DIFFRACTIVE LENS EXHIBITING ENHANCED OPTICAL PERFORMANCE

• US 20090268155A1
• Filed: 04/23/2009
• Published: 10/29/2009
• Est. Priority Date: 04/24/2008
• Status: Active Grant

• Current Assignee: Amo Groningen B.V (Johnson & Johnson)
• Original Assignee: AMO Regional Holdings (Abbott Laboratories Incorporated)
• Inventors: Weeber, Hendrik A.
• Granted Patent: US 8,231,219 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: G02C 2202/20 Diffractive and Fresnel lenses or lens portions
• CPC Class Codes: G02C 7/042 Simultaneous type
• CPC Class Codes: G02C 7/044 Annular configuration, e.g. pupil tuned

Abstract

The present invention provides improved ophthalmic lenses and methods for their design and use. Monofocal and multifocal diffractive ophthalmic lenses having reduced light scatter, improved light energy distribution properties, and/or other improvements in optical performance are provided. These properties are provided, at least in part, by the diffractive profiles of the invention, often having subtlety shaped echelettes with appropriately curving profiles. Smooth diffractive profiles may be used reduce light scatter. Diffractive profiles may be configured to limit the light energy in certain selected orders, thereby improving viewing quality and mitigating unwanted effects such as dysphotopsia. Diffractive profiles of may additionally or alternatively vary the light energy distributed between individual echelettes, providing additional advantages in various viewing situations.

Claims

1. A multifocal ophthalmic lens, comprising:

an anterior face with an anterior refractive profile and a posterior face with a posterior refractive profile, the faces disposed about an optical axis; and

a diffractive profile imposed on one of the refractive profiles, the diffractive profile characterized by a plurality of echelettes;

the plurality of echelettes comprising a central echelette and a plurality of surrounding echelettes disposed about the central echelette, at least one of the surrounding echelettes having an echelette form that is unequal to the echelette form of any of a remaining plurality of surrounding echelettes.

2. The ophthalmic lens of claim 1, wherein each of the surrounding echelettes has an echelette form that is unequal to the echelette form of any of the remaining surrounding echelettes.

3. The ophthalmic lens of claim 1, wherein each of the surrounding echelettes has the same echelette height.

4. The ophthalmic lens of claim 1, wherein, when the lens is disposed within an eye, a diffraction efficiency of the zeroth diffractive order, the first diffractive order, or both the zeroth diffractive order and the first diffractive orders of the lens varies depending on a number of the surrounding echelettes that are illuminated by light from a light source

5. The ophthalmic lens of claim 1, wherein the diffractive profile is characterized by a continuous function over a plurality of echelettes.

40. The ophthalmic lens of claim 4, wherein the light source is a point light source located at least 6 meters from the lens.

41. The ophthalmic lens of claim 1, wherein the lens is made of a material having a refractive index that changes with increasing radius from the optical axis.

42. The ophthalmic lens of claim 41, wherein the lens material has a refractive index that decreases with increasing radius from the optical axis.

43. The ophthalmic lens of claim 41, wherein the lens material and the diffractive profile are configured so that the lens has a negative spherical aberration suitable.

44. The ophthalmic lens of claim 43, wherein the diffractive profile is configured to provide a chromatic correction for at least one focus of the lens.

6. A multifocal ophthalmic lens, comprising:

an anterior face with an anterior refractive profile and a posterior face with a posterior refractive profile, the faces disposed about an optical axis;

a diffractive profile imposed on one of the refractive profiles, the diffractive profile comprising a plurality of echelettes with associated echelette heights that are substantially equal to one another, the diffractive profile having at least two diffractive orders for providing vision in the visible waveband;

the at least two diffractive orders having diffraction efficiencies that change with radius from the optical axis.

7. The multifocal ophthalmic lens of claim 6, wherein the diffractive profile is characterized by a continuous function over the plurality of echelettes.

8. The multifocal ophthalmic lens of claim 6, wherein the echelettes comprise a central echelette and N additional echelettes, the N additional echelettes comprising a first echelette disposed about the central echelette, a second echelette disposed about the first echelette, up to an Nth echelette disposed about an (N−

1)th echelette.

9. The multifocal ophthalmic lens of claim 8, wherein the at least two diffractive orders include a zeroth diffractive order and first diffractive order each having diffraction efficiencies which change with the number of surrounding echelettes.

10. The multifocal ophthalmic lens of claim 8, wherein N is at least 4 and the zeroth and first diffractive orders having diffraction efficiencies which change depending on the number of surrounding echelettes.

