Multifocal lens with a diffractive optical power region

• US 9,411,172 B2
• Filed: 10/22/2012
• Issued: 08/09/2016
• Est. Priority Date: 07/03/2007
• Status: Active Grant

• Current Assignee: Carl Zeiss Vision International GMBH (Carl-Zeiss-Stiftung)
• Original Assignee: Mitsui Chemicals Incorporated (Mitsui Chemicals)
• Inventors: Haddock, Joshua, Kokonaski, William, Clarke, Roger, Mattison-Shupnick, Mark, Blum, Ronald D.
• Primary Examiner(s): Greece, James
• Application Number:
  US13/656,943
• Publication Number:
  US 20130114128A1
• Time in Patent Office: 1,387 Days
• Field of Search: 351/159.11, 351/159.01, 351/159.12, 351/159.15, 351/159.35, 351/159.44, 351/159.75
• US Class Current: 1/1
• CPC Class Codes: G02B 5/1895 such optical elements having dioptric power
• CPC Class Codes: G02C 2202/20 Diffractive and Fresnel lenses or lens portions
• CPC Class Codes: G02C 7/06 bifocal; multifocal ; progressive G02C7/041 takes precedence
• CPC Class Codes: G02C 7/061 Spectacle lenses with progressively varying focal power
• CPC Class Codes: G02C 7/083 Electrooptic lenses

Abstract

A lens system is presented having a diffractive optical power region. The diffractive optical power region has a plurality of concentric surface relief diffractive structures. A greater portion of light incident on a diffractive structure near the center point contributes to the optical power than light incident on a diffractive structure peripherally spaced therefrom.

Claims

1. A lens system comprising:

a diffractive optical power region comprising a plurality of concentric diffractive structures, wherein a greater fraction of light incident on a diffractive structure near the center point of the concentric diffractive structures contributes to the optical power of the diffractive optical power region than light incident on a diffractive structure peripherally spaced therefrom, wherein the diffractive optical power region is cropped so as to include at least one discontinuous diffractive structure and at least one diffractive structure with a complete closed curve.

2. The lens system of claim 1, wherein the plurality of concentric diffractive structures comprise a series of crests and adjacent troughs forming a sawtooth pattern, wherein each concentric diffractive structure extends from a trough to an adjacent crest of the sawtooth pattern, wherein the distance between a crest and an adjacent trough of the diffractive structure near the center point is greater than the distance between a crest and an adjacent trough of the diffractive structure peripherally spaced therefrom.

3. The lens system of claim 2, further comprising:

a first electrode layer formed along the sawtooth pattern;

electro-active material formed along the first electrode layer;

a second electrode layer formed along the electro-active material and electrically connected to the first electrode layer;

a controller for applying voltage across the first and second electrode layers; and

wherein when the controller applies voltage across the first and second electrode layers, the refractive index of electro-active material is altered to provide the optical power of the diffractive optical power region and wherein the difference in the fraction of light which contributes to the optical power of the diffractive optical power region is due to the difference in the height of the diffractive structure near the center point and the height of the diffractive structure spaced therefrom.

4. The lens system of claim 1, wherein the concentric diffractive structures comprise individually addressable electrodes and the diffractive optical power region comprises:

a controller for applying voltages to a plurality of the individually addressable electrodes; and

electro-active material disposed between the individually addressable electrodes, wherein when the controller applies voltages to the plurality of individually addressable electrodes, the refractive index of the electroactive material is altered to provide the optical power of the diffractive optical power region and wherein the difference in the fraction of light which contributes to the optical power of the diffractive optical power region is due to a difference in the refractive index of the electro-active material between adjacent individually addressable electrodes of the diffractive structure near the center point and the refractive index of the electro-active material between adjacent individually addressable electrodes of the diffractive structure spaced therefrom.

5. The lens system of claim 4, wherein the individually addressable electrodes include concentric curved electrodes.

6. The lens system of claim 4, wherein the individually addressable electrodes include pixels.

7. The lens system of claim 1, wherein the fraction contributed to the optical power monotonically decreases as the radial distance of the diffractive structure increases from the center point.

