Progressive addition lens operating in combination with a multi-order diffractive optic
A multi-focal spectacle lens is presented having far distance, intermediate distance, and near distance vision correction, in which the lens includes a progressive addition surface with a progression of optical power. The lens further includes a multi-order diffractive surface relief structure with an optical add power. The multi-order diffractive structure reduces chromatic aberration as compared to a conventional diffractive structure of equivalent optical power. The lens may also include a wavefront splitting device diffractive structure for generating multiple optical powers simultaneously. When the progressive addition surface and the multi-order diffractive surface relief structure are in optical communication an overall progression of optical add power may be provided by the combination of the progressive addition surface with the multi-order surface relief diffractive structure.
1. A multi-focal spectacle lens having far distance, intermediate distance, and near distance vision correction, comprising:
a. a progressive addition surface with a progression of optical power;
b. a multi-order diffractive surface relief structure with an optical add power for reducing chromatic aberrations, wherein when the progressive addition surface and the multi-order diffractive surface relief structure are in optical communication an overall progression of optical add power is provided by the combination of the progressive addition surface with the multi-order diffractive surface relief structure; and
c. the diffractive structure comprises electro-active material.
2. The lens of claim 1 , wherein the electro-active material comprises cholesteric liquid crystal.
3. The lens of claim 1 , further comprising a wavefront splitting device in optical communication with the multi-order diffractive surface relief structure.
4. The lens of claim 1 , further comprising a thin film layer in optical communication with the progressive addition surface.
5. An ophthalmic lens having far distance, intermediate distance, and near distance vision correction, comprising:
a. a front piece having a convex front surface;
b. a back piece having a concave rear surface; and
c. a multi-order diffractive surface relief structure positioned between the front piece and the back piece, wherein said multi-order diffractive surface relief structure has an optical add power and reduces chromatic aberration;
d. a portion of a progressive addition surface provided on at least one of the front surface or the rear surface in optical communication with the multi-order diffractive surface relief structure, wherein an overall progression of optical add power is provided by the addition of the progressive addition surface and the optical add power of the diffractive lens structure; and
e. the diffractive structure comprises electro-active material.
6. The lens of claim 5 , wherein the electro-active material comprises cholesteric liquid crystal.
7. The lens of claim 5 , further comprising a wavefront splitting device disposed between the front piece and the back piece, wherein the wavefront splitting device is in optical communication with the multi-order diffractive surface relief structure.
8. The lens of claim 5 , further comprising a thin film layer disposed between the front piece and the back piece, wherein the thin film layer is in optical communication with the progressive addition surface.
9. The lens of claim 5 , wherein the refractive index of the front piece is different than the refractive index of the back piece.
10. The lens of claim 5 , wherein the refractive index of the front piece is the same as the refractive index of the back piece.
11. The lens of claim 10 , wherein the refractive index of the thin film is different from the refractive index of the front and back pieces.
12. The lens of claim 8 , wherein the refractive index of the thin film is different from the refractive index of the front piece and different than the refractive index of the back piece.
13. The lens of claim 5 , wherein all of the optical power contributed by the progressive addition surface is provided on the front surface.
14. The lens of claim 5 , wherein all of the optical power contributed by the progressive addition surface is provided on the rear surface.
15. The lens of claim 5 , wherein a portion of the optical power contributed by a progressive addition surface is provided on the front surface and the remaining optical power contributed by a progressive addition surface is provided on the rear surface.