11. The multifocal ophthalmic lens of claim 6, wherein any one of the echelette heights does not vary by more than 20 percent from an average of all the echelette heights.

12. A multifocal ophthalmic lens, comprising:

an anterior face with an anterior refractive profile and a posterior face with a posterior refractive profile, the faces disposed about an optical axis;

a diffractive profile imposed on one of the refractive profiles, the diffractive profile comprising a plurality of echelette with associated step heights that are substantially equal to one another, the diffractive profile having, in the visible waveband, a first diffractive order and a second diffractive order having a diffraction add power;

the first and second diffractive orders having diffraction efficiencies which change with radius from the optical axis.

13. The multifocal ophthalmic lens of claim 12, wherein the diffractive profile is characterized by a continuous function over the plurality of echelettes.

14. The multifocal ophthalmic lens of claim 12, wherein the echelettes comprise a central echelette and N additional echelettes, the N additional echelettes comprising a first echelette disposed about the central echelette, a second echelette disposed about the first echelette, up to an Nth echelette disposed about an (N−

1)th echelette.

15. The multifocal ophthalmic lens of claim 14, wherein the first and second diffractive orders having diffraction efficiencies which change with the number of surrounding echelettes.

16. The multifocal ophthalmic lens of claim 14, wherein N is at least 4 and the first and second diffractive orders having diffraction efficiencies which change depending on the number of surrounding echelettes.

17. The multifocal ophthalmic lens of claim 12, wherein any one of the step heights does not vary by more than 20 percent from an average of all the step heights.

18-23. -23. (canceled)

24. A multifocal ophthalmic lens, comprising:

an anterior face with an anterior refractive profile and a posterior face with a posterior refractive profile, the faces disposed about an optical axis;

a diffractive profile imposed on one of the refractive profiles, the diffractive profile characterized by a continuous function over a plurality of echelettes and having, in the visible waveband, a zeroth diffractive order, a first diffractive order associated with an add power of the lens, and minus one diffractive order; and

the minus one diffractive order having a lower diffraction efficiency than a reference lens having the same refractive profiles and add power, the reference lens having a diffractive profile that is parabolic.

25. The multifocal ophthalmic lens of claim 24, wherein the diffraction efficiency of the minus one diffractive order is less than about 4 percent.

26. The multifocal ophthalmic lens of claim 24, wherein the diffraction efficiency of the minus one diffractive order is less than 2.5 percent.

27. The multifocal ophthalmic lens of claim 24, wherein:

the diffractive profile is characterized by a continuous function over a plurality of echelettes, the continuous function defined by the relationship;

$\mathrm{\Delta <br><br>}<br><br>\left(\mathrm{\rho <br><br>}\right);<br><br>={\mathrm{\Delta <br><br>}}_0·<br><br>[\begin{array}{c}\left[1-{\left(\frac{\mathrm{\rho <br><br>}}{r_1^2}\right)}^{\mathrm{en}}\right]·<br><br>\left[1-\left(\frac{\mathrm{\rho <br><br>}}{r_1^2}\right)\right]+\left[{\left(\left(\frac{\mathrm{\rho <br><br>}}{r_1^2}\right)\right)}^{\mathrm{en}}\right]·<br><br>\\ \left[0.5+0.5·<br><br>\cos <br><br>\left[\mathrm{\pi <br><br>}·<br><br>\frac{\mathrm{\rho <br><br>}}{q_1^2}·<br><br>\left[\begin{array}{c}1.0+\left(\mathrm{\rho <br><br>}-q_1^2\right)·<br><br>\\ \left[\begin{array}{c}\mathrm{Y\_min}+\left(\mathrm{Y\_max}-\mathrm{Y\_min}\right)·<br><br>\\ \left[0.5·<br><br>\tanh <br><br>\left[\frac{\left(\mathrm{\rho <br><br>}-\mathrm{X\_shift}\right)}{m}\right]+0.5\right]\end{array}\right]\end{array}\right]\right]\right]\end{array}<br><br>]$

where ρ

is the square of a radius from the optical axis, en is an exponential power;

r₁ is a radius of the first or central echelette, q₁ affects a size of a primary zone of each echelette, r₁−

q₁ affects a size of a secondary zone of each echelette;

Y_min and m are parameters influencing the shape of the echelette;

Y_max is equal to (2q₁²−

r₁²)/(r₁²−

q₁²)/r₁²;

X_shift is equal to q₁²; and

Δ

ρ

is a height of the profile.

28-39. -39. (canceled)