.

Claims (11)

In the transmission type diffractive optical element comprising a diffraction pattern,
The diffraction pattern comprises a plurality of layers,
The minimum distance (Δh) in the thickness direction between the plurality of layers is 60 to 200 nm,
The light conversion efficiency of the diffractive optical element is 63% or more, a value calculated by Equation 1 below.
The total height (H) of the diffraction pattern is 800 to 1350 nm of the transmission type diffractive optical element.
(Equation 1)

(In Equation 1 above, {Usig(x')} ² means the intensity of the desired output field, {Uin(ξ)} ² below means the intensity of the input field, and the alpha value is the scaling factor. As , it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated Intensity of the Output Field, x' means the position value of the Desired Output Field (on the xy plane), and ξ is the input It means the position value in the field, and W _sig means the Optimization Region.)
In the transmission type diffractive optical element comprising a diffraction pattern,
The diffraction pattern comprises a plurality of layers,
The minimum distance (Δh) in the thickness direction between the plurality of layers is 45 to 190 nm,
The light conversion efficiency of the diffractive optical element has a value calculated by Equation 1 below 51% or more,
The total height (H) of the diffraction pattern is a transmission type diffractive optical element of 800 to 1350 nm.
(Equation 1)

(In Equation 1 above, {Usig(x')} ² means the intensity of the desired output field, {Uin(ξ)} ² below means the intensity of the input field, and the alpha value is the scaling factor. As , it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated Intensity of the Output Field, x' means the position value of the Desired Output Field (on the xy plane), and ξ is the input It means the position value in the field, and W _sig means the Optimization Region.)
Base;
and a transmission type diffractive optical element layer positioned on the base and including a diffraction pattern;
The diffraction pattern includes a plurality of layers, and the minimum distance (Δh) in the thickness direction between the plurality of layers is 60 to 200 nm,
The light conversion efficiency of the diffractive optical element is 63% or more, a value calculated by Equation 1 below,
The total height (H) of the diffraction pattern is 800 to 1350 nm; A film comprising a transmission type diffractive optical element layer, characterized in that.
(Equation 1)

(In Equation 1 above, {Usig(x')} ² means the intensity of the desired output field, {Uin(ξ)} ² below means the intensity of the input field, and the alpha value is the scaling factor. As , it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated Intensity of the Output Field, x' means the position value of the Desired Output Field (on the xy plane), and ξ is the input It means the position value in the field, and W _sig means the Optimization Region.)
Base;
and a transmission type diffractive optical element layer positioned on the base and including a diffraction pattern;
The diffraction pattern includes a plurality of layers, and the minimum distance (Δh) in the thickness direction between the plurality of layers is 45 to 190 nm,
The light conversion efficiency of the diffractive optical element is 51% or more, a value calculated by Equation 1 below,
The total height (H) of the diffraction pattern is 800 to 1350 nm; A film comprising a transmission type diffractive optical element layer, characterized in that.
5. The method according to claim 3 or 4,
A film comprising a transmissive diffractive optical element layer comprising a; residue positioned between the diffraction pattern and the base.
5. The method according to claim 3 or 4,
A film comprising a transmissive diffractive optical element layer, wherein the base is transparent PET.
5. The method according to claim 3 or 4,
The diffractive optical element layer is a film comprising a transmissive diffractive optical element layer which is a urethane-based or acrylic-based resin.
5. The method according to claim 3 or 4,
A film comprising a transmission-type diffractive optical element layer further comprising an adhesive layer, an adhesive layer, or a double-sided tape positioned under the base.
5. The method according to claim 3 or 4,
A film comprising a transmissive diffractive optical element layer further comprising a printed layer positioned on the upper and/or lower portion of the base.
(a) transforming an original image image into a diffraction optical elements (DOE) mask through Fourier transform and inverse Fourier transform;
(b) separating the DOE mask into 4 or 5 DOE unit masks;
(c) manufacturing each of the four or five DOE unit masks;
(d) manufacturing a master stamp including a diffraction pattern on a silicon substrate by sequentially exposing and etching each of the DOE unit masks;
(a) transforming an original image image into a diffraction optical elements (DOE) mask through Fourier transform and inverse Fourier transform;
(b) separating the DOE mask into 4 or 5 DOE unit masks;
(c) manufacturing each of the four or five DOE unit masks;
(d) manufacturing a master stamp including a diffraction pattern on a silicon substrate by sequentially exposing and etching each of the DOE unit masks;
(e) imprinting the diffractive optical element using the master stamp; a film manufacturing method comprising a transmissive diffractive optical element layer comprising a.

Images