CN112147797B - Ophthalmic lens - Google Patents
Ophthalmic lens Download PDFInfo
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- CN112147797B CN112147797B CN201910566518.4A CN201910566518A CN112147797B CN 112147797 B CN112147797 B CN 112147797B CN 201910566518 A CN201910566518 A CN 201910566518A CN 112147797 B CN112147797 B CN 112147797B
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- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
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- G02C7/02—Lenses; Lens systems ; Methods of designing lenses
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Abstract
The invention discloses an ophthalmic lens. At least one optical surface of the ophthalmic lens is provided with at least one first diffractive structure comprising at least one first diffractive element and at least one second diffractive structure comprising at least one second diffractive element, the phase difference in each first diffractive element being equal to 2 pi and the phase difference in each second diffractive element being equal to 4 pi. In the ophthalmic lens according to the embodiment of the invention, the phase difference in each first diffraction unit in the first diffraction structure is 2 pi, the designed wavelength light is focused on the + 1-order diffraction focus, the phase difference in each second diffraction unit in the second diffraction structure is 4 pi, and the designed wavelength light is focused on the + 2-order diffraction focus, so that the loss of high-order diffraction energy is avoided, and the visual quality is improved.
Description
Technical Field
The invention relates to the field of medical instruments, and more particularly to an ophthalmic lens.
Background
The diffractive structure of the diffractive ophthalmic lens realizes the convergence of light rays at different focuses by using different diffraction orders. In the related-art diffractive ophthalmic lens, 0-order and + 1-order diffractive focuses are used for imaging, and higher-order diffractive focuses cannot be utilized. Therefore, the light condensed at higher orders by diffraction cannot be effectively utilized, resulting in energy loss of approximately 13% to 18%. The loss of energy can result in a degradation of the imaging quality of the ophthalmic lens.
Disclosure of Invention
The invention provides an ophthalmic lens.
At least one optical surface of an ophthalmic lens according to an embodiment of the invention is provided with at least one first diffractive structure comprising at least one first diffractive element and at least one second diffractive structure comprising at least one second diffractive element, the phase difference within each first diffractive element being equal to 2 pi and the phase difference within each second diffractive element being equal to 4 pi.
In the ophthalmic lens provided by the embodiment of the invention, the phase difference in each first diffraction unit in the first diffraction structure is 2 pi, the designed wavelength light is focused on a + 1-order diffraction focus, the phase difference in each second diffraction unit in the second diffraction structure is 4 pi, and the designed wavelength light is focused on a + 2-order diffraction focus, so that the loss of high-order diffraction energy is avoided, and the visual quality is improved.
In certain embodiments, the +1 st order diffractive power of the first diffractive structure is different from the +2 nd order diffractive power of the second diffractive structure.
In some embodiments, the +1 st order diffractive power of the second diffractive structure is equal to half of the +2 nd order diffractive power of the second diffractive structure.
In some embodiments, the smallest integer ratio of the +1 st order diffractive power of the first diffractive structures to the +1 st order diffractive power of the second diffractive structures is M: N, each of the first diffractive structures comprises an integer number of the first diffractive units that is M, and each of the second diffractive structures comprises an integer number of the second diffractive units that is N.
In certain embodiments, the ophthalmic lens comprises a plurality of the first diffractive structures and a plurality of the second diffractive structures, the first diffractive structures alternating with the second diffractive structures.
In certain embodiments, in the first aperture range, the first diffractive unit and the second diffractive unit are disposed 2M: N: M: 2N: M: N, M: N: 2M: N: M: 2N, 2N: M: N: 2M: N: M or N: M: 2N: M: N: 2M outward from the optical axis of the ophthalmic lens.
In some embodiments, the first diffractive structure is formed with a +1 order diffractive focus and the second diffractive structure is formed with a +2 order diffractive focus.
In some embodiments, the first diffractive unit and the second diffractive unit are arranged M: N outward from the optical axis of the ophthalmic lens within the second aperture range.
In some embodiments, the first diffractive structure is formed with a +1 order diffractive focal point, the second diffractive structure is formed with a +2 order diffractive focal point, and the first diffractive structure and the second diffractive structure interfere to form an intermediate optical focal point having an optical power between an optical power of the +1 order diffractive focal point and an optical power of the +2 order diffractive focal point.
In certain embodiments, the ophthalmic lens exhibits a single focal point, and the first diffractive unit and the second diffractive unit are arranged M: N outward from an optical axis of the ophthalmic lens.
In some embodiments, the first diffractive structure is formed with a +1 order diffractive focal point, the second diffractive structure is formed with a +2 order diffractive focal point, the first diffractive structure interferes with the second diffractive structure to form a third focal point, and the +1 order diffractive focal point, the +2 order diffractive focal point, and the third focal point merge into the single focal point.
In certain embodiments, the power of the +1 st order diffractive focal point and the power of the +2 nd order diffractive focal point differ by less than 2.0D, and the power of the third focal point is equal to half of the sum of the power of the +1 st order diffractive focal point and the power of the +2 nd order diffractive focal point.
In some embodiments, the ophthalmic lens is formed with bifocal points, and the first diffractive unit and the second diffractive unit are arranged 2M: 2N outward from an optical axis of the ophthalmic lens.
In some embodiments, the first diffractive structure is formed with a +1 order diffractive focal point, the second diffractive structure is formed with a +2 order diffractive focal point, a plurality of the first diffractive structures interfere to increase a depth of focus of the +1 order diffractive focal point, and a plurality of the second diffractive structures interfere to increase a depth of focus of the +2 order diffractive focal point.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic structural view of an ophthalmic lens according to an embodiment of the present invention;
FIG. 2 is a schematic view of the arrangement of the first and second diffractive structures of FIG. 1 separated from the diffractive optical surface;
FIG. 3 is an initial phase diagram of an ophthalmic lens according to an embodiment of the present invention;
FIG. 4 is a phase diagram after phase shifting the ophthalmic lens of FIG. 3;
fig. 5 to 8 are schematic arrangements of the first and second diffraction structures according to the embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it is to be understood that the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to imply that the number of technical features indicated are in fact significant. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and settings of a specific example are described below. Of course, they are merely examples and are not intended to limit the present invention. Moreover, the present disclosure may repeat reference numerals and/or reference letters in the various examples, which have been repeated for purposes of simplicity and clarity and do not in themselves dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.
Referring to fig. 1 and 2, an ophthalmic lens 100 is provided according to an embodiment of the invention. At least one optical surface 110 of the ophthalmic lens 100 is provided with at least one first diffractive structure 10 and at least one second diffractive structure 20. The first diffractive structure 10 comprises at least one first diffractive element 12 and the second diffractive structure 20 comprises at least one second diffractive element 22. The phase difference in each first diffraction cell 12 is equal to 2 pi and the phase difference in each second diffraction cell 22 is equal to 4 pi.
In the ophthalmic lens 100 according to the embodiment of the present invention, the phase difference in each first diffraction cell 12 in the first diffraction structure 10 is 2 pi, the designed wavelength light is focused on the +1 order diffraction focus, the phase difference in each second diffraction cell 22 in the second diffraction structure 20 is 4 pi, and the designed wavelength light is focused on the +2 order diffraction focus, thereby avoiding the loss of high order diffraction energy and improving the visual quality.
In particular, the ophthalmic lens 100 includes first and second optical surfaces 112, 114 on opposite sides. At least one optical surface 110 of the ophthalmic lens 100 is provided with at least one first diffractive structure 10 and at least one second diffractive structure 20, i.e. either the first optical surface 112 or the second optical surface 114 is provided with the first diffractive structure 10 and the second diffractive structure 20, or both the first optical surface 112 and the second optical surface 114 are provided with the first diffractive structure 10 and the second diffractive structure 20. In the illustrated embodiment, the first optical surface 112 has a first diffractive structure 10 and a second diffractive structure 20.
It will be appreciated that the phase difference within each first diffractive element 12 is equal to 2 pi, i.e. the height difference H1 within the first diffractive elements 12 in the first diffractive structure 10 results in an optical path difference for a design wavelength ray (e.g. 546 nm) incident parallel to the optical axis a equal to one wavelength of the incident ray. The first diffractive structure 10 forms a +1 order diffractive focal point by virtue of +1 order diffraction. For lens analysis of the first diffraction unit 12, the designed wavelength light 100% converges at the +1 st order diffraction focus, and no energy loss occurs in the designed wavelength light. The phase difference in each second diffractive element 22 is equal to 4 pi, i.e. the height difference H2 in the second diffractive element 22 in the second diffractive structure 20 results in the optical path difference of a light ray of the design wavelength (e.g. 546 nm) incident parallel to the optical axis a being equal to two wavelengths of the incident light ray. The second diffractive structure 20 forms a +2 order diffractive focal point by virtue of +2 order diffraction. For lens analysis of the second diffraction unit 22, the designed wavelength light 100% converges at the +2 th order diffraction focus, and no energy loss occurs in the designed wavelength light. Accordingly, the ophthalmic lens 100 of the present invention is advantageous for improving the imaging quality, i.e., the visual quality.
In the present invention, the single first diffractive structure 10 forms a +1 st order diffraction focus, and does not form a +2 nd order diffraction focus and higher; the single second diffractive structure 20 forms a +2 order diffractive focal point, and does not form a +3 order and higher order diffractive focal points. The combination of the first 10 and second 20 diffractive structures makes it possible to form further diffractive foci by interference.
The diffraction units include a first diffraction unit 12 and a second diffraction unit 22. The height difference in the diffraction cell means a height difference from the highest point to the lowest point in the diffraction cell. The height differences H1 in all the first diffraction cells 12 of the first diffraction structure 10 are equal, and the height differences H2 in all the second diffraction cells 22 of the second diffraction structure 20 are also equal. The height difference in the diffraction unit causes light wave propagation delay, and when the height difference between the highest point and the lowest point just slows down light propagation by a designed wavelength, the phase difference is 2 pi; the phase difference is 4 pi when the height difference between the highest point and the lowest point just slows down the light propagation by two design wavelengths.
It is understood that in the present invention, the diffraction unit includes the first diffraction unit 12 and the second diffraction unit 22. Diffraction steps are present between the diffraction cells to separate adjacent diffraction cells. The diffraction steps include a first diffraction step 14 and a second diffraction step 24. Specifically, a first diffraction step 14 exists between two adjacent first diffraction units 12, a second diffraction step 24 exists between two adjacent second diffraction units 22, and the first diffraction step 14 or the second diffraction step 24 exists between the adjacent first diffraction units 12 and the adjacent second diffraction units 22.
The optical surface 110 is provided with the first diffractive structure 10 and the second diffractive structure 20, and forms a diffractive optical surface. The diffractive optical surface can be seen as a basic asphere/sphere (optical surface 110) in combination with the first diffractive structure 10 and the second diffractive structure 20. In the present invention, the first diffractive structure 10 and the second diffractive structure 20 are discussed separately from the diffractive optical surface. Since the optical surface 110 is curved, its base aspheric/spherical surface has a height difference itself. Thus, the height difference shown in fig. 1 is the sum of the height difference within the diffraction unit and the height difference of the base aspheric/spherical surface itself. The height difference within the diffraction cell is the height difference within the diffraction cell shown in the isolated diffraction structure of fig. 2.
In certain embodiments, the +1 st order diffractive power D of the first diffractive structure 10 1 A +2 order diffractive power D different from the second diffractive structure 20 2 。
It will be appreciated that the first diffractive structure 10 is formed with a +1 order diffractive focus and the second diffractive structure 20 is formed with a +2 order diffractive focus. The +1 st order diffractive power D of the first diffractive structure 10 1 That is, the power D of the +1 st order diffraction focus of the first diffractive structure 10 1 . The +2 th order diffractive power D of the second diffractive structure 20 2 That means the power D of the +2 th order diffraction focus of the second diffractive structure 20 2 . The +1 st order diffractive power D of the first diffractive structure 10 1 A +2 order diffractive power D different from that of the second diffractive structure 20 2 Such that the ophthalmic lens 100 can form at least two focal points.
In some embodiments, the +1 st order diffractive power B of the second diffractive structure 20 is equal to half of the +2 nd order diffractive power D of the second diffractive structure 20 2 I.e. B = D 2 /2。
It will be appreciated that the +1 st order diffractive power B of the second diffractive structure 20 may be the same as the +1 st order diffractive power D of the first diffractive structure 10 1 Equal or unequal. For +1 of the first diffractive structure 10Order diffractive power D 1 The +1 st order diffractive power D of the first diffractive structure 10 is equal to the +1 st order diffractive power B of the second diffractive structure 20, which makes the design of the diffractive structure easier 1 Also equal to the +2 th order diffractive power D of the second diffractive structure 20 2 Half of that.
In certain embodiments, the +1 st order diffractive power D of the first diffractive structure 10 1 The minimum integer ratio of the +1 st order diffraction power B to the second diffraction structure 20 is M: N, the number of first diffraction units 12 included in each first diffraction structure 10 is an integer multiple of M, and the number of second diffraction units 22 included in each second diffraction structure 20 is an integer multiple of N.
Thus, the number of first diffraction cells 12 in each first diffraction structure 10 is determined from M and the number of second diffraction cells 22 in each second diffraction structure 20 is determined from N. The number of first diffraction units 12 and the number of second diffraction units 22 and the +1 st order diffraction power D of the first diffraction structure 10 1 And +1 st order diffractive power B of the second diffractive structure 20. The number of first diffraction units 12 and the number of second diffraction units 22 and the +1 st order diffraction power D of the first diffraction structure 10 1 And the +1 st order diffractive power B of the second diffractive structure 20 satisfy the following relationship, M: N = D 1 B. Wherein, M and N may be equal or unequal.
By arranging the first diffraction unit 12 and the second diffraction unit 22 differently, the ophthalmic lens 100 having different optical characteristics can be formed. The energy distribution at different focal points can be adjusted according to the difference in the number of first diffraction units 12 and second diffraction units 22. According to the positions of the first diffraction unit 12 and the second diffraction unit 22 on the optical surface 110, different apertures can be adjusted to have different diffraction focuses.
In certain embodiments, the ophthalmic lens 100 comprises a plurality of first diffractive structures 10 and a plurality of second diffractive structures 20. The first diffractive structures 10 are alternately arranged with the second diffractive structures 20.
In this way, the first diffractive structures 10 and the second diffractive structures 20 are alternately arranged on the optical surface 110 to form a diffractive optical surface.
In some embodiments, in the first aperture range, the first diffractive unit 12 and the second diffractive unit 22 are disposed 2M: N: M: 2N: M: N, M: N: 2M: N: M: 2N, 2N: M: N: 2M: N: M or N: M: 2N: M: N: 2M outward from the optical axis A of the ophthalmic lens 100.
It is understood that the ophthalmic lens 100 includes a plurality of first diffractive structures 10 and a plurality of second diffractive structures 20 alternately arranged. Wherein the number of first diffractive elements 12 and the number of second diffractive elements 22 may be arranged 2M: N: M: 2N: M: N, M: N: 2M: N: M: 2N, 2N: M: N: 2M: N: M or N: M: 2N: M: N: 2M outwardly from the optical axis A of ophthalmic lens 100.
In the present embodiment, in the diffraction zone of the first aperture range, the first diffraction structure 10 is formed with a +1 order diffraction focus, and the second diffraction structure 20 is formed with a +2 order diffraction focus. Two focuses are formed by the first diffraction structure 10 and the second diffraction structure 20, the first diffraction structure 10 converges light rays at the + 1-order diffraction focus, and the second diffraction structure 20 converges light rays at the + 2-order diffraction focus, so that light rays with designed wavelength are completely focused at the two focuses, no energy loss exists, and the visual quality is improved. Theoretically, the first diffractive structure 10 and the second diffractive structure 20 form a bifocal point, but when the first diffractive structure 10 and the second diffractive structure 20 are combined with an aspheric/spherical structure to form the ophthalmic lens 100, the ophthalmic lens 100 will exhibit a trifocal point due to the influence of factors such as spherical aberration of the ophthalmic lens 100, and the third focal point is located between the two focal points formed by the first diffractive structure 10 and the second diffractive structure 20, so that an effective in-view focal point can be formed.
Further, a first diffraction structure 10, a second diffraction structure 20, a refractive structure having a focal length equal to the far-vision focus, or other diffraction structures may be provided in the region connected to the diffraction zone.
In some embodiments, the first diffractive unit 12 and the second diffractive unit 22 are arranged M: N outward from the optical axis a of the ophthalmic lens 100 within the second aperture range.
It is understood that the ophthalmic lens 100 includes a plurality of first diffractive structures 10 and a plurality of second diffractive structures 20 alternately arranged. Wherein the number of the first diffraction units 12 and the number of the second diffraction units 22 can be arranged outward from the optical axis a of the ophthalmic lens 100 in an M: N repetition.
In the present embodiment, in the diffraction zone of the second aperture range, the first diffraction structure 10 forms a +1 st order diffraction focus, the second diffraction structure 20 forms a +2 nd order diffraction focus, and the first diffraction structure 10 and the second diffraction structure 20 interfere with each other to form an intermediate focus. The optical power of the intermediate focus is between the optical power of the +1 st order diffraction focus and the optical power of the +2 nd order diffraction focus. Therefore, the light with the designed wavelength is completely focused on three focuses without energy loss, thereby improving the visual quality.
Further, a first diffraction structure 10, a second diffraction structure 20, a refractive structure having a focal length equal to the far-vision focus, or other diffraction structures may be provided in the region connected to the diffraction zone.
In the present invention, the aperture (e.g., the first aperture and the second aperture) represents the diameter of any one of a circular region centered on the optical center or the diameter range of an annular region in the optical surface range of the ophthalmic lens 100. Wherein the first aperture, the second aperture may be present on the optical surface of the ophthalmic lens 100 alone or in combination with the first aperture and the second aperture on the optical surface of the ophthalmic lens 100. When the first aperture and the second aperture are present in combination at the optical surface of the ophthalmic lens 100, the second aperture is located within the diameter of the annulus outside the first aperture.
In some embodiments, the ophthalmic lens 100 exhibits a single focal point, and the first diffractive unit 12 and the second diffractive unit 22 are arranged M: N outward from the optical axis a of the ophthalmic lens 100.
It is understood that the ophthalmic lens 100 includes a plurality of first diffractive structures 10 and a plurality of second diffractive structures 20 alternately arranged. Wherein the number of first diffractive units 12 and the number of second diffractive units 22 can be arranged outward from the optical axis a of the ophthalmic lens 100 in an M: N repetition.
In the present embodiment, in the diffraction zone, the first diffraction structure 10 forms a +1 order diffraction focus, the second diffraction structure 20 forms a +2 order diffraction focus, and the first diffraction structure 10 and the second diffraction structure 20 interfere with each otherA third focal point is formed. The +1 st order diffraction focus, the +2 nd order diffraction focus and the third focus are fused into a single focus. Focal power D of +1 st order diffraction focus 1 And the focal power D of +2 diffraction orders 2 Is less than 2.0D, the focal power of the third focal point is equal to the focal power D of the +1 order diffraction focal point 1 And focal power D of +2 diffraction orders 2 Half of the sum of (A), (B), (C), (D) and (C) 1 +D 2 )/2. Due to D 2 And D 1 Is less than 2.0D, the three foci can be merged into a single focus with a greater depth of focus. Therefore, the light with the designed wavelength is completely focused on the single focus with larger focal depth, no energy loss exists, and the visual quality is improved.
