Ophthalmic lens with electro-optical function

1. An opthalamic spectacle lens comprising a transparent substrate and electro-optical means integrated with the substrate to perform an optical function in response to an electrical stimulus, the lens further comprising:

(a) at least one photovoltaic cell integrated with the substrate to power the electro-optical means in response to an incident light; and

(b) a control circuit for controlling the electrical voltage produced by said photovoltaic cell, said control circuit being integrated with the substrate.

2. The lens according to claim 1 , wherein the photovoltaic cell is sensitive to visible light.

3. The lens according to claim 1 , wherein the photovoltaic cell is semiconductor-based.

4. The lens according to claim 3 , wherein the photovoltaic cell is based on single crystal, or is based on microcrystalline or amorphous silicon.

5. The lens according to claim 3 , wherein the photovoltaic cell is based on cadmium telluride, or is based on a chalcopyrite containing copper.

6. The lens according to claim 3 , wherein the photovoltaic cell is incorporated in an opaque component integrated with the substrate and occupying an area of less than 10% of the area of the lens.

7. The lens according to claim 3 , wherein several photovoltaic cells are distributed in series over the area of the lens.

8. The lens according to claim 1 , wherein several photovoltaic cells are distributed over the area of the lens at least one electrical voltage control circuit is integrated with the substrate.

9. The lens according to claim 1 , wherein the photovoltaic cell is partially transparent and possesses a light-collecting surface that covers at least a portion of the surface of the lens.

10. The lens according to claim 9 , wherein the photovoltaic cell is of the photo-electrochemical type.

11. The lens according to claim 10 , wherein the photovoltaic cell includes at least one electrode based on indium and tin oxide or based on fluorine-doped tin oxide.

12. The lens according to claim 10 , wherein the photovoltaic cell incorporates nanocrystals or fullerenes.

13. The lens according to claim 1 , wherein the electro-optical means comprise a variable light transmission system.

14. The lens according to claim 13 , wherein the variable light transmission system is based on liquid crystals.

15. The lens according to claim 13 , wherein the variable light transmission system is of electrophoretic type.

16. The lens according to claim 1 , comprising a control circuit for controlling the electrical voltage produced by the photovoltaic cell, said control circuit being integrated with the substrate.

17. The lens according to claim 1 , wherein the control circuit is partially transparent.

18. The lens according to claim 1 , wherein the control circuit comprises a step-up circuit for raising the electrical voltage produced by the photovoltaic cell.

19. The lens according to claim 1 , further comprising control means for interrupting the power supplied by the photovoltaic cell to the electro-optical means.

20. A vision device including at least one opthalamic spectacle lens according to claim 1 .

21. A vision device according to claim 20 , comprising a pair of spectacles.

22. A pair of spectacles comprising a pair of opthalamic spectacle lenses each comprising each comprising a transparent substrate and electro-optical means intregrated with the substrate to perform an optical function in response to an electrical stimulus, the lens further comprising:

(a) at least one photovoltaic cell integrated with the substrate to power the electro-optical means in response to an incident light; and

(b) a control circuit for controlling the electrical voltage produced by said photovoltaic cell, said control circuit being integrated with the substrate.