8. The lens system of claim 7, wherein the fraction contributed to the optical power is constant within a first radial distance and decreases within a second greater radial distance.

9. The lens system of claim 1, wherein the fraction is approximately zero at the peripheral edge of the diffractive optical power region.

10. The lens system of claim 1, wherein the fraction is approximated by a piecewise function.

11. The lens system of claim 1, wherein the optical power is constant.

12. The lens system of claim 1, wherein the optical power is progressive.

13. The lens system of claim 1, wherein the at least one diffractive structure with the complete closed curve forms a circle or an ellipse.

14. The lens system of claim 1, wherein the complete closed curve is located radially interior to the at least one discontinuous diffractive structure.

15. The lens system of claim 1,

the diffractive optical power region has a peripheral edge, wherein the diffractive optical power region focuses light to a focal point, wherein the amount of light focused on the focal point from the center point is greater than the amount of light focused on the focal point from the peripheral edge.

16. The lens system of claim 15, wherein the amount of light focused on the focal point monotonically decreases as the distance increases from the center point.

17. The lens system of claim 15, wherein the amount of light focused on the focal point is scaled by a function having a range of from zero to one.

18. The lens system of claim 15, wherein the amount of light focused on the focal point is approximately zero at the peripheral edge of the diffractive optical power region.

19. The lens system of claim 15, wherein the amount of light focused on the focal point is nonzero at the peripheral edge of the diffractive optical power region.

20. The lens system of claim 15, wherein the lens system is static.

21. The lens system of claim 15, wherein the lens system is dynamic.

22. The lens system of claim 21, wherein the plurality of concentric diffractive structures are surface relief structures and have a series of crests and adjacent troughs forming a sawtooth pattern, wherein each concentric diffractive structure extends from a trough to an adjacent crest of the sawtooth pattern, wherein the distance between a first crest and a first adjacent trough near the center point is greater than the distance between a second crest and a second adjacent trough spaced from the center point, wherein:

the diffractive optical power region includes a first region comprising a plurality of the concentric diffractive structures for focusing light of a specific wavelength A to a focal length f, wherein the radius of the n^th concentric diffractive structure of the first region from the center point is greater than √

{square root over (2nλ

f)}; and

wherein the lens system is electro-active.

23. The lens system of claim 15,

wherein a first region comprises the plurality of concentric diffractive structures that are surface relief structures and focus light of a specific wavelength λ

to a focal length f, wherein the radius of the n^th concentric diffractive structure from the center point is greater than √

{square root over (2nλ

f)}.

24. The lens system of claim 23, wherein the diffractive optical power region provides a progression of decreasing optical power.

25. The lens system of claim 23, wherein the diffractive optical power region further comprises a second region having a plurality of concentric diffractive structures that are surface relief structures, wherein the radius of the n^th concentric diffractive structure of the second region from the center point thereof is approximately equal to √

{square root over (2nλ

f)}.

26. The lens system of claim 25, wherein the second region provides a constant optical power.

27. The lens system of claim 25, wherein the second region is positioned radially interior to the first region.

28. The lens system of claim 23, wherein the radial widths of at least some of the diffractive structures of the first region are equal to one another.

29. The lens system of claim 15,

wherein a first region comprises a plurality of concentric diffractive structures that are surface relief structures and focus light of a specific wavelength λ

to a focal length f, wherein the radius of the n^th concentric diffractive structure from the center point is less than √

{square root over (2nλ

f)}.

30. The lens system of claim 29, wherein the radial widths of at least some of the diffractive structures of the first region are equal to one another.

31. The lens system of claim 29, wherein the diffractive optical power region provides a progression of increasing optical power.

32. The lens system of claim 29, wherein the diffractive optical power region further comprises a second region having a plurality of concentric diffractive structures that are surface relief structures, wherein the radius of the n^th concentric diffractive structure of the second region from the center point thereof is approximately equal to √

{square root over (2nλ

f)}.

33. The lens system of claim 32, wherein the second region provides a constant optical power.

34. The lens system of claim 32, wherein the second region is positioned radially interior to the first region.