Further, a first diffraction structure 10, a second diffraction structure 20, a refractive structure having a focal length equal to the far-viewing focus, or other diffraction structures may be provided in the region connected to the diffraction zone.
In some embodiments, the ophthalmic lens 100 is formed with bifocal points, and the first diffractive unit 12 and the second diffractive unit 22 are arranged 2M: 2N outward from the optical axis A of the ophthalmic lens 100.
It is understood that the ophthalmic lens 100 includes a plurality of first diffractive structures 10 and a plurality of second diffractive structures 20 alternately arranged. Wherein the number of first diffractive units 12 and the number of second diffractive units 22 can be arranged outward from the optical axis a of the ophthalmic lens 100 in a 2M: 2N repetition.
In the present embodiment, in the diffraction zone, the first diffraction structures 10 form +1 order diffraction focuses, the second diffraction structures 20 form +2 order diffraction focuses, the plurality of first diffraction structures 10 interfere with each other to increase the focal depth of the +1 order diffraction focuses, and the plurality of second diffraction structures 20 interfere with each other to increase the focal depth of the +2 order diffraction focuses. Specifically, the first diffractive structure 10 converges light to the +1 st order diffractive focus, and the second diffractive structure 20 converges light to the +2 nd order diffractive focus. Due to the interference effect of the plurality of first diffraction structures 10, two new focuses are formed on both sides of the +1 st order diffraction focus, but the two new focuses are close to the +1 st order diffraction focus, thereby exhibiting one focus with an increased depth of focus. Two new focuses are formed on both sides of the +2 order diffraction focus due to the interference of the plurality of second diffraction structures 20, but the two new focuses are close to the +2 order diffraction focus, thereby representing one focus with an increased depth of focus. In this way, the design wavelength light is completely focused to exhibit these two focal points without energy loss, thereby improving visual quality.
Further, a first diffraction structure 10, a second diffraction structure 20, a refractive structure having a focal length equal to the far-vision focus, or other diffraction structures may be provided in the region connected to the diffraction zone.
The following describes an ophthalmic lens 100 according to an embodiment of the present invention with specific examples.
Design of the diffractive structures (first diffractive structure 10 and second diffractive structure 20):
(1) Firstly, determining a q value, wherein the q value is the ratio of the optical path difference of the design wavelength caused by the height difference in the diffraction unit to the design wavelength, and the q value determines the distribution of energy at each focal point. Q =1 for the first diffractive structure 10 and q =2 for the second diffractive structure 20.
(2) Determination of the diffraction order in which the light can be used effectively: the first diffractive element 12,q =1 of the first diffractive structure 10, the diffraction order m =1, and the second diffractive element 22,q =2 of the second diffractive structure 20, the diffraction order m =2.
The focal power of the m-th diffraction focus is D m Focal power D of the 1 st order diffraction focus 1 ＝D m /m。
In the ophthalmic lens 110, the amplitude transfer function can be expressed as the following fourier series function:
wherein p represents the multiple of the design wavelength with a phase difference of 2 pi, m represents the diffraction order, r represents the distance from a point in the diffraction structure to the optical center, and λ 0 Representing the design wavelength, F 0 The diffraction focal length representing the design wavelength. α represents a wavelength-influencing factor, i.e., the influence on the amplitude when the wavelength is not equal to the design wavelength, as follows:
wherein λ represents a wavelength, λ 0 Denotes a design wavelength, n (λ) 0 ) Denotes a refractive index of the lens for a design wavelength, and n (λ) denotes a refractive index of the lens for a wavelength.
The m-th order diffraction energy for a diffractive structure can be obtained by the square of the fourier coefficient of t (r) as follows:
η m ＝sin c 2 (αp＝m)
(3) Determining the position r of the diffraction step n ：
Where n denotes the position of the nth diffraction step (half aperture starting from the optical axis A of the ophthalmic lens 100), λ 0 Representing the design wavelength, D m Additional diffraction orders, f, of the m-th order 1 Focal length representing +1 order diffractive add focus: f. of 1 ＝1000/(D m In terms of a/m). The focal length of the mth order diffraction additional focus is as follows: f. of m ＝f 1 /m。
Height difference within diffraction cell and height of diffraction step:
wherein q =1 for the first diffractive structure 10 and q =2, λ for the second diffractive structure 20 0 Denotes the design wavelength, n (λ) 0 ) Representing the refractive index of the lens at the design wavelength, n m Representing the refractive index of the medium.
