Apodized diffractive IOL with frustrated diffractive region

• US 20080030677A1
• Filed: 08/02/2006
• Published: 02/07/2008
• Est. Priority Date: 08/02/2006
• Status: Active Grant

• Current Assignee: Alcon Incorporated
• Original Assignee: Alcon Manufacturing Limited (Alcon Incorporated)
• Inventors: Simpson, Michael J.
• Granted Patent: US 7,572,007 B2
• Time in Patent Office: Days
• US Class Current: 351/161
• CPC Class Codes: A61F 2/1618 Multifocal lenses
• CPC Class Codes: A61F 2/1654 Diffractive lenses
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08
• 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 7/02 Lenses; Lens systems ; Methods of designing lenses

Abstract

In one aspect, the present invention provides a diffractive ophthalmic lens (e.g., a diffractive IOL) that includes an optic having an anterior surface and a posterior surface, where the optic provides a far focus. A frustrated diffractive structure comprising a plurality of diffractive zones is disposed on at least one of those surfaces so as to provide a near focus. Each zone is separated from an adjacent zone by a zone boundary that imparts an optical delay to the incident light. Further, at least two consecutive zone boundaries are configured such that a difference between their associated phase delays for at least one wavelength of the incident light is greater than about 1/4 wavelength so as to direct a portion of the incident light to a location between the near and far foci.

Claims

1. An ophthalmic lens, comprising

an optic having an anterior surface and a posterior surface, said optic providing a far focus,

a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces so as to provide a near focus, wherein each zone is separated from an adjacent zone by a zone boundary imparting an optical phase delay to incident light,

wherein at least two consecutive zone boundaries are configured such that a difference between their associated phase delays for at least one wavelength is greater than about 1/20 wavelength so as to direct a portion of the incident light to a location between said near and far foci.

2. The lens of claim 1, wherein a difference between the phase delays provided by said two consecutive zone boundaries is in a range of about ¼

wavelength to about 1 wavelength.

3. The lens of claim 1, wherein said zone boundaries comprise a plurality of steps.

4. The lens of claim 3, wherein at least two consecutive steps exhibit a differential height adapted to provide said difference in their associated phase delays.

5. The lens of claim 4, wherein a portion of said steps exhibit decreasing step heights as a function of increasing distance from a center of the surface on which the diffractive structure is disposed.

6. The lens of claim 1, wherein said diffractive structure comprises a truncated diffractive structure that covers a portion of the surface on which it is disposed.

7. The lens of claim 1, wherein said at least one wavelength is in a range of about 400 nm to about 700 nm.

8. The lens of claim 7, wherein said at least one wavelength is about 550 nm.

9. The lens of claim 1, wherein said optic provides a far-focus optical power in a range of about 6 D to about 34 D .

10. The lens of claim 1, wherein said diffractive structure provides an add power in a range of about 2 D to about 4 D.

11. The lens of claim 1, wherein said optic is formed of a biocompatible material.

12. The lens of claim 11, wherein said biocompatiable material comprises any of soft acrylic, silicone, and hydrogel.

13. The lens of claim 1, wherein said lens comprises an IOL.

14. An ophthalmic lens, comprising

an optic having an anterior surface and a posterior surface,

a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces, each zone being separated from an adjacent zone by a zone boundary,

said optic providing a far focus corresponding to a zeroth diffraction order of said diffractive zones and a near focus corresponding to a 1^st diffraction order of said diffractive zones,

wherein said zone boundaries are characterized by a plurality of non-uniform step heights generating non-uniform phase delays adapted to direct a portion of incident light to a location between said near and far foci so as to enhance intermediate vision.

15. The lens of claim 14, wherein said non-uniform step heights comprise at least two consecutive steps each imparting a phase delay to incident light such that a difference between the phase delays associated with said consecutive steps for at least one wavelength of the incident light is greater than about

16. The lens of claim 15, wherein said optic provides a far-focus optical power in a range of about 6 D to about 34 D .

17. The lens of claim 15, wherein said optic provides a near-focus optical power corresponding to an add power in a range of about 2 D to about 4 D.

18. The lens of claim 14, wherein said diffractive zones are surrounded by a portion of the respective surface that lacks diffractive elements.

19. An ophthalmic lens, comprising

an optic having an anterior surface and a posterior surface, said optic providing a far-focus optical power,

a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces for providing a near-focus optical power,

wherein at least two of said diffractive zones exhibit sufficiently different surface curvatures so as to cause a portion of light incident on said optic to be directed to an intermediate location between said near and far foci for enhancing intermediate vision.

20. The lens of claim 19, wherein a difference in the curvatures of said at least two zones is in a range of about 10% to about 50%.

21. The lens of claim 20, wherein said two diffractive zones comprise two adjacent zones.

22. The lens of claim 19, wherein said ophthalmic lens comprises an IOL.

23. The lens of claim 19, wherein said far-focus optical power is in a range of about 6 D to about 34 D .

24. The lens of claim 19, wherein said near-focus optical power corresponds to an add power in a range of about 2 D to about 4 D.

25. An ophthalmic lens, comprising

an optic having an anterior surface and a posterior surface, said optic providing a far focus,

a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces for providing a near focus,

wherein a surface of at least one of said diffractive zones exhibits an asphericity such that said diffractive structure directs at least a portion of incident light to an intermediate location between said near and far foci.

26. The lens of claim 25, wherein said asphericity is characterized by a conic constant in a range of about −

10 to about −

1000.

27. The lens of claim 25, wherein said far focus is characterized by an optical power in a range of about 6 D to about 34 D .

28. The lens of claim 25, wherein said ophthalmic lens comprises an IOL.

29. The lens of claim 25, wherein said near focus is characterized by an add power in a range of about 2 D to about 4 D.

30. An ophthalmic lens, comprising

an optic having an anterior optical surface and a posterior optical surface,

said optic providing a far focus,

a plurality of annular diffractive zones disposed on one of said surfaces about an optical axis of said optic so as to provide a near focus,

wherein at least one of said zones (i) has a boundary with a radial location defined by the following relation:

r_i²=r₀²+2λ

f

wherein

i denotes the zone number (i=0 denotes the central zone),

λ

denotes a design wavelength,

f denotes a focal length of the near focus, and

r₀ denotes the radius of the central zone, and

wherein at least another zone has a boundary with a radial location that differs

sufficiently from that defined by the above relation for a putative respective zone so as to direct a portion of incident light to an intermediate location between said far and near foci.

31. The lens of claim 30, wherein the radial location of said at least another zone differs from that defined by said relation by a factor in a range of about 20% to about 50%.

32. The lens of claim 30, wherein A is in a range of about 400 nm to about 700 nm.

33. The lens of claim 30, wherein said near focus corresponds to an add power in a range of about 2 D to about 4 D.

34. An ophthalmic lens, comprising

an optic having an anterior optical surface and a posterior optical surface, said optic providing a far focus,

a plurality of diffractive zones disposed on at least one of said surfaces to provide a near focus,

wherein said zones comprise a central zone having a radius that is sufficiently different from √

{square root over (λ

f)}, where A denotes a design wavelength and denotes a focal length of the near focus, such that at least a portion of incident light is directed to an intermediate location between said near and far foci.

35. The lens of claim 34, wherein A is in a range of about 400 nm to about 700 nm.

36. The lens of claim 34, wherein said near focus corresponds to an add power in a range of about 2 D to about 4 D