DIFFRACTIVE MULTIFOCAL LENS HAVING RADIALLY VARYING LIGHT DISTRIBUTION

• US 20110109875A1
• Filed: 01/14/2011
• Published: 05/12/2011
• Est. Priority Date: 04/24/2008
• Status: Active Grant

• Current Assignee: Amo Groningen B.V (Johnson & Johnson)
• Original Assignee: Amo Groningen B.V (Johnson & Johnson)
• Inventors: Weeber, Henk A.
• Granted Patent: US 8,382,281 B2
• Time in Patent Office: Days
• US Class Current: 351/168
• 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 and/or improved light energy distribution properties are provided. These properties are provided by the diffractive profiles of the invention, often having subtlely shaped echelettes with appropriately curving profiles. Light scatter may be generated by the sharp corners associated with vertical steps between adjacent conventional diffractive echelettes. Smooth diffractive profiles of the invention reduce light scatter. Light energy directed towards non-viewing diffractive orders may have a unwanted effects on vision quality. Diffractive profiles of the invention may limit the light energy in certain, selected orders, thereby improving viewing quality and mitigating unwanted effects such as dysphotopsia. Diffractive profiles of the invention can also vary the light energy distributed between individual echelettes, providing additional advantages in various viewing situations.

Claims

1-20. -20. (canceled)

21. 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 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 diffraction orders having diffraction efficiencies which change with radius from the optical axis.

22. The multifocal ophthalmic lens of claim 8, wherein the anterior face and the posterior face define a clear aperture.

23. The multifocal ophthalmic lens of claim 8, wherein the diffractive profile is characterized by a continuous function over the plurality of echelettes.

24. The multifocal ophthalmic lens of claim 8, 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.

25. The multifocal ophthalmic lens of claim 12, wherein the first and second diffraction orders having diffraction efficiencies which change with the number of surrounding echelettes.

26. The multifocal ophthalmic lens of claim 12, wherein N is at least 4 and the first and second diffraction orders having diffraction efficiencies which change depending on the number of surrounding echelettes.

27. The multifocal ophthalmic lens of claim 8, wherein any one of the step heights does not vary by more than 20 percent from an average of all the step heights.