Referring to FIGS. 2, 3 and 4, the phase difference in each first diffraction cell 12 is equal to 2 π and the phase difference in each second diffraction cell 22 is equal to 4 π. Due to the difference in height and phase difference between the first diffractive unit 12 and the second diffractive unit 22, a phase shift is introduced when designing the ophthalmic lens 100, which may change the energy distribution of different focal points. Before the phase shift, the height difference H1 in the first diffraction unit 12 is equal to the height H1 of the first diffraction step 14, and the height difference H2 in the second diffraction unit 22 is equal to the height H2 of the second diffraction step 24. After the phase shift, the height difference H1 in the first diffraction unit 12 is not equal to the height H1 of the first diffraction step 14 and the height difference H2 in the second diffraction unit 22 is not equal to the height H2 of the second diffraction step 24.
Specific examples of diffractive structures for the ophthalmic lens 100 of the present invention are as follows:
in the following examples, the refractive index of the material of ophthalmic lens 100 is 1.531, the refractive index of the ambient medium in which ophthalmic lens 100 is located is 1.336, and the design wavelength is 546 nm.
Example one
Referring to FIG. 5, the power D of the +1 st order diffraction focus of the first diffractive structure 10 1 The same power B as the +1 st order diffraction focus of the second diffractive structure 20, i.e. the zone area corresponding to a single first diffractive unit 12 of the first diffractive structure 10 is the same as the zone area corresponding to a single second diffractive unit 22 of the second diffractive structure 20, M: N = D 1 ∶B＝1∶1。
For 546 nm wavelength light, the first diffractive structure 10 forms an optical power D by +1 st order diffraction 1 Focal point of = 3.0D.
For 546 nm wavelength light, the second diffractive structure 20 forms an optical power D by +2 diffraction orders 2 Focus of + 6.0D.
Specifically, in the range of the first aperture of 3.413 mm, outward from the optical axis a of the ophthalmic lens 100, the first diffractive structures 10 and the second diffractive structures 20 are alternately arranged, the number of the first diffractive units 12 and the number of the second diffractive units 22 are 2: 1: 2: 1, and theoretically, two focal points having powers of +6.0D and +3.0D can be formed, and actually, when the ophthalmic lens 100 is formed by combining the first diffractive structures 10 and the second diffractive structures 20 with the basic aspheric/spherical structure, due to the spherical aberration of the ophthalmic lens 100 and other factors, a third focal point having a power of +4.5D is formed between the two focal points having powers of +6.0D and +3.0D, so that three focal points having powers of +6.0D, +4.5D and +3.0D are expressed. The first aperture range includes 8 diffraction units, wherein the number of the first diffraction unit 12 and the number of the second diffraction unit 22 are respectively 4.
The first diffractive structures 10 alternate with the second diffractive structures 20 at a second aperture having a diameter in the range of 3.413 mm to 4.180 mm. In this interval, each first diffractive structure 10 contains one first diffractive element 12 and each second diffractive structure 20 contains one second diffractive element 22. In this interval, three focal points having powers of +6.0D, +4.5D, and +3.0D are formed, and more energy is concentrated at the focal point having a power of + 4.5D. The second aperture range includes 4 diffraction units, wherein the number of the first diffraction unit 12 and the number of the second diffraction unit 22 are 2 respectively.
In the area outside the second aperture range, a first diffractive structure 10 is further provided, comprising 4 first diffractive units 12.
The entire diffractive optical surface of the ophthalmic lens 100 exhibits three focal points with optical powers of +3.0D, +4.5D, + 6.0D. Relevant parameters of the ophthalmic lens 100 are shown in the following table.
In the ophthalmic lens 100 of the present embodiment, for the design wavelength, the light is converged at three focal points with the focal powers of +3.0D, +4.5D, +6.0D, without loss of the energy of the other higher diffraction order focal points, which is beneficial to improvement of the imaging quality.
Example two
Referring to FIG. 6, the power D of the +1 st order diffraction focus of the first diffractive structure 10 1 The same power B as the +1 st order diffraction focus of the second diffractive structure 20, i.e. the zone area corresponding to a single first diffractive unit 12 of the first diffractive structure 10 is the same as the zone area corresponding to a single second diffractive unit 22 of the second diffractive structure 20, M: N = D 1 ∶B＝1∶1。
For 546 nm wavelength light, the first diffractive structure 10 forms an optical power D by +1 st order diffraction 1 Focus of + 1.0D.
For 546 nm wavelength light, the second diffractive structure 20 forms an optical power D through +2 order diffraction 2 = 2.0D focus.
The difference in focal power between the first diffractive structure 10 and the second diffractive structure 20 is 1.0D.
Specifically, in the diffraction zone, outward from the optical axis a of the ophthalmic lens 100, the first diffractive structures 10 are alternately arranged with the second diffractive structures 20. In this interval, each first diffractive structure 10 contains one first diffractive element 12, and each second diffractive structure 20 contains one second diffractive element 22. In this interval, three focal points having powers of +1.0D, +1.5D, and +2.0D are formed. Since the power difference between the three focal points is small and the energy is concentrated mainly at the focal point having the power of +1.5D, the entire diffractive optical surface of the ophthalmic lens 100 exhibits a focal point having a larger depth of focus, which has the power of +1.5D. Relevant parameters of the ophthalmic lens 100 are shown in the following table.
In the ophthalmic lens 100 of the present embodiment, for the design wavelength, through theoretical analysis, the light will converge at three focal points with focal powers of +1.0D, +1.5D, +2.0D, but actually appear as a large focal depth focal point with focal power of +1.5D, without loss of other higher diffraction order focal energy, which is beneficial to improvement of the imaging quality.
EXAMPLE III
Referring to FIG. 7, the power D of the +1 st order diffraction focus of the first diffractive structure 10 1 The same power B as the +1 st order diffraction focus of the second diffractive structure 20, i.e. the zone area corresponding to a single first diffractive unit 12 of the first diffractive structure 10 and the second diffractive unitThe corresponding wave band areas of the single second diffraction unit 22 of the radiation structure 20 are the same, and M: N = D 1 ∶B＝1∶1。
For 546 nm wavelength light, the first diffractive structure 10 forms an optical power D by +1 st order diffraction 1 = 1.5D focus.
For 546 nm wavelength light, the second diffractive structure 20 forms an optical power D by +2 diffraction orders 2 = 3.0D focus.
The difference in focal power between the first diffractive structure 10 and the second diffractive structure 20 is +1.5D.
Specifically, in the diffraction zone, outward from the optical axis a of the ophthalmic lens 100, the first diffractive structures 10 are alternately arranged with the second diffractive structures 20. In this interval, each first diffractive structure 10 contains two first diffractive elements 12, and each second diffractive structure 20 contains two second diffractive elements 22. In this interval, two focal points having powers of +1.5D and +3.0D are formed. Due to the interference of the plurality of first diffractive structures 10, there will be an energy distribution at powers +1.125D and +1.875D, but it blends in with a focal point having a power of +1.5D, representing a large depth of focus focal point having a power of +1.5D. Due to the interference of the plurality of second diffractive structures 20, there will be an energy distribution at powers +3.375D and +2.625D, but it blends in with the focus at power +3.0D, representing a large depth of focus at power + 3.0D. Relevant parameters of the ophthalmic lens 100 are shown in the following table.
In the ophthalmic lens 100 of the present embodiment, for the design wavelength, through theoretical analysis, the light will converge at six focal points with powers of +1.125D, +1.875D, +1.5D, +3.375D, +2.625D, +3.0D, but actually appear as two large focal depth focal points with powers of +1.5D and +3.0D, without loss of energy of other higher diffraction order focal points, which is beneficial for improvement of the imaging quality.
Example four
Referring to FIG. 8, the power D of the +1 st order diffraction focus of the first diffractive structure 10 1 M: N = D, the same as the power B of the +1 st order diffractive focal point of the second diffractive structure 20 1 ∶B。
For 546 nm wavelength light, the first diffractive structure 10 forms an optical power D by +1 diffraction order 1 = 9.0D focus.
For 546 nm wavelength light, the second diffractive structure 20 forms an optical power D by +2 diffraction orders 2 Focal point of +12.0D (focal power B of its corresponding +1 st order diffraction focal point = + 6.0D). Thus, M: N = D 1 ∶B＝3∶2。
Specifically, in the range of the first aperture of 3.413 mm, the second diffraction structures 20 and the first diffraction structures 10 are alternately arranged outward from the optical axis a of the ophthalmic lens 100, and the number of the second diffraction units 22 and the number of the first diffraction units 12 are 4: 3: 2: 6: 2: 3, and theoretically two focal points having powers of +12.0D and +9.0D can be formed, and in practice, when the first diffraction structure 10 and the second diffraction structure 20 are combined with the base aspheric/spherical structure to form the ophthalmic lens 100, due to the spherical aberration of the ophthalmic lens 100 and other factors, a third focal point having a power of +10.5D is formed between the two focal points having powers of +12.0D and +9.0D, so as to represent three focal points having powers of +12.0D, +10.5D and +9.0D, wherein the focal point having a power of +10.5D realizes a good intermediate visual effect. The first aperture range includes 20 diffraction units, including 12 first diffraction units 12 and 8 second diffraction units 22.
The second diffractive structures 20 are alternately arranged with the first diffractive structures 10 at a second aperture having a diameter in a range of 3.413 mm to 4.180 mm. In this interval, each first diffractive structure 10 contains three first diffractive elements 12 and each second diffractive structure 20 contains two second diffractive elements 22. In this interval, the energy distribution of the apparent focal point having the power of +10.5D can be enhanced. The second aperture includes 10 diffraction units, including 6 first diffraction units 12 and 4 second diffraction units 22.
