Adaptive electro-active lens with variable focal length

• US 20060164593A1
• Filed: 01/18/2006
• Published: 07/27/2006
• Est. Priority Date: 01/21/2005
• Status: Active Grant

• Current Assignee: Johnson & Johnson Vision Care (Johnson & Johnson)
• Original Assignee: Johnson & Johnson Vision Care (Johnson & Johnson)
• Inventors: Li, Guoqiang, Peyghambarian, Nasser, Ayras, Pekka
• Granted Patent: US 8,885,139 B2
• Time in Patent Office: Days
• US Class Current: 349/200
• CPC Class Codes: G02F 1/13 based on liquid crystals, e.g. single liquid crystal display cells
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection
• CPC Class Codes: G02F 1/294 Variable focal length devices

Abstract

An adjustable focusing electrically controllable electroactive lens is provided. The adjustable focusing electrically controllable electroactive lens can adjust the focal length discretely or continuously. The lens can be incorporated in a variety of optical devices including spectacles.

Claims

1. An adjustable focusing electrically controllable electroactive lens comprising:

a liquid crystal layer positioned between a pair of transparent substrates;

a Fresnel zone patterned electrode having M zones, each zone having L individually addressable subzones positioned between the liquid crystal layer and the inward-facing surface of the first transparent substrate, where M and L are positive integers; and

a conductive layer between the liquid crystal layer and the inward-facing surface of the second transparent substrate.

2. The lens of claim 1, wherein the individually addressable subzones of the Fresnel zone patterned electrode are on the same horizontal plane.

3. The lens of claim 1, wherein the liquid crystal is selected from the group consisting of:

nematic, cholesteric, electroactive polymer, polymer liquid crystal, polymer dispersed liquid crystal, polymer-stabilized liquid crystal, and self-assembled nonlinear supramolecular structures.

4. The lens of claim 3, wherein the liquid crystal is nematic.

5. The lens of claim 4, wherein the liquid crystal is E7.

6. The lens of claim 1, wherein the transparent substrates are glass.

7. The lens of claim 1, wherein the transparent substrates are plastic.

8. The lens of claim 1, further comprising an electrical control electrically connected to the individually addressable subzones and the conductive layer.

9. The lens of claim 8, wherein the electrical control applies a positive or negative voltage to the individually addressable subzones.

10. The lens of claim 9, wherein the voltage is between negative 3 volts and positive 3 volts.

11. The lens of claim 8, further comprising a range-finding device electrically connected to the electrical control.

12. The lens of claim 1, wherein the patterned electrode and conductive layer are transparent.

13. The lens of claim 12, wherein the patterned electrode and conductive layer are indium-tin-oxide.

14. The lens of claim 1, further comprising an alignment layer surrounding the liquid crystal layer.

15. The lens of claim 14, wherein the alignment layer is polyvinyl alcohol.

16. The lens of claim 14, wherein the alignment layer is nylon 6,6.

17. The lens of claim 1, wherein the transparent substrates are between about 3 and about 20 microns apart.

18. The lens of claim 1, wherein the focal length is positive.

19. The lens of claim 1, wherein the focal length is negative.

20. A method of adjusting the focal length of a lens by integer multiples of an original focal length F comprising:

providing a lens comprising a liquid crystal layer enclosed between a pair of transparent substrates;

a Fresnel zone patterned electrode positioned between the liquid crystal layer and the inward-facing surface of the first transparent substrate, said patterned electrode having M zones, each zone having L subzones, said patterned electrode having a total of M-L individually addressable electrodes;

a conductive layer between the liquid crystal layer and the inward-facing surface of the second transparent substrate; and

an electrical control electrically connected to the electrode zones and the conductive layer;

applying the same voltage to each k individually addressable electrodes to adjust the focal length to k-F, where k is an integer from 1 to M·

L.

21. The method of claim 20, wherein the voltage applied is between negative 3 volts and positive 3 volts.

22. A method of continuously adjusting the focal length of a lens comprising:

(a) providing a lens comprising a liquid crystal layer enclosed between a pair of transparent substrates;

a Fresnel zone patterned electrode having L diffraction levels positioned between the liquid crystal layer and the inward-facing surface of the first transparent substrate, said patterned electrodes being a circular array of individually addressable rings;

a conