METHOD FOR MANUFACTURING DIFFRACTIVE MULTI-FOCAL OPHTHALMIC LENS AND DIFFRACTIVE MULTI-FOCAL OPHTHALMIC LENS

Abstract

A method for manufacturing a diffractive multi-focal ophthalmic lens capable of generating at least three focal points in an optical axis direction using a diffractive structure comprising a plurality of zones in a concentric circle form. A composite profile is generated by overlapping at least two starting profiles comprising a plurality of zones in a concentric circle form, and an adjusted profile is generated in which at least one of phase and amplitude is adjusted by employing a zone of the composite profile as a subject in order to set an intensity distribution in the optical axis direction and determine optical characteristics, to manufacture the diffractive multi-focal ophthalmic lens for which the adjusted profile is provided in at least a portion of the diffractive structure.

Claims

1. A method for manufacturing a diffractive multi-focal ophthalmic lens capable of generating at least three focal points in an optical axis direction using a diffractive structure comprising a plurality of zones in a concentric circle form, the method comprising: generating a composite profile by overlapping at least two starting profiles comprising a plurality of zones in a concentric circle form; generating an adjusted profile by adjusting at least one of phase and amplitude with a zone of the composite profile as a subject in order to set an intensity distribution in the optical axis direction and determine optical characteristics; and manufacturing the diffractive multi-focal ophthalmic lens for which the adjusted profile is provided in at least a portion of the diffractive structure.

2. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein the at least two starting profiles all have a phase expressed as a blaze shaped function in relation to a lens radial distance in at least a portion of a region overlapped, and the phase of the composite profile is also expressed as a blaze shaped function.

3. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 2, wherein the blaze shaped function of the composite profile is expressed by Equation 1. $\begin{matrix} φ (r) = \frac{φ_{i} - φ_{i - 1}}{r_{i} - r_{i - 1}} \times r + \frac{φ_{i - 1} \times r_{i} - φ_{i} \times r_{i - 1}}{r_{i} - r_{i - 1}} + τ & [Equation .Math. .Math. 1] \end{matrix}$ r: Radial distance from the lens center r.sub.i−1: Inner diameter of the ith zone (radius) r.sub.i: Outer diameter of the ith zone (radius) φ.sub.i−1: Phase at the inner diameter (radius) position of the ith zone φ.sub.i: Phase at the outer diameter (radius) position of the ith zone τ: Phase shift

4. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 3, wherein adjustment of the phase with the zone of the composite profile as the subject is performed by varying at least one of a phase constant h expressed by Equation 2 using φ.sub.i and φ.sub.i−1 of Equation 1, and a phase shift τ of Equation 1. $\begin{matrix} h = \frac{φ_{i - 1} - φ_{i}}{2 .Math. π} & [Equation .Math. .Math. 2] \end{matrix}$

5. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 4, wherein when adjusting the phase of the composite profile, the adjusted profile is set so as to include the zones for which the phase constant h changes periodically in a radial direction.

6. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 4, wherein when adjusting the phase of the composite profile, the adjusted profile is set so as to include the zones for which the phase shift τ changes periodically in a radial direction.

7. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein adjustment of the amplitude of the composite profile is performed by adjusting a light transmittance in the zone of the composite profile.

8. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 7, wherein when adjusting the amplitude of the composite profile, the adjusted profile is set so as to include the zones for which the light transmittance changes periodically in a radial direction.

9. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein by adjusting at least one of the phase and amplitude of the composite profile, at least two zones positioned continuously in a radial direction in the composite profile are integrated.

10. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein at least one of the starting profiles is a first starting profile having a zone pitch expressed by Equation 3 in at least a portion thereof. $\begin{matrix} r_{n} = \sqrt{r_{1}^{2} + \frac{2 .Math. .Math. λ (n - 1)}{P_{1}}} & [Equation .Math. .Math. 3] \end{matrix}$ r.sub.n: nth zone radius of the first starting profile r.sub.1: First zone radius of the first starting profile P.sub.1: Addition power of the first starting profile n: Natural number λ: Design wavelength

11. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 10, wherein a first zone radius r.sub.1 of the first starting profile is expressed by Equation 4. $\begin{matrix} r_{1} = \sqrt{\frac{2 .Math. .Math. λ}{P_{1}}} & [Equation .Math. .Math. 4] \end{matrix}$

12. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 10, wherein in addition to the first starting profile, a second starting profile having a zone pitch expressed by Equation 5 in at least a portion thereof is used as the starting profile. $\begin{matrix} r_{m} = \sqrt{r_{1}^{′2} + \frac{2 .Math. .Math. λ (m - 1)}{P_{2}}} & [Equation .Math. .Math. 5] \end{matrix}$ r.sub.m: mth zone radius of the second starting profile r.sub.1′: First zone radius of the second starting profile P.sub.2: Addition power of the second starting profile m: Natural number λ: Design wavelength

13. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 12, wherein a first zone radius r.sub.1′ of the second starting profile is expressed by Equation 6. $\begin{matrix} r_{1}^{'} = \sqrt{\frac{2 .Math. .Math. λ}{P_{2}}} & [Equation .Math. .Math. 6] \end{matrix}$

14. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 12, wherein an addition power P.sub.2 given by the second starting profile is expressed by a relational expression of Equation 7 using an addition power P.sub.1 given by the first starting profile, a and b are mutually different natural numbers, and quotients when a and b are divided by a mutual greatest common divisor thereof are both an integer other than 1. $\begin{matrix} P_{2} = \frac{a}{b} \times P_{1} & [Equation .Math. .Math. 7] \end{matrix}$

15. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 14, wherein a and b in Equation 7 are set to be a/b>½.

16. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 14, wherein in regards to a and b in Equation 7, a synchronous structure, for which a b-number of zone pitches that are continuous in the first starting profile and an a-number of zone pitches that are continuous in the second starting profile are mutually the same within the same region, is set for at least a portion of a region where the first starting profile and the second starting profile are overlapped.

17. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein the composite profile includes the diffractive structure for which in addition to the first starting profile and the second starting profile, a third starting profile is further overlapped on the same region.

18. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 17, wherein at least a portion of the third starting profile has a zone pitch given by Equation 8, and an addition power P.sub.3 given by the third starting profile is different from both of the addition powers given by the first and second starting profiles. $\begin{matrix} r_{q} = \sqrt{r_{1}^{″2} + \frac{2 .Math. .Math. λ (q - 1)}{P_{3}}} & [Equation .Math. .Math. 8] \end{matrix}$ r.sub.q: qth zone radius of the third starting profile r.sub.1″: First zone radius of the third starting profile P.sub.3: Addition power of the third starting profile q: Natural number λ: Design wavelength

19. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 18, wherein a first zone radius r.sub.1″ of the third starting profile is expressed by Equation 9. $\begin{matrix} r_{1}^{″} = \sqrt{\frac{2 .Math. .Math. λ}{P_{3}}} & [Equation .Math. .Math. 9] \end{matrix}$

20. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 17, wherein at least a portion of the composite profile has a synchronous structure for which, with c.sub.1, c.sub.2 and c.sub.3 all being mutually different natural numbers, a c.sub.3-number of zone pitches continuous in the third starting profile is the same as either a c.sub.1-number of zone pitches continuous in the first starting profile or a c.sub.2-number of zone pitches continuous in the second starting profile.

21. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 17, wherein the addition power P.sub.2 given by the second starting profile is expressed by a relational expression of Equation 10 using the addition power P.sub.1 given by the first starting profile, while the addition power P.sub.3 given by the third starting profile is determined by Equation 11 using the addition power P.sub.1, and with a greatest common divisor being z for three integers of (b×e), (a×e), and (b×d) expressed using a, b, d, and e in Equation 10 and Equation 11, at least a portion of the composite profile has a synchronous structure for which a (b×e)/z-number of continuous zone pitches in the first starting profile, an (a×e)/z-number of continuous zone pitches in the second starting profile, and a (b×d)/z-number of continuous zone pitches in the third starting profile are mutually the same. $\begin{matrix} P_{2} = \frac{a}{b} \times P_{1} & [Equation .Math. .Math. 10] \end{matrix}$ (a, b: Mutually different natural numbers) $\begin{matrix} P_{3} = \frac{d}{e} \times P_{1} & [Equation .Math. .Math. 11] \end{matrix}$ (d, e: Mutually different natural numbers)

22. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 17, wherein in addition to the first starting profile, the second starting profile, and the third starting profile, a fourth starting profile is also set, and the composite profile includes the diffractive structure which has the first, second, third, and fourth starting profiles overlapped on the same region.

23. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 22, wherein in addition to the first starting profile, the second starting profile, the third starting profile, and the fourth starting profile, a fifth starting profile is also set, and the composite profile includes the diffractive structure which has the first, second, third, fourth, and fifth starting profiles overlapped on the same region.

24. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein the diffractive structure comprises a relief structure reflecting an optical path length correlating to the phase.

25. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein one of the at least three focal points is used for far vision, another focal point is used for near vision, and yet another focal point is used for intermediate vision.

26. The method for manufacturing the diffractive multi-focal ophthalmic lens according to claim 1, wherein settings are made such that the focal point for far vision is given by a 0th order diffracted light of the diffractive structure, and the focal point for near vision and the focal point for intermediate vision are respectively given by a +1 order diffracted light of the first starting profile and the second starting profile.

27. A diffractive multi-focal ophthalmic lens comprising a diffractive structure comprising a plurality of zones in a concentric circle form, the diffractive structure being capable of generating at lease three focal points in an optical axis direction, wherein: the diffractive structure comprises a composite profile which includes a phase profile that is dividable into a plurality of starting profiles being overlapped each other, and for which radial direction positions of the respective zones are set according to the plurality of starting profiles, and an adjusted profile is set for which at least one of the zones of the composite profile is a zone having a different phase and/or amplitude from an overlapping of the plurality of starting profiles.

28. The diffractive multi-focal ophthalmic lens according to claim 27, wherein by the adjusted profile being set for which at least one of the zones of the composite profile is the zone having the different phase and/or amplitude from the overlapping of the plurality of starting profiles, compared to the phase profile comprising the overlapping of the plurality of starting profiles, a level of multi-order light for a light intensity distribution in the optical axis direction is suppressed.

29. The diffractive multi-focal ophthalmic lens according to claim 27, wherein in at least one of the plurality of starting profiles, at least a portion thereof has a Fresnel pitch.

30. The diffractive multi-focal ophthalmic lens according to claim 27, wherein a radius of each zone that is a non-Fresnel pitch in a mode where the plurality of starting profiles are overlapped is substantially a Fresnel pitch in the adjusted profile by the plurality of zones being integrally consolidated.

31. The diffractive multi-focal ophthalmic lens according to claim 27, wherein at least a portion of the phase of the adjusted profile is expressed as a blaze shaped function in relation to a lens radial distance.

32. The diffractive multi-focal ophthalmic lens according to claim 27, wherein in the plurality of starting profiles, at least a portion of each phase is expressed as a blaze shaped function in relation to a lens radial distance.

33. The diffractive multi-focal ophthalmic lens according to claim 31, wherein the blaze shaped function is expressed by Equation 12. $\begin{matrix} φ (r) = \frac{φ_{i} - φ_{i - 1}}{r_{i} - r_{i - 1}} \times r + \frac{φ_{i - 1} \times r_{i} - φ_{i} \times r_{i - 1}}{r_{i} - r_{i - 1}} + τ & [Equation .Math. .Math. 12] \end{matrix}$ r: Radial distance from the lens center r.sub.i−1: Inner diameter of the ith zone (radius) r.sub.i: Outer diameter of the ith zone (radius) φ.sub.i−1: Phase at the inner diameter (radius) position of the ith zone φ.sub.i: Phase at the outer diameter (radius) position of the ith zone τ: Phase shift

34. A diffractive multi-focal ophthalmic lens set comprising a plurality of types of diffractive multi-focal ophthalmic lenses combined into a series, each of the diffractive multi-focal ophthalmic lenses capable of generating at least three focal points in an optical axis direction using a diffractive structure comprising a plurality of zones in a concentric circle form, the diffractive structure comprising a composite profile which includes a phase profile that is dividable into a plurality of starting profiles being overlapped each other, and for which radial direction positions of the respective zones are set according to the plurality of starting profiles, wherein adjusted profiles are set in the respective diffractive multi-focal ophthalmic lenses for which, for each adjusted profile, at least one of the zones of the composite profile is a zone having a different phase and/or amplitude from an overlapping of the plurality of starting profiles, and light intensity distributions of the diffractive multi-focal ophthalmic lenses in the optical axis direction are made mutually different by settings of the adjusted profiles being mutually different.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0134] FIG. 1 is a graph of the phase function with the r-φ coordinate system expressing the relationship of the phase 4 of the phase modulation structure provided in the diffractive lens with the lens radial direction position r.

[0135] FIGS. 2A-2D show graphs with FIGS. 2A, 2B, 2C and 2D each showing the blaze as one mode of the phase function for the diffractive lens.

[0136] FIG. 3 is a graph using the phase shift z to show the status when the blaze is shifted in the φ axis direction in relation to the reference line of the graph with the blaze phase function φ(r) expressed on the reference line.

[0137] FIGS. 4A-4C are graphs for describing the relative relationship of each phase function for starting profiles (1) and (2) having a blaze shaped phase function and the composite profile generated by overlapping those.

[0138] FIGS. 5A-5D are drawings relating to the composite profile of example 1 of the present invention, where FIGS. 5A and 5B show each phase profile of starting profiles (1) and (2) as the first and second zone profiles, FIG. 5C shows the composite profile as the overlapped phase profiles, and FIG. 5D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0139] FIG. 6A is a graph of the phase function showing together the adjusted profile as example 1 obtained by changing and adjusting the phase constant of a specific zone with the composite profile shown in FIG. 5C and the composite profile before adjustment, and FIG. 6B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0140] FIGS. 7A and 7B are drawings relating to the composite profile as example 2 of the present invention, where FIG. 7A shows the composite profile as overlapped phase profiles, and FIG. 7B is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0141] FIG. 8A is a graph of the phase function showing together the adjusted profile as example 2 obtained by changing and adjusting the phase constant of a specific zone with the composite profile shown in FIG. 7A and the composite profile before adjustment, and FIG. 8B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0142] FIGS. 9A and 9B are drawings relating to the composite profile as example 3 of the present invention, where FIG. 9A shows the composite profile as overlapped phase profiles, and FIG. 9B is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0143] FIG. 10A is a graph of the phase function showing together the adjusted profile as example 3 obtained by changing and adjusting the phase constant of a specific zone with the composite profile shown in FIG. 9A and the composite profile before adjustment, and FIG. 10B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0144] FIGS. 11A-11C are drawings relating to the diffractive multi-focal lens of example 4 of the present invention, where FIG. 11A is a graph of the phase function showing together the adjusted profile of example 4 obtained by adjusting the phase and amplitude with the composite profile of example 3 as the subject and the composite profile before adjustment, FIG. 11B is a front view showing in model form a lens for which transmittance was adjusted when doing amplitude adjustment of a specific zone, and FIG. 11C is a graph showing together the light intensity distribution of the diffractive multi-focal lens having the adjusted profile of this example and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0145] FIGS. 12A-12C are drawings relating to the diffractive multi-focal lens of example 5 of the present invention, where FIG. 12A is a graph of the phase function showing together the adjusted profile of example 5 obtained by adjusting the phase and amplitude with the composite profile of example 3 as the subject and the composite profile before adjustment, FIG. 12B is a front view showing in model form a lens for which transmittance was adjusted when doing amplitude adjustment of a specific zone, and FIG. 12C is a graph showing together the light intensity distribution of the diffractive multi-focal lens having the adjusted profile of this example and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0146] FIGS. 13A-13D are drawings relating to the composite profile as example 6 of the present invention, where FIGS. 13A and 13B show each phase profile of starting profiles (1) and (2) as the first and second zone profiles, FIG. 13C shows the composite profile as the overlapped phase profiles, and FIG. 13D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0147] FIG. 14A is a graph of the phase function showing together the adjusted profile as example 6 obtained by adjusting the phase of a specific zone with the composite profile shown in FIG. 13C and the composite profile before adjustment, and FIG. 14B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0148] FIGS. 15A and 15B are drawings relating to the diffractive multi-focal lens of example 7 of the present invention obtained by implementing a different phase adjustment to that of example 6 on the same composite profile as example 6, where FIG. 15A is a graph of the phase function showing together the adjusted profile as example 7 obtained by adjusting the phase of a specific zone with the composite profile shown in FIG. 13C and the composite profile before adjustment, and FIG. 15B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0149] FIGS. 16A-16C show the results of simulation of the imaging characteristics projected on the retina surface in a state with the diffractive multi-focal lens constituted from the composite profile of example 6 set in the eye as an intraocular lens or contact lens, where FIG. 16A is a front view of the image that appears on the retina, FIG. 16B is a graph of the intensity distribution on the image plane, and FIG. 16C is a Landolt ring image expressing visual performance.

[0150] FIGS. 17A-17C show the results of simulation of the imaging characteristics projected on the retina surface in a state with the diffractive multi-focal lens constituted from the adjusted profile of example 6 set in the eye as an intraocular lens or contact lens, where FIG. 17A is a front view of the image that appears on the retina, FIG. 17B is a graph of the intensity distribution on the image plane, and FIG. 17C is a Landolt ring image expressing visual performance.

[0151] FIGS. 18A-18E show the results of simulation of the imaging characteristics projected on the retina surface in a state with the diffractive multi-focal lens constituted from the adjusted profile of example 7 set in the eye as an intraocular lens or contact lens, where FIG. 18A is a front view of the image that appears on the retina, FIG. 18B is a graph of the intensity distribution on the image plane, and FIG. 18C is a Landolt ring image expressing visual performance. FIG. 18D is a drawing showing the site at which the intensity distribution of the Landolt ring projected on the retina is displayed, and FIG. 18E is a drawing showing the intensity distribution of FIG. 16C, FIG. 17C, and FIG. 18C.

[0152] FIGS. 19A-19E are drawings relating to the composite profile with example 8 of the present invention, where FIGS. 19A, 19B and 19C show each phase profile of starting profiles (1), (2) and (3) as the first, second and third zone profiles, FIG. 19D shows the composite profile as the overlapped phase profiles, and FIG. 19E is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0153] FIG. 20A is a graph of the phase function showing together the adjusted profile as example 8 obtained by adjusting the phase of a specific zone with the composite profile shown in FIG. 19D and the composite profile before adjustment, and FIG. 20B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment.

[0154] FIGS. 21A-21C are explanatory drawings showing matching with the standard Fresnel pitch for the zone pitch with the adjusted profile of the diffractive multi-focal lens of example 8, where FIG. 21A is a graph showing the adjusted profile of example 8, FIG. 21B is a graph showing the zone profile of the standard Fresnel pitch, and FIG. 21C is a graph showing the adjusted profile of example 7.

[0155] FIGS. 22A-22F are drawings relating to the diffractive multi-focal lens of example 9 that has a standard Fresnel pitch by which four focal points can be generated by phase adjustment of specific zones, where FIG. 22A is a graph of the phase function of the adjusted profile, FIG. 22B is a graph of the light intensity distribution, and FIGS. 22C-22F are Landolt images showing the simulation results of visual performance when the diffractive multi-focal lens is set in the eye as an intraocular lens.

[0156] FIGS. 23A and 23B are drawings relating to the diffractive multi-focal lens of example 10 for which it is possible to realize four focal points with even more simplified zone pitches by performing phase adjustment on specific zones in relation to the diffractive multi-focal lens of example 9 having the standard Fresnel pitch, where FIG. 23A is a graph showing the phase function of the adjusted profile, and FIG. 23B is a graph of the light intensity distribution.

[0157] FIGS. 24A-24C are drawings relating to the composite profile of example 11 of the present invention, where FIG. 24A shows each phase profile of starting profiles (1) and (2) as the first and second zone profiles, FIG. 24B shows the composite profile as the overlapped phase profiles, and FIG. 24C is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0158] FIG. 25A is a graph of the phase function showing together the adjusted profile as example 11 obtained by adjusting the phase of a specific zone with the composite profile shown in FIG. 24B and the composite profile before adjustment, FIG. 25B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment, and FIG. 25C is a drawing showing an enlarged view of the region enclosed by the dotted line in FIG. 25B.

[0159] FIGS. 26A-26C are drawings relating to the composite profile of example 12 of the present invention, where FIG. 26A shows each phase profile of starting profiles (1) and (2) as the first and second zone profiles, FIG. 26B shows the composite profile as the overlapped phase profiles, and FIG. 26C is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0160] FIG. 27A is a graph of the phase function showing together the adjusted profile as example 12 obtained by adjusting the phase of a specific zone with the composite profile shown in FIG. 26B and the composite profile before adjustment, FIG. 27B is a graph showing together the light intensity distribution of the diffractive multi-focal lens having that adjusted profile and the light intensity distribution of the diffractive multi-focal lens having the composite profile before adjustment, and FIG. 27C is a drawing showing an enlarged view of the region enclosed by the dotted line in FIG. 27B.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0161] Following, by showing and describing some examples as modes for carrying out the present invention, the present invention will be made clear in more specific terms.

Example Conditions and the Like

[0162] To start, we will describe the calculation simulation methods, conditions and the like used with the examples below. For the calculation software, an item was used that can calculate amplitude distribution and intensity distribution from each zone based on a diffraction integral equation derived from a theory known in the field called the scalar diffraction theory. Using this calculation software, we calculated the intensity distribution on the optical axis. A far point light source was set up as light source for calculation, and the calculation was performed on the assumption that parallel light beams in the same phase enter into the lens. Also, in the calculation, it was assumed that the media on the object and image sides are vacuum and the lens is an ideal lens having no aberration (light beams passing through the lens form an image at the same focal point regardless of the emitting position of the light). Further, the calculation was performed based on the assumption that the wavelength equals 546 nm and the refractive power of the lens for the 0th order diffracted light (basic refractive power) equals 7D, considering ophthalmology or the like.

[0163] For the intensity distribution on the optical axis, the distance on the optical axis from the lens position as the base point to the image plane was converted to diopters, the focal point position of the 0th order diffracted light was standardized as 0 D, and intensity was plotted on that standardized scale. Unless otherwise noted, the lens aperture range for which the calculation simulation was performed was the region up to the zone number noted in each example.

[0164] In the examples using a blaze shaped phase, the mathematical formula for the blaze is based on Equation 3. In regards to the first, second, and so on starting profiles and composite profile, the phase of the blaze is noted using the phase constant h of Equation 4. Also, unless otherwise noted, the phase shift in Equation 3 is zero.

[0165] Also, for the zone diameter in the tables and drawings noted in the examples, the phase profiles are set as being centrosymmetric to the lens, and are shown across the radial direction region from the center of the lens cross section. Unless otherwise noted, the light transmittance when passing through the zone was 100%.

[0166] However, according to the method of the present invention, when manufacturing the diffractive multi-focal lens that is able to generate at least three focal points in the optical axis direction using the diffractive structure comprising a plurality of zones in a concentric circle form, typically, control of the optical characteristics settings is performed according to a mode including steps (A) to (E) below, and this mode was followed for each of the examples below.

[0167] (A) A step of preparing a plurality of starting profiles for which phase and amplitude for modulating the light that passes through the zone are given for each zone, comprising a plurality of zones in a concentric circle form.

[0168] (B) A step of having at least two of the starting profiles be overlapped in the same region in the zone radial direction to be one profile.

[0169] (C) A step of recording on the composite profile as one profile the zone positions of starting profiles overlapped with each other, and arranging the new phase and amplitude made by overlapping the phase and amplitude of the starting profiles in the corresponding zone radial direction on the composite profile.

[0170] (D) A step of determining the optical characteristics by setting the intensity distribution in the optical axis direction by adjusting at least one of the phase and amplitude of the composite profile for at least one of the zones recorded on the composite profile.

[0171] (E) A step of manufacturing the diffractive multi-focal lens for which the adjusted profile having the adjusted phase and amplitude is provided on at least a portion of the diffractive structure.

Example 1

[0172] (i) Preparation of the Composite Profile

[0173] First, we will describe the specifications of the diffractive lens equipped with the composite profile that is the base for adjusting at least one of the phase and amplitude according to the present invention. The diffractive lens has as a base an item showing imaging characteristics for which at least three focal points are generated at optional positions on the optical axis, and the image characteristics are given by using a diffractive structure having a composite profile for which two starting profiles (1) and (2) are overlapped on the same region.

[0174] Both starting profiles (1) and (2) have the phase function as a blaze shaped function, where with the starting profile (1), based on Equation 13 which is the standard setting equation, the zone pitch is determined such that the addition power P.sub.1 is P.sub.1=4 diopters (hereafter, diopter is abbreviated as D). With the starting profile (2), based on the standard setting equation of Equation 14, the zone pitch is determined such that the addition power P.sub.2 is ¾ of P.sub.1 with P.sub.2=3 D. The phase constant of starting profiles (1) and (2) are respectively 0.48 and 0.39. The composite profile was obtained by both starting profiles having this profile being overlapped on the same region which is the overlapping region, and adding the phase. Details of the starting profiles and composite profile are shown in Table 1 and FIGS. 5A. B5 and 5C.

TABLE-US-00001 TABLE 1 Starting profile (1) Starting profile (2) Addition power Addition power P.sub.1 = 4 D P.sub.2 = 3 D Composite profile(Example 1) Zone Zone Zone radius Zone radius Phase Zone radius Phase Zone (mm) Phase No. (mm) constant No. (mm) constant No. Outer radius Inner radius (radians) n r.sub.n h m r text missing or illegible when filed h i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.48 1 0.6033 0.39 1 0.5225 0 −2.4049 2.7332 2 0.7389 0.48 2 0.8532 0.39 2 0.6033 0.5225 −0.8436 0.6110 3 0.9050 0.48 3 1.0450 0.39 3 0.7389 0.6033 −1.6123 1.6068 4 1.0450 0.48 4 1.2066 0.39 4 0.8532 0.7389 −1.7932 1.4036 5 1.1683 0.48 5 1.3491 0.39 5 0.9050 0.8532 −0.9441 0.6572 6 1.2798 0.48 6 1.4778 0.39 6 1.0450 0.9050 −2.7332 2.0718 7 1.3824 0.48 7 1.5962 0.39 7 1.1683 1.0450 −2.1524 2.7332 8 1.4778 0.48 8 1.7065 0.39 8 1.2066 1.1683 −0.7535 0.8635 9 1.5675 0.48 9 1.8100 0.39 9 1.2798 1.2066 −1.5421 1.6969 10 1.6523 0.48 10 1.3491 1.2798 −1.7584 1.4789 11 1.7329 0.48 11 1.3824 1.3491 −0.9168 0.6971 12 1.8100 0.48 12 1.4778 1.3824 −2.7332 2.0992 13 1.5675 1.4778 −2.1379 2.7332 14 1.5962 1.5675 −0.7404 0.8780 15 1.6523 1.5962 −1.5284 1.7101 16 1.7065 1.6523 −1.7437 1.4875 17 1.7329 1.7065 −0.9091 0.7067 18 1.8100 1.7329 −2.7332 2.1069 text missing or illegible when filed indicates data missing or illegible when filed

[0175] With this composite profile, there is a synchronous structure for which the zone radii of starting profiles (1) and (2) are matched using the zone numbers for which n=4Ω and m=3Ω (Ω is a natural number), and for which four continuous zone pitches of starting profile (1) and three continuous zone pitches of starting profile (2) are the same. As a result, the composite profile for which these profiles are synthesized has six blazes newly formed in the region having that synchronous structure. Therefore, a structure is exhibited which has phase profiles of a similar pattern repeated in zone units of the first to sixth, seventh to twelfth, thirteenth to eighteenth, and so on for the composite profile (hereafter called a repeated structure).

[0176] Also, these repeated structures give the basic information of which zones are adjusted when the following adjusting the phase and amplitude. The intensity distribution on the optical axis of the composite profile having that repeated blaze structure is shown in FIG. 5D.

[0177] As can be understood from FIG. 5D, with the intensity distribution of this composite profile, we can see that three main peaks are generated at positions of 0 D, 3 D, and 4 D. The peak generated at 0 D is based on the 0th order diffracted light of this composite profile, the 4 D peak is based on the +1 order diffracted light of starting profile (1), and the 3 D peak is based on the +1 order diffracted light of starting profile (2).

[0178] The features of this composite profile are in being able to generate focal points at positions correlating to the addition power set with the starting profile, and in being able to generate at least three focal points at any position by freely setting the addition power of the starting profile.

[0179] Because of that, if the diffractive multi-focal lens comprising the composite profile of this example is used for an ophthalmic lens, for example, it is possible to use the 0 D peak as the focal point for far vision, the 4 D peak as the peak for the focal point for ensuring visual power in near regions, and the 3 D peak as the focal point for ensuring visual power in the intermediate regions between these. Also, when using this example as an intraocular lens that is inserted and fixed in the human eye, focal points are respectively generated at positions of approximately 35 cm in front for the 4 D power for near use, and approximately 45 to 50 cm in front for the 3 D power for intermediate use. The focal point position for intermediate use correlates exactly to the distance at which a personal computer monitor screen is positioned, and thus, it is possible to make a multi-focal ophthalmic lens that is useful for work viewing monitor screens such as of a personal computer or the like in addition to for far and near distances.

[0180] However, in the intensity distribution diagram of FIG. 5D, we can see that a plurality of peaks is generated though the intensity of other than these main peaks is small. These peaks other than the main peaks are generated secondarily by interference of diffracted light of orders other than those noted above, and are called multi-order light or the like. When multi-order light is generated, incidental light is distributed to unnecessary points, the intensity of the target important peaks decreases, and thus, this is one cause of loss of brightness, clarity or the like when viewing an object.

[0181] Furthermore, the light that is imaged on the focal point positions of the multi-order light is mixed in the image plane of the target focal point position as stray light, and can be a cause of halo, glare or the like. Halo is a ring shaped or band shaped light that appear around a light source when viewing a far point light source at night, and when a halo is generated, there is sometimes a decrease in visibility at night. Halo reflects the distribution of light in noise form that is generated near the image plane center of the focal point position of 0th order diffracted light used as the focal point for far vision. This noise is generated by stray light such as the multi-order light noted above. The farther the generation position of the multi-order light on the optical axis becomes from the focal point position of the 0th order diffracted light, the broader a halo becomes.

[0182] With the diffractive lens having this kind of composite profile, the method for adjusting the phase with the composite profile to reduce multi-order light, and the diffractive multi-focal lens equipped with the adjusted profile obtained as a result are shown hereafter as example 1.

[0183] (ii) Generation of the Adjusted Profile Using Phase Adjustment

[0184] When doing adjustment, first, the phase is divided into the phase constant and the phase shift for each zone of the composite profile. By dividing in this way, it becomes possible to easily understand the details of the repeated structure of the phases of the composite profile using numerical value data, and to consistently perform the adjustment described later also using that variable. In specific terms, using the phases φ.sub.i−1 and φ.sub.i′ of the composite profile described above, based on Equation 3 and Equation 4, the phase constant h for each zone was found as h=(φ.sub.i−1′−φ.sub.i′)/2 π, and the phase shift τ was found as r=(φ.sub.i−1′+φ.sub.i′)/2. Table 2 shows the phase constant and phase shift found by separating in this way. In the table, column (A) shows the zone number of the composite profile. Column (B) shows the zone diameter (outer diameter and inner diameter) of each zone. Column (C) shows the phase constant when the blaze of the composite profile is decomposed into the phase constant and phase shift. Column (D) shows the phase shift of the composite profile. As described previously, with this example, the composite profile is synthesized so that starting profiles (1) and (2) have synchronous structures, so a similar blaze repeated structure is formed with the first to sixth, seventh to twelfth, and thirteenth to eighteenth zones, and for both the phase constant and the phase shift, almost the same numerical values are allocated to zones corresponding to this repeated structure.

TABLE-US-00002 TABLE 2 Zone radius Composite profile (mm) (Example 1) Adjusted profile(Example 1) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant shift constant shift adjustment adjustment i r.sub.i r.sub.i−1 h τ h τ φ.sub.i′ φ.sub.i−1′ 1 0.5225 0 0.818 0.1641 0.7 0.1885 −2.0106 2.3876 2 0.6033 0.5225 0.232 −0.1163 0.7 0.0942 −2.1049 2.2934 3 0.7389 0.6083 0.512 −0.0028 0.4 0 −1.2566 1.2566 4 0.8532 0.7389 0.509 −0.1948 0.4 −0.0785 −1.3352 1.1781 5 0.9050 0.8532 0.255 −0.1435 0.7 −0.1571 −2.3562 2.0420 6 1.0450 0.9050 0.765 −0.3307 0.7 −0.2513 −2.4504 1.9478 7 1.1683 1.0450 0.778 0.2904 0.7 0.1885 −2.0106 2.3876 8 1.2066 1.1683 0.257 0.0550 0.7 0.0942 −2.1049 2.2934 9 1.2798 1.2066 0.515 0.0774 0.4 0 −1.2566 1.2566 10 1.3491 1.2798 0.514 −0.1398 0.4 −0.0785 −1.3352 1.1781 11 1.3824 1.3491 0.257 −0.1098 0.7 −0.1571 −2.3562 2.0420 12 1.4778 1.3824 0.769 −0.3170 0.7 −0.2513 −2.4504 1.9478 13 1.5675 1.4778 0.775 0.2976 0.7 0.1885 −2.0106 2.3876 14 1.5962 1.5675 0.258 0.0688 0.7 0.0942 −2.1049 2.2934 15 1.6523 1.5962 0.515 0.0908 0.4 0 −1.2566 1.2566 16 1.7005 1.6523 0.514 −0.1281 0.4 −0.0785 −1.3352 1.1781 17 1.7329 1.7085 0.257 −0.1012 0.7 −0.1571 −2.3562 2.0420 18 1.8100 1.7329 0.770 −0.3132 0.7 −0.2513 −2.4504 1.9478 (A) (B) (C) (D) (E) (F) (G)

[0185] The phase constant and phase shift were changed according to Table 2 to perform phase adjustment. The phase of each zone with the adjusted profile obtained as a result is shown together in Table 2. Column (E) in the table shows the varied phase constant, and column (F) shows the varied phase shift. Also, column (G) shows the conversion of the blaze after the adjustment to peak and valley phases φ.sub.i−1′ and φ.sub.i′.

[0186] With this example, the adjusted value of the phase constant and the phase shift from the first to sixth is one pattern, and a combination of this numerical value was also allocated to the seventh to twelfth and thirteenth to eighteenth. The significant change points from the composite profile are the points for which items for which the phase constant of the second, fifth, eighth, eleventh, fourteenth, and seventeenth zones was 0.23 to 0.26 were changed to 0.7. For the remainder, both the phase constant and the phase shift were changed in a range that remains at the fine adjustment level as shown in Table 2. This profile after adjustment is shown together with the composite profile in FIG. 6A. In the drawing, the solid line shows the adjusted profile after adjustment, and the dotted line shows the composite profile before adjustment.

[0187] We can see from the drawing that for zones set so that the phase constant becomes larger, the tilt of the blaze becomes larger. The intensity distribution on the optical axis of the profile adjusted in this way is shown in FIG. 6B. From FIG. 6B, we can see that the appearance position of the major peaks and the intensity of the major peaks do not change before and after adjustment. We can see that what changes are the peaks of the multi-order light of the high order region, and with the composite profile, a number of the multi-order light peaks that stood out are reduced (see the arrow positions in the drawing).

[0188] By adjusting the phase in composite profile zone units in this way, it is possible to reduce the excess peaks due to multi-order light while maintaining the intensity distribution of peaks set with the composite profile. Specifically, obtaining the composite profile by overlapping the starting profiles initially with the present invention means preparing profiles that can generate at least three focal points at any position as shown with this example. These excellent imaging characteristics make it possible to have an even more excellent diffractive multi-focal lens by reducing halo and glare by improving the resolution through further tuning with the composite profile zone as the subject, and this kind of effect can be said to be a technical effect that can not be achieved realistically by adjusting the zones as the subject with each starting profile.

[0189] In other words, when the phase or amplitude is modulated in zone units with the starting profiles as the subject, these modulated modes give an influence over two or more zones with the composite profile made by overlapping of the starting profiles, and a plurality of zones change in conjunction. Therefore, it is not possible to give as much freedom for the adjustment with the starting profiles as is possible with the zone unit adjustment with the composite profile.

Example 2

[0190] (i) Preparation of the Composite Profile

[0191] When acquiring the composite profile, the same starting profiles (1) and (2) as example 1 noted above were used other than that only the phase constant was varied. The phase constant of starting profiles (1) and (2) are respectively 0.33 and 0.4. The same as with example 1, the starting profiles (1) and (2) were overlapped in the same region to obtain the composite profile. The details of the composite profile are shown in Table 3 and FIG. 7A. Also, the intensity distribution on the optical axis of the composite profile of this example is shown in FIG. 7B.

TABLE-US-00003 TABLE 3 Starting profile (1) Starting profile (2) Addition power Addition power Composite profile(Example 2) P.sub.1 = 4 D P.sub.2 = 3 D Zone radius Zone Zone (mm) Zone radius Phase Zone radius Phase Zone Outer Inner Phase No. (mm) constant No. (mm) constant No. radius radius (radians) n r.sub.i h m r text missing or illegible when filed h i r.sub.i r.sub.i−1 φ ′ φ .sub.−1′ 1 0.5225 0.33 1 0.6033 0.4 1 0.5225 0 −1.9566 2.2934 2 0.7389 0.33 2 0.8532 0.4 2 0.6033 0.5225 −0.9943 0.1168 3 0.9050 0.33 3 1.0450 0.4 3 0.7389 0.6033 −1.1437 1.5190 4 1.0450 0.33 4 1.2066 0.4 4 0.8532 0.7389 −1.6471 0.9297 5 1.1683 0.33 5 1.3491 0.4 5 0.9050 0.8532 −0.4584 0.8661 6 1.2798 0.33 6 1.4778 0.4 6 1.0450 0.9050 −2.2934 1.6150 7 1.3824 0.33 7 1.5962 0.4 7 1.1683 1.0450 −1.6977 2.2934 8 1.4778 0.33 8 1.7065 0.4 8 1.2066 1.1683 −0.9324 0.3758 9 1.5675 0.33 9 1.8100 0.4 9 1.2798 1.2066 −1.0717 1.5809 10 1.6523 0.33 10 1.3491 1.2798 −1.6197 1.0017 11 1.7329 0.33 11 1.3824 1.3491 −0.4304 0.8935 12 1.8100 0.33 12 1.4778 1.3824 −2.2934 1.6431 13 1.5675 1.4778 −1.6828 2.2934 14 1.5962 1.5675 −0.9233 0.3906 15 1.6523 1.5962 −1.0577 1.5900 16 1.7065 1.6523 −1.6131 1.0158 17 1.7329 1.7065 −0.4225 0.9002 18 1.8100 1.7329 −2.2934 1.6510 text missing or illegible when filed indicates data missing or illegible when filed

[0192] For the starting profiles (1) and (2) of the composite profile of this example, the same starting profiles (1) and (2) as with example 1 were used other than that the phase constant was varied, so the zone position of the composite profile is the same as that of example 1. On the other hand, the blaze step and peak and valley positions are different from those of example 1, but the same repeated structure is exhibited within the region having the synchronous structure. Also, for the intensity distribution of the composite profile, peaks are generated at the same position as example 1. However, because the phase constant is varied, the peak intensity differs from that of example 1 in accordance with that change.

[0193] With this example, 0 D has the highest intensity, with next being 3 D, and 4 D being set so as to be the smallest. The phase constant of starting profile (1) is set to be smaller than that of example 1 at 0.33, so the contribution of the +1 order light from the starting profile (1) is smaller in accordance with that phase constant variation, and as a result, the 4 D peak intensity is smaller. When that multi-focal lens is used as an ophthalmic lens, it can be a lens that emphasizes the visual performance of the 3 D medium region.

[0194] With the composite profile of this example as well, small peak groups are generated in high order regions (regions of approximately 6 to 8 D). The phase of the composite profile was adjusted to reduce the multi-order light. The diffractive multi-focal lens equipped with the adjusted profile obtained as a result is shown hereafter as example 2.

[0195] (ii) Generation of the Adjusted Profile by Phase Adjustment

[0196] When doing adjustment, the same as with example 1, first, the phase information of the composite profile is divided into the phase constant and the phase shift, and the phase adjustment is performed based on that. The details of the divided composite profile phase constant and phase shift as well as the adjusted profile are shown in Table 4.

TABLE-US-00004 TABLE 4 Zone radius Composite profile (mm) (Example 2) Adjusted profile(Example 2) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant shift constant shift adjustment adjustment i r text missing or illegible when filed r h τ h τ φ.sub.i′ φ.sub.i−1′ 1 0.5225 0 0.676 0.168 0.6 0.157 −1.7279 2.0420 2 0.6033 0.5225 0.177 −0.439 0 −0.314 −0.3142 −0.3142 3 0.7389 0.6033 0.424 0.188 0.4 0.094 −1.1624 1.3509 4 0.8532 0.7389 0.410 −0.359 0.4 −0.314 −1.5708 0.9425 5 0.9050 0.8532 0.211 0.204 0 0.047 0.0471 0.0471 6 1.0450 0.9050 0.622 −0.339 0.7 −0.785 −2.9845 1.4137 7 1.1683 1.0450 0.635 0.298 0.6 0.471 −1.4137 2.3562 8 1.2066 1.1683 0.208 −0.278 0 −0.126 −0.1257 −0.1257 9 1.2798 1.2066 0.422 0.255 0.4 0.173 −1.0838 1.4294 10 1.3491 1.2798 0.417 −0.309 0.4 −0.236 −1.4923 1.0210 11 1.3824 1.3491 0.211 0.232 0 0.079 0.0785 0.0785 12 1.4778 1.3824 0.627 −0.325 0.7 −0.785 −2.9845 1.4137 13 1.5675 1.4778 0.633 0.305 0.6 0.471 −1.4137 2.3562 14 1.5962 1.5675 0.209 −0.266 0 −0.126 −0.1257 −0.1257 15 1.6523 1.5962 0.421 0.266 0.4 0.188 −1.0681 1.4451 16 1.7065 1.6523 0.418 −0.299 0.4 −0.220 −1.4765 1.0367 17 1.7329 1.7065 0.211 0.239 0 0.094 0.0942 0.0942 18 1.8100 1.7329 0.628 −0.321 0.7 −0.314 −2.5133 1.8850 text missing or illegible when filed indicates data missing or illegible when filed

[0197] When doing the adjustment of this example, the phase constant has the numerical value varied in the region of from the first to sixth zones, and that combination pattern was similarly set for from the seventh to twelfth and the thirteenth to eighteenth. In regards to the phase shift, the combination pattern between from the seventh to twelfth and from the thirteenth to eighteenth regions are almost the same, and the combination pattern with the first to sixth region was set to be slightly different. The adjusted profile is shown in FIG. 8A.

[0198] The characteristic feature of the adjusted profile of this example is that the phase constant of the second, fifth, eighth, eleventh, fourteenth, and seventeenth zones is h=0, and there is no tilt. The zones with h=0 are also one form of blaze with the present invention, and function as diffractive zones. The phase shift does not vary greatly from the composite profile setting value, and other than being adjusted by being slightly shifted to the minus side for the sixth and twelfth zones, was kept in the fine adjustment range. FIG. 8B shows the intensity distribution on the optical axis of this adjusted profile.

[0199] From FIG. 8B, we can see that the major peak generation positions and their intensity are kept almost the same before and after adjustment. On the other hand, we can see that there is a decrease in regards to small peaks due to multi-order light of the high order regions. Because of that, by the decrease in the multi-order light, when using the lens of this example as an ophthalmic lens, it is possible to obtain a diffractive multi-focal ophthalmic lens for which halo and glare are reduced when viewing far at night, while ensuring visual performance in the far, near, and intermediate regions.

Example 3

[0200] (i) Preparation of the Composite Profile

[0201] When acquiring the composite profile, the same starting profiles (1) and (2) as example 1 noted above were used other than that only the phase constant was varied. The phase constant of starting profiles (1) and (2) are respectively 0.47 and 0.47. The same as with example 1, the starting profiles (1) and (2) were overlapped in the same region to obtain the composite profile. The details of the composite profile are shown in Table 5 and FIG. 9A. Also, the intensity distribution on the optical axis of the composite profile of this example is shown in FIG. 9B.

TABLE-US-00005 TABLE 5 Starting profile (1) Starting profile (2) Addition power Addition power P.sub.1 = 4 D P.sub.2 = 3 D Composite profile(Example 3) Zone Zone Zone radius Zone radius Phase Zone radius Phase Zone (mm) Phase No. (mm) constant No. (mm) constant No. Outer radius Inner radius (radians) n r text missing or illegible when filed h m r h i r r φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.47 1 0.6033 0.47 1 0.5225 0 −2.5575 2.9531 2 0.7389 0.47 2 0.8532 0.47 2 0.6033 0.5225 −1.1029 0.3956 3 0.9050 0.47 3 1.0450 0.47 3 0.7389 0.6033 −1.6023 1.8502 4 1.0450 0.47 4 1.2066 0.47 4 0.8532 0.7389 −2.0327 1.3508 5 1.1683 0.47 5 1.3491 0.47 5 0.9050 0.8532 −0.7971 0.9204 6 1.2798 0.47 6 1.4778 0.47 6 1.0450 0.9050 −2.9531 2.1560 7 1.3824 0.47 7 1.5962 0.47 7 1.1683 1.0450 −2.2532 2.9531 8 1.4778 0.47 8 1.7065 0.47 8 1.2066 1.1683 −1.0147 0.6999 9 1.5675 0.47 9 1.8100 0.47 9 1.2798 1.2066 −1.5177 1.9884 10 1.6523 0.47 10 1.3491 1.2798 −1.9937 1.4354 11 1.7329 0.47 11 1.3824 1.3491 −0.7641 0.9594 12 1.8100 0.47 12 1.4778 1.3824 −2.9531 2.1890 13 1.5675 1.4778 −2.2357 2.9531 14 1.5962 1.5675 −1.0018 0.7174 15 1.6523 1.5962 −1.5012 1.9513 16 1.7065 1.6523 −1.9842 1.4519 17 1.7329 1.7065 −0.7548 0.9689 18 1.8100 1.7329 −2.9531 2.1983 text missing or illegible when filed indicates data missing or illegible when filed

[0202] For the starting profiles (1) and (2) of the composite profile of this example, the same starting profiles (1) and (2) as with example 1 and 2 were used other than that the phase constant was varied, so the zone position of the composite profile is the same as that of example 1. On the other hand, the blaze step and peak and valley positions on the phase axis are different from those of example 1 and 2, but the same repeated structure is exhibited within the region having the synchronous structure. Also, for the intensity distribution of the composite profile, peaks are generated at the same positions as example 1 and 2. However, because the phase constant is varied, the peak intensity differs from that of example 1 and 2 in accordance with that change.

[0203] With the composite profile of this example, the phase constant of starting profiles (1) and (2) are set to be equal so as to have the peak intensity of the 0 D, 3 D, and 4 D positions be approximately the same. As shown in FIG. 9B, the peak of the respective positions have approximately the same intensity. When using the diffractive lens comprising this composite profile as an ophthalmic lens, it is possible for it to be a multi-focal ophthalmic lens with specifications for which the visual performance will be approximately the same in the respective far, near, and intermediate regions.

[0204] However, with the composite profile of this example, as can be seen from FIG. 9B, a peak group due to high intensity multi-order light is generated in the high order region. In particular, peaks at 7 D show intensity that is about half that of the major peaks, and generation of those high intensity peaks decreases the gain of the light of the major peaks, and there is the risk of aggravating halo and glare. The phase of the composite profile was adjusted to reduce the multi-order light. The diffractive multi-focal lens equipped with the adjusted profile obtained as a result is shown hereafter as example 3.

[0205] (ii) Generation of the Adjusted Profile by Phase Adjustment

[0206] When doing adjustment, the same as with example 1 and 2, first, the phase information of the composite profile is divided into the phase constant and the phase shift, and the phase adjustment is performed based on that. The details of the divided composite profile phase constant and phase shift as well as the adjusted profile are shown in Table 6.

TABLE-US-00006 TABLE 6 Zone radius Composite profile (mm) (Example 3) Adjusted profile(Example 3) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant shift constant shift adjustment adjustment i r.sub.i r text missing or illegible when filed h τ h τ φ.sub.i′ φ.sub.i−1′ 1 0.5225 0 0.877 0.198 0.7 0.157 −2.0420 2.3562 2 0.6033 0.5225 0.239 −0.354 0.7 −0.314 −2.5133 1.8850 3 0.7389 0.6033 0.549 0.124 0.1 0 −0.3142 0.3142 4 0.8532 0.7389 0.539 −0.341 0.7 0 −2.1991 2.1991 5 0.9050 0.8582 0.273 0.062 0.7 0.063 −2.1363 2.2619 6 1.0450 0.9050 0.813 −0.399 0.7 −1.257 −3.4558 0.9425 7 1.1683 1.0450 0.829 0.350 0.7 0 −2.1991 2.1991 8 1.2066 1.1683 0.273 −0.157 0.7 0 −2.1991 2.1991 9 1.2798 1.2066 0.550 0.210 0.1 0.157 −0.1571 0.4712 10 1.3491 1.2798 0.546 −0.279 0.7 0 −2.1991 2.1991 11 1.3824 1.3491 0.274 0.098 0.7 0 −2.1991 2.1991 12 1.4778 1.3324 0.818 −0.382 0.7 −0.942 −3.1416 1.2566 13 1.5675 1.4778 0.826 0.359 0.7 0 −2.1991 2.1991 14 1.5962 1.5675 0.274 −0.142 0.7 0 −2.1991 2.1991 15 1.6523 1.5962 0.549 0.225 0.1 0.157 −0.1571 0.4712 16 1.7065 1.6523 0.547 −0.266 0.7 0 −2.1991 2.1991 17 1.7329 1.7065 0.274 0.107 0.7 0 −2.1991 2.1991 18 1.8100 1.7329 0.820 −0.377 0.7 −0.628 −2.8274 1.5708 text missing or illegible when filed indicates data missing or illegible when filed

[0207] With this example, adjustment of the composite profile was performed while referencing the pattern of the divided phase constant and phase shift. The main change points are that the phase constants of the second, fifth, eighth, eleventh, fourteenth, and seventeenth zones that were around 0.24 to 0.27 were made to be a large value of 0.7, and the phase constants of the third, ninth, and fifteenth zones that were approximately 0.55 were made to be a small value of 0.1. There were also points such as significantly shifting the phase shift with the sixth and twelfth zones in the minus direction. Other than that was kept to a fine adjustment level. An adjusted profile diagram and the intensity distribution on the optical axis after the changes are respectively shown in FIGS. 10A and 10B.

[0208] From FIG. 10B, we can see that the major peak generation positions and their intensity are kept almost the same before and after adjustment. On the other hand, we can see that the peak of approximately 7 D which was marked with the composite profile before adjustment (arrow A in FIG. 10B) decreased to approximately half. We can also see that the intensity of the approximately 6 D peak (arrow B in the same drawing) also significantly decreased. By decreasing the peaks by these multi-order lights, that portion is distributed to an increase in the 4 D peak intensity (arrow C), and this brings an effect of improving the gain of the light of the major peaks.

[0209] As a result of the light intensity distribution on the optical axis being controlled so as to be able to decrease multi-order light in this way and improve the light intensity at each focal point position that accompanies this, when using the lens of this example as an ophthalmic lens, it is possible to have a diffractive multi-focal lens for which halo and glare are reduced when viewing far at night, while ensuring vision power in far, near, and intermediate regions.

Example 4

[0210] With examples 1 to 3, we described the method for controlling multi-order light by adjusting the phase. With this example, we will describe the method for controlling when using amplitude adjustment together in addition to phase adjustment.

[0211] With this example, the same composite profile was used as with example 3 for the composite profile. Specifically, this example is an example when using together amplitude adjustment with the composite profile of example 3 as the subject. In specific terms, as shown in Table 7, the phase constant and phase shift are newly adjusted for the composite profile of example 3, and the light transmittance was varied for amplitude adjustment.

TABLE-US-00007 TABLE 7 Zone radius Composite profile Adjusted profile(Example 4) (mm) (Example 3) Trans- Zone Outer Inner Phase Phase Phase Phase After After mit- No. radius radius constant shift constant shift adjustment adjustment tance i r.sub.i r.sub.i−1 h τ h τ φ text missing or illegible when filed ′ φ ′ (%) 1 0.5225 0 0.877 0.198 0.766 0.168 −2.2394 2.5761 100 2 0.6033 0.5225 0.239 −0.354 0.210 −0.262 −0.9228 0.3995 50 3 0.7389 0.6033 0.549 0.124 0.480 0.082 −1.4265 1.5905 100 4 0.8532 0.7389 0.539 −0.341 0.472 −0.271 −1.7537 1.2124 100 5 0.9050 0.8532 0.273 0.062 0.239 0.009 −0.7412 0.7596 50 6 1.0450 0.9050 0.813 −0.399 0.712 −0.339 −2.5761 1.8978 100 7 1.1683 1.0450 0.829 0.350 0.725 0.298 −1.9804 2.5761 100 8 1.2066 1.1683 0.273 −0.157 0.239 −0.093 −0.8439 0.6585 50 9 1.2798 1.2066 0.550 0.210 0.481 0.157 −1.3545 1.6693 100 10 1.3491 1.2798 0.546 −0.279 0.478 −0.217 −1.7188 1.2845 100 11 1.8824 1.3491 0.274 0.098 0.240 0.041 −0.7131 0.7945 50 12 1.4778 1.3824 0.818 −0.382 0.717 −0.325 −2.5761 1.9258 100 13 1.5675 1.4778 0.826 0.359 0.723 0.305 −1.9656 2.5761 100 14 1.5962 1.5675 0.274 −0.142 0.240 −0.080 −0.8324 0.6733 50 15 1.6523 1.5962 0.549 0.225 0.481 0.170 −1.3404 1.6809 100 16 1.7065 1.6523 0.547 −0.266 0.479 −0.206 −1.7103 1.2985 100 17 1.7329 1.7065 0.274 0.107 0.240 0.049 −0.7052 0.8030 50 18 1.8100 1.7329 0.820 −0.377 0.718 −0.321 −2.5761 1.9337 100 text missing or illegible when filed indicates data missing or illegible when filed

[0212] Amplitude adjustment correlates to varying the amplitude function A (x) of Equation 2 noted above. The specific adjustment of the amplitude can be performed by controlling the light transmittance. With this example, when light made incident on a designated zone with the composite profile is emitted without being blocked, the transmittance is 100%, and for example when it is 80%, the amplitude function is a multiple of 0.8, and when it is 50%, 0.5 is multiplied on the amplitude function, and a simulation was done by calculating the intensity distribution from the conjugate absolute value of the wave function comprising that amplitude function.

[0213] With this example, while the phase adjustment of the composite profile is kept at a fine adjustment level, there is joint use of amplitude adjustment for which the transmittance of the second, fifth, eighth, eleventh, fourteenth, and seventeenth zones is 50%. That transmittance setting can be implemented using a method such as reducing the transmittance by dyeing the concerned region using a dye or the like, for example.

[0214] With this example, the adjusted profile obtained from the composite profile described above is shown in FIG. 11A. The phase adjustment is kept at a fine adjustment level, so there is no significant difference in the phase profile before and after adjustment. The zone with the transmittance at 50% is shown in the drawing. FIG. 11B shows a front view when the profile drawing is used as an actual lens. In the drawing, the gray region correlates to the zone for which the transmittance is 50%.

[0215] FIG. 11C shows a comparison of the intensity distribution in the optical axis direction of the adjusted profile of this example with that of the comparison profile. As can be understood from FIG. 11C, there is no change in the major peak generating position before and after adjustment. We can also see that there is no change in the intensity ratio of 0 D, 3 D, and 4 D, and that the intensity ratio of the composite profile is maintained.

[0216] Meanwhile, with the composite profile, the marked peak of approximately 7 D (arrow A) was further reduced even more than with example 3, and we can see that it was reduced to about ¼. Also, the significant reduction amount of the multi-order light peak is distributed to an increase in intensity of the major peak, and we can see that the respective intensity of the major peaks of 0 D, 3 D, and 4 D became larger.

[0217] When an item for which amplitude adjustment is used together in this way is used as an ophthalmic lens, there is an increase in the gain of each focal point peak while reducing halo and glare, so there is further improvement in clarity of visual performance and the like of each focal point position.

Example 5

[0218] With this example, the same as with example 4, this is a specific example when using amplitude adjustment together in addition to phase adjustment. With example 4, we described an example of performing amplitude adjustment with the transmittance at 50%, but with this example, we will describe a case when transmittance is 0%, in other words, of using together amplitude adjustment such as that completely blocks the transmission of light.

[0219] Specifically, with this example, with the same composite profile as example 3 as the subject, phase and amplitude adjustment of that profile were performed. To vary the amplitude adjustment conditions, phase adjustment was implemented again so as to correspond to that amplitude adjustment. The details of that adjusted profile are shown in Table 8.

TABLE-US-00008 TABLE 8 Zone radius Composite profile Adjusted profile(Example 5) (mm) (Example 3) Trans- Zone Outer Inner Phase Phase Phase Phase After After mit- No. radius radius constant shift constant shift adjustment adjustment tance text missing or illegible when filed r r h τ h τ φ.sub.i′ φ.sub.i−1′ (%) 1 0.5225 0 0.877 0.198 0.656 0.139 −1.921 2.199 100 2 0.6033 0.5225 0.239 −0.354 0.182 −0.170 −0.743 0.403 0 3 0.7389 0.6033 0.549 0.124 0.411 0.040 −1.251 1.331 100 4 0.8532 0.7389 0.539 −0.341 0.406 −0.200 −1.475 1.074 100 5 0.9050 0.8532 0.273 0.062 0.204 −0.043 −0.685 0.599 0 6 1.0450 0.9050 0.813 −0.399 0.611 −0.280 −2.199 1.639 100 7 1.1683 1.0450 0.829 0.350 0.622 0.246 −1.708 2.199 100 8 1.2066 1.1683 0.273 −0.157 0.205 −0.028 −0.673 0.617 0 9 1.2798 1.2066 0.550 0.210 0.412 0.105 −1.191 1.400 100 10 1.3491 1.2798 0.546 −0.279 0.410 −0.155 −1.444 1.134 100 11 1.3824 1.3491 0.274 0.098 0.206 −0.016 −0.662 0.630 0 12 1.4778 1.3824 0.818 −0.382 0.615 −0.268 −2.199 1.663 100 13 1.5675 1.4778 0.826 0.359 0.620 0.252 −1.695 2.199 100 14 1.5962 1.5675 0.274 −0.142 0.206 −0.017 −0.663 0.629 0 15 1.6523 1.5962 0.549 0.225 0.412 0.115 −1.180 1.410 100 16 1.7065 1.6523 0.547 −0.266 0.411 −0.146 −1.436 1.145 100 17 1.7329 1.7065 0.274 0.107 0.206 −0.009 −0.656 0.637 0 18 1.8100 1.7329 0.820 −0.377 0.616 −0.265 −2.199 1.669 100 text missing or illegible when filed indicates data missing or illegible when filed

[0220] The phase adjustment of this example was performed so as to make the overall phase constant smaller. In addition to that phase adjustment, used together was amplitude adjustment such that the transmittance of the second, fifth, eighth, eleventh, fourteenth, and seventeenth zones is 0%. The transmittance setting can be implemented with a method such as blocking the light completely by coating a pigment or the like on the concerned region, for example.

[0221] The adjusted profile of this example is shown in FIG. 12A. Compared to the composite profile, the overall phase constant was set to be small, so the profile blaze step is a little smaller by that amount. The zone with the transmittance at 0% is shown in the drawing. FIG. 12B shows a front view when the profile drawing is actually used as a lens. In the drawing, the blacked out region correlates to the zone for which the transmittance is 0%.

[0222] FIG. 12C shows a comparison of the intensity distribution in the optical axis direction of the adjusted profile of this example with that of the comparison profile. As can be understood from FIG. 12C, there is no change in the major peak generating position before and after adjustment. We can also see that there is also no change in the intensity ratio of 0 D, 3 D, and 4 D, and that the intensity ratio of the composite profile is maintained.

[0223] Meanwhile, with the composite profile, the marked multi-order light peak was further reduced even more than with example 4, and we can see in particular that the peak of approximately 7 D that stood out (arrow A) was reduced to close to zero. Also, a reduction effect worked for almost all the multi-order light peaks, and the amount of reduction of these peaks was redistributed to an intensity increase in the major peaks, and we can see this brought a significant increase in gain for all the major peaks.

[0224] The general trend is for gain to decrease when there is a zone for which the transmittance is zero, but the trend with this example is different, with a significant increase in gain even while there is a zone with transmittance of zero. This shows that the adjustment conditions of this example are conditions that make it possible to lead diffracted light to the major focal point positions with high efficiency and without waste.

[0225] Therefore, when the diffractive multi-focal lens based on the adjusted profile of this example is used as an ophthalmic lens, it is possible to have an ophthalmic lens with further reduction of halo and glare, and also to be useful as an ophthalmic lens that can realize even sharper visual performance in all regions of far, near, and intermediate with significantly increased gain of each major peak.

Example 6

[0226] Next, we will describe using the example below as an example of adjusting at least one of phase and amplitude with an item for which the composite profile specifications were changed by changing the addition power of the starting profile (2). First, example 6 is a specific example of a mode of changing the type of the composite profile for adjustment.

[0227] (i) Preparation of the Composite Profile

[0228] When acquiring the composite profile, both starting profiles (1) and (2) have the phase function as a blaze shaped function, where based on Equation 13 and Equation 14 which are standard setting equations, the respective zone pitches are determined such that with the starting profile (1), the addition power P.sub.1 is P.sub.1=4 D, and with the starting profile (2), it is determined such that the addition power P.sub.2 is ⅔ of P, with P.sub.2=2.666 D. The phase constant of starting profiles (1) and (2) are respectively 0.4 and 0.4.

[0229] Also, the composite profile was obtained by overlapping both starting profiles (1) and (2) having this profile on the same region and adding the phase. The details of starting profiles (1) and (2) and the composite profile are shown in Table 9 and FIGS. 13A, 13B, and 13C.

TABLE-US-00009 TABLE 9 Starting profile (1) Starting profile (2) Addition power Addition power P.sub.1 = 4 D P.sub.2 = 2.666 D Composite profile(Example 6) Zone Zone Zone radius Zone radius Phase Zone radius Phase Zone (mm) Phase No. (mm) constant No. (mm) constant No. Outer radius Inner radius (radians) n r.sub.n h m r.sub.m h i r text missing or illegible when filed r φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6399 0.4 1 0.5225 0 −2.0521 2.5133 2 0.7389 0.4 2 0.9050 0.4 2 0.6399 0.5225 −1.3637 0.4612 3 0.9050 0.4 3 1.1084 0.4 3 0.7389 0.6399 −0.9387 1.1496 4 1.0450 0.4 4 1.2798 0.4 4 0.9050 0.7389 −2.5133 1.5746 5 1.1683 0.4 5 1.4309 0.4 5 1.0450 0.9050 −1.7300 2.5133 6 1.2798 0.4 6 1.5675 0.4 6 1.1084 1.0450 −1.2916 0.7833 7 1.3824 0.4 7 1.6931 0.4 7 1.1683 1.1084 −0.8788 1.2216 8 1.4778 0.4 8 1.8100 0.4 8 1.2798 1.1683 −2.5133 1.6345 9 1.5675 0.4 9 1.3824 1.2798 −1.7061 2.5133 10 1.6523 0.4 10 1.4309 1.3824 −1.2776 0.8072 11 1.7329 0.4 11 1.4778 1.4309 −0.8636 1.2357 12 1.8100 0.4 12 1.5675 1.4778 −2.5133 1.6497 13 1.6523 1.5675 −1.6967 2.5133 14 1.6931 1.6523 −1.2716 0.8165 15 1.7329 1.6931 −0.8565 1.2417 16 1.8100 1.7329 −2.5133 1.6567 text missing or illegible when filed indicates data missing or illegible when filed

[0230] With the composite profile of this example, there is a synchronous structure for which the zone radii of starting profiles (1) and (2) are matched using the zone numbers for which n=3 fl and m=2Ω (Ω is a natural number), and for which three continuous zone pitches of starting profile (1) and two continuous zone pitches of starting profile (2) are the same. As a result, an item for which these profiles are synthesized has four blazes newly formed in the synchronous region. Therefore, a structure is exhibited which has phase profiles of a similar pattern repeated in zone units of the first to fourth, fifth to eighth, ninth to twelfth, thirteenth to sixteenth, and so on for the composite profile. FIG. 13D shows the intensity distribution on the optical axis of the composite profile obtained in this way.

[0231] The intensity distribution of this composite profile is an item for which three major peaks are generated at the positions of 0 D, 2.67 D, and 4 D. The peak generated at 0 D is based on the 0th order diffracted light of this composite profile, the 4 D peak is based on the +1 order diffracted light of starting profile (1), and the 2.67 D peak is based on the +1 order diffracted light of starting profile (2).

[0232] The difference between the composite profile of this example and that of the group of previously noted examples is the point that the addition power of starting profile (2) is changed, and with this example, by setting the addition power of starting profile (2) to 2.67 D, even the composite profile definitely has a peak generated at the point of 2.67 D. We can see that in this way, it is possible to generate at least three focal points freely simply by changing the addition power of the starting profile.

[0233] Also, the intensity distribution of the composite profile of this example has the 0 D peak intensity as the highest, and while the 2.67 and 4 D peaks are lower than that, they became equal. When using the diffractive lens comprising that profile as an intraocular lens, the 0 D peak for far vision is the highest, and the 4 D and 2.67 D peaks for near vision and intermediate vision are almost equal, so this becomes standard as the specification of an actual intraocular lens for which far vision is normally the most important. For a patient using this lens, far vision is ensured, it is possible to also have visual ability at the reading position, and it is also possible to do work while viewing a personal computer monitor since it is also possible to see at a position correlating to 2.67 D, specifically, a point of approximately 50 to 60 cm in front.

[0234] However, as can be seen from FIG. 13D, with the composite profile of this example, excess peaks are generated due to multi-order light, so there is a risk of halo, glare or the like occurring with a decrease in the gain of the major peaks due to those peaks. In particular, the high order region (5 D to 8 D region) peaks are a cause of expanded halos, and reduction of these peaks is important. In light of that, at least one of phase and amplitude of the composite profile is adjusted to perform reduction of peaks due to multi-order light without changing the composite profile intensity ratio, and the diffractive multi-focal lens equipped with the adjusted profile obtained as a result is shown hereafter as example 6.

[0235] (ii) Generation of the Adjusted Profile Using Phase Adjustment

[0236] When doing adjustment, the same as the group of examples noted above, first, the phase information of the composite profile is divided into the phase constant and the phase shift, and the phase adjustment is performed based on that. The details of the divided composite profile phase constant and phase shift as well as the adjusted profile are shown in Table 10.

TABLE-US-00010 TABLE 10 Zone radius Composite profile (mm) (Example 6) Adjusted profile(Example 6) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant shift constant Shift adjustment adjustment i r.sub.i r.sub.i−1 h τ h τ φ text missing or illegible when filed ′ φ ′ 1 0.5225 0 0.727 0.231 0.6 0.157 −1.7279 2.0420 2 0.6399 0.5225 0.290 −0.451 0.2 0.628 0 1.2566 3 0.7389 0.6399 0.332 0.105 0.2 0.628 0 1.2566 4 0.9050 0.7389 0.651 −0.469 0.6 −0.628 −2.5133 1.2566 5 1.0450 0.9050 0.675 0.392 0.6 0.157 −1.7279 2.0420 6 1.1084 1.0450 0.330 −0.254 0.2 0.628 0 1.2566 7 1.1683 1.1084 0.334 0.171 0.2 0.628 0 1.2566 8 1.2798 1.1683 0.660 −0.439 0.6 −0.628 −2.5133 1.2566 9 1.3824 1.2798 0.672 0.404 0.6 0.157 −1.7279 2.0420 10 1.4309 1.3824 0.332 −0.235 0.2 0.628 0 1.2566 11 1.4778 1.4309 0.334 0.186 0.2 0.628 0 1.2566 12 1.5675 1.4778 0.668 −0.432 0.6 −0.628 −2.5133 1.2566 13 1.6523 1.5675 0.670 0.408 0.6 0.157 −1.7279 2.0420 14 1.6931 1.6523 0.332 −0.228 0.2 0.628 0 1.2566 15 1.7329 1.6931 0.334 0.193 0.2 0.628 0 1.2566 16 1.8100 1.7329 0.664 −0.428 0.6 −0.628 −2.5133 1.2566 text missing or illegible when filed indicates data missing or illegible when filed

[0237] The composite profile of this example is made by repeating a similar phase structure with four continuous zone pitches, so considering that regularity, first, phase adjustment was performed for the first to fourth zones. For the phase constant, this remains at the fine adjustment level, but the phase shift was changed significantly. Specifically, the second and third phase shifts were shifted greatly to the plus side, and the blaze valley position of those zones were made to be on the reference line. The pattern adjusted in this way was also set for the fifth to eighth, ninth to twelfth, and thirteenth to sixteenth zones which are the other repeated regions.

[0238] The adjusted profile and intensity distribution on the optical axis obtained in this way are respectively shown in FIG. 14A and FIG. 14B compared with the composite profile.

[0239] With this example, we can see that by this phase adjustment, the intensity of the high order region multi-order light peaks (arrows in FIG. 14B) is reduced. Regarding the major peaks, though the intensity ratio does not change with the composite profile before adjustment, the amount of reduction of the multi-order light peaks increases the major peak intensity by that amount because it is redistributed to these major peaks, which was found to increase gain.

Example 7

[0240] With example 6 noted above, by implementing phase adjustment with the composite profile zones as the subject, peaks due to multi-order light are reduced, and it was shown that it is possible to control light intensity distribution. With this example, we will describe an example of other phase adjustment conditions.

[0241] First, the phase constant and phase shift were varied with the same composite profile as was used with example 6 as the subject. The details of the obtained adjusted profile are shown in Table 11.

TABLE-US-00011 TABLE 11 Zone radius Composite profile (mm) (Example 6) Adjusted profile(Example 7) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant Shift constant Shift adjustment adjustment i r text missing or illegible when filed r h τ h τ φ.sub.i′ φ.sub.i−1′ 1 0.5225 0 0.727 0.231 0.6 0.157 −1.7279 2.0420 2 0.6399 0.5225 0.290 −0.451 0 0.628 0.6283 0.6283 3 0.7389 0.6399 0.332 0.105 0 0.628 0.6283 0.6283 4 0.9050 0.7389 0.651 −0.469 0.6 −0.628 −2.5133 1.2566 5 1.0450 0.9050 0.675 0.392 0.6 0.157 −1.7279 2.0420 6 1.1084 1.0450 0.330 −0.254 0 0.628 0.6283 0.6283 7 1.1683 1.1084 0.334 0.171 0 0.628 0.6283 0.6283 8 1.2798 1.1683 0.660 −0.439 0.6 −0.628 −2.5133 1.2566 9 1.3824 1.2798 0.672 0.404 0.6 0.157 −1.7279 2.0420 10 1.4309 1.3824 0.332 −0.235 0 0.628 0.6283 0.6283 11 1.4778 1.4309 0.334 0.186 0 0.628 0.6283 0.6283 12 1.5675 1.4778 0.663 −0.432 0.6 −0.628 −2.5133 1.2566 13 1.6523 1.5675 0.670 0.408 0.6 0.157 −1.7279 2.0420 14 1.6931 1.6523 0.332 −0.228 0 0.628 0.6283 0.6283 15 1.7329 1.6931 0.334 0.193 0 0.628 0.6283 0.6283 16 1.8100 1.7329 0.664 −0.428 0.6 −0.628 −2.5133 1.2566 text missing or illegible when filed indicates data missing or illegible when filed

[0242] With this example, with the adjustment conditions of example 6, there is no difference other than that the phase constant of the second and third zones is h=0, and that change is applied to the same repeated regions with the phase constant of the sixth, seventh, tenth, eleventh, fourteenth, and fifteenth zones as h=0. This change was used to set the adjustment conditions of this example. The adjusted profile obtained with this example and the intensity distribution on the optical axis are respectively shown in FIGS. 15A and 15B.

[0243] With this example, with both the second and third zones with the phase adjustment conditions, the phase constant h=0, and the phase shift was set to be the same, so these are zones become one integrated single unit zone that is parallel to the reference line which has no blaze tilt. This structure is set in each repeated region. The intensity distribution of this adjusted profile is one for which the multi-order light peaks of the high order regions shown with example 6 are further reduced, and the intensity of the 0th order diffraction peaks is further increased.

[0244] Incidentally, in relation to examples 6 and 7 described above, an investigation was done by simulation of the imaging characteristics projected on the plane of retina in a state inserted into the human eye with these examples as actual intraocular lens specifications. Specifically, a simulated operation was made in a state with the adjusted profile of examples 6 and 7 and the composite profile of example 6 as a comparative example being provided as a relief structure on the front surface of the intraocular lens, and that intraocular lens being inserted in the human eye, and an investigation was done of the image formed on the retina when viewing far objects with that eye optical system.

[0245] In specific terms, to study the state of halos when viewing far street lamps, car headlights or the like at night, light emitted from a light source with a point light source at a far distance made incident as plane waves on the eyeball, the intensity distribution on the image plane of the 0 D peak focal point position used for far vision was calculated, and the halo was evaluated using this intensity distribution. The intensity distribution on the image plane for that point light source will hereafter be called the point spread function.

[0246] Furthermore, to also confirm visual performance when viewing an object with spreading at a far distance, simulation was also done of visual performance when viewing a Landolt ring correlating to visual acuity of 0.2. In regard to the Landolt ring simulation, the Landolt ring image data was converted to actual size when projected on the retina, and a convolution calculation was implemented between that converted image and the point spread function noted above, and the image data obtained from those results was used as the image that is imaged on the retina.

[0247] The simulation was performed under the following conditions using VirtualLab (product name) made by Light Trans GmbH.

Eye optical system: System for which the cornea, aqueous humor, iris, intraocular lens,
vitreous humor, and retina are arranged in that order, and the refractive index and
shape are set based on human eye data
Intraocular lens power: 20 D
Light source: Far point type light source
Light wavelength: 546 nm
Pupil diameter: Diameter 3.6 mm

[0248] The simulated results of the composite profile of example 6, the adjusted profile of example 6, and the adjusted profile of example 7 are respectively shown in FIGS. 16A, 16B, and 16C, FIGS. 17A, 17B, and 17C, and FIGS. 18A, 18B, and 18C. In the drawings, FIGS. 16A, 17A and 18A do image display of the point spread function obtained from the simulation calculation, and regards this as a halo image. The maximum value of the brightness scale between images is the same and made so it is possible to compare as is. Also, in the drawings, FIGS. 16B, 17B and 18B plot the intensity of the point spread function image plane center in relation to the radial direction. In the drawings, FIGS. 16C, 17C and 18C show the results of convolution calculation of the Landolt ring and the point spread function noted above. Also, to quantitatively compare the brightness of the Landolt ring on the image plane, the intensity distribution of the region shown by the arrow of FIG. 18D is shown in FIG. 18E in regards to each example.

[0249] From the results shown in FIGS. 16A and 16B, we can see that with the composite profile before adjustment, the halo spread is large, and in the halo shaped region that spread to the periphery, a group of noise form small peaks are generated. These small peaks such as noise are generated by light that forms peak groups by multi-order light being imaged on the retina, and we can see that the existence of the peak group by multi-order light brings halo spread.

[0250] In contrast to this, from the results shown in FIGS. 17A and 17B, with the adjusted profile of example 6, we can see that the halo spread is smaller than with the composite profile. For the point spread function as well, we can see that there is a significant decrease in the noise form peak intensity. This is because with the adjusted profile of example 6, the intensity of the peak group due to multi-order light is decreased, and as a result, the halo spread is reduced.

[0251] Also, from the results shown in FIGS. 18A and 18B, we can see that with the adjusted profile of example 7, the noise due to multi-order light is further decreased, and with the halo simulation as well, the halo spread is suppressed more.

[0252] Furthermore, from the Landolt ring simulation results shown in each of FIGS. 16C, 17C and 18C, we can see that the composite profile of example 6 has the lowest brightness, the brightness becomes higher in the sequence of the adjusted profile of example 6 and then example 7, and the contrast becomes higher in sequence. This contrast is also clear from the intensity distribution drawing of FIG. 18E. This is due to the fact that as described above, with the adjusted profile of example 6 and 7, the multi-order light peaks decrease, and the gain of the intensity of the major peaks improves.

[0253] Therefore, as can be understood from the simulation results when using as the intraocular lens, we can see that the tuning by phase and amplitude adjustment of the present invention is successful in reducing halo and improving contrast.

Example 8

[0254] With examples 1 to 7 described above, regarding phase and amplitude adjustment, the subject was a composite profile synthesized from two starting profiles. With example 8, we will describe an example of adjusting the composite profile when there are three starting profiles.

[0255] (i) Preparation of the Composite Profile

[0256] The third starting profile in addition to starting profiles (1) and (2) will be called starting profile (3). The phase function of the respective starting profiles used when acquiring the composite profile are blaze shaped functions, where based on Equation 13, Equation 14, and Equation 22 which are standard setting equations, the respective zone pitches are determined such that with the starting profile (1), the addition power P.sub.1 is P.sub.1=4 D, with the starting profile (2), the addition power P.sub.2 is ⅔ of P.sub.1 with P.sub.2=2.666 D, and with starting profile (3), the addition power P.sub.3 is ⅓ of P.sub.1, with P.sub.3=1.333 D. The phase constant of starting profiles (1), (2) and (3) are respectively 0.425, 0.325, and 0.25. The starting profiles are overlapped on the same region, and the composite profile was obtained by adding the phase. Details of the starting profiles and composite profile are shown in Table 12 and FIGS. 19A, 19B, 19C, and 19D.

TABLE-US-00012 TABLE 12 Starting profile (1) Starting profile (2) Starting profile (3) Addition power P.sub.1 = 4 D Addition power P.sub.2 = 2.666 D Addition power P.sub.3 = 1.333 D Composite profile (Example 8) Zone Phase Zone Phase Zone Phase Zone radius (mm) Zone radius con- Zone radius con- Zone radius con- Zone Outer Inner No. (mm) stant No. (mm) stant No. (mm) stant No. radius radius Phase (radians) n r.sub.n h m r.sub.n h q r text missing or illegible when filed h i r r.sub.i−1 φ ′ φ.sub.i−1′ 1 0.5225 0.425 1 0.6399 0.325 1 0.9050 0.25 1 0.5225 0 −2.1030 3.1416 2 0.7389 0.425 2 0.9050 0.325 2 1.2798 0.25 2 0.6399 0.5225 −1.4600 0.5674 3 0.9050 0.425 3 1.1084 0.325 3 1.5675 0.25 3 0.7389 0.6399 −1.5740 0.5820 4 1.0450 0.425 4 1.2798 0.325 4 1.8100 0.25 4 0.9050 0.7389 −3.1416 1.0964 5 1.1683 0.425 5 1.4309 0.325 5 1.0450 0.9050 −1.5210 3.1416 6 1.2798 0.425 6 1.5675 0.325 6 1.1084 1.0450 −1.1251 1.1493 7 1.3824 0.425 7 1.6931 0.825 7 1.1683 1.1084 −1.3463 0.9170 8 1.4778 0.425 8 1.8100 0.325 8 1.2798 1.1683 −3.1416 1.3241 9 1.5675 0.425 9 1.3824 1.2798 −1.4749 3.1416 10 1.6523 0.425 10 1.4809 1.3324 −1.0829 1.1954 11 1.7329 0.425 11 1.4778 1.4309 −1.3117 0.9592 12 1.8100 0.425 12 1.5675 1.4778 −3.1416 1.3587 13 1.6523 1.5675 −1.4566 3.1416 14 1.6931 1.6523 −1.0651 1.2137 15 1.7329 1.6931 −1.2964 0.9770 16 1.8100 1.7329 −3.1416 1.3740 text missing or illegible when filed indicates data missing or illegible when filed

[0257] With the composite profile comprising three stating profiles of this example, from the relational expressions of Equation 12 and Equation 23 noted above, a=2, b=3, d=1, and e=3 are allocated, and a characteristic feature is that a synchronous structure is formed for which the zone diameter matches with a number of zone pitches correlating to the quotient with each respective number divided using the greatest common divisor of z=3 of the three integral values for which (b×e)=9, (a×e)=6, and (b×d)=3. Specifically, the zone diameters match for pitches of the zone count being (b×e)/z=9/3=3 for starting profile (1), (a×e)/z=6/3=2 for starting profile (2), and (b×d)/z=3/3=1 for starting profile (3). We can see this relationship from FIGS. 19A, 19B, 19C, and 19D. With the composite profile, a structure is formed which has phase distribution of the same form repeated in zone regions with four zones of the first to fourth, fifth to eighth, ninth to twelfth, and thirteenth to sixteenth as units.

[0258] FIG. 19E shows the intensity distribution on the optical axis of this composite profile. With this composite profile, four peaks of about the same intensity are generated at positions of 0 D, 1.33 D, 2.66 D, and 4 D. When a lens that uses a diffractive structure for this composite profile is used as an ophthalmic lens, for example, this is suitable as specifications for a four focal point multi-focal ophthalmic lens with 0 D for far vision, 4 D for near vision, 2.66 D for intermediate vision for viewing a personal computer monitor or the like, and 1.33 D for a second intermediate vision for seeing a range of about 1 m to 2 m in front. This second intermediate vision focal point is a focal point that is useful for clearly seeing dust or trash when sweeping a floor or the like. Also, since the peak intensities are respectively the same, the visual performance is balanced for the respective regions.

[0259] However, with the composite profile of this example, as can be seen from FIG. 19E, several peaks due to multi-order light are generated with the light intensity distribution. These peaks hinder improvement in gain of the major peaks, and are also the cause of halo and glare. In light of that, at least one of phase and amplitude of the composite profile is adjusted to perform reduction of peaks due to multi-order light, and as a result, the diffractive multi-focal lens equipped with the adjusted profile shown hereafter was obtained as example 8.

[0260] (ii) Generation of the Adjusted Profile by Phase Adjustment

When doing adjustment, the same as with the examples noted above, first, the phase information of the composite profile is divided into the phase constant and the phase shift, and the phase adjustment is performed based on that. The details of the divided composite profile phase constant and phase shift as well as the adjusted profile are shown in Table 13.

TABLE-US-00013 TABLE 13 Zone radius Composite profile (mm) (Example 8) Adjusted profile(Example 8) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant Shift constant Shift adjustment adjustment i r.sub.i r text missing or illegible when filed h τ h τ φ.sub.i′ φ.sub.i−1′ 1 0.5225 0 0.835 0.519 0.7 −0.785 −2.9845 1.4137 2 0.6399 0.5225 0.323 −0.446 0.2 1.037 0.4084 1.6650 3 0.7389 0.6399 0.343 −0.496 0.2 −0.220 −0.8482 0.4084 4 0.9050 0.7389 0.674 −1.023 0.3 −1.068 −2.0106 −0.1257 5 1.0450 0.9050 0.742 0.810 0.7 −0.785 −2.9845 1.4137 6 1.1084 1.0450 0.362 0.012 0.2 1.100 0.4712 1.7279 7 1.1683 1.1084 0.360 −0.215 0.2 −0.157 −0.7854 0.4712 8 1.2798 1.1683 0.711 −0.909 0.4 −1.068 −2.3248 0.1885 9 1.3824 1.2798 0.735 0.833 0.7 −0.785 −2.9845 1.4137 10 1.4309 1.3824 0.363 0.056 0.2 1.100 0.4712 1.7279 11 1.4778 1.4309 0.361 −0.176 0.2 −0.157 −0.7854 0.4712 12 1.5675 1.4778 0.716 −0.891 0.4 −1.068 −2.3248 0.1885 13 1.6523 1.5675 0.732 0.842 0.7 −0.785 −2.9845 1.4137 14 1.6931 1.6523 0.363 0.074 0.2 1.100 0.4712 1.7279 15 1.7829 1.6931 0.362 −0.160 0.2 −0.157 −0.7854 0.4712 16 1.8100 1.7329 0.719 −0.884 0.4 −1.068 −2.3248 0.1885 text missing or illegible when filed indicates data missing or illegible when filed

[0261] When obtaining the adjusted profile with this example, the main adjustment points implemented on each zone of the composite profile are as follows. Regarding the phase constant, the big change points by adjustment were that the phase constant of the fourth, eighth, twelfth, and sixteenth zones of the composite profile which were in a range from 0.67 to 0.72 were set to small values of 0.3 or 0.4, and regarding phase shift, the first, fifth, ninth, and thirteenth zones before adjustment which were arranged at the plus side were shifted to the minus side, and the second, sixth, tenth, and fourteenth zones were shifted to the plus side.

[0262] FIG. 20A shows the adjusted profile obtained by this adjustment. The feature points with the adjusted profile are that the peak and valley positions of the blaze of the second and third, sixth and seventh, tenth and eleventh, and fourteenth and fifteenth zones almost match, and since the tilt of the zones are almost the same as each other, that these mutual zones are regarded as essentially having a continuous-roof single blaze shape form.

[0263] FIG. 20B shows the intensity distribution in the optical axis direction of the adjusted profile. This intensity distribution has a significant reduction in peaks due to multi-order light acknowledged with this composite profile. Also, the intensity ratio before adjustment is maintained with the four major peaks, and we can see that at the amount by which the multi-order light peaks decrease, there is a significant increase in the gain leading to an increase in the intensity of these major peaks.

[0264] By preparing the composite profile from three starting profiles in this way, and using the method for adjusting at least one of phase and amplitude, four focal points can be formed freely, and unnecessary peaks due to multi-order light can be reduced, making it possible to provide a multi-focal lens with excellent sharpness when viewing objects in each focal point region, and for which halo, glare and the like are reduced.

Example 9

[0265] With example 8 noted above, we described that as a result of phase adjustment, the adjacent zones of the second and third, sixth and seventh, tenth and eleventh, and fourteenth and fifteenth are regarded essentially as one continuous-roof blaze shape. When this essentially one continuous-roof blaze is regarded as one zone, the adjusted profile of example 8 has the same zone pitches as the standard Fresnel pitch for which the addition power is 4 D. The relationship of this zone pitch is shown in FIGS. 21A and 21B. When regarding the adjacent zones of the adjusted profile of example 8 as one zone, we can see that this matches with the zone pitch of the standard Fresnel zone. Specifically, in the mode where the plurality of starting profiles are overlapped, the radius of each zone is a non-Fresnel pitch as shown in FIG. 19, for example. Meanwhile, in the adjusted profile, as shown in FIGS. 20 to 21, the radius of each zone can be understood to be substantially a Fresnel pitch by the plurality of zones being integrally consolidated.

[0266] On the other hand, there is the same relationship with the adjusted profile of example 7 as well, and with that adjusted profile, the adjacent zones of the second and third, sixth and seventh, tenth and eleventh, and fourteenth and fifteenth have the phase constant as h=0, and because the phase shift is the same value, this is one zone that is essentially completely integrated. The drawing of that adjusted profile of example 7 is shown together as FIG. 21C. Similarly, we can see that the standard Fresnel zone has the same zone pitch. The adjusted profile of example 7 was designed as an item that mainly generates three focal points.

[0267] When the phase function is in blaze form, although differing according to the blaze step, it is generally understood that the number of focal points given by the standard Fresnel zone is only two comprising a combination of an n order and (n+1) order diffracted light such as 0th order and first order diffracted light, or first order and second order diffracted light or the like corresponding to the set addition power. However, here, even with the standard Fresnel zone, depending on the phase and amplitude adjustment, it is possible to have diffraction specifications that give at least three focal points. If we can apply the theory that even with the standard Fresnel zone diffractive lens, this is an item that could be obtained as a result of adjusting phase and amplitude of designated zones with the composite profile of a plurality of starting profiles based on the present invention, we can understand this as a diffractive multi-focal lens that gives three or more focal points based on the plurality of starting profiles. Said another way, even with the standard Fresnel zone diffractive lens, it is possible to understand the profile obtained by adjusting the phase and amplitude of that zone as being divided into a plurality of starting profiles, and we can understand this as a diffractive multi-focal lens of a structure equipped with three or more focal points according to the present invention.

[0268] With this example, we performed design of a diffractive lens that can be a four focal point lens suitable as an intraocular lens by using a method for adjusting at least one of phase and amplitude of the standard Fresnel zone based on this kind of new information, specifically, a diffractive multi-focal lens that can be understood as being obtained as a result of implementing adjustment of phase or amplitude on a specified zone of the composite profile obtained by overlapping the zones of the plurality of starting profiles.

[0269] In specific terms, first, the zone profiles were set using the standard setting equation such that the addition power is 4 D. In regards to the zone profile, a blaze shaped phase function is set for each zone, and an adjusted profile was obtained for which the blaze phase constant and phase shift were adjusted. The details of the adjusted profile of this example are shown in Table 14.

TABLE-US-00014 TABLE 14 Zone radius (mm) Adjusted profile(Example 9) Zone Outer Inner Phase Phase After After No. radius radius constant Shift adjustment adjustment i r.sub.i r.sub.i−1 h τ φ.sub.i′ φ.sub.i−1′ 1 0.5225 0 0.6 −0.314 −2.1991 1.5708 2 0.7389 0.5225 0.4 0.628 −0.6283 1.8850 3 0.9050 0.7389 0.3 −0.565 −1.5080 0.3770 4 1.0450 0.9050 0.6 −0.314 −2.1991 1.5708 5 1.1683 1.0450 0.4 0.628 −0.6283 1.8850 6 1.2798 1.1683 0.3 −0.565 −1.5080 0.3770 7 1.3824 1.2798 0.6 −0.314 −2.1991 1.5708 8 1.4778 1.3824 0.4 0.628 −0.6283 1.8850 9 1.5675 1.4778 0.3 −0.565 −1.5080 0.3770 10 1.6523 1.5675 0.6 −0.314 −2.1991 1.5708 11 1.7329 1.6523 0.4 0.628 −0.6283 1.8850 12 1.8100 1.7329 0.3 −0.565 −1.5080 0.3770

[0270] The drawing of the adjusted profile of this example is shown in FIG. 22A. The adjusted profile of this example is a profile directly set from the standard Fresnel zone having referenced the phase information of the adjusted profile of example 8 noted above. FIG. 22B shows the intensity distribution on the optical axis of the adjusted profile. The intensity distribution of this adjusted profile has the greatest intensity at the 0 D peak, and this is distributed continuously next with 4 D, followed by 2.66 D and 1.33 D peaks. Also, a pattern is shown with which almost no peak groups due to multi-order light are found. In this way, this is a profile comprising standard Fresnel zones, but because it is a profile derived via tuning using the adjustment of the present invention, it also realizes the effect of suppressing peaks due to multi-order light while generating four focal points.

[0271] We performed a simulation evaluation using the human eye optical system for a case of using the lens of this example which uses a diffractive structure for the profile as an intraocular lens. The simulation was performed using the same Light Trans GmbH. VirtualLab (product name) as was used with examples 6 and 7 noted above, and using the same conditions. Also, at each focal point position, a calculation of the point spread function of each focal point position was calculated to find and understand how a Landolt ring correlating to visual acuity of 1.2 is seen, and convolution calculation was performed between the point spread function and the image data of the Landolt ring of the size correlating to visual acuity of 1.2 on the retina, and this was used as the imaging data projected on the retina.

[0272] The results of the simulation are respectively shown in FIGS. 22C, 22D, 22E, and 22F. Each position of 0 D, 1.33 D, 2.66 D, and 4 D for the intensity distribution of FIG. 22B can be estimated as being at distances of infinity (actually distance of 4 to 5 mm or greater), 90 cm, 50 cm, and 35 cm with the eye as the base point. At each position, though there are differences in contrast or in lightness and darkness of the background, the gap of Landolt ring is sufficiently perceivable, and we can see that this can be a lens for which sufficient vision is possible of objects at each respective position. Therefore, this lens is useful for far vision, but also for near distance reading and work, for work while viewing a personal computer, and also for work such as sweeping a floor or the like.

[0273] In this way, even with a standard Fresnel zone, it is possible to establish this as a diffractive multi-focal lens with a structure according to the present invention, specifically, even with a standard Fresnel zone, it is possible to generate at least three focal points whether with phase or amplitude adjustment based on the technical concept of the present invention, and possible to have imaging characteristics for which multi-order light is controlled.

Example 10

[0274] However, when we look at the phase form of the adjusted profile of example 9 noted above, the tilt of adjacent zones second and third, fifth and sixth, eighth and ninth, and eleventh and twelfth is almost the same, and the peak and valley positions are close. Therefore, it is possible to regard these mutually adjacent zones as essentially being one zone. Also, it is conceivable for multiple focal points to be generated in the new zone pitches for which the zones are integrated into essentially one zone. In light of that, design was performed for a diffractive lens for which it is possible to be a multi-focal lens with phase being readjusted with the new zone pitches for which these zones were integrated.

[0275] The details of the profile of the diffractive multi-focal lens as example obtained as a result are shown in Table 15.

TABLE-US-00015 TABLE 15 Zone radius (mm) Adjusted profile(Example 10) Zone Outer Inner Phase Phase After After No. radius radius constant Shift adjustment adjustment i r text missing or illegible when filed r.sub.i−1 h τ φ.sub.i′ φ ′ 1 0.5225 0 0.7 −0.251 −2.4504 1.9478 2 0.9050 0.5225 0.4 0.314 −0.9425 1.5708 3 1.0450 0.9050 0.7 −0.157 −2.3562 2.0420 4 1.2798 1.0450 0.4 0.000 −1.2566 1.2566 5 1.3824 1.2798 0.7 −0.157 −2.3562 2.0420 6 1.5675 1.3824 0.4 0.000 −1.2566 1.2566 7 1.6523 1.5675 0.7 −0.157 −2.3562 2.0420 8 1.8100 1.6523 0.4 0.000 −1.2566 1.2566 text missing or illegible when filed indicates data missing or illegible when filed

[0276] This profile is such that the (3n−1)th zone and the 3n-th zone (n is a natural number) of the standard Fresnel zone are integrated into one zone, so this is a zone pitch that cannot be determined with the standard Fresnel zone setting equation. Also, with the same aperture diameter, the constituent zone count is even smaller than with the standard Fresnel zone. A drawing of the adjusted profile of this example is shown in FIG. 23A. Also, the intensity distribution in the optical axis direction of this profile is shown in FIG. 23B. From these drawings, with the diffractive multi-focal lens of this example, we can see that more than with the standard Fresnel zone, there is a simpler zone structure, and the multi-focal point generating function is maintained.

[0277] From the results shown with examples 9 and 10 described above, based on the technical concepts of the present invention, for the adjusted profile for which adjustment was implemented for each zone with the composite profile generated by overlapping a plurality of starting profiles as a base, we can understand that it is possible to realize a simplified zone structure for this adjusted profile. This means that, said another way, if the adjusted profile is the subject, by going through adjustment of the phase or amplitude for each zone, it is possible to restore the adjusted profile to the structure of the standard Fresnel zone or an even more simplified profile (specifically, simplification of the zone structure), and even with the simplified profile, it is possible to generate at least three focal points freely at any position, and to obtain a diffractive lens for which the generation of multi-order light is suppressed. Also, the profile with this simplified structure is included in the technical concept of the present invention, and in addition to being able to achieve the technical effects based on the present invention, aside from the effects relating particularly to imaging characteristics, because the structure is simple, this also links to things such as ease of manufacturing when actually creating a diffractive structure with the profile in a relief shape, making it possible to obtain further effects.

Example 11

[0278] Next, though the fact that it is possible to obtain an adjusted profile through the profile synthesized from starting profiles (1) and (2) in relation to the asynchronous structure for which none of the zone diameter match is as described previously, we will show a specific example hereafter to make this even easier to understand.

[0279] (i) Preparation of the Composite Profile

[0280] Both starting profiles (1) and (2) have the phase function as a blaze shaped function, where the same as with example 6, the addition power of starting profiles (1) and (2) are set as P.sub.1=4 diopters and P.sub.2=2.666 D. The first zone radius of starting profile (1) is set freely at r.sub.1=0.47 mm, and the first zone radius of starting profile (2) is set at r.sub.1′=0.3872 mm, so the zone pitch of each starting profile was determined based on the general setting equations Equation 8 and Equation 10. The phase constant of starting profiles (1) and (2) are respectively 0.4 and 0.35. With this example, the phase φ.sub.0 of the first zone was determined based on Equation 25 noted below. The composite profile was obtained by overlapping the starting profiles (1) and (2) on the same region and adding the phase.

[00014] $\begin{matrix} φ_{0} = h \times π \times (\frac{P \times r_{1}^{2}}{λ} - 1) & [Equation .Math. .Math. 25] \end{matrix}$

φ.sub.0: Phase of inner diameter position of the first zone
h: Phase constant
P: Addition power
r.sub.1: First zone radius
λ: Design wavelength

[0281] The details of the starting profiles (1) and (2) and the composite profile are shown in Table 16 and FIGS. 24A and 24B.

TABLE-US-00016 TABLE 16 Starting profile(1) Starting profile(2) Addition power Addition power Composite profile(Example 11) P.sub.1 = 4 D P.sub.2 = 2.666 D Zone radius Zone Zone (mm) Zone radius Phase Zone radius Phase Zone Outer Inner Phase No. (mm) constant No. (mm) constant No. radius radius (radians) n r text missing or illegible when filed h m r h i r r φ ′ φ .sub.−1′ 1 0.47 0.4 1 0.3872 0.35 1 0.3872 0 −1.9980 0.4827 2 0.7027 0.4 2 0.7479 0.35 2 0.47 0.3872 −0.6616 0.2010 3 0.8757 0.4 3 0.9843 0.35 3 0.7027 0.47 −2.0807 1.8516 4 1.0197 0.4 4 1.1740 0.35 4 0.7479 0.7027 −0.4995 0.4325 5 1.1458 0.4 5 1.3371 0.35 5 0.8757 0.7479 −1.3456 1.6995 6 1.2593 0.4 6 1.4823 0.35 6 0.9843 0.8757 −1.7384 1.1676 7 1.3634 0.4 7 1.6146 0.35 7 1.0197 0.9843 −0.5674 0.4606 8 1.4601 0.4 8 1.7367 0.35 8 1.1458 1.0197 −2.0286 1.9458 9 1.5507 0.4 9 1.1740 1.1458 −0.4685 0.4845 10 1.6364 0.4 10 1.2593 1.1740 −1.3067 1.7305 11 1.7178 0.4 11 1.3371 1.2593 −1.7218 1.2065 12 1.3634 1.3371 −0.5548 0.4772 13 1.4601 1.3634 −2.0188 1.9583 14 1.4823 1.4601 −0.4604 0.4943 15 1.5507 1.4823 −1.2945 1.7387 16 1.6146 1.5507 −1.7158 1.2186 17 1.6364 1.6146 −0.5498 0.4832 18 1.7178 1.6364 −2.0146 1.9634 text missing or illegible when filed indicates data missing or illegible when filed

[0282] From FIG. 24A, we can see that the zone radii of starting profiles (1) and (2) are in an asynchronous relationship for which they do not match in any region. As shown in FIG. 24B, the composite profile obtained by synthesizing the starting profiles exhibits a structure for which similar phase units are repeated in zone units of the first to fifth, sixth to tenth, eleventh to fifteenth, and so on (or the second to sixth, seventh to eleventh, twelfth to sixteenth, and so on). The starting profiles of this example are in an asynchronous structure relationship, but we can see as shown in FIG. 24C that the composite profile has focal point peaks formed at positions at which the addition power set with the respective starting profiles are 4 D and approximately 2.67 D. Therefore, the diffractive lens based on the composite profile is useful as the same three focal point intraocular lens as that of example 6.

[0283] However, with the composite profile of this example, excess peaks due to multi-order light (arrow A in FIG. 24C) are generated at the point of approximately 6.7 D. Next, readjustment of the phase was performed with the composite profile, and a reduction of the multi-order light was performed.

[0284] (ii) Generation of the Adjusted Profile by Phase Adjustment

[0285] The composite profile of this example is made by repeating a similar phase structure with five continuous zone pitches, so considering that regularity, first, phase adjustment was performed for the first to fifth zones. The phase shift was increased in the minus direction for the second and fourth zones, and the phase constant was made a little smaller and the phase shift was increased in the plus direction for the fifth zone. The same phase adjustments were also implemented on the remaining zone units of the sixth to tenth, eleventh to fifteenth, and sixteenth to eighteenth. The details of the adjusted profile are shown in Table 17 and FIG. 25A.

TABLE-US-00017 TABLE 17 Zone radius Composite profile (mm) (Example 11) Adjusted profile(Example 11) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant Shift constant Shift adjustment adjustment i r.sub.i r.sub.i− text missing or illegible when filed h τ h τ φ.sub.i′ φ.sub.i−1′ 1 0.3872 0 0.394 −0.757 0.35 −0.459 −1.5585 0.6405 2 0.47 0.3872 0.137 −0.230 0.1 −0.593 −0.9075 −0.2792 3 0.7027 0.47 0.625 −0.114 0.6 −0.065 1.9504 1.8194 4 0.7479 0.7027 0.148 −0.033 0.1 −0.635 −0.9492 −0.3209 5 0.8757 0.7479 0.484 0.1769 0.35 0.413 −0.6862 1.5128 6 0.9848 0.8757 0.462 −0.285 0.45 −0.030 −1.4444 1.3830 7 1.0197 0.9843 0.163 −0.053 0.15 −0.436 −0.9079 0.0345 8 1.1458 1.0197 0.632 −0.041 0.6 −0.023 −1.9086 1.8612 9 1.1740 1.1458 0.151 0.008 0.1 −0.597 −0.9117 −0.2834 10 1.2593 1.1740 0.483 0.211 0.35 0.443 −0.6562 1.5428 11 1.3371 1.2593 0.466 −0.257 0.45 −0.011 −1.4250 1.4024 12 1.3634 1.3371 0.164 −0.038 0.15 −0.424 −0.8960 0.0464 13 1.4601 1.3634 0.633 −0.030 0.6 −0.017 −1.9022 1.8676 14 1.4823 1.4601 0.151 0.016 0.1 −0.589 −0.9041 −0.2757 15 1.5507 1.4823 0.482 0.222 0.35 0.452 −0.6472 1.5518 16 1.6146 1.5507 0.467 −0.248 0.45 −0.004 −1.4185 1.4088 17 1.6364 1.6146 0.164 −0.033 0.15 −0.420 −0.8916 0.0508 18 1.7178 1.6364 0.633 −0.025 0.6 −0.014 −1.8996 1.8703 text missing or illegible when filed indicates data missing or illegible when filed

[0286] Also, the intensity distribution on the optical axis with the adjusted profile is compared with the composite profile and shown in FIG. 25B (solid line is the adjusted profile, dotted line is the composite profile). We can see that by doing this phase adjustment, the multi-order light peaks shown by arrow A in the drawing are decreased. Also, we can see that the 0th order diffracted light peak intensity increases, and there is also in increase in that peak gain.

[0287] When the adjusted profile of this example is used for an intraocular lens, the multi-order light decreases, and when using the 0th order diffracted light for far vision, the gain of that diffracted light increases, so more so than in the case when using a lens from a composite profile, the generation of halo and glare are suppressed, and there is further qualitative improvement in far visual performance without losing visual performance for near vision and intermediate vision.

[0288] Also, from the investigation results described above regarding this example as well, even if there is an asynchronous structure relationship for which matching is not seen for any of the zone diameters with the starting profiles, it is possible to understand the present invention as operating effectively.

Example 12

[0289] This example is for making the present invention even easier to understand by showing an example for referencing a specific example when the addition power of the starting profile (I) is varied.

[0290] (i) Preparation of the Composite Profile

[0291] Both starting profiles (1) and (2) have the phase function as a blaze shaped function, where the starting profile (1) is set so that the addition power is P.sub.1=2 diopters, and starting profile (2) is set so that the addition power P.sub.2 is ¾ of P.sub.1 with P.sub.2=1.5 diopters. For the respective zone pitches, starting profile (1) was determined using the standard setting equation of Equation 13, and starting profile (2) was determined using the general setting equation of Equation 10, with the first zone radius set at r.sub.1′=0.6033 mm. The phase constant of starting profiles (1) and (2) are respectively 0.4 and 0.3, and the phase φ.sub.0 of the first zone of starting profile (2) was determined based on Equation 25. The composite profile was obtained by starting profiles (1) and (2) being respectively overlapped on the same region, and the phase being added. The details of the starting profiles (1) and (2) and the composite profile are shown in Table 18 and FIGS. 26A and 26B.

TABLE-US-00018 TABLE 18 Starting profile(1) Staring profile(2) Addition power Addition power Composite profile(Example 12) P.sub.1 = 2 D P.sub.2 = 1.5 D Zone radius Zone Zone (mm) Zone radius Phase Zone radius Phase Zone Outer Inner Phase No. (mm) constant No. (mm) constant No. radius radius (radians) n r text missing or illegible when filed h m r h i r r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.7389 0.4 1 0.6033 0.3 1 0.6033 0 −1.7379 1.2566 2 1.0449 0.4 2 1.0449 0.3 2 0.7389 0.6033 −0.8928 0.1470 3 1.2798 0.4 3 1.3490 0.3 3 1.0449 0.7389 −2.1991 1.6204 4 1.4778 0.4 4 1.5962 0.3 4 1.2798 1.0449 −1.7699 2.1991 5 1.6522 0.4 5 1.8099 0.3 5 1.3490 1.2798 −0.5646 0.7432 6 1.8099 0.4 6 2.0009 0.3 6 1.4778 1.3490 −1.2961 1.3203 7 1.9549 0.4 7 2.1753 0.3 7 1.5962 1.4778 −1.3918 1.2171 8 2.0899 0.4 8 2.3366 0.3 8 1.6522 1.5962 −0.8082 0.4930 9 2.2167 0.4 9 2.4875 0.3 9 1.8099 1.6522 −2.1991 1.7049 10 2.3366 0.4 10 2.6298 0.3 10 1.9549 1.8099 −1.7451 2.1991 11 2.4507 0.4 11 2.0009 1.9549 −0.5424 0.7681 12 2.5596 0.4 12 2.0899 2.0009 −1.2762 1.3425 13 2.1753 2.0899 −1.3776 1.2369 14 2.2167 1.1753 −0.7982 0.5073 15 2.3366 2.2167 −2.1991 1.7150 16 2.4507 2.3366 −1.7387 2.1991 17 2.4875 2.4507 −0.5358 0.7745 18 2.5596 2.4875 −1.2697 1.3491 text missing or illegible when filed indicates data missing or illegible when filed

[0292] With this example, while the addition power of starting profile (2) is set to be a ¾ of P.sub.1, the same as with example 1, the addition power of starting profile (1) is set to be smaller than that of the group of examples noted above at P.sub.1=2 diopters. Also, from the second zone of starting profiles (1) and (2), the zone diameters match each other, and thereafter, there is a synchronous structure for which four continuous zone pitches of starting profile (1) and three continuous zone pitches of starting profile (2) match. The synchronous structure is formed at a different point than with example 1, but the repeated pattern of the composite profile phase is similar to that of example 1. In other words, the repeated structure is formed with six zones such as the first to sixth, seventh to twelfth, thirteenth to eighteenth and the like as the unit.

[0293] FIG. 26C shows the intensity distribution on the optical axis of this composite profile. With this composite profile, a peak is generated by the 0th order diffracted light, and peaks based on the +1 order diffracted light of starting profiles (1) and (2) are generated at the points of 2 D and 1.5 D.

[0294] Patients for which the intraocular lens is used, for example, cataract patients, lose their own power of accommodation, so the near vision focal point position for reading needs to be a 4 D equivalent with the intraocular lens alone. However, with the typical presbyopia patient who still has a small amount of his own power of accommodation remaining, a contact lens prescription is suitable, and with the contact lens, the focal point position with the lens alone that is required with use together with the patient's own power of accommodation is sufficient as a 2 D equivalent. Therefore, by allocating 2 D for near vision, 1.5 D for intermediate vision, and 0 D for far vision, this example useful as a three focal point contact lens for presbyopia patients who still have a small amount of their own power of accommodation remaining. With this prescription example as well, a focal point is set for intermediate vision, so visual acuity is broadly ensured of course for far vision but also from reading distance to the distance for seeing a personal computer monitor screen.

[0295] However, with the composite profile of this example, a plurality of multi-order light diffracted light is generated, so the problem of halo and glare occurs. In light of that, phase adjustment was performed on this composite profile to suppress multi-order light.

[0296] (ii) Generation of the Adjusted Profile by Phase Adjustment

[0297] The composite profile of this example is made by repeating a similar phase structure with six continuous zone pitches, so considering that regularity, first, phase adjustment was performed for the first to sixth zones. The second and fifth zone phase constant was h=0, and the phase shift was slightly increased in the minus direction. Zones other than these had the phase constant and phase shift kept at the fine adjustment level. Phase adjustment was implemented in the same way on the remaining zone units of the seventh to twelfth, and thirteenth to eighteenth. The details of the adjusted profile are shown in Table 19 and FIG. 27A. Also, the intensity distribution on the optical axis compared with the composite profile is shown in FIG. 27B (solid line is the adjusted profile, dotted line is the composite profile).

TABLE-US-00019 TABLE 19 Zone radius Composite profile (mm) (Example 12) Adjusted profile(Example 12) Zone Outer Inner Phase Phase Phase Phase After After No. radius radius constant Shift constant Shift adjustment adjustment i r.sub.i r.sub.i−1 h τ h τ φ.sub.i′ φ.sub.i−1′ 1 0.6033 0 0.476 −0.240 0.4 −0.083 −1.3401 1.1730 2 0.7339 0.6033 0.165 −0.372 0 −0.628 −0.6283 −0.6283 3 1.0449 0.7389 0.607 −0.289 0.6 −0.192 −2.0778 1.6920 4 1.2798 1.0449 0.631 0.214 0.5 0.286 −1.2847 1.8568 5 1.3490 1.2798 0.208 0.089 0 −0.314 −0.3141 −0.3141 6 1.4778 1.3490 0.416 0.012 0.4 −0.138 −1.3950 1.1182 7 1.5962 1.4778 0.415 −0.087 0.4 0.076 −1.1803 1.3329 8 1.6522 1.5962 0.207 −0.157 0 −0.628 −0.6283 −0.6283 9 1.8099 1.6522 0.621 −0.247 0.6 −0.329 −2.2143 1.5555 10 1.9549 1.8099 0.627 0.226 0.5 0.302 −1.2681 1.8734 11 2.0009 1.9549 0.208 0.112 0 0 0 0 12 2.0899 2.0009 0.416 0.083 0.4 −0.120 −1.3773 1.1359 13 2.1753 2.0899 0.416 −0.070 0.4 0.090 −1.1666 1.3466 14 2.2167 2.1753 0.207 −0.145 0 0.510 0.5109 0.5109 15 2.3366 2.2167 0.622 −0.242 0.5 −0.322 −1.8935 1.2480 16 2.4507 2.3866 0.626 0.230 0.6 0.153 −1.7315 2.0384 17 2.4875 2.4507 0.208 0.119 0 0.314 0.3141 0.3141 18 2.5596 2.4875 0.416 0.039 0.4 −0.115 −1.3718 1.1414

[0298] As shown in FIG. 27B, we can see that by doing this phase adjustment, the multi-order light peaks shown by arrow A in FIG. 26C are decreased. Also, we can see that the 0th order diffracted light peak intensity increases, and there is also in increase in that peak gain. When the adjusted profile of this example is used for a contact lens, while maintaining the ability to form three focal points with the composite profile, the generation of halo and glare are suppressed, and there is further qualitative improvement in far visual performance along with an increase in gain of the 0th order diffracted light without losing visual performance for near vision and intermediate vision.

[0299] Above, we gave a detailed description of the embodiments of carrying out the present invention while showing a number of representative examples, but the present invention is not to be interpreted as being limited by those specific noted contents, and it is possible to add various changes, revisions, improvements or the like based on the knowledge of a person skilled in the art, and any such mode is included in the scope of the claims of the invention as long as it does not stray from the gist of the invention.

[0300] For example, the diffractive structure that realizes the zone profiles set with phase adjustment implemented can be set on either the front surface or back surface of the target optical lens. It is also possible to install it on the lens interior, and for example as noted in Japanese Unexamined Patent Publication No. JP-A-2001-042112, it is also possible to form the diffractive structure of the present invention on a laminated surface comprising two materials for which the refractive index is different.

[0301] Also, as the ophthalmic lens to which the present invention is applied, specific subjects can include contact lenses, glasses, intraocular lenses or the like, and subjects can also include a cornea insertion lens for correcting vision embedded substantially within the cornea, an artificial cornea or the like. Also, with contact lenses, it is possible to suitably use these for hard contact lenses that are hard and oxygen permeable, soft contact lenses that are hydrogel or non-hydrogel, soft contact lenses that are oxygen permeable hydrogel or non-hydrogel containing a silicon component, or the like. For intraocular lenses as well, it is possible to suitably use these for any intraocular lens such as a hard intraocular lens, a soft intraocular lens that can be bent and inserted in the eye, and the like.

[0302] Incidentally, an intraocular lens was described for examples 1 to 11, and a contact lens was described for example 12, but aside from the geometrical lens shape and dimensions, only the refractive power that is the optical base (refractive power of 0th order diffracted light) differs for the intraocular lens and contract lens, and there is no difference in optical characteristics including the focal point position, intensity distribution and the like relating to the addition power exhibited based on the diffractive structure. Also, for both the intraocular lens and contact lens, to begin with, the refractive power that is the base is not limited to being an item that is set appropriately to each individual it is applied to. Therefore, with the examples, in order to clarify more specifically, we presented examples specifying one or the other of the intraocular lens or contact lens, but with any of the examples, the simulation results can be understood to indicate the intraocular lens or contact lens without distinguishing between them. In other words, in that sense, each example discloses the same example for both an intraocular lens and a contact lens.

METHOD FOR MANUFACTURING DIFFRACTIVE MULTI-FOCAL OPHTHALMIC LENS AND DIFFRACTIVE MULTI-FOCAL OPHTHALMIC LENS

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