The entire diffractive optical surface of the ophthalmic lens 100 exhibits three focal points having powers of +9.0D, +10.5D, + 12.0D. Relevant parameters of the ophthalmic lens 100 are shown in the following table.
In the ophthalmic lens 100 of the present embodiment, for the design wavelength, the light is converged at three focal points with the focal powers of +9.0D, +10.5D, +12.0D, and there is no loss of the energy of the other higher diffraction order focal points, which is beneficial to the improvement of the imaging quality.
In the description herein, references to the description of the terms "one embodiment," "certain embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (11)
1. An ophthalmic lens, characterized in that at least one optical surface of said ophthalmic lens is provided with at least one first diffractive structure comprising at least one first diffractive element and at least one second diffractive structure comprising at least one second diffractive element, the phase difference within each first diffractive element being equal to 2 π and the phase difference within each second diffractive element being equal to 4 π;
the minimum integer ratio of the +1 order diffraction power of the first diffraction structures to the +1 order diffraction power of the second diffraction structures is M: N, the number of the first diffraction units included in each first diffraction structure is an integer multiple of M, and the number of the second diffraction units included in each second diffraction structure is an integer multiple of N;
the ophthalmic lens comprises a plurality of the first diffractive structures and a plurality of the second diffractive structures, the first diffractive structures alternating with the second diffractive structures;
within a first aperture range, the first diffractive unit and the second diffractive unit are arranged 2M: N: M: 2N: M: N, M: N: 2M: N: M: 2N, 2N: M: N: 2M: N: M or N: M: 2N: M: N: 2M outward from the optical axis of the ophthalmic lens.
2. An ophthalmic lens according to claim 1, characterized in that the +1 st order diffractive power of the first diffractive structure is different from the +2 nd order diffractive power of the second diffractive structure.
3. An ophthalmic lens according to claim 1, characterized in that the +1 order diffractive power of the second diffractive structure is equal to half the +2 order diffractive power of the second diffractive structure.
4. An ophthalmic lens according to claim 1, characterized in that the first diffractive structure is formed with a +1 order diffractive focus and the second diffractive structure is formed with a +2 order diffractive focus.
5. An ophthalmic lens according to claim 1, characterized in that the first diffractive unit and the second diffractive unit are arranged M: N outward from the optical axis of the ophthalmic lens in the second aperture range.
6. An ophthalmic lens according to claim 5, characterized in that the first diffractive structure is formed with a +1 order diffractive focus, the second diffractive structure is formed with a +2 order diffractive focus, the first diffractive structure and the second diffractive structure interfere to form an intermediate vision focus having an optical power between the optical power of the +1 order diffractive focus and the optical power of the +2 order diffractive focus.
7. An ophthalmic lens according to claim 1, characterized in that the ophthalmic lens exhibits a single focus, the first diffractive unit and the second diffractive unit being arranged M: N outwards from the optical axis of the ophthalmic lens.
8. An ophthalmic lens according to claim 7, characterized in that the first diffractive structure is formed with a +1 order diffractive focus, the second diffractive structure is formed with a +2 order diffractive focus, the first diffractive structure and the second diffractive structure interfere to form a third focus, the +1 order diffractive focus, the +2 order diffractive focus and the third focus merge into the single focus.
9. An ophthalmic lens according to claim 8, characterized in that the power of the +1 order diffractive focal point differs from the power of the +2 order diffractive focal point by less than 2.0D, and the power of the third focal point is equal to half the sum of the power of the +1 order diffractive focal point and the power of the +2 order diffractive focal point.
10. An ophthalmic lens according to claim 1, characterized in that the ophthalmic lens is formed with bifocal points, the first diffractive unit and the second diffractive unit being arranged 2M: 2N outwards from the optical axis of the ophthalmic lens.
11. The ophthalmic lens according to claim 10, wherein the first diffractive structure is formed with a +1 order diffractive focal point, the second diffractive structure is formed with a +2 order diffractive focal point, a plurality of the first diffractive structures interfere to increase a depth of focus of the +1 order diffractive focal point, and a plurality of the second diffractive structures interfere to increase a depth of focus of the +2 order diffractive focal point.
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| US7441894B2 (en) * | 2006-02-09 | 2008-10-28 | Alcon Manufacturing, Ltd. | Pseudo-accommodative IOL having diffractive zones with varying areas |
| WO2011052188A1 (en) * | 2009-11-02 | 2011-05-05 | パナソニック株式会社 | Diffraction grating lens and imaging device using same |
| WO2014033543A2 (en) * | 2012-08-31 | 2014-03-06 | Amo Groningen B.V. | Multi-ring lens, systems and methods for extended depth of focus |
| EP3130314A1 (en) * | 2015-08-12 | 2017-02-15 | PhysIOL SA | Trifocal intraocular lens with extended range of vision and correction of longitudinal chromatic aberration |
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