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

Abstract

A diffractive multi-focal lens having a diffractive structure comprising a plurality of concentric circular zones, wherein: at least a portion of the diffractive structure is provided with an overlapping region in which at least two zone profiles overlap in the same region; in the overlapping region, at least a portion of a first zone profile has a zone pitch represented by a prescribed equation, and at least a portion of a second zone profile has a zone pitch represented by another prescribed equation; and an addition power P.sub.1 given by the first zone profile and an addition power P.sub.2 given by the second zone profile are determined by a prescribed relational expression, in which a and b are mutually different real numbers, and a value of a/b cannot be expressed by a natural number X or by 1/X.

Claims

1. A diffractive multi-focal lens having a diffractive structure comprising a plurality of zones in a concentric circle form, characterized in that: the diffractive structure includes an overlapping region for which at least two zone profiles are overlapped on the same region in at least a portion thereof; and at the overlapping region, at least a portion of a first zone profile of the at least two zone profiles has a zone pitch expressed by Equation 1, and at least a portion of a second zone profile of the at least two zone profiles has a zone pitch expressed by Equation 2, and an addition power P.sub.1 given by the first zone profile and an addition power P.sub.2 given by the second zone profile are determined by a relational expression of Equation 3, where a and b are mutually different integers of zero or greater, while quotients when a and b are divided by a mutual greatest common divisor thereof are both an integer other than 1, and a value of a/b is a value that cannot be expressed by a natural number X or by 1/X. $\begin{matrix} r_{n} = \sqrt{r_{1}^{2} + \frac{2 .Math. .Math. λ (n - 1)}{P_{1}}} & [Equation .Math. .Math. 1] \end{matrix}$ λ: Design wavelength r.sub.n: nth zone radius of the first zone profile r.sub.1: First zone radius of the first zone profile P.sub.1: Addition power of the first zone profile n: Natural number $\begin{matrix} r_{m} = \sqrt{r_{1}^{' .Math. .Math. 2} + \frac{2 .Math. .Math. λ (m - 1)}{P_{2}}} & [Equation .Math. .Math. 2] \end{matrix}$ λ: Design wavelength r.sub.m: mth zone radius of the second zone profile r.sub.1′: First zone radius of the second zone profile P.sub.2: Addition power of the second zone profile m: Natural number $\begin{matrix} P_{2} = \frac{a}{b} \times P_{1} & [Equation .Math. .Math. 3] \end{matrix}$

2. The diffractive multi-focal lens according to claim 1, wherein a and b in Equation 3 are set to be a/b>1/2.

3. The diffractive multi-focal lens according to claim 1 or 2, wherein in regards to a and b in Equation 3, a synchronous structure, for which a b-number of zone pitches that are continuous in the first zone profile and an a-number of zone pitches that are continuous in the second zone profile are mutually the same within the same region, is set for at least a portion of the overlapping region of the diffractive structure.

4. The diffractive multi-focal lens according to any one of claims 1-3, wherein a first zone radius r.sub.1 of the first zone profile and a first zone radius r.sub.1′ of the second zone profile are expressed respectively by Equation 4 and Equation 5. $\begin{matrix} r_{1} = \sqrt{\frac{2 .Math. .Math. λ}{P_{1}}} & [Equation .Math. .Math. 4] \\ r_{1}^{'} = \sqrt{\frac{2 .Math. .Math. λ}{P_{2}}} & [Equation .Math. .Math. 5] \end{matrix}$

5. The diffractive multi-focal lens according to any one of claims 1-4, wherein in the overlapping region, at least one type of equal-pitch zone is provided for which two or more zones are provided at equal pitches on at least one of the first zone profile and the second zone profile.

6. The diffractive multi-focal lens according to claim 5, wherein the equal-pitch zone is provided adjacent in a lens radial direction in relation to at least one of the region for which the zone pitch is represented by Equation 1 with the first zone profile, and the region for which the zone pitch is represented by Equation 2 with the second zone profile.

7. The diffractive multi-focal lens according to claim 5 or 6, wherein the at least one type of equal-pitch zone comprises a plurality of types of equal-pitch zones for which mutually different zone pitches are set.

8. The diffractive multi-focal lens according to any one of claims 1-7, wherein in addition to the first zone profile and the second zone profile, a third zone profile is set, and the diffractive structure includes the first, second, and third zone profiles overlapped on the same region.

9. The diffractive multi-focal lens according to claim 8, wherein at least a portion of the third zone profile has a zone pitch given by Equation 6, and an addition power P.sub.3 given by the third zone profile is different from both of the addition powers given by the first and second zone profiles. $\begin{matrix} r_{q} = \sqrt{r_{1}^{″ .Math. .Math. 2} + \frac{2 .Math. .Math. λ (q - 1)}{P_{3}}} & [Equation .Math. .Math. 6] \end{matrix}$ λ: Design wavelength r.sub.q: qth zone radius of the third zone profile r.sub.1″: First zone radius of the third zone profile P.sub.3: Addition power of the third zone profile q: Natural number

10. The diffractive multi-focal lens according to claim 9, wherein a first zone radius r.sub.1″ of the third zone profile is expressed by Equation 7. $\begin{matrix} r_{1}^{″} = \sqrt{\frac{2 .Math. .Math. λ}{P_{3}}} & [Equation .Math. .Math. 7] \end{matrix}$

11. The diffractive multi-focal lens according to any one of claims 8-10, wherein at least a portion of the diffractive structure 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 zone profile is the same as either a c.sub.1-number of zone pitches continuous in the first zone profile or a c.sub.2-number of zone pitches continuous in the second zone profile.

12. The diffractive multi-focal lens according to any one of claims 8-11, wherein an addition power P.sub.3 given by the third zone profile is determined by Equation 8, and with a greatest common divisor being z for three integers of (b×e), (a×e), and (b×d) expressed using d and e in Equation 8 and a and b in Equation 3, at least a portion of the diffractive structure has a synchronous structure for which a (b×e)/z-number of continuous zone pitches in the first zone profile, an (a×e)/z-number of continuous zone pitches in the second zone profile, and a (b×d)/z-number of continuous zone pitches in the third zone profile are mutually the same. $\begin{matrix} P_{3} = \frac{d}{e} \times P_{1} & [Equation .Math. .Math. 8] \end{matrix}$ (d, e: Mutually different integers of zero or greater)

13. The diffractive multi-focal lens according to any one of claims 8-12, wherein in addition to the first zone profile, the second zone profile, and the third zone profile, a fourth zone profile is also set, and the diffractive structure includes the first, second, third, and fourth zone profiles overlapped on the same region.

14. The diffractive multi-focal lens according to claim 13, wherein in addition to the first zone profile, the second zone profile, the third zone profile, and the fourth zone profile, a fifth zone profile is also set, and the diffractive structure includes the first, second, third, fourth, and fifth zone profiles overlapped on the same region.

15. The diffractive multi-focal lens according to any one of claims 1-14 wherein the diffractive structure is formed with a diffractive structure characterized by a phase function to modulate a phase of a light.

16. The diffractive multi-focal lens according to claim 15, wherein the phase function comprises a blaze shaped function.

17. The diffractive multi-focal lens according to claim 16, wherein the blaze shaped phase function φ(r) is expressed by Equation 9. $\begin{matrix} φ (r) = \frac{φ_{i} - φ_{i - 1}}{r_{i} - r_{i - 1}} \times r + \frac{φ_{i - 1} \times r_{i} - φ_{i} \times r_{i - 1}}{r_{i} - r_{i - 1}} + τ & [Equation .Math. .Math. 9] \end{matrix}$ 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

18. The diffractive multi-focal lens according to any one of claims 1-17, wherein the diffractive structure comprises a relief structure reflecting an optical path length correlating to a phase.

19. The diffractive multi-focal lens according to any one of claims 1-18 wherein the diffractive multi-focal lens is an ophthalmic lens.

20. The diffractive multi-focal lens according to any one of claims 1-19, wherein the diffractive multi-focal lens is able to generate at least three focal points.

21. The diffractive multi-focal lens according to claim 20, wherein the diffractive multi-focal lens is an ophthalmic lens for which of the three focal points, one focal point is used for far vision, and another focal point is used for near vision, and the other focal point is used for intermediate vision.

22. The diffractive multi-focal lens according to claim 21, wherein 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 given by a +1 order diffracted light by the first zone profile and the second zone profile.

23. The diffractive multi-focal lens according to any one of claims 20-22, wherein at least three focal points given by the overlapping region for which the first zone profile and the second zone profile are overlapped are generated with a lens aperture diameter of a predetermined setting diameter or greater.

24. The diffractive multi-focal lens according to any one of claims 1-23, wherein with a position of an outer diameter radius of an nth zone, n being a natural number, of the first zone profile being a boundary radius position, at one side of an inner circumference side and an outer circumference side of the boundary radius position, the diffractive structure of the first zone profile is provided but the diffractive structure of the second zone profile is not provided, and at the other side of the inner circumference side and the outer circumference side of the boundary radius position, the diffractive structure for which the first zone profile and the second zone profile are overlapped is provided.

25. The diffractive multi-focal lens according to claim 24, wherein at the inner circumference side of the boundary radius position, the diffractive structure of the first zone profile is provided but the diffractive structure of the second zone profile is not provided, and at the outer circumference side of the boundary radius position, the diffractive structure for which the first zone profile and the second zone profile are overlapped is provided.

26. A method for manufacturing a diffractive multi-focal lens having a diffractive structure comprising a plurality of zones in a concentric circle form, characterized by forming an overlapping region for which a first zone profile and a second zone profile are overlapped on the same region in at least a portion of the diffractive structure, the first zone profile having a zone pitch expressed by Equation 10 in at least a portion thereof and the second zone profile having a zone pitch expressed by Equation 11 in at least a portion thereof, and an addition power P.sub.1 given by the first zone profile and an addition power P.sub.2 given by the second zone profile being determined by a relational expression of Equation 12, where a and b are mutually different integers of zero or greater, while being set so that quotients when a and b are divided by a mutual greatest common divisor thereof are both an integer other than 1, and a value of a/b is a value that cannot be expressed by a natural number X or by 1/X. $\begin{matrix} r_{n} = \sqrt{r_{1}^{2} + \frac{2 .Math. .Math. λ (n - 1)}{P_{1}}} & [Equation .Math. .Math. 10] \end{matrix}$ λ: Design wavelength r.sub.n: nth zone radius of the first zone profile r.sub.1: First zone radius of the first zone profile P.sub.1: Addition power of the first zone profile n: Natural number $\begin{matrix} r_{m} = \sqrt{r_{1}^{' .Math. .Math. 2} + \frac{2 .Math. .Math. λ (m - 1)}{P_{2}}} & [Equation .Math. .Math. 11] \end{matrix}$ λ: Design wavelength r.sub.m: mth zone radius of the second zone profile r.sub.1′: First zone radius of the second zone profile P.sub.2: Addition power of the second zone profile n: Natural number $\begin{matrix} P_{2} = \frac{a}{b} \times P_{1} & [Equation .Math. .Math. 12] \end{matrix}$

27. The method for manufacturing the diffractive multi-focal lens according to claim 26, wherein a and b in Equation 12 are set to values that satisfy a relationship of a/b>1/2.

28. The method for manufacturing the diffractive multi-focal lens according to claim 26 or 27, wherein by adjusting at least one of a phase constant and a phase shift for at least one of the first zone profile and the second zone profile that are overlapped with each other, an intensity distribution in an optical axis direction is adjusted and set.

29. The method for manufacturing the diffractive multi-focal lens according to claim 28, wherein the at least one of the phase constant and the phase shift for the zone profile is adjusted to be mutually different between regions in a lens radial direction in the zone profile.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0146] FIG. 1 is a graph of the phase function with the r-φ coordinate system expressing the relationship of the phase φ of the phase modulation structure provided in the diffractive lens with the lens radial direction position r.

[0147] FIGS. 2A-2E show graphs with FIGS. 2A, 2B, 2C, and 2D respectively showing the blaze as one mode of the phase function for the diffractive lens. FIG. 2E is a graph using the phase shift τ to show the status when the blaze is shifted in the φ axis direction in relation to the reference line.

[0148] FIGS. 3A-3C are graphs for describing the relative relationship of each phase function for profiles (1) and (2) and the composite profile generated by overlapping those.

[0149] FIGS. 4A-4D show graphs relating to the diffractive multi-focal lens of the background art structure provided based on the inventions noted in Patent Documents 1 and 2, where FIG. 4C shows as a composite profile the phase profile for the diffractive structure for which the two zones of the first zone profile shown in FIG. 4A are synchronized and overlapped with one zone of the second zone profile shown in FIG. 4B, and the intensity distribution in the optical axis direction is shown in FIG. 4D.

[0150] FIGS. 5A-5D show graphs relating to the diffractive multi-focal lens of the background art structure provided based on the invention noted in Patent Document 1, where FIG. 5C shows a composite profile for the diffractive structure for which the three zones of the first zone profile shown in FIG. 5A are synchronized and overlapped with one zone of the second zone profile shown in FIG. 5B, and the intensity distribution in the optical axis direction is shown in FIG. 5D.

[0151] FIGS. 6A-6E are drawings relating to the diffractive multi-focal lens as example 1 of the present invention, where FIGS. 6A and 6B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 6C shows the composite profile as the overlapped phase profiles, FIG. 6D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping, and FIG. 6E is a graph showing the intensity distribution in the optical axis direction for the aperture diameter of the first to twelfth zone regions of the diffractive structure.

[0152] FIGS. 7A-7D are drawings relating to the diffractive multi-focal lens as example 2 of the present invention, where FIGS. 7A and 7B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 7C shows the composite profile as the overlapped phase profiles, and FIG. 7D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0153] FIGS. 8A-8D are drawings relating to the diffractive multi-focal lens as example 3 of the present invention, where FIGS. 8A and 8B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 8C shows the composite profile as the overlapped phase profiles, and FIG. 8D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0154] FIGS. 9A-9D are drawings relating to the diffractive multi-focal lens as example 4 of the present invention, where FIGS. 9A and 9B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 9C shows the composite profile as the overlapped phase profiles, and FIG. 9D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0155] FIGS. 10A-10E are drawings relating to the diffractive multi-focal lens as example 5 of the present invention, where FIGS. 10A and 10B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 10C shows the composite profile as the overlapped phase profiles, and FIG. 10D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping. FIG. 10E is a graph showing the intensity distribution in the optical axis direction for the aperture diameter of the first to fourteenth zone regions of the diffractive structure constituted by overlapping.

[0156] FIGS. 11A-11D are drawings relating to the diffractive multi-focal lens as example 6 of the present invention, where FIGS. 11A and 11B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 11C shows the composite profile as the overlapped phase profiles, and FIG. 11D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0157] FIGS. 12A-12D are drawings relating to the diffractive multi-focal lens as example 7 of the present invention, where FIGS. 12A and 12B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 12C shows the composite profile as the overlapped phase profiles, and FIG. 12D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0158] FIGS. 13A-13C are drawings relating to the diffractive multi-focal lens as example 8 of the present invention, where FIG. 13A shows each phase profile of profiles (1) and (2) as the first zone profile and second zone profile, FIG. 13B shows the composite profile as the overlapped phase profiles, and FIG. 13C is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0159] FIGS. 14A-14C are drawings relating to the diffractive multi-focal lens as example 9 of the present invention, where FIG. 14A shows each phase profile of profiles (1) and (2) as the first zone profile and second zone profile, FIG. 14B shows the composite profile as the overlapped phase profiles, and FIG. 14C is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0160] FIGS. 15A-15E are drawings relating to the diffractive multi-focal lens as example 10 of the present invention, where FIGS. 15A and 15B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 15C shows the composite profile as the overlapped phase profiles, and FIG. 15D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping. FIG. 15E shows the intensity distribution in the optical axis direction of profile (2) as a reference drawing.

[0161] FIGS. 16A-16D are drawings relating to the diffractive multi-focal lens as example 11 of the present invention, where FIGS. 16A and 16B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 16C shows the composite profile as the overlapped phase profiles, and FIG. 16D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0162] FIGS. 17A-17D are drawings relating to the diffractive multi-focal lens as example 12 of the present invention, where FIGS. 17A and 17B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 17C shows the composite profile as the overlapped phase profiles, and FIG. 17D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0163] FIGS. 18A-18E are drawings relating to the diffractive multi-focal lens as example 13 of the present invention, where FIGS. 18A and 18B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 18C shows the composite profile as the overlapped phase profiles, and FIG. 18D is a graph showing the intensity distribution in the optical axis direction of the first to sixth zone regions with the first zone profile which are non-overlapping regions. FIG. 18E is a graph showing the intensity distribution in the optical axis direction of the region also including overlapping regions.

[0164] FIGS. 19A-19E are drawings relating to the diffractive multi-focal lens as example 14 of the present invention, where FIGS. 19A and 19B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 19C shows the composite profile as the overlapped phase profiles, and FIG. 19D is a graph showing the intensity distribution in the optical axis direction of the first to fifth zone regions with the first zone profile which are non-overlapping regions. FIG. 19E is a graph showing the intensity distribution in the optical axis direction of the region also including overlapping regions.

[0165] FIGS. 20A-20D are drawings relating to the diffractive multi-focal lens as example 15 of the present invention, where FIGS. 20A and 20B show each phase profile of profiles (1) and (2) as the first and second zone profiles, FIG. 20C shows the composite profile as the overlapped phase profiles, and FIG. 20D is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0166] FIGS. 21A-21E are drawings relating to the diffractive multi-focal lens as example 16 of the present invention, where FIGS. 21A, 21B and 21C show the respective phase profile of profiles (1), (2) and (3) as the first, second and third zone profiles, FIG. 21D shows the composite profile as the overlapped phase profiles, and FIG. 21E is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0167] FIGS. 22A-22E are drawings relating to the diffractive multi-focal lens as example 17 of the present invention, where FIGS. 22A, 22B and 22C show the respective phase profile of profiles (1), (2) and (3) as the first, second and third zone profiles, FIG. 22D shows the composite profile as the overlapped phase profiles, and FIG. 22E is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0168] FIGS. 23A-23E are drawings relating to the diffractive multi-focal lens as example 18 of the present invention, where FIGS. 23A, 23B and 23C show the respective phase profile of profiles (1), (2) and (3) as the first, second and third zone profiles, FIG. 23D shows the composite profile as the overlapped phase profiles, and FIG. 23E is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0169] FIGS. 24A-24E are drawings relating to the diffractive multi-focal lens as example 19 of the present invention, where FIGS. 24A, 24B and 24C show the respective phase profile of profiles (1), (2) and (3) as the first, second and third zone profiles, FIG. 24D shows the composite profile as the overlapped phase profiles, and FIG. 24E is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0170] FIGS. 25A-25E are drawings relating to the diffractive multi-focal lens as example 20 of the present invention, where FIGS. 25A, 25B and 25C show the respective phase profile of profiles (1), (2) and (3) as the first, second and third zone profiles, FIG. 25D shows the composite profile as the overlapped phase profiles, and FIG. 25E is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0171] FIGS. 26A-26F are drawings relating to the diffractive multi-focal lens as example 21 of the present invention, where FIGS. 26A, 26B, 26C and 26D show the respective phase profile of profiles (1), (2), (3) and (4) as the first, second, third and fourth zone profiles, FIG. 26E shows the overlapped and synthesized phase profiles, and FIG. 26F is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0172] FIGS. 27A-27F are drawings relating to the diffractive multi-focal lens as example 22 of the present invention, where FIGS. 27A, 27B, 27C and 27D show the respective phase profile of profiles (1), (2), (3) and (4) as the first, second, third and fourth zone profiles, FIG. 27E shows the overlapped and synthesized phase profiles, and FIG. 27F is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0173] FIGS. 28A-28G are drawings relating to the diffractive multi-focal lens as example 23 of the present invention, where FIGS. 28A, 28B, 28C, 28D and 28E show the respective phase profile of profiles (1), (2), (3), (4) and (5) as the first, second, third, fourth and fifth zone profiles, FIG. 28F shows the overlapped and synthesized phase profiles, and FIG. 28G is a graph showing the intensity distribution in the optical axis direction of the diffractive structure constituted by overlapping.

[0174] FIGS. 29A-29D are drawings relating to the diffractive multi-focal lens as example 24 of the present invention, where FIGS. 29A, 29B, 29C and 29D are graphs showing the intensity distribution in the optical axis direction of the diffractive structure constituted by combining and overlapping the first zone profile and second zone profile of example 6 with different phase constants.

[0175] FIGS. 30A-30C are drawings relating to the diffractive multi-focal lens as example 25 of the present invention, where FIG. 30A shows the composite profile as overlapped phase profiles when the regions are changed to vary the phase constants of the first zone profile and the second zone profile of example 6, and FIGS. 30B and 30C are graphs showing the intensity distribution in the optical axis direction of the diffractive structure in the opening range of aperture diameter A and aperture diameter B.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0176] Following, by describing modes for carrying out the present invention, the present invention will be made clear in more specific terms.

Example Conditions and the Like

[0177] To start, we will describe the calculation simulation methods, conditions and the like used with the examples below. The calculation software 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 7 D (Diopter).

[0178] 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.

[0179] 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 zone profiles before synthesis (hereafter, these are called “starting profiles” or the like), unless otherwise noted, the phase shift in Equation 3 is zero, and the phase of the blaze is noted using the phase constant h of Equation 4. The phase of the composite profile is noted as φi′, φi−1′ as described previously.

[0180] Also, the phase profiles are set as being centrosymmetric to the lens, and the zone diameter in the tables and drawings noted in the examples are shown across the radial direction region from the center of the lens cross section. Furthermore, in the examples, the first, second, and so on zone profiles of the present invention are noted as profile (1), (2), and so on, and the phase profile for the overlapping region formed by overlapping of a plurality of zone profiles is noted as the composite profile.

Example 1

[0181] In the diffractive structure with a blaze shaped phase modulation, based on the previously described standard setting equations Equation 11 and Equation 12, the profile (1), for which the zone pitch is set so as to have the addition power P.sub.1 be 4 diopters (hereafter, diopters are noted as D) and the profile (2), for which the zone pitch is set with a=3 and b=4 based on Equation 8 so that the addition power P.sub.2 is 3 D which is 3/4 the addition power of profile (1), are respectively prepared, and the composite profile was obtained by synthesizing the zone phase functions for both profiles. The details of the composite profile are shown in Table 1 and FIG. 6.

TABLE-US-00001 TABLE 1 [Exmaple 1] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3D (Example 1) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6033 0.3 1 0.5225 0 −1.9466 2.1991 2 0.7389 0.4 2 0.8532 0.3 2 0.6033 0.5225 −0.6245 0.5667 3 0.9050 0.4 3 1.0450 0.3 3 0.7389 0.6033 −1.3369 1.2605 4 1.0450 0.4 4 1.2066 0.3 4 0.8532 0.7389 −1.4158 1.1764 5 1.1683 0.4 5 1.3491 0.3 5 0.9050 0.8532 −0.8229 0.4691 6 1.2798 0.4 6 1.4778 0.3 6 1.0450 0.9050 −2.1991 1.6904 7 1.3824 0.4 7 1.5962 0.3 7 1.1683 1.0460 −1.7523 2.1991 8 1.4778 0.4 8 1.7065 0.3 8 1.2066 1.1683 −0.5494 0.7609 9 1.5675 0.4 9 1.8100 0.3 9 1.2798 1.2066 −1.2829 1.3355 10 1.6523 0.4 10 1.3491 1.2798 −1.3826 1.2304 11 1.7329 0.4 11 1.3824 1.3491 −0.8019 0.5024 12 1.8100 0.4 12 1.4778 1.3824 −2.1991 1.7114 13 1.5675 1.4778 −1.7412 2.1991 14 1.5962 1.5675 −0.5384 0.7720 15 1.6523 1.5962 −1.2724 1.3465 16 1.7065 1.6523 −1.3746 1.2409 17 1.7329 1.7065 −0.7960 0.5104 18 1.8100 1.7329 −2.1991 1.7173

[0182] This composite profile is obtained by overlapping and synthesizing the profile (1) up to the 12th zone and the profile (2) up to the 9th zone. The phase constant of profile (1) is set at a constant h=0.4 for all blazes, and a constant h=0.3 for all blazes for profile (2) as well. The profiles are shown in FIGS. 6A and 6B.

[0183] With this example, as can be understood from the relational expressions of Equation 16 and Equation 17, there is a synchronous structure for which the zone radii of profiles (1) and (2) that correspond to the zone numbers for which n=4Ω and m=3Ω respectively (Ω is a natural number) are matched, and for which four continuous zone pitches of profile (1) and three continuous zone pitches of profile (2) are the same. As a result, the composite profile for which these profiles are synthesized has six blazes newly formed in the synchronous region. Therefore, a structure is exhibited which has similar phase profiles 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). When the zone numbers constituting the repeated structure are equally shifted (for example, shifted to the second to seventh, eighth to thirteenth, and fourteenth to nineteenth (the nineteenth is not shown in the table)), the profile shape distribution of the repeated structure is different from that before shifting but is similar among the structure units (FIG. 6C). The results of calculating the optical axis direction intensity distribution of the composite profile is shown in FIG. 6D.

[0184] From this intensity distribution diagram, we can see that peaks are generated at 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 profile (1), and the 3 D peak is based on the +1 order diffracted light of profile (2).

[0185] 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.

[0186] With the background art technology disclosed in Patent Documents 1 and 2, in comparison with this example, in contrast to the fact that the intermediate region focal point position is a maximum of 1/2 the addition power of profile (1), in other words, that it is only possible to set to a point of 4×(1/2)=2 D at a maximum, with this example, it is possible to set the intermediate focal point up to the 3 D point. It is possible to set the intermediate focal point to a nearer side than the setting position of the background art in this way, so for example with a patient who has an intraocular lens inserted, who does not have his own power of accommodation, it is possible to ensure a focal point at suitable positions from the reading position to the viewing position for a personal computer.

[0187] Also, with this example, profiles (1) and (2) are synthesized over the entire diffractive structure, so the same intensity distribution is realized in any aperture range (lens diameter region) of the diffractive structure. FIG. 6E shows the optical axis direction intensity distribution of the composite profile radius of approximately 1.48 mm (from zones 1 to 12), and shows the intensity ratio for far, intermediate, and near, which is similar to FIG. 6D. Therefore, it is especially effective as a multi-focal ophthalmic lens or the like for giving far, intermediate and near vision that is stable and is not dependent on changes in pupil size due to changes in the illumination environment, for example.

Example 2

[0188] The same as with example 1, with a blaze shaped phase modulation type diffractive structure, using standard setting equations Equation 11 and Equation 12, two types of profiles were synthesized, for which the addition power P.sub.1 of profile (1) is set to 4 D, and for which the addition power P.sub.2 of profile (2) is set to P.sub.2=4×(4/5)=3.2 D with a=4 and b=5 in Equation 8 so that it is 4/5 of the addition power of profile (1). The phase constants of profiles (1) and (2) are respectively set at h=0.4 and h=0.4 (FIGS. 7A and 7B). The details of the composite profile obtained by synthesizing the phase functions of profiles (1) and (2) are shown respectively in Table 2 and FIG. 7C.

TABLE-US-00002 TABLE 2 [Exmaple 2] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3.2D (Example 2) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.5842 0.4 1 0.5225 0 −2.2479 2.5133 2 0.7389 0.4 2 0.8261 0.4 2 0.5842 0.5225 −0.7162 0.2653 3 0.9050 0.4 3 1.0118 0.4 3 0.7389 0.5842 −1.6074 1.7971 4 1.0450 0.4 4 1.1683 0.4 4 0.8261 0.7389 −1.3199 0.9059 5 1.1683 0.4 5 1.3062 0.4 5 0.9050 0.8261 −1.0673 1.1933 6 1.2798 0.4 6 1.4309 0.4 6 1.0118 0.9050 −1.9176 1.4459 7 1.3824 0.4 7 1.5456 0.4 7 1.0450 1.0118 −0.5328 0.5957 8 1.4778 0.4 8 1.6523 0.4 8 1.1683 1.0450 −2.5133 1.9805 9 1.5675 0.4 9 1.7525 0.4 9 1.2798 1.1683 −2.0323 2.5133 10 1.6523 0.4 10 1.8473 0.4 10 1.3062 1.2798 −0.6468 0.4810 11 1.7329 0.4 11 1.9376 0.4 11 1.3824 1.3062 −1.5362 1.8665 12 1.8100 0.4 12 2.0236 0.4 12 1.4309 1.3824 −1.2776 0.9781 13 1.8839 0.4 13 1.4778 1.4309 −1.0287 1.2357 14 1.9550 0.4 14 1.5456 1.4778 −1.8986 1.4846 15 2.0236 0.4 15 1.5675 1.5456 −0.5163 0.6146 16 1.6623 1.5675 −2.5133 1.9969 17 1.7329 1.6523 −2.0222 2.5133 18 1.7525 1.7329 −0.6387 0.4910 19 1.8100 1.7525 −1.5238 1.8746 20 1.8473 1.8100 −1.2692 0.9895 21 1.8839 1.8473 −1.0197 1.2441 22 1.9375 1.8839 −1.8936 1.4935 23 1.9550 1.9375 −0.5115 0.6197 24 2.0236 1.9550 −2.5133 2.0018

[0189] With this example, there is a synchronous structure for which the zone radii of profiles (1) and (2) are matched using the zone numbers for which n=5Ω and m=4Ω (Ω is a natural number), and for which five continuous zone pitches of profile (1) and four continuous zone pitches of profile (2) are the same. As a result, the composite profile for which these profiles are synthesized has eight blazes newly formed in the synchronous region. Therefore, a new repeated structure is formed at the first to eighth, ninth to sixteenth, and seventeenth to twenty-fourth zones with the composite profile. The results of calculating the optical axis direction intensity distribution of the composite profile are shown in FIG. 7D.

[0190] From this intensity distribution diagram, we can see that main peaks are generated at 0 D, 3.2 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 profile (1), and the 3.2 D peak is based on the +1 order diffracted light of profile (2).

[0191] This example is an example in which the focal point position of the intermediate region is adjusted to be shifted further to the near side than with example 1. When used for an ophthalmic lens, for example, these are specifications particularly suited as a multi-focal ophthalmic lens that can be applied in cases of work while viewing a personal computer more closely.

[0192] Also, with this example as well, profiles (1) and (2) are synthesized over the entire diffractive structure, so the same as with example 1, the same intensity distribution is realized in any opening range of the diffractive structure.

Example 3

[0193] This example is an example for which the addition power P.sub.2 of profile (2) is set to be (3/5) of the addition power P.sub.1 of profile 1, and other than that, this was synthesized under the same conditions as example 2. With this example, the addition power of profile (2) is set as P.sub.2=4×(3/5)=2.4 D. The details of the composite provide are shown in Table 3 and FIG. 8C.

TABLE-US-00003 TABLE 3 [Exmaple 3] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 2.4D (Example 3) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6745 0.4 1 0.5225 0 −1.9468 2.5133 2 0.7389 0.4 2 0.9539 0.4 2 0.6745 0.5225 −1.7656 0.5665 3 0.9050 0.4 3 1.1683 0.4 3 0.7389 0.6745 −0.5791 0.7476 4 1.0450 0.4 4 1.3491 0.4 4 0.9050 0.7389 −2.0729 1.9342 5 1.1683 0.4 5 1.5083 0.4 5 0.9539 0.9050 −0.8788 0.4403 6 1.2798 0.4 6 1.6523 0.4 6 1.0450 0.9539 −1.0673 1.6345 7 1.3824 0.4 7 1.7847 0.4 7 1.1683 1.0450 −2.5133 1.4459 8 1.4778 0.4 8 1.9079 0.4 8 1.2798 1.1683 −1.5506 2.5133 9 1.5675 0.4 9 2.0236 0.4 9 1.3491 1.2798 −1.6967 0.9627 10 1.6523 0.4 10 1.3824 1.3491 −0.5258 0.8165 11 1.7329 0.4 11 1.4778 1.3824 −2.0323 1.9874 12 1.8100 0.4 12 1.5083 1.4778 −0.8544 0.4810 13 1.8839 0.4 13 1.5675 1.5083 −1.0330 1.6589 14 1.9550 0.4 14 1.6523 1.5675 −2.5133 1.4803 15 2.0236 0.4 15 1.7329 1.6523 −1.5310 2.5133 16 1.7847 1.7329 −1.6876 0.9823 17 1.8100 1.7847 −0.5163 0.8257 18 1.8839 1.8100 −2.0238 1.9969 19 1.9079 1.8839 −0.8482 0.4895 20 1.9550 1.9079 −1.0232 1.6651 21 2.0236 1.9550 −2.5133 1.4901

[0194] With this example, there is a synchronous structure for which the zone radii of profiles (1) and (2) are matched using the zone numbers for which n=5 S and m=3 t (1 is a natural number), and for which five continuous zone pitches of profile (1) and three continuous zone pitches of profile (2) are the same (FIGS. 8A and 8B). As a result, the composite profile for which these profiles are synthesized has seven blazes newly formed in the synchronous region (FIG. 8C). Therefore, a new repeated structure is formed at the first to seventh, eighth to fourteenth, and fifteenth to twenty-first zone units with the composite profile. The results of calculating the optical axis direction intensity distribution of the composite profile are shown in FIG. 8D.

[0195] When the addition power of profile (2) was set as 2.4 D, the position of the intermediate focal point peak is generated a little farther from the near focal point position than with examples 1 and 2. By varying the addition power of profile (2) in this way, we can see that it is possible to freely set the intermediate focal point peak to any position.

Example 4

[0196] Other than the addition power P.sub.2 of profile (2) of example 2 being made to be (2/5) of the addition power P.sub.1 of profile (1), this is an example that obtains the composite profile with the same conditions as with example 2. With this example, the addition power of profile (2) is set as P.sub.2=4×(2/5)=1.6 D. Details of the composite profile are shown in Table 4 and FIG. 9C.

TABLE-US-00004 TABLE 4 [Example 4] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 1.6D (Example 4) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.8261 0.4 1 0.5225 0 −1.5895 2.5133 2 0.7389 0.4 2 1.1683 0.4 2 0.7389 0.5225 −2.2479 0.9237 3 0.9050 0.4 3 1.4309 0.4 3 0.8261 0.7389 −1.3199 0.2653 4 1.0450 0.4 4 1.6523 0.4 4 0.9050 0.8261 −0.5791 1.1933 5 1.1683 0.4 5 1.8473 0.4 5 1.0450 0.9050 −1.6074 1.9342 6 1.2798 0.4 6 2.0236 0.4 6 1.1683 1.0450 −2.5133 0.9059 7 1.3824 0.4 7 1.2798 1.1683 −1.0673 2.5133 8 1.4778 0.4 8 1.3824 1.2798 −2.0489 1.4459 9 1.5675 0.4 9 1.4309 1.3824 −1.2776 0.4644 10 1.6523 0.4 10 1.4778 1.4309 −0.5328 1.2357 11 1.7329 0.4 11 1.5675 1.4778 −1.5506 1.9805 12 1.8100 0.4 12 1.6523 1.5675 −2.5133 0.9627 13 1.8839 0.4 13 1.7329 1.6523 −1.0393 2.5133 14 1.9550 0.4 14 1.8100 1.7329 −2.0323 1.4740 15 2.0236 0.4 15 1.8473 1.8100 −1.2692 0.4810 16 1.8839 1.8473 −0.5215 1.2441 17 1.9550 1.8839 −1.5352 1.9918 18 2.0236 1.9550 −2.5133 0.9781

[0197] With this example, there is a synchronous structure for which the zone radii of profiles (1) and (2) are matched using the zone numbers for which n=5Ω and m=2Ω (Ω is a natural number), and for which five continuous zone pitches of profile (1) and two continuous zone pitches of profile (2) are the same (FIGS. 9A and 9B). As a result, the composite profile for which these profiles are synthesized has six blazes newly formed in the synchronous region (FIG. 9C). Therefore, a new repeated structure is formed at the first to sixth, seventh to twelfth, and thirteenth to eighteenth zone units with the composite profile. The results of calculating the optical axis direction intensity distribution of the composite profile are shown in FIG. 9D.

[0198] With this example, by using 1.6 D as the addition power of profile (2), we can see that a peak is generated at the intermediate point of approximately 1.6 D with the composite profile. The intermediate focal point position is set to be shifted to the farther side than with examples 1 to 3. This intermediate focal point position correlates to the focal point position for clearly visually recognizing trash or the like that has fallen on the floor or the like for users with a lot of work such as sweeping or the like. Therefore, this is a useful item as a multi-focal ophthalmic lens or the like for users with many opportunities to engage in this kind of housework or the like.

[0199] For the intermediate region focal point position shown with this example, with the background art noted in Patent Documents 1 and 2, the focal point position close to this could only be set to either P.sub.2=4×(1/2)=2 D or P.sub.2=4×(1/3)=1.333 D, but with this example, the addition power can be set as P.sub.2=4×(2/5)=1.6 D, so it is possible to set a finer level intermediate focal point.

Example 5

[0200] Other than the addition power P.sub.2 of profile (2) of example 2 being made to be (7/11) of the addition power P.sub.1 of profile (1), this is an example that obtains the composite profile with the same conditions as with example 2. Details of the composite profile are shown in Table 5 and FIG. 10C.

TABLE-US-00005 TABLE 5 [Example 5] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 2.545D (Example 5) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6550 0.4 1 0.5225 0 −2.0049 2.5133 2 0.7389 0.4 2 0.9263 0.4 2 0.6550 0.5225 −1.5385 0.5084 3 0.9050 0.4 3 1.1345 0.4 3 0.7389 0.6550 −0.7776 0.9747 4 1.0450 0.4 4 1.3100 0.4 4 0.9050 0.7389 −2.3160 1.7357 5 1.1683 0.4 5 1.4646 0.4 5 0.9263 0.9050 −0.3823 0.1973 6 1.2798 0.4 6 1.6044 0.4 6 1.0450 0.9263 −1.4331 2.1310 7 1.3824 0.4 7 1.7329 0.4 7 1.1345 1.0450 −1.8231 1.0802 8 1.4778 0.4 8 1.1683 1.1345 −0.4851 0.6902 9 1.5675 0.4 9 1.2798 1.1683 −2.0820 2.0282 10 1.6523 0.4 10 1.3100 1.2798 −0.7382 0.4313 11 1.7329 0.4 11 1.3824 1.3100 −1.1773 1.7751 12 1.4646 1.3824 −2.1643 1.3360 13 1.4778 1.4646 −0.2383 0.3490 14 1.5675 1.4778 −1.8501 2.2750 15 1.6044 1.5675 −1.0934 0.6632 16 1.6523 1.6044 −0.9365 1.4199 17 1.7329 1.6523 −2.5133 1.5767

[0201] With this example, there is a synchronous structure for which the zone radii of profiles (1) and (2) are matched using the zone numbers for which n=11Ω and m=7Ω (Ω is a natural number), and for which eleven continuous zone pitches of profile (1) and seven continuous zone pitches of profile (2) are the same (FIGS. 10A and 10B). As a result, the composite profile for which these profiles are synthesized has seventeen blazes newly formed in the synchronous region (FIG. 10C). Therefore, a new repeated structure is formed at the first to seventeenth and eighteenth to thirty-fourth zone units with the composite profile (eighteenth to thirty-fourth items are not displayed). The results of calculating the optical axis direction intensity distribution of the composite profile are shown in FIG. 10D. With this example, the addition power of profile (2) is set as P.sub.2=4×(7/11)≈2.545 D. In the intensity distribution diagram as well, we can clearly see that a peak is generated at that point (point of approximately 2.5 D).

[0202] Also, with this example, the composite profile repetition unit is 17 zones. FIG. 10D examines the intensity distribution of the repetition unit within one region (from the first to seventeenth zone numbers), but it is possible for the focal point peak to be generated at a position correlating to the addition power for which even one repetition unit is set (composite profile first to seventeenth regions), and we can see that a plurality of repetition units is not a required condition. Also, even if the repetition unit is one, all of the zones constituting that unit are not required, and for example FIG. 10E shows the intensity distribution of the regions from the first to the fourteenth within the repetition unit, but since a peak having the same intensity ratio is formed in the same position as FIG. 10D, it is acceptable for the zone constitution of at least a portion of the repetition unit to have a diffractive structure.

[0203] The examples in example 1 to example 5 noted above all have the zone radii of profiles (1) and (2) set based on the standard setting equations of Equation 11 and Equation 12, and show the specification and image characteristics of a composite profile having a structure for which a designated number of zones including the first zone are continuous and synchronized.

[0204] For examples of composite profiles when the synchronous structure position shifts to a different zone number, we will list and describe several examples.

Example 6 (Example when the First Zone Radius is Changed to Change the Synchronous Position)

[0205] This example is an example that is the same as example 1 other than using the general setting equation noted above to change the zone pitch of profile (2). In specific terms, this shows a profile example for which the first zone radius r.sub.1′ of profile (2) with the general setting equation of Equation 7 is the same as the first zone radius r.sub.1 of profile (1), the zone pitch of profile (2) is reset, and this is overlapped with profile (1) and synthesized. Details of profiles (1) and (2) and the composite profile are respectively shown in Table 6 and FIGS. 11A, 11B, and 11C.

TABLE-US-00006 TABLE 6 [Example 6] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3D (Example 6) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.5225 0.3 1 0.5225 0 −2.1991 2.1991 2 0.7389 0.4 2 0.7981 0.3 2 0.7389 0.5225 −1.7942 2.1991 3 0.9050 0.4 3 1.0005 0.3 3 0.7981 0.7389 −0.5818 0.7190 4 1.0450 0.4 4 1.1683 0.3 4 0.9050 0.7981 −1.3095 1.3031 5 1.1683 0.4 5 1.3149 0.3 5 1.0005 0.9050 −1.4005 1.2038 6 1.2798 0.4 6 1.4467 0.3 6 1.0450 1.0005 −0.8138 0.4845 7 1.3824 0.4 7 1.5675 0.3 7 1.1683 1.0450 −2.1991 1.6995 8 1.4778 0.4 8 1.6796 0.3 8 1.2798 1.1683 −1.7481 2.1991 9 1.5675 0.4 9 1.7847 0.3 9 1.3149 1.2798 −0.5454 0.7651 10 1.6523 0.4 10 1.8839 0.3 10 1.3824 1.3149 −1.2791 1.3396 11 1.7329 0.4 11 1.4467 1.3824 −1.3798 1.2342 12 1.8100 0.4 12 1.4778 1.4467 −0.7998 0.5052 13 1.8839 0.4 13 1.5675 1.4778 −2.1991 1.7134 14 1.6523 1.5675 −1.7399 2.1991 15 1.6796 1.6523 −0.5370 0.7734 16 1.7329 1.6796 −1.2709 1.3479 17 1.7847 1.7329 −1.3734 1.2423 18 1.8100 1.7847 −0.7951 0.5115 19 1.8839 1.8100 −2.1991 1.7182

[0206] The zone numbers for which the zone radii match between profile (2) and profile (1) that have been set and changed is n=1+4Ω with profile 1 and m=1+3Ω with profile (2) (Ω is a natural number).

[0207] Comparing this example and the composite profile of example 1 (FIG. 6C), the continuous zone count for each profile that made a synchronous structure and the number of zones contained in the synchronous structure are the same as example 1 and do not change, but the position of the repeated structure with the composite profile is different from example 1, and with this example, is changed to the second to seventh and the eighth to thirteenth. Even with that difference, the repeating unit structure with the composite profile is very similar, the intensity distribution does not differ from example 1, and we can see that it is possible to form the focal point peak at a position correlating to the addition power of profiles (1) and (2). An ophthalmic lens comprising the composite profile of this example, the same as the example details noted previously, is also particularly useful as a multi-focal ophthalmic lens such as for an intraocular lens or the like, for example.

[0208] In accordance with the first zone radius variable of profile (2), it is also acceptable to adjust the phase of the first zone blaze based on Equation 26 noted below. This adjustment can be used particularly effectively to improve the diffraction efficiency when the first zone radius is made smaller or the like.

[00019] $\begin{matrix} φ_{0} = h \times π \times (\frac{P \times r_{1}^{2}}{λ} - 1) & [Equation .Math. .Math. 26] \end{matrix}$

φ.sub.0: Phase of r.sub.0 position
h: Phase constant
P: Addition power
r.sub.1: 1st zone radius

λ: Wavelength

[0209] With the examples noted hereafter, even when the first zone radius is a variable, unless otherwise noted, as described with the definition of terms in [i] described previously, the phase of the first zone is set so as to be |φ.sub.i|=|φ.sub.i-1|.

Example 7 (when the First Zone Radii of Both Profiles (1) and (2) are Varied)

[0210] Next, we will show an example of a composite profile when the first zone radius of profiles (1) and (2) are varied, the first zone radii are set so that both of them are 0.3 mm, and the zone pitch of each profile is set. The addition power for both profiles (1) and (2) are set the same as for example 1, and the phase constant is also the same. However, only the first zone of each profile has the phase adjusted based on Equation 26. The zone pitches of profiles (1) and (2) have the first zone radius set to 0.3 mm and are respectively set based on general setting equations of Equation 6 and Equation 7. The details of profiles (1) and (2) and the composite profile are shown in Table 7 and FIGS. 12A, 12B, and 12C.

TABLE-US-00007 TABLE 7 [Example 7] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3D (Example 7) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.3 0.4 1 0.3 0.3 1 0.3 0 −2.1991 −0.9045 2 0.6025 0.4 2 0.6738 0.3 2 0.6025 0.3 −1.8396 2.1991 3 0.7975 0.4 3 0.9044 0.3 3 0.6738 0.6025 −0.6048 0.6737 4 0.9534 0.4 4 1.0872 0.3 4 0.7975 0.6738 −1.3251 1.2802 5 1.0872 0.4 5 1.2434 0.3 5 0.9044 0.7975 −1.4096 1.1881 6 1.2062 0.4 6 1.3820 0.3 6 0.9534 0.9044 −0.8193 0.4754 7 1.3145 0.4 7 1.5080 0.3 7 1.0872 0.9534 −2.1991 1.6939 8 1.4146 0.4 8 1.6242 0.3 8 1.2062 1.0872 −1.7508 2.1991 9 1.5080 0.4 9 1.7326 0.3 9 1.2434 1.2062 −0.5479 0.7625 10 1.5959 0.4 10 1.8347 0.3 10 1.3145 1.2434 −1.2815 1.3370 11 1.6793 0.4 11 1.3820 1.3145 −1.3816 1.2318 12 1.7587 0.4 12 1.4146 1.3820 −0.8011 0.5034 13 1.8347 0.4 13 1.5080 1.4146 −2.1991 1.7121 14 1.5959 1.5080 −1.7407 2.1991 15 1.6242 1.5959 −0.5379 0.7725 16 1.6793 1.6242 −1.2719 1.3470 17 1.7326 1.6793 −1.3742 1.2414 18 1.7587 1.7326 −0.7957 0.5108 19 1.8347 1.7587 −2.1991 1.7176 Profile (1) Phase of 1st zone φ.sub.1 = −1.2566, φ.sub.0 = −0.4281 Profile (2) Phase of 1st zone φ.sub.1 = −0.9425, φ.sub.0 = −0.4764

[0211] The profile of this example is set so that the first zone radius is 0.3 mm, and compared to example 1 and example 6, the first zone is set further to the inside. With this example, in accordance with the variation of the first zone radius for both profiles (1) and (2), the zone pitch of the entire region is different for examples 1 and 6, but there is no change in the synchronous zone count, and there is the same repeating unit as the previous examples. For the intensity distribution of the composite profile, we can see that the peak is formed at the point corresponding to the addition power determined by profiles (1) and (2) the same as for examples 1 and 6 as shown in FIG. 12D.

[0212] The diffractive type multi-focal lens for which this first zone radius is varied and the first zone is set to be further to the center can be suitably applied to an ophthalmic lens such as a contact lens, intraocular lens or the like, and for example is effective as a multi-focal ophthalmic lens such as an intraocular lens for patients for which the pupil diameter became smaller with aging, such as an older person or the like.

[0213] With examples 6 and 7, the examples have the first zone radius of profile (1) or (2) set freely using general setting equations Equation 6 and Equation 7. The zone pitch with the first zone radius changed based on the general setting equation is different from the zone pitch set with the standard setting equation, but if the addition power is the same, the synchronous zone count is the same as with example 1 and examples 6 and 7, and it is possible to obtain a multi-focal lens that can form focal points at positions corresponding to the addition power of each profile.

Example 8 (Asynchronous Example)

[0214] In examples 6 and 7, we described examples of profiles for which the synchronous structure was maintained though the first zone radius of the structural profile was varied. This example shows an example that does not have a synchronous structure.

[0215] The addition power of profiles (1) and (2) and the zone pitch of profile (1) are the same as with example 1, and the zone pitch of profile (2) has the first zone radius set at 0.56 mm based on the general setting equation of Equation 7. The details of profiles (1) and (2) and the composite profile in this case are shown in Table 8 and FIGS. 13A and 13B.

TABLE-US-00008 TABLE 8 [Example 8] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3D (Example 8) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.56 0.3 1 0.5225 0 −2.0729 2.1991 2 0.7389 0.4 2 0.8232 0.3 2 0.56 0.5225 −0.1214 0.4404 3 0.9050 0.4 3 1.0206 0.3 3 0.7389 0.56 −1.5957 1.7636 4 1.0450 0.4 4 1.1856 0.3 4 0.8232 0.7389 −0.9608 0.9176 5 1.1683 0.4 5 1.3303 0.3 5 0.9050 0.8232 −1.0954 0.9241 6 1.2798 0.4 6 1.4607 0.3 6 1.0206 0.9050 −1.7611 1.4179 7 1.3824 0.4 7 1.5304 0.3 7 1.0450 1.0206 −0.5929 0.1239 8 1.4778 0.4 8 1.6916 0.3 8 1.1683 1.0450 −2.0021 1.9204 9 1.5675 0.4 9 1.7960 0.3 9 1.1856 1.1683 −0.0746 0.5112 10 1.6523 0.4 10 1.8946 0.3 10 1.2798 1.1856 −1.5422 1.8104 11 1.7329 0.4 11 1.3303 1.2798 −0.9216 0.9710 12 1.8100 0.4 12 1.3824 1.3303 −1.0675 0.9634 13 1.8839 0.4 13 1.4607 1.3824 −1.7475 1.4457 14 1.4778 1.4607 −0.5843 0.1375 15 1.5675 1.4778 −1.9960 1.9290 16 1.5804 1.5675 −0.0681 0.5173 17 1.6523 1.5804 −1.5323 1.8168 18 1.6916 1.6523 −0.9123 0.9810 19 1.7329 1.6916 −1.0599 0.9726 20 1.7960 1.7329 −1.7432 1.4534 21 1.8100 1.7960 −0.5813 0.1417 22 1.8839 1.8100 −1.9938 1.9320

[0216] With FIG. 13, for profiles (1) and (2) different from the examples displayed in the diagrams up to now, both profiles are displayed simultaneously in the same drawing to clarify the zone diameter positional relationship. With this example, there is no location for which the zone diameter of either profile (1) or (2) is the same, and a synchronous structure is not formed. However, with the synthesized profile, a repeated structure is formed in the first to seventh, eighth to fourteenth, and fifteenth to twenty-first zone units, and the number of zones constituting the repeated structure is seven. With the composite profile of this example, though the repeated structure and the number of zones constituting it differ from those of examples 1, 6, and 7, the intensity distribution (FIG. 13C) can be seen to have a peak generated at a position correlating to the addition power set by profiles (1) and (2) the same as with the group of examples noted above.

[0217] As can be seen from this example, a synchronous structure with common regions is not a required condition, and it is possible to obtain a diffractive multi-focal lens that forms focal points at desired positions even without each profile that is overlapped having a synchronous structure with common regions. It is possible to further expand the degree of freedom of design with examples that do not have a synchronous structure, and when using it as an ophthalmic lens, there is a great advantage when designing a multi-focal ophthalmic lens according to the demands of a wider variety of users.

Example 9 (Example of Synthesis when the Addition Power is Expressed Using an Irrational Number)

[0218] With example 8, we described the fact that there are composite profiles for which it is possible to set the desired focal points even when the zone diameters do not match. From this example as well, it is also conceivable that it is possible to generate focal points at desired positions even with a combination for which the ratio of the addition power of profiles (1) and (2) are not in an integral ratio relationship. This example 9 shows an example of a composite profile for which the addition power of profile (1) is left as is at 4 D, and the zone pitch of profile (2) is set based on the standard setting equation of Equation 12 so that the addition power of profile (2) is a multiple of 1/1(2) in relation to that of profile (1) (approximately 2.828 D). The phase constant of profile (2) was set as h=0.4. The details of each profile and the composite profile are shown in Table 9 and FIGS. 14A and 14B.

TABLE-US-00009 TABLE 9 [Example 9] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 2.828D (Example 9) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6214 0.4 1 0.5225 0 −2.1134 2.5133 2 0.7389 0.4 2 0.8787 0.4 2 0.6214 0.5225 −1.1480 0.3999 3 0.9050 0.4 3 1.0762 0.4 3 0.7389 0.6214 −1.1480 1.3652 4 1.0450 0.4 4 1.2427 0.4 4 0.8787 0.7389 −2.1159 1.3652 5 1.1683 0.4 5 1.3894 0.4 5 0.9050 0.8787 −0.3342 0.3974 6 1.2798 0.4 6 1.5220 0.4 6 1.0450 0.9050 −2.1159 2.1791 7 1.3824 0.4 7 1.6439 0.4 7 1.0762 1.0450 −0.6363 0.3974 8 1.4778 0.4 8 1.7575 0.4 8 1.1683 1.0762 −1.3905 1.8770 9 1.5675 0.4 9 1.8641 0.4 9 1.2427 1.1683 −1.6763 1.1227 10 1.6523 0.4 10 1.9649 0.4 10 1.2798 1.2427 −0.6363 0.8370 11 1.7329 0.4 11 2.0608 0.4 11 1.3824 1.2798 −2.3933 1.8770 12 1.8100 0.4 12 1.3894 1.3824 −0.1843 0.1199 13 1.8839 0.4 13 1.4778 1.3894 −1.6763 2.3290 14 1.9550 0.4 14 1.5220 1.4778 −1.2381 0.8370 15 2.0236 0.4 15 1.5675 1.5220 −0.9374 1.2751 16 1.6439 1.5675 −2.2665 1.5759 17 1.6523 1.6439 −0.1843 0.2467 18 1.7329 1.6523 −1.9700 2.3290 19 1.7575 1.7329 −0.8003 0.5433 20 1.8100 1.7575 −1.2381 1.7130 21 1.8641 1.8100 −1.8393 1.2751 22 1.8839 1.8641 −0.4940 0.6739 23 1.9550 1.8839 −2.2665 2.0193 24 1.9649 1.9550 −0.3626 0.2467 25 2.0236 1.9649 −1.5388 2.1507

[0219] Because the addition power of profile (2) was set to be an irrational number multiple, there are no locations for which the zone diameters of either of profiles (1) or (2) match, but the intensity distribution on the optical axis of the composite profile (FIG. 14C) shows an intensity distribution for which the focal point peak is generated at a point correlating to the addition power set with profiles (1) and (2).

[0220] In contrast to the examples for which the addition power was set with a rational number in the previous examples, with this example, there is no structure that is exactly synchronous because the addition power is set with an irrational number. However, as can be seen from FIG. 14A, the seventh zone radius of profile (1) and the fifth zone radius of profile (2), and the fourteenth zone radius of profile (1) and the tenth zone radius of profile (2) are close, and it is possible to regard the zone radii as almost matching. Also, from the knowledge that the desired image characteristics can be manifested even without having a synchronous structure with example 8, this example shows image characteristics that have almost no difference at all with the profile synthesized with a=5 and b=7 with Equation 8. As yet another example, for example when the addition power of profile (2) is set as a multiple of 1/√(2.5) of that of profile (1), 1/φ(2.5)=1/1.581 . . . , and it is possible to express this approximately in the form of a rational number as 5/8. In this case, characteristics are shown that have almost no difference from the image characteristics of a profile synthesized with a=5 and b=8.

[0221] With this example 9, an irrational number is used as b in Equation 8, and from the results of this example as well, a and b in Equation 8 can be understood as being able to be defined broadly as real numbers including irrational numbers. Of course, even in a case when set with an irrational number, it is possible to express this in the form of a rational number that approximates that as noted previously, so it is of course possible to also use an integer as a hierarchical requirement for a and b. Therefore, even in a case when the values of a and b are mathematically set as irrational numbers, it is possible to regard this as a rational number as an optical technical concept to understand the optical characteristics, and as long as the optical effects of the present invention are achieved, whether or not the value of a and b is a rational number or irrational number is not typically a big problem technically in terms of practical use, and such cases are included within the present invention.

[0222] Also, as can also be understood from this example 9, by setting the addition power of profile (2) with an irrational number multiple of that of profile (1), it is possible to further improve the degree of freedom for setting the intermediate focal point position.

Example 10 (Synthesis of a Profile Having a Fresnel Pitch and a Profile Having Equal-Pitch Regions in a Zone Region)

[0223] Profile (1) is the same as that of example 1 except that the phase constant is set at h=0.3, and for the zone pitch of profile (2) the first zone radius is the same as that of profile (1), and the second zone and thereafter has a zone pitch for which the zone pitches have equal pitches of 0.174 mm. The phase constant of profile (2) is set at h=0.4. Details of the composite profile of the profiles are respectively shown in Table 10 and FIGS. 15A, 15B, and 15C. Also, the intensity distribution of the first to twelfth zone regions of the composite profile are shown in FIG. 15D. We can see from the intensity distribution diagram that clear peaks are formed in the respective far, near, and intermediate regions.

TABLE-US-00010 TABLE 10 [Example 10] Profile (1) Profile (2) Addition power Equal-pitch zone Composite profile P.sub.1 = 4D included (Example 10) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.3 1 0.5225 0.4 1 0.5225 0 −2.1991 2.1991 2 0.7389 0.3 2 0.6967 0.4 2 0.6967 0.5225 −1.8311 2.1991 3 0.9050 0.3 3 0.8708 0.4 3 0.7389 0.6967 −0.2957 0.6822 4 1.0450 0.3 4 1.0450 0.4 4 0.8708 0.7389 −1.8113 1.5893 5 1.1633 0.3 5 1.2192 0.4 5 0.9050 0.8708 −0.1788 0.7019 6 1.2798 0.3 6 1.3933 0.4 6 1.0450 0.9050 −2.1991 1.7061 7 1.3824 0.3 7 1.5675 0.4 7 1.1683 1.0450 −1.4658 2.1991 8 1.4778 0.3 8 1.2192 1.1683 −1.1732 0.4192 9 1.5675 0.3 9 1.2798 1.2192 −0.5616 1.3401 10 1.3824 1.2798 −2.0414 1.3233 11 1.3933 1.3824 −0.5300 −0.1565 12 1.4778 1.3933 −0.9055 1.9833 13 1.5675 1.4778 −2.1991 0.9795

[0224] This example differs from the group of examples noted previously (examples 1 to 9), and is a composite example of when equal pitches are included in the zone pitch of one profile. The zone pitch of the second zone and thereafter of profile (2) is set as 0.174 mm, and with this example, the zone diameter is matched for the fourth and ninth zones of profile (1) and the fourth and seventh zones of profile (2). Differing from the previous examples in which the profiles having a Fresnel pitch are synthesized, zone diameters are matched synchronously by different integer values, namely, three zones from the second to fourth and five zones from the fifth to ninth of the profile (1) with three zones from the second to fourth and three zones from the fifth to seventh of the profile (2). When the number of constituent equal-pitch zones is high as with this example, it is not possible to specify the addition power defined with the Fresnel zone setting equation of Equation 1. However, as was noted in the sixth mode section of the present invention in the Means to Solve the Problems section, by interpreting that it is not possible to specify the addition power P.sub.2 with a=0 for Equation 8, this example is also a preferable example of the present invention. The essential addition power P.sub.2 of the profile for which equal-pitch zones are the main constituents has an intensity distribution like that shown in FIG. 15E with this example, for example (first to seventh zone regions of profile (2)), and though this does not give a clear +1 order diffraction peak, by the cooperative effect of mutual interference and the like of light with synthesis with other profiles, it is possible to generate a clear intermediate region peak like that shown in FIG. 15D. Therefore, even a profile that does not follow the Fresnel zone setting equation like that of this example can be an important starting profile.

[0225] With this composite profile, though there is not a regular repeated structure, there is shown an intensity distribution for which peaks are formed in the respective far, near, and intermediate regions. Thus, the composite profile comprising this combination also is useful as a multi-focal ophthalmic lens.

[0226] This kind of combination of profiles (1) and (2) is not limited only to Fresnel pitches, but can also be used with items having other pitch formats, such as an item constituted from equal pitches such as with this example, for example.

Example 11 (Synthesis of a Profile Having a Fresnel Pitch and a Profile with Two Different Equal-Pitch Zones)

[0227] The addition power of profile (1) is 4 D the same as with example 1, and with respect to the profile (2), the addition power P.sub.2 of zones from the first to third is set based on the standard setting equation expressed by Equation 12 so that P.sub.2=4×(3/4)=3 D, the zones from the fourth to sixth are equal-pitch zones whose pitch is 0.1443 mm, and the zones from the seventh to ninth are equal-pitch zones whose pitch is 0.1107 mm. The composite profile of this example is constituted by overlapping the profiles (1) and (2). For both profiles (1) and (2), the phase constant is set at h=0.4.

[0228] Profile (2) of this example has two equal-pitch zones of different pitches coexisting in the profile, and compared to the example for which there was the same equal-pitch zone with example 10, this example shows a case of being constituted with different equal-pitch zones. The details of profiles (1) and (2) and the composite profile are shown respectively in Table 11 and FIGS. 16A, 16B, and 16C.

TABLE-US-00011 TABLE 11 [Example 11] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3D (Example 11) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6033 0.4 1 0.5225 0 −2.1766 2.5133 2 0.7389 0.4 2 0.8532 0.4 2 0.6033 0.5225 −0.9387 0.3367 3 0.9050 0.4 3 1.0450 0.4 3 0.7389 0.6033 −1.3637 1.5746 4 1.0450 0.4 4 1.1893 0.4 4 0.8532 0.7389 −1.7300 1.1496 5 1.1683 0.4 5 1.3336 0.4 5 0.9050 0.8532 −0.6783 0.7833 6 1.2798 0.4 6 1.4778 0.4 6 1.0450 0.9050 −2.5133 1.8349 7 1.3824 0.4 7 1.5885 0.4 7 1.1683 1.0450 −2.1485 2.5133 8 1.4778 0.4 8 1.6993 0.4 8 1.1893 1.1683 −0.4719 0.3647 9 1.5675 0.4 9 1.8100 0.4 9 1.2798 1.1893 −1.5777 2.0414 10 1.6523 0.4 10 1.3336 1.2798 −1.3164 0.9356 11 1.7329 0.4 11 1.3824 1.3336 −0.8507 1.1969 12 1.8100 0.4 12 1.4778 1.3824 −2.5133 1.6626 13 1.5675 1.4778 −2.0350 2.5133 14 1.5885 1.5675 −0.6244 0.4782 15 1.6523 1.5885 −1.4466 1.8888 16 1.6993 1.6523 −1.4644 1.0667 17 1.7329 1.6993 −0.7640 1.0489 18 1.8100 1.7329 −2.5133 1.7492

[0229] Profile (2) of this example has two different equal-pitch zones as shown in FIG. 16B, and three continuous zone pitches of profile (2) are equal to the four continuous zone pitches of profile (1). The number of zones for the synchronous structure is not different from example 1, but the blaze shape distribution of each synchronous unit is slightly different with the composite profile. However, the optical axis direction intensity distribution of the composite profile (FIG. 16D) has a peak generated at the focal point position based on the addition power of each profile, the same as with example 1. Even when including equal pitches and overlapping profiles existing in a plurality of regions for which there are two or more different equal-pitch zones in this way, the target image characteristics can be obtained.

Example 12 (Partial Synthesis (Part 1))

[0230] With the present invention, it is also possible to use an item for which the profiles are partially overlapped and synthesized. With this example, shown is an example of an item for which profile (1) and profile (2) used with example 6 are partially overlapped and synthesized.

[0231] Specifically, with example 6, profile (1) and profile (2) had the entire regions overlapped, but with this example, from the first to third zones of the composite profile are a diffractive structure with the profile (1) left as is, and profile (1) and profile (2) are overlapped at the region outside from the third zone radius point (0.9050 mm). The details of this partial synthesis are shown in Table 12 and FIGS. 17A, 17B, and 17C.

TABLE-US-00012 TABLE 12 [Example 12] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3D (Example 12) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.5 1 0.5225 0 1 0.5225 0 −1.5708 1.5708 2 0.7389 0.5 2 0.7981 0 2 0.7389 0.5225 −1.5708 1.5708 3 0.9050 0.5 3 1.0005 0.4 3 0.9050 0.7389 −1.5708 1.5708 4 1.0450 0.4 4 1.1683 0.4 4 1.0005 0.9050 −1.7146 1.1862 5 1.1683 0.4 5 1.3149 0.4 5 1.0450 1.0005 −0.6662 0.7986 6 1.2798 0.4 6 1.4467 0.4 6 1.1683 1.0450 −2.5133 1.8471 7 1.3824 0.4 7 1.5675 0.4 7 1.2798 1.1683 −1.9120 2.5133 8 1.4778 0.4 8 1.6796 0.4 8 1.3149 1.2798 −0.8595 0.6013 9 1.5675 0.4 9 1.7847 0.4 9 1.3824 1.3149 −1.2866 1.6537 10 1.6523 0.4 10 1.8839 0.4 10 1.4467 1.3824 −1.6939 1.2267 11 1.7329 0.4 11 1.4778 1.4467 −0.6476 0.8193 12 1.8100 0.4 12 1.5675 1.4778 −2.5133 1.8657 13 1.6523 1.5675 −1.9009 2.5133 14 1.6796 1.6523 −0.8512 0.6123 15 1.7329 1.6796 −1.2757 1.6621 16 1.7847 1.7329 −1.6876 1.2376 17 1.8100 1.7847 −0.6412 0.8257

[0232] With this example, the phase constant of the blaze of the first to third zones of profile (1) is set to h=0.5, and with profile (2), the phase constant of the first and second zones is an item showing that the phase of this region is zero, and is displayed as h=0. Also, with the third zone of profile (2), the phase constant is zero until the region at which the third zone of profile (1) overlaps, and from thereafter, the phase constant is set as h=0.4. From the drawing, the composite profile has only profile (1) from the first to third zones, and has profiles (1) and (2) overlapping from the fourth and thereafter so as to be a partially synthesized profile.

[0233] FIG. 17D shows the intensity distribution of the composite profile. Even with a partially synthesized profile, a focal point peak is generated at a point correlating to the set addition power of profiles (1) and (2).

[0234] When the multi-focal lens having this kind of diffractive structure of this example 12 is used as an ophthalmic lens such as a contact lens, intraocular lens or the like, for example, in an environment for which the illuminance is high and the pupil diameter is small such as outdoors during fine weather or the like, it functions mainly as an ophthalmic lens for intensity distribution only of profile (1), in other words, a two focal point type for far and near points. On the other hand, for example in an environment for which the illuminance is somewhat low such as inside an office, at the sink, or the like, for example, the composite profile region is exposed by the pupil diameter being enlarged, so it has intensity distribution including that region, and functions as a three point type lens that also has an intermediate region point.

[0235] Therefore, with this example of partial synthesis, as described in section iii, Other Problems That The Present Invention Can Solve Optionally As Needed, in environments with high illuminance, since the depth of focus becomes deeper as the pupil becomes smaller, it is possible to see the intermediate region even with a far and near two point lens, and on the other hand, the depth of focus becomes shallow in an environment in which the illuminance is somewhat dark such as in an office or the like, and in light of the relationship of requirements for ophthalmic lenses for human eye physiology, such as that it is more necessary to reliably form a focal point in the intermediate region since the frequency of occurrence of personal computer work and the like is increasing, this can be an example of specifications for a multi-focal ophthalmic lens for which it is possible to selectively form focal points to match the user's work objective and work environment.

Example 13 (Partial Synthesis (Part 2))

[0236] With example 12, an example was shown of partial synthesis from midway in the third zone of profile (2). For this example, as a different example of partial synthesis, we will show an example of a case of synthesis after freely setting the matching point in a case when doing partial synthesis from a point for which the zone diameters of profile (1) and profile (2) match.

[0237] Specifically, with this example, the addition power and zone pitch of profile (1), and the addition power of profile (2) are the same as with example 1, and the zone pitch of profile (2) is determined based on Equation 7 which is a general setting equation such that the zone radius of profile (2) matches the sixth zone radius of profile (1). The phase constant being set as h=0.5 from the first to sixth zones of profile (1) and being set as h=0.4 from the seventh zone and thereafter, and from the second zone and thereafter of profile (2) being set to h=0.5 are all different from example 1. The phase constant of the first zone of profile (2) is displayed as h=0 as an item indicating that the phase of this region is zero.

[0238] In specific terms, the first zone radius of profile (2) is the same as the sixth zone radius of profile (1), and this zone radius is substituted for r.sub.1′ of Equation 7 for determining from the second the zone pitch of profile (2) and thereafter. The details of profile (1), profile (2) set in this way, and the composite profile of these are shown in Table 13 and FIGS. 18A, 18B, and 18C.

TABLE-US-00013 TABLE 13 [Example 13] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 4D P.sub.2 = 3D (Example 13) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.5 1 1.2738 0 1 0.5225 0 −1.5708 1.5708 2 0.7389 0.5 2 1.4149 0.5 2 0.7389 0.5225 −1.5708 1.5708 3 0.9050 0.5 3 1.5382 0.5 3 0.9050 0.7389 −1.5708 1.5708 4 1.0450 0.5 4 1.6523 0.5 4 1.0450 0.9050 −1.5708 1.5708 5 1.1683 0.5 5 1.7590 0.5 5 1.1683 1.0450 −1.5708 1.5708 6 1.2798 0.5 6 1.8596 0.5 6 1.2798 1.1683 −1.5708 1.5708 7 1.3824 0.4 7 1.9550 0.5 7 1.3824 1.2798 −2.0708 2.8274 8 1.4778 0.4 8 1.4149 1.3824 −1.1708 0.4424 9 1.5675 0.4 9 1.4778 1.4149 −1.2894 1.9708 10 1.6523 0.4 10 1.5382 1.4778 −2.0060 1.2239 11 1.7329 0.4 11 1.5675 1.5382 −0.4927 1.1356 12 1.8100 0.4 12 1.6523 1.5675 −2.8274 2.0206 13 1.8839 0.4 13 1.7329 1.6523 −2.0602 2.8274 14 1.9550 0.4 14 1.7590 1.7329 −1.1642 0.4531 15 1.8100 1.7590 −1.2785 1.9774 16 1.8596 1.8100 −2.0008 1.2348 17 1.8339 1.8596 −0.4862 1.1408 18 1.9550 1.8839 −2.8274 2.0271

[0239] With this example, the first to sixth zones of the composite profile are profile (1), and from the seventh and thereafter are a partially synthesized profile of profiles (1) and (2).

[0240] When the aperture diameter is up to the range of the sixth zone (radius approximately 1.3 mm), as shown in FIG. 18D, the profile of this example functions as a two focal point lens having peaks at two locations of far (0 D) and near (4 D) based on profile (1), and when the aperture diameter becomes larger than that range, including the contribution from the partial composite profile, a peak is also generated at the point of approximately 3 D, and it functions as a three focal point lens (FIG. 18E). Therefore, with the partial composite profile of this example, when used for an ophthalmic lens, for example, this can also have specifications as an ophthalmic lens for which it is possible to selectively form focal points to match the user's work objective and work environment.

Example 14 (Partial Synthesis (Part 3)—Item Comprising the Non-synthesized Part (Fresnel+Equal Pitches)

[0241] As profile (1), an item was used for which the third to fifth zones of profile (1) of example 1 are substituted for the three zones for which the pitch of this space is divided equally into three equal pitches (pitch of 0.143 mm).

[0242] As shown in Table 14, the phase constant of each zone of profile (1) is set to h=0.5 up to the first to fifth zones, and other than that is set to h=0.4. Meanwhile, with profile (2), the first zone radius is made to be the same as the fifth zone diameter of profile (1) (radius 1.168 mm), this zone radius is substituted for r.sub.1′ of Equation 7, the general setting equation, and the zone pitch is determined such that the addition power is 3 D. Also, the phase constant of the first zone of profile (2) is set to h=0, from the second zone and thereafter is set to h=0.4, and the phase of the first zone is zero. The details of each profile and the composite profile (partial composite profile) are shown in Table 14 and FIGS. 19A, 19B, and 19C.

TABLE-US-00014 TABLE 14 [Example 14] Profile (1) Addition power P.sub.1 = 4D Profile (2) Equal-pitch zone Addition power Composite profile partially included P.sub.2 = 3D (Example 14) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.5 1 1.1683 0 1 0.5225 0 −1.5708 1.5708 2 0.7389 0.5 2 1.3149 0.4 2 0.7389 0.5225 −1.5708 1.5708 3 0.8821 0.5 3 1.4467 0.4 3 0.8821 0.7389 −1.5708 1.5708 4 1.0252 0.5 4 1.5675 0.4 4 1.0252 0.8821 −1.5708 1.5708 5 1.1683 0.5 5 1.6796 0.4 5 1.1683 1.0252 −1.5708 1.5708 6 1.2798 0.4 6 1.7847 0.4 6 1.2798 1.1683 −1.9120 2.5133 7 1.3824 0.4 7 1.8839 0.4 7 1.3149 1.2798 −0.8595 0.6013 8 1.4778 0.4 8 1.3824 1.3149 −1.2866 1.6537 9 1.5675 0.4 9 1.4467 1.3824 −1.6939 1.2267 10 1.6523 0.4 10 1.4778 1.4467 −0.6476 0.8193 11 1.7329 0.4 11 1.5675 1.4778 −2.5133 1.8657 12 1.8100 0.4 12 1.6523 1.5675 −1.9009 2.5133 13 1.8839 0.4 13 1.6796 1.6523 −0.8512 0.6123 14 1.7329 1.6796 −1.2757 1.6621 15 1.7847 1.7329 −1.6876 1.2376 16 1.8100 1.7847 −0.6412 0.8257 17 1.8839 1.8100 −2.5133 1.8720

[0243] The substantial composite region of this example is the sixth and thereafter of profile (1) and the second and thereafter of profile (2), and this is an example for which these are partially synthesized. In the region for which the aperture diameter correlates to the first to fifth of the composite profile, the image characteristics of profile (1) are shown (FIG. 19D). Because it includes equal-pitch regions, the region of only profile (1) shows intensity distribution for which a small peak is also generated in the intermediate region. If the aperture diameter expands to a size greater than this, an item is shown for which the image characteristics also have the contribution from the composite profile synthesized, and the peak strength of the intermediate region is further strengthened (FIG. 19E).

[0244] In this way, with this example, a peak is already generated in the intermediate region in the profile (1) only region (first to fifth zones), so for example when used for an ophthalmic lens, even in an environment when the illuminance is high and the pupil diameter is small such as outdoors during fine weather or the like, it is possible to have an ophthalmic lens for which ensuring of intermediate region visual acuity is more reliable, and the intermediate visual acuity is even more greatly ensured for work such as viewing a personal computer monitor screen, for example, in environments for which the pupil is slightly dilated such as in an office, and vision is sufficiently possible in near regions as well.

[0245] Incidentally, with examples 12, 13, and 14 for which a composite profile was provided in partial regions in the lens radial direction noted above, these are examples for which the lens peripheral region is partially synthesized, but the different zone profile partial synthesis is not limited to that region, and it is also possible to have partial synthesis limited to regions near the lens center. Furthermore, it is acceptable for there to be one or a plurality of locations of composite regions at any location in the lens radial direction.

[0246] With examples 12, 13, and 14, when doing partial synthesis, Equation 7 noted above is used to set the zone position of profile (2) from any position. Equation 7 which is a general setting equation is used to freely vary the first zone radius of the starting profiles with examples 6, 7, and 8, but it is also possible to set a zone pitch that can also be used with this partial synthesis and have the part being partially synthesized regarded as the first zone radius. At this time, when the partially synthesized position is matched with the zone radius of the other profile, a synchronous structure is formed between zones of both profiles within the partially synthesized profile. Meanwhile, when partial synthesis is done from a position midway in a certain zone of the other profile, an asynchronous structure results. For the difference in synchronous and asynchronous structures with partially synthesized parts, as has already been shown with examples 6, 7, 8 and the like, there are no differences specific to those image characteristics, and multi-focal characteristics as shown with the present invention can be manifested.

[0247] Also, to match the zone radii for both profiles at the start point or end point of the partially synthesized region for profiles (1) and (2), it is possible to use Equation 16 and Equation 17 described previously to specify the zone diameter to be matched between zone profiles (1) and (2).

Example 15 (Variable Example of Addition Power of Profile (1))

[0248] With the examples up to now, we showed examples when the addition power of profile (1) was 4 D. That addition power is close to the actual addition power particularly when using as an intraocular lens among ophthalmic lenses. This example describes an example of the composite profile when the addition power of profile (1) is varied and set at 2 D. That addition power is the realistic addition power when the ophthalmic lens is a contact lens. Even if the addition power of profile (1) is varied, we will describe with the examples below that this does not change the usefulness and effect of the present invention.

[0249] The same as with example 1, with a blaze shaped phase modulation type diffractive structure, two types of profiles were synthesized, for which the addition power Pt of profile (1) is set to 2 D, and for which the addition power P.sub.2 of profile (2) is set to P.sub.2=2×(3/4)=1.5 D so that it is 3/4 of the addition power of profile (1). The phase constants of profiles (1) and (2) are respectively set at h=0.45 and h=0.35 (FIGS. 20A and 20B). The details of the composite profile obtained by synthesizing the phase functions of profiles (1) and (2) are shown respectively in Table 15 and FIG. 20C.

TABLE-US-00015 TABLE 15 [Example 15] Profile (1) Profile (2) Addition power Addition power Composite profile P.sub.1 = 2D P.sub.2 = 1.5D (Example 15) Zone Zone Zone radius radius radius (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone Outer radius Inner radius (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.7389 0.45 1 0.8532 0.35 1 0.7389 0 −2.2186 2.5133 2 1.0450 0.45 2 1.2066 0.35 2 0.8532 0.7389 −0.7418 0.6088 3 1.2798 0.45 3 1.4778 0.35 3 1.0450 0.8532 −1.5074 1.4573 4 1.4778 0.45 4 1.7065 0.35 4 1.2066 1.0450 −1.6321 1.3201 5 1.6523 0.45 5 1.9079 0.35 5 1.2798 1.2066 −0.9077 0.5670 6 1.8100 0.45 6 2.0900 0.35 6 1.4778 1.2798 −2.5133 1.9197 7 1.9550 0.45 7 1.6523 1.4778 −1.9920 2.5133 8 2.0900 0.45 8 1.7065 1.6523 −0.6574 0.8354 9 1.8100 1.7065 −1.4443 1.5417 10 1.9079 1.8100 −1.5947 1.3831 11 1.9550 1.9079 −0.8831 0.6044 12 2.0900 1.9550 −2.5133 1.9443

[0250] This example is the same as example 1 except for the addition power of profile (1) being set to 2 D (the phase constant is changed as noted in Table 15). Therefore, the structure of the composite profile is almost the same as that of example 1, and the number of zones synchronized is also the same as with example 1.

[0251] Also, the intensity distribution of the composite profile of this example is as noted in FIG. 20D, and three peaks are formed, the peak of 0 D as the focal point for far vision, the peak of the 2 D position as the focal point for near vision, and the peak of the 1.5 D position as the focal point for intermediate vision. There is a difference in the peak appearance position due to varying the addition power, but in regards to the mode of the intensity distribution, it shows the same characteristics as those of example 1.

[0252] This example is useful as a multi-focal contact lens for patients with advanced presbyopia but who still have a certain amount of their own residual power of accommodation, reading is possible with a 2 D focal point for near vision, and vision is ensured for the relatively near intermediate distance such as for personal computer work or the like using the 1.5 D focal point set for intermediate vision.

Example 16 (Example of Synthesis of Three or More Profiles (Part 1))

[0253] Next, this example 16 shows the image characteristics of the composite profile in the case of three or more starting profiles. With this example, three profiles, profiles (1), (2), and (3), are prepared as starting profiles, and an example is shown of the composite profile obtained by synthesizing their respective phase functions.

[0254] The zone diameter of profile (1) was set using the standard setting equation of Equation 11 so that the addition power is P.sub.1=4 D. With profile (2), the zone diameter was set based on the standard setting equation of Equation 12 so that the addition power is P.sub.2=P.sub.1×(2/3)≈2.666 D. Next, the addition power of profile (3) was set based on the standard setting equation of Equation 20 so that P.sub.3=P.sub.1×(1/3) 1.333 D. The phase constants of profiles (1), (2), and (3) were respectively set to 0.4, 0.3, and 0.25. The details of each profile and the composite profile are shown in Table 16 and FIGS. 21A to 21D.

TABLE-US-00016 TABLE 16 [Example 16] Profile (1) Profile (2) Profile (3) Addition power Addition power Addition power P.sub.1 = 4 D P.sub.2 = 2.666 D P.sub.3 = 1.333 D Composite profile (Example 16) Zone Zone Zone Zone radius (mm) radius radius radius Outer Inner Zone (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone radius radius Phase (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. q r.sub.q constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6399 0.3 1 0.9050 0.25 1 0.5225 0 −1.9747 2.9845 2 0.7389 0.4 2 0.9050 0.3 2 1.2798 0.25 2 0.6399 0.5225 −1.3748 0.5386 3 0.9050 0.4 3 1.1084 0.3 3 1.5675 0.25 3 0.7389 0.6399 −1.5153 0.5101 4 1.0450 0.4 4 1.2798 0.3 4 1.8100 0.25 4 0.9050 0.7389 −2.9845 0.9980 5 1.1683 0.4 5 1.4309 0.3 5 2.0236 0.25 5 1.0450 0.9050 −1.4129 2.9845 6 1.2798 0.4 6 1.5675 0.3 6 2.2168 0.25 6 1.1084 1.0450 −1.0444 1.1004 7 1.3824 0.4 7 1.6931 0.3 7 1.1683 1.1084 −1.2914 0.8406 8 1.4778 0.4 8 1.8100 0.3 8 1.2793 1.1683 −2.9845 1.2219 9 1.5675 0.4 9 1.9198 0.3 9 1.3824 1.2798 −1.3683 2.9845 10 1.6523 0.4 10 2.0288 0.3 10 1.4309 1.3824 −1.0030 1.1450 11 1.7329 0.4 11 2.1224 0.3 11 1.4778 1.4309 −1.2577 0.8819 12 1.8100 0.4 12 2.2168 0.3 12 1.5675 1.4778 −2.9845 1.2556 13 1.8839 0.4 13 1.6523 1.5675 −1.3506 2.9845 14 1.9550 0.4 14 1.6931 1.6523 −0.9856 1.1627 15 2.0236 0.4 15 1.7329 1.6931 −1.2429 0.8994 16 2.0900 0.4 16 1.8100 1.7329 −2.9845 1.2704 17 2.1548 0.4 17 1.8839 1.8100 −1.3410 2.9845 18 2.2168 0.4 18 1.9198 1.8839 −0.9760 1.1723 19 1.9550 1.9198 −1.2345 0.9090 20 2.0236 1.9550 −2.9845 1.2788 21 2.0900 2.0236 −1.3350 2.9845 22 2.1224 2.0900 −0.9699 1.1782 23 2.1543 2.1224 −1.2291 0.9151 24 2.2168 2.1543 −2.9845 1.2342

[0255] The addition power of profile (2), because it is set so as to be (2/3) of P.sub.1, the zone diameter of the third, sixth, ninth, and so on of profile (1) and the zone diameters of the second, fourth, sixth, and so on of profile (2) match. On the other hand, the addition power of profile (3) is set to be (1/3) of P.sub.1, so the zone diameters of the third, sixth, ninth, and so on of profile (1) and the zone diameters of the first, second, third, and so on of profile (3) match. Also, between profiles (2) and (3), the zone diameters of the second, fourth, sixth, and so on of profile (2) and of the first, second, third, and so on of profile (3) match.

[0256] With the composite profile, the zone positions for which all three profile zone diameters match are the fourth, eighth, twelfth, sixteenth, . . . zone positions. With these zone positions, three profile zones are synchronized, so the steps of the blaze at the zones in front of and behind these zone positions (the fourth, fifth, eighth, ninth, twelfth, thirteenth, sixteenth, seventeenth, and so on zone numbers of the composite profile) are at their maximum size, and a repeated structure appears with a synchronous structure for which the region in which all the zone diameters of the three profiles match is the periodic unit.

[0257] FIG. 21E shows the intensity distribution of that composite profile.

[0258] We can see that in addition to the peak of the 0th order diffracted light set for far vision, peaks are generated at the points corresponding to the addition power of each starting profile. Also, with the combination of phase constants set with the starting profiles of this example, we can see that the strength of each peak is almost equal.

[0259] With the profile synthesized from three profiles as noted with this example, when used as a multi-focal ophthalmic lens, one more focal point is formed in the intermediate region, and vision in the intermediate region range is further ensured. Also, in addition to use as a multi-focal ophthalmic lens, this is also useful as a lens element for general use in the optical field that needs multi-focal characteristics.

Example 17 (Example of Synthesis of Three or More Profiles (Part 2))

[0260] Profile (1) is made to be the same as with example 16, and with profile (2), the zone diameter was set based on the standard setting equation of Equation 12 so that the addition power is P.sub.2=P.sub.1×(3/4)=3 D. Next, setting was done based on the standard setting equation of Equation 20 so that the addition power of profile (3) is P.sub.3=P.sub.1×(1/2)=2 D. The phase constant of profiles (1), (2), and (3) are respectively set to 0.3, 0.35, and 0.25. A composite profile was obtained for which the phase functions of these three profiles were added. The details of the starting profiles and the composite profile are shown in Table 17 and FIGS. 22A to 22D.

TABLE-US-00017 TABLE 17 [Example 17] Profile (1) Profile (2) Profile (3) Addition power Addition power Addition power P.sub.1 = 4 D P.sub.2 = 3 D P.sub.3 = 2 D Composite profile (Example 17) Zone Zone Zone Zone radius (mm) radius radius radius Outer Inner Zone (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone radius radius Phase (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. q r.sub.q constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.3 1 0.6033 0.35 1 0.7389 0.25 1 0.5225 0 −2.0727 2.8274 2 0.7389 0.3 2 0.8532 0.35 2 1.0450 0.25 2 0.6033 0.5225 −1.3882 −0.1978 3 0.9050 0.3 3 1.0450 0.35 3 1.2798 0.25 3 0.7389 0.6033 −1.8215 0.8409 4 1.0450 0.3 4 1.2066 0.35 4 1.4778 0.25 4 0.8532 0.7389 −1.2558 1.6342 5 1.1683 0.3 5 1.3491 0.35 5 1.6528 0.25 5 0.9050 0.8532 −0.5034 0.9433 6 1.2798 0.3 6 1.4778 0.35 6 1.8100 0.25 6 1.0450 0.9050 −2.8274 1.3816 7 1.3824 0.3 7 1.5962 0.35 7 1.9550 0.25 7 1.1683 1.0450 −1.5604 2.8274 8 1.4778 0.3 8 1.7065 0.35 8 2.0900 0.25 8 1.2066 1.1583 −1.1008 0.3246 9 1.5675 0.3 9 1.8100 0.35 9 1.2798 1.2060 −1.7686 1.0935 10 1.5523 0.3 10 1.9079 0.35 10 1.3491 1.2798 −1.1935 1.6973 11 1.7329 0.3 11 2.0010 0.35 11 1.3824 1.3491 −0.4401 1.0056 12 1.5100 0.3 12 2.0900 0.35 12 1.4778 1.3824 −2.8274 1.4449 13 1.3839 0.3 13 1.5676 1.4778 −1.5297 2.8274 14 1.9550 0.3 14 1.5962 1.5075 −1.0774 0.3553 15 2.0236 0.3 15 1.6523 1.5962 −1.7462 1.1217 16 2.0900 0.3 16 1.7065 1.6523 −1.1780 1.7095 17 1.7329 1.7065 −0.4229 1.0212 18 1.8100 1.7329 −2.8274 1.4621 19 1.8839 1.8100 −1.5181 2.8274 20 1.9079 1.8839 −1.0653 0.3669 21 1.9550 1.9079 −1.7410 1.1808 22 2.0010 1.9550 −1.1709 1.7148 23 2.0236 2.0010 −0.4149 1.0282 24 2.0900 2.0236 −2.8274 1.4701

[0261] With this example the profile (1) fourth, eighth, twelfth, . . . and the profile (2) third sixth, ninth, . . . zone diameters match. Between profiles (1) and (3) the profile (1) second, fourth, sixth, eighth, . . . and the profile (3) first, second, third, fourth, . . . zone diameters match. Furthermore, between profiles (2) and (3), the profile (2) third, sixth, ninth, . . . and the profile (3) second, fourth, sixth, . . . zone diameters match.

[0262] With the profiles synthesized based on this relationship, as shown in FIG. 22D, the steps of the blaze are at their maximum at the zones in front of and behind the point where all three profile zone diameters match (sixth, seventh and twelfth, thirteenth zones, . . . continues thereafter). Also, the blaze steps are the next biggest at the zones in front of and behind the location where only profiles (1) and (3) match (third, fourth and ninth, tenth, . . . continues thereafter). With this composite profile as well, a repeated structure appears for which the region for which all the three profile zone diameters match is the periodic unit.

[0263] FIG. 22E shows the intensity distribution of this composite profile. We can see that peaks are generated at the points corresponding to the set addition power of each profile. From this intensity distribution, the multi-focal lens of this example is useful as a multi-focal ophthalmic lens for near vision such as reading or the like, but also for which visual acuity is assured for a broad range from TV viewing distance to personal computer monitor distance. It also has value with use as an optical element that similarly requires multi-focal characteristics like those of the previous examples.

[0264] For this example, we will describe hereafter the characteristics of the synchronous structure when three or more profiles are synthesized as shown in the thirteenth mode with the Means for Solving the Problems section described previously. The addition power P.sub.2 and P.sub.3 of profile (2) and profile (3) are expressed with Equation 8 and Equation 21 noted above using the addition power P, of profile (1).

[0265] When a, b, d, and e of Equation 8 and Equation 21 are integers of zero or greater, and z is the greatest common divisor of (b×e), (a×e), and (b×d), there is a synchronous structure for which continuous zone pitches are mutually the same for (b×e)/z with the first zone profile, (a×e)/z with the second zone profile, and (b x d)/z with the third zone profile. In other words, with this example, since a=3, b=4, d=1, and e=2, (b×e)=8, (a×e)=6, and (b×d)=4, the quotients when each of these is divided by 2 which is the greatest common divisor are 4, 3, and 2, and the pitch of this number of zones is the same between any of the profiles. This synchronous structure is clear from FIGS. 22A, 22B, and 22C. Incidentally, with example 16, zone pitches counts of 3, 2, and 1 are synchronized in relation to profiles (1), (2), and (3) from that relational expression. In this way, by determining the addition power of the respective zones using the relational expressions of Equation 8 and Equation 21, it is possible to form a synchronous structure for three or more profiles.

Example 18 (Example of Synthesis of Three or More Profiles (Part 3))

[0266] Other than the fact that a zone pitch was newly set based on the standard setting equation of Equation 20 with the addition power of profile (3) with example 17 noted above being set to P.sub.3=P.sub.1×(1/4)=1 D, the specifications are the same as those of example 17. The phase constants of profiles (1), (2), and (3) are 0.4, 0.2, and 0.2. The details of each profile and the composite profile are shown in Table 18 and FIGS. 23A to 23D.

TABLE-US-00018 TABLE 18 [Example 18] Profile (1) Profile (2) Profile (3) Addition power Addition power Addition power P.sub.1 = 4 D P.sub.2 = 3 D P.sub.3 = 1 D Composite profile (Example 18) Zone Zone Zone Zone radius (mm) radius radius radius Outer Inner Zone (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone radius radius Phase (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. q r.sub.q constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.6033 0.2 1 1.0450 0.2 1 0.5225 0 −1.7166 2.5133 2 0.7389 0.4 2 0.8532 0.2 2 1.4775 0.2 2 0.6033 0.5225 −0.4075 0.7967 3 0.9050 0.4 3 1.0450 0.2 3 1.8100 0.2 3 0.7389 0.6033 −1.5704 0.8491 4 1.0450 0.4 4 1.2066 0.2 4 2.0900 0.2 4 0.8532 0.7389 −1.4994 0.9429 5 1.1683 0.4 5 1.3491 0.2 5 0.9050 0.8532 −1.4275 −0.2427 6 1.2798 0.4 6 1.4778 0.2 6 1.0450 0.9050 −2.5133 1.0858 7 1.3824 0.4 7 1.5962 0.2 7 1.1683 1.0450 −1.3169 2.5133 8 1.4778 0.4 8 1.7065 0.2 8 1.2066 1.1683 −0.0763 1.1964 9 1.5675 0.4 9 1.8100 0.2 9 1.2798 1.2056 −1.3276 1.1804 10 1.6523 0.4 10 1.9079 0.2 10 1.3491 1.2798 −1.3229 1.1858 11 1.7329 0.4 11 2.0010 0.2 11 1.3524 1.3491 −1.3047 −0.0563 12 1.8100 0.4 12 2.0900 0.2 12 1.4778 1.3624 −2.5133 1.2686 13 1.8839 0.4 13 1.5675 1.4778 −1.2908 2.5133 14 1.9550 0.4 14 1.5962 1.5675 −0.0440 1.2227 15 2.0236 0.4 15 1.6523 1.5962 −1.2988 1.2127 16 2.0900 0.4 16 1.7065 1.6523 −1.2971 1.2145 17 1.7329 1.7065 −1.2863 −0.0404 18 1.8100 1.7329 −2.5133 1.2270 19 1.8839 1.8100 −1.2803 2.5133 20 1.9079 1.8839 −0.0309 1.2330 21 1.9550 1.9079 −1.2866 1.2257 22 2.0010 1.9550 −1.2868 1.2266 23 2.0236 2.0010 −1.2581 −0.0291 24 2.0900 2.0256 −2.5133 1.2351

[0267] The same as the group of examples noted above (examples 16 and 17), this example also has the same synchronous structure shown in FIG. 23D. The intensity distribution of the composite profile is shown in FIG. 23E. We can see that a peak is generated at the points correlating to the set addition power of each profile.

Example 19 (Example of Synthesis of Three or More Profiles (Part 4))

[0268] Profile (1) is the same as with the group of examples noted above (examples 16 to 18), and the respective zone pitches are set based on the standard setting equations Equation 12 and Equation 20 such that the addition power of profile (2) is P.sub.2=P.sub.1×(4/5)=3.2 D, and the addition power of each profile (3) is P.sub.3=P.sub.1×(5)=1.6 D. The phase constants of profiles (1), (2), and (3) are respectively set to 0.4, 0.25, and 0.3. The details of each profile and the composite profile are shown in Table 19 and FIGS. 24A to 24D. Also, the intensity distribution is shown in FIG. 24E.

TABLE-US-00019 TABLE 19 [Example 19] Profile (1) Profile (2) Profile (3) Addition power Addition power Addition power P.sub.1 = 4 D P.sub.2 = 3.2 D P.sub.3 = 1.6 D Composite profile (Example 19) Zone Zone Zone Zone radius (mm) radius radius radius Outer Inner Zone (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone radius radius Phase (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. q r.sub.q constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.5842 0.25 1 0.8261 0.3 1 0.5225 0 −2.1259 2.9845 2 0.7389 0.4 2 0.8261 0.25 2 1.1863 0.3 2 0.6842 0.5225 −0.6353 0.3874 3 0.9050 0.4 3 1.0118 0.25 3 1.4309 0.3 3 0.7389 0.5842 −2.2193 0.9355 4 1.0450 0.4 4 1.1683 0.25 4 1.6528 0.3 4 0.8261 0.7389 −1.7912 0.2940 5 1.1683 0.4 5 1.3062 0.25 5 1.8478 0.3 5 0.9050 0.8261 −0.6302 1.6646 6 1.2798 0.4 6 1.4309 0.25 6 2.0238 0.3 6 1.0118 0.9050 −1.6266 1.8831 7 1.3524 0.4 7 1.5456 0.25 7 1.0460 1.0113 −1.0073 0.0442 8 1.4778 0.4 8 1.6623 0.25 8 1.1683 1.0450 −2.9845 1.4460 9 1.5875 0.4 9 1.7525 0.25 9 1.2798 1.1683 −1.5995 2.9845 10 1.6523 0.4 10 1.8473 0.25 10 1.3062 1.2798 −0.2231 0.9135 11 1.7329 0.4 11 1.9375 0.25 11 1.3824 1.3062 −2.0249 1.3477 12 1.8100 0.4 12 2.0236 0.25 12 1.4309 1.3824 −1.7488 0.4884 13 1.8839 0.4 13 1.4778 1.4309 −0.5713 1.7069 14 1.9550 0.4 14 1.5456 1.4778 −1.4612 1.9420 15 2.0236 0.4 15 1.5675 1.5456 −1.0144 0.1099 16 1.6523 1.5675 −2.9846 1.4985 17 1.7329 1.8523 −1.5721 2.9845 18 1.7525 1.7329 −0.1937 0.9411 19 1.8190 1.7525 −2.0053 1.3771 20 1.8473 1.8100 −1.7404 0.5079 21 1.3839 1.8473 −0.5572 1.7153 22 1.9375 1.8839 −1.4438 1.9561 23 1.9550 1.9376 −0.9998 0.1270 24 2.0236 1.9550 −2.9845 1.5134

[0269] With the composite profile of this example as well, we can see that peaks are generated at points correlating to the set addition power of each respective profile. Also, with the phase constants set with this example, the near and two intermediate region peak strengths are almost equal. By having that intensity distribution, for example with an ophthalmic lens, this is an item that achieves balance of vision from near to a broad intermediate region.

Example 20 (Example of Synthesis of Three or More Profiles (Part 5) when the Rational Number Denominator Differs)

[0270] Profile (1) is the same as with the group of examples noted above (examples 16 to 19), and the zone diameters are set based on the standard setting equations of Equation 12 and Equation 20 such that the addition power of profile (2) is P.sub.2=P.sub.1×(3/4)=3 D, and the addition power of profile (3) is P.sub.3=P.sub.1×(1/3)≈1.333 D. The phase constants of profiles (1), (2), and (3) are respectively 0.3, 0.4, and 0.3. The details of each profile and the composite profile are shown in Table 20 and FIGS. 25A to 25D. Also, the intensity distribution is shown in FIG. 25E.

TABLE-US-00020 TABLE 20 [Example 20] Profile (1) Profile (2) Profile (3) Addition power Addition power Addition power P.sub.1 = 4 D P.sub.2 = 3 D P.sub.3 = 1.333 D Composite profile (Example 20) Zone Zone Zone Zone radius (mm) radius radius radius Outer Inner Zone (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone radius radius Phase (radians) No. n r.sub.n constant h No. m r.sub.m constant h No. q r.sub.q constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.3 1 0.8033 0.4 1 0.9030 0.3 1 0.5225 0 −2.0082 8.1416 2 0.7389 0.3 2 0.8532 0.4 2 1.2793 0.3 2 0.6033 0.5225 −1.3323 −0.1232 3 0.9050 0.3 3 1.0450 0.4 3 1.5875 0.3 3 0.7389 0.8033 −1.8461 1.1810 4 1.0450 0.3 4 1.2066 0.4 4 1.8100 0.3 4 0.8532 0.7389 −2.4463 0.2389 5 1.1883 0.3 5 1.3491 0.4 5 2.0236 0.3 5 0.9050 0.8532 −1.8067 0.0670 6 1.2798 0.3 6 1.4778 0.4 6 2.2168 0.3 6 1.0450 0.9050 −1.9606 2.4632 7 1.3824 0.3 7 1.5962 0.4 7 2.3944 0.3 7 1.1683 1.0450 −1.9852 2.4376 8 1.4778 0.3 8 1.7065 0.4 8 1.2066 1.1683 −1.5383 −0.1002 9 1.5675 0.3 9 1.8100 0.4 9 1.2798 1.2066 −1.9199 0.9770 10 1.6523 0.3 10 1.9070 0.4 10 1.3491 1.2798 −1.0979 1.8500 11 1.7329 0.3 11 2.0010 0.4 11 1.3824 1.8491 −0.0656 1.4154 12 1.8100 0.3 12 2.0900 0.4 12 1.4778 1.8824 −2.5541 1.8193 13 1.8839 0.3 13 2.1759 0.4 13 1.5675 1.4778 −2.5311 1.8441 14 1.9550 0.3 14 2.2574 0.4 14 1.5962 1.5675 −0.2347 1.2388 15 2.0236 0.3 15 2.3367 0.4 15 1.6523 1.5962 −0.6801 2.2786 16 2.0900 0.3 16 1.7085 1.6523 −1.7185 1.2049 17 2.1543 0.3 17 1.7329 1.7065 −0.6717 0.7947 18 2.2168 0.3 18 1.8100 1.7329 −3.1416 1.3132 19 2.2775 0.3 19 1.8839 1.8100 −1.2927 3.1416 20 2.3387 0.3 20 1.9079 1.8839 −0.8716 0.5923 21 1.9550 1.9079 −1.2945 1.6416 22 2.0010 1.9550 −2.3210 0.5904 23 2.0236 2.0010 −1.2670 0.1923 24 2.0900 2.0236 −1.9043 2.5029 25 2.1543 2.0900 −1.9131 2.4939 26 2.1753 2.1543 −1.4868 −0.0281 27 2.2168 2.1753 −1.8968 1.0267 28 2.2574 2.2168 −1.0657 1.8733 29 2.2775 2.2574 −0.0245 1.4476 30 2.3367 2.2775 −2.5292 1.8604

[0271] This example is an example for which with setting of the addition power of profiles (2) and (3), the number of denominators is made to be different when displaying with rational numbers. This is (3/4) with profile (2), and (1/3) with profile (3). Even in a case when the rational number denominators are made to be different as with this example, it is possible to know the details of the synchronous structure using the numeric expression for determining the addition power of each profile.

[0272] Specifically, with this example, a=3, b=4, d=1, and e=3 with Equation 8 and Equation 21, and from the relational expression of the synchronous structure described with example 17, (b×e)/z=12, (a×e)/z=9, and (b×d)/z=4 respectively in relation to profiles (1), (2), and (3). The synchronous structure has continuous zone pitches with these numerical values. This synchronous structure is clear from FIGS. 25A, 25B, and 25C. With synthesis of profiles with different denominators in this way as well, peaks are generated at points correlating to the set addition power of each profile (FIG. 25E).

Example 21 (Example of Synthesis of Three or More Profiles (Part 6) Example 1 of Synthesizing Four Profiles)

[0273] Next, we will describe this synthesis example with four profiles. Profile (1) is the same as with the group of examples noted above (examples 16 to 20). Setting was done with the standard setting equations Equation 12 and Equation 20 such that with profile (2), the addition power is P.sub.2=P.sub.1×(3/4)=3 D, and with profile (3), the addition power is P.sub.3=P.sub.1×(2/4)=2 D. Also, with profile (4), the zone diameter is set with P.sub.3=P.sub.4 substituted in the standard setting equation of Equation 20 so that the addition power is P.sub.4=P.sub.1×(1/4)=1 D. With the examples hereafter, when synthesizing four or more profiles, the setting of the zone pitch of the fourth, fifth and so on profiles is done substituting with the standard setting equation of Equation 20 which is the setting equation for the third zone profile, or with the general setting equation of Equation 18. The phase constants for profiles (1), (2), (3), and (4) are respectively set to 0.3, 0.3, 0.15, and 0.15. The composite profile is obtained by synthesizing the phase function of these four profiles. The details of profiles (1) to (4) and the composite profile are shown in Table 21 and FIGS. 26A to 26E.

TABLE-US-00021 TABLE 21 [Example 21] Profile (1) Profile (2) Profile (3) Profile (4) Addition Addition Addition Addition Composite profile (Example 21) power P.sub.1 = 4D power P.sub.1 = 3D power P.sub.1 = 2D power P.sub.1 = 1D Zone Zone Zone Zone Zone Phase radius (mm) radius Phase radius Phase radius Phase radius con- Outer Inner Phase Zone (mm) constant Zone (mm) constant Zone (mm) constant Zone (mm) stant Zone radius radius (radians) No. n r.sub.n h No. m r.sub.n h No. q r.sub.n h No. u r.sub.n h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.3 1 0.6033 0.3 1 0.7389 0.15 1 1.0450 0.15 1 0.5225 0 −1.8376 2.8374 2 0.7369 0.3 2 0.8532 0.3 2 1.0450 0.15 2 1.4778 0.15 2 0.6033 0.5225 −1.0752 0.0573 3 0.9053 0.3 3 1.0450 0.3 3 1.2798 0.15 3 1.8100 0.15 3 0.7389 0.6053 −1.6892 0.8098 4 1.0453 0.3 4 1.2066 0.3 4 1.4778 0.15 4 2.0900 0.15 4 0.8532 0.7389 −1.4765 1.1363 5 1.1683 0.3 5 1.3491 0.3 5 1.6523 0.15 5 0.9050 0.6532 −0.8939 0.4064 6 1.2798 0.3 6 1.4778 0.3 6 1.8100 0.15 6 1.0450 0.9050 −2.5274 0.9911 7 1.3684 0.3 7 1.5962 0.3 7 1.9550 0.15 7 1.1683 1.0450 −1.2693 2.8274 8 1.4778 0.3 8 1.7065 0.3 8 2.0900 0.15 8 1.3056 1.1683 −0.7059 0.6257 9 1.5675 0.3 9 1.8100 0.3 9 1.2798 1.2066 −1.4801 1.1790 10 1.6523 0.3 10 1.9079 0.3 10 1.3891 1.2798 −1.3217 1.3473 11 1.7329 0.3 11 2.0010 0.3 11 1.3824 1.3491 −0.7680 0.5632 12 1.8100 0.3 12 2.0900 0.3 12 1.4778 1.3824 −2.8274 1.1169 13 1.6839 0.3 13 1.8675 1.4778 −1.2233 2.8274 14 1.9550 0.3 14 1.5962 1.5573 −0.6727 0.6616 15 2.0236 0.3 15 1.6523 1.5962 −1.4532 1.2122 16 2.0903 0.3 16 1.7065 1.6523 −1.2956 1.3743 17 1.7329 1.7065 −0.7451 0.5883 18 1.8100 1.7329 −2.8274 1.1398 19 1.8839 1.8100 −1.3095 2.8274 20 1.9079 1.6839 −0.6595 0.6755 21 1.9550 1.9079 −1.4418 1.2255 22 2.0010 1.9550 −1.2856 1.3856 23 2.0236 2.0010 −0.7347 0.5994 24 2.0900 2.0236 −2.8274 1.1502

[0274] Even when the number of starting profiles is increased to four, the blaze step becomes the maximum size at the zones in front of and behind the point for which all the zone diameters of each profile match (sixth, seventh, twelfth, thirteenth, eighteenth, nineteenth, and so on of the composite profile). A repeated structure appears that has as the periodic unit the region for which all the zone diameters of the four profiles match. The intensity distribution of that composite profile is shown in FIG. 26F. We can see that peaks are generated at the points correlating to the set addition power of each profile. Also, the peak intensity of the three intermediate regions with combining of the phase constants of this example are almost equal. The profiles that give this intensity distribution generate further many focal points, so this is useful as an ophthalmic lens that can ensure vision for a broad region.

[0275] Also, as with this example, by further increasing the number of zone profiles constituting the composite profile by mutually overlapping them compared to the examples noted previously, the number of focal points also increases accordingly, so the value of use increases as various types of optical elements for other optical fields in addition to as an ophthalmic lens.

Example 22 (Example of Synthesis of Three or More Profiles (Part 7) Example 2 of Synthesizing Four Profiles)

[0276] Profile (1) is the same as with the group of examples noted above (examples 16 to 21). The zone pitches of the respective profiles were set using the standard setting equations of Equation 12 and Equation 20 such that with profile (2), the addition power is P.sub.2=P.sub.1×(4/5)=3.2 D, with profile (3), the addition power is P.sub.3=P.sub.1×(2/5)=1.6 D, and with profile (4), the addition power is P.sub.4=P.sub.1×(1/5)=0.8 D. The phase constants of profiles (1), (2), (3), and (4) are set respectively at 0.4, 0.2, 0.2, and 0.2.

[0277] The composite profile was obtained by adding the phase functions of the four profiles. The details of profiles (1) to (4) and the composite profile are shown in Table 22 and FIGS. 27A to 27E.

TABLE-US-00022 TABLE 22 [Example 22] Profile (1) Profile (2) Profile (3) Profile (4) Addition Addition Addition Addition Composite profile (Example 22) power P.sub.1 = 4D power P.sub.1 = 3.2D power P.sub.1 = 1.6D power P.sub.1 = 0.8D Zone Zone Zone Zone Zone radius (mm) radius Phase Zone radius Phase radius Phase radius Phase Outer Inner Phase Zone (mm) constant No. (mm) constant Zone (mm) constant Zone (mm) constant Zone radius radius (radians) No. n r.sub.n h m r.sub.n h No. q r.sub.n h No. u r.sub.n h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 0.5225 0.4 1 0.5842 0.2 1 0.8261 0.2 1 1.1683 0.2 1 0.5225 0 −1.6524 3.1415 2 0.7389 0.4 2 0.8861 0.2 2 1.1683 0.2 2 1.6523 0.2 2 0.5842 0.5225 −0.3481 0.6509 3 0.9050 0.4 3 1.0118 0.2 3 1.4309 0.2 3 2.0236 0.2 3 0.6745 0.5842 −0.8449 0.9085 4 1.0450 0.4 4 1.1683 0.2 4 1.6523 0.2 4 0.7889 0.6745 −2.0941 −0.8449 5 1.1683 0.4 5 1.3062 0.2 5 1.8473 0.2 5 0.8261 0.7389 −1.5802 0.4192 6 1.2798 0.4 6 1.4389 0.2 6 2.0236 0.2 6 0.9053 0.8261 −1.1683 0.9331 7 1.3824 0.4 7 1.5456 0.2 7 0.9539 0.9350 −0.0976 1.8450 8 1.4778 0.4 8 1.6523 0.2 8 1.0118 0.9539 −1.8027 −0.0976 9 1.5675 0.4 9 1.7585 0.2 9 1.0450 1.0118 −1.5557 −0.5461 10 1.5523 0.4 10 1.8473 0.2 10 1.1683 1.0450 −3.1415 0.9475 11 1.7329 0.4 11 1.9375 0.2 11 1.2796 1.1683 −1.2111 0.1416 12 1.8100 0.4 12 2.0236 0.2 12 1.3088 1.2496 0.2201 1.3022 13 1.8839 0.4 13 1.3491 1.3082 −0.3213 1.4767 14 1.9550 0.4 14 1.3824 1.3491 −1.7195 −0.3213 15 2.0236 0.4 15 1.4309 1.3824 −1.3311 0.7937 16 1.4778 1.4309 −0.9561 1.1622 17 1.5083 1.4778 0.1166 1.5572 18 1.5455 1.5063 −1.6441 0.1166 19 1.5675 1.5456 −1.4416 −0.3874 20 1.6523 1.5675 −3.1416 1.0716 21 1.7529 1.6523 −1.1754 3.1416 22 1.7525 1.7529 0.2613 1.3379 23 1.7847 1.7525 −0.2733 1.5179 24 1.8100 1.7847 −1.6834 −0.2733 25 1.8473 1.8100 −1.3009 0.8899 26 1.8839 1.8473 −0.9361 1.2124 27 1.9079 1.8839 0.1523 1.5872 28 1.9375 1.9079 −1.6164 0.1523 29 1.9550 1.9375 −1.4195 −0.3597 30 2.0336 1.9550 −3.1416 1.0938

[0278] This example is an example when the rational number denominator of each profile is 5, and a repeated structure appears for which the periodic unit is the region for which all the zone diameters of the four profiles match. The intensity distribution of the composite profile (FIG. 27F) has peaks generated at points correlating to the set addition power of each profile. This example has four zone profiles synthesized, the same as with example 21, but the addition power of each zone profile is varied and set, and we can see that each focal point peak is generated at different positions from those of example 21. In this way, the setting of each peak position can be performed freely even with the number of starting profiles increased.

Example 23 (Example of Synthesis of Three or More Profiles (Part 8) Example of Synthesizing Five Profiles)

[0279] This example is an example when five profiles are synthesized. Profile (1) is the same as with the group of examples noted above (examples 16 to 22). The zone diameters of the respective profiles were set using the standard setting equations of Equation 12 and Equation 20 such that with profile (2), the addition power is P.sub.2=P.sub.1×(4/5)=3.2 D, with profile (3), the addition power is P.sub.3=P.sub.1×(3/5)=2.4 D, with profile (4), the addition power is P.sub.4=P.sub.1×(2/5)=1.6 D, and with profile (5), the addition power is P.sub.5=P.sub.1×(1/5)=0.8 D. The phase constants of profiles (1), (2), (3), (4), and (5) are respectively set at 0.4, 0.25, 0.25, 0.1, and 0.1.

[0280] The composite profile was obtained by synthesizing the phase functions of those five profiles. The details of profiles (1) to (5) and the composite profile are shown in Table 23 and FIGS. 28A to 28F.

TABLE-US-00023 TABLE 23 [Example 23] Profile (1) Profile (2) Profile (3) Profile (4) Addition Addition Addition Addition power P.sub.1 = 4D power P.sub.1 = 3.2D power P.sub.1 = 2.4D power P.sub.1 = 1.6D Zone Zone Zone Zone radius radius radius radius Zone (mm) Phase Zone (mm) Phase Zone (mm) Phase Zone (mm) Phase No. n r.sub.n constant h No. m r.sub.n constant h No. q r.sub.n constant h No. q r.sub.n constant h 1 0.5225 0.4 1 0.5842 0.25 1 0.8745 0.25 1 0.8961 0.1 2 0.7389 0.4 2 0.8261 0.25 2 0.9639 0.25 2 1.1683 0.1 3 0.9050 0.4 3 1.0118 0.25 3 1.1663 0.25 3 1.4309 0.1 4 1.0450 0.4 4 1.1683 0.25 4 1.3491 0.25 4 1.6523 0.1 5 1.1683 0.4 5 1.3062 0.25 5 1.5083 0.25 5 1.8473 0.1 6 1.2798 0.4 6 1.4309 0.25 6 1.6523 0.25 6 2.0236 0.1 7 1.3824 0.4 7 1.5456 0.25 7 1.7847 0.25 8 1.4778 0.4 8 1.6523 0.25 8 1.9079 0.25 9 1.5675 0.4 9 1.7525 0.25 9 2.0236 0.25 10 1.6523 0.4 10 1.8473 0.25 11 1.7329 0.4 11 1.9375 0.25 12 1.8100 0.4 12 2.0236 0.25 13 1.8839 0.4 14 1.9550 0.4 15 2.0236 0.4 Profile (5) Addition power P.sub.1 = 0.8D Composite profile (Example 23) Zone radius Zone radius (mm) Zone (mm) Phase Zone Outer radius Inner radius Phase (radians) No. q r.sub.n constant h No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ 1 1.1683 0.1 1 0.5225 0 −2.3576 3.4558 2 1.6523 0.1 2 0.5842 0.5225 −0.9500 0.1557 3 2.0236 0.1 3 0.6745 0.5842 −1.3431 0.6306 4 0.7399 0.6745 −1.3854 0.2277 5 0.8261 0.7389 −1.3590 1.1288 6 0.9050 0.8261 −1.6517 0.5392 7 0.9829 0.9050 −0.8228 0.9616 8 1.0118 0.9539 −1.3417 0.7480 9 1.0450 1.0118 −1.0214 0.2391 10 1.1683 1.0450 −3.4558 1.4918 11 1.3798 1.1683 −1.7085 3.4558 12 1.3062 1.2798 −0.4694 0.8048 13 1.3491 1.3062 −1.0187 1.1014 14 1.3824 1.3491 −1.1358 0.5521 15 1.4309 1.3824 −1.1691 1.3775 16 1.4778 1.4309 −1.5057 1.0300 17 1.5083 1.4778 −0.6910 1.0076 18 1.5456 1.5083 −1.2353 0.6798 19 1.5875 1.5456 −0.9318 0.3365 20 1.6523 1.5675 −3.4558 1.5815 21 1.7829 1.6523 −1.6746 3.4558 22 1.7525 1.7329 −0.4354 0.8387 23 1.7847 1.7525 −0.9880 1.1554 24 1.8100 1.7847 −1.1975 0.5843 25 1.8173 1.8100 −1.1411 1.4068 26 1.8839 1.8473 −1.4890 1.0581 27 1.9079 1.8839 −0.6670 1.0313 28 1.9375 1.9079 −1.2140 0.9037 29 1.9650 1.9375 −0.9127 0.3688 30 2.0236 1.9550 −3.4558 1.6006

[0281] The blaze steps are at maximum size at the points for which the zone diameters of each profile all match, even when the number of starting profiles is increased to five (tenth, eleventh, twentieth, twenty-first, and so on of the composite profile). Also, a repeated structure appears for which the period unit is the region for which the zone diameters of the five profiles all match. The intensity distribution of that composite profile is shown in FIG. 28G

[0282] From the intensity distribution diagram of this example, we can see that peaks are generated at points correlating to the set addition power of each profile. Therefore, an item having this composite profile, equipped with a plurality of focal point positions, the same as example 22 noted above and the like, can have the plurality of required focal points set efficiently and with good precision, and can also be used as another optical element, not just as an ophthalmic lens.

[0283] Next, we will describe the specifications of a multi-focal lens for which the adjustment method of the intensity distribution on the optical axis and the strength ratio of the focal point peaks of the diffractive multi-focal lens of the present invention are varied. Specifically, as the method of varying the peak strength ratio of the diffractive multi-focal lens of the present invention, we will describe a method of varying the phase constants of each starting profile based on the examples hereafter.

Example 24 (Example of Method for Controlling Intensity Distribution with the Phase Constant of the Starting Profiles Varied)

[0284] The composite profile was obtained by varying the phase constants of profiles (1) and (2) which are the starting profiles in order to vary the strength ratio of the near region peak (4 D) and the intermediate region peak (3 D) of the composite profile of example 6. As shown in Table 24, when the phase constants are varied, the intensity distributions are respectively shown in FIGS. 29A, 29B, 29C, and 29D. FIG. 29A is the same as the item in FIG. 11D of example 6. With example 6, the peak intensity of the intermediate region is set low.

[0285] The intensity distribution of the composite profile when the phase constants of profiles (1) and (2) of example 6 are varied as 0.3 and 0.4 respectively is shown in FIG. 29B. In this case, the peak strength of the intermediate region is greater than the peak strength of the near region. Items with this profile structure have specifications for an ophthalmic lens for the many users who work with personal computers.

[0286] When the phase constants are varied at 0.35 and 0.35, the intensity distribution is as shown in FIG. 29C. The peak strength of near and intermediate are approximately equal. In this case, this is one lens specification for which the visions for near work and intermediate work are approximately equal.

[0287] Furthermore, when the phase constants are varied at 0.45 and 0.4, the peak strengths for far, intermediate and near are approximately equal. In this case, this is a lens specification for which balance is achieved so that the respective visions for the far, near, and intermediate regions are approximately equal. It is possible to vary freely the strength of each peak by varying the phase constants of the starting profiles in this way.

TABLE-US-00024 TABLE 24 [Example 24] Combination of phase constant of starting profiles Profile (1) Profile (2) Note Phase 0.4 0.3 FIG. 28A (Example 6) constant 0.3 0.4 FIG. 28B (h) 0.35 0.35 FIG. 28C 0.45 0.4 FIG. 28D

[0288] Furthermore, the phase constants can also be constant for the entire zone region of the starting profiles, or can be partially different. For example, it is possible to have the peak intensity of the intermediate focal point for when the aperture diameter is small be low, and to have the peak intensity of the intermediate focal point be high for when the aperture diameter is large by varying the phase constants of the starting profiles among the different regions. The method for controlling the intensity distribution when varying the phase constants of the starting profiles among the different regions and the lens specification obtained by this are described based on example 25.

Example 25 (Example of Varying the Phase Constants of the Starting Profile)

[0289] A composite profile was obtained with the phase constants of profiles (1) and (2) constituting from the first to seventh zones of the composite profile of example 6 respectively set at 0.45 and 0.15, and with the phase constants of profiles (1) and (2) constituting from the eighth to nineteenth zones respectively set at 0.4 and 0.5.

[0290] The details of the composite profile are shown in Table 25 and FIG. 30A. In the drawing, the region noted as aperture diameter A is the region for which the phase constants of profiles (1) and (2) are set to 0.45 and 0.15, and the aperture diameter B shows the overall region including the region for which the phase constants of profiles (1) and (2) are set as 0.4 and 0.5. The intensity distribution for the zones from the first to seventh, and up to the nineteenth of the profiles are respectively shown in FIGS. 30B and 30C.

[0291] With the aperture diameter A region, the intensity distribution has the peak intensity of the intermediate region set low. This region corresponds to the pupil diameter in an environment with high illuminance such as outdoors in fine weather, and in this environment, there are cases when it is possible to not have the peak strength of the intermediate region be that high, with the setting specifications made as necessary.

[0292] In the aperture diameter B region, an intermediate focal point peak is clearly formed. In other words, when the pupil dilates when the illuminance decreases, this is a lens specification that will ensure clear intermediate visual acuity. By partially varying the phase constant of the starting profiles in this way as well, it is possible to have specifications of an ophthalmic lens for giving suitable intensity distribution in accordance with the environment.

TABLE-US-00025 TABLE 25 [Example 25] Composite profile Zone radius Profile Profile (mm) Phase (1) (2) Zone Outer radius Inner radius (radians) Phase Phase No. i r.sub.i r.sub.i−1 φ.sub.i′ φ.sub.i−1′ constant constant 1 0.5225 0 −1.8850 1.8850 0.45 0.15 2 0.7389 0.5225 −1.6825 1.8850 3 0.7981 0.7389 −0.0655 1.1449 4 0.9050 0.7981 −1.4401 0.8770 5 1.0005 0.9050 −0.9865 1.3873 6 1.0450 1.0005 −1.1923 −0.0440 7 1.1683 1.0450 −1.8850 1.6351 8 1.2798 1.1683 −2.0758 2.8274 0.4 0.5 9 1.3149 1.2798 −1.1737 0.4375 10 1.3824 1.3149 −1.2941 1.9679 11 1.4467 1.3824 −2.0081 1.2192 12 1.4778 1.4467 −0.4953 1.1335 13 1.5675 1.4778 −2.8274 2.0180 14 1.6523 1.5675 −2.0620 2.8274 15 1.6796 1.6523 −1.1653 0.1413 16 1.7329 1.6796 −1.2805 1.9763 17 1.7847 1.7329 −2.0017 1.2328 18 1.8100 1.7847 −0.4874 1.1399 19 1.8839 1.8100 −2.8274 2.0259

[0293] As can be seen from examples 24 and 25 noted above, by varying the phase constant of the starting profiles, it is possible to control the peak intensity of each region as desired. The value of the phase constant of the starting profile is not necessarily set in a specific range when obtaining the target intensity distribution, but in fact it is possible to selectively set an item that will give a suitably desirable combination with the phase constants of other starting profiles or the like. In addition, it is also possible to vary the phase shift with Equation 22 as another method for varying the phase of the starting profile.

[0294] 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.

[0295] 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.

[0296] Also, for the lens for which the present invention can be applied as well, this is not limited to being an ophthalmic lens, and it can be applied to a multi-focal optic lens or the like for an electrical device, a mechanical device or the like in addition to for a generally optical device. 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, an artificial cornea or the like for correcting vision embedded substantially within the cornea. 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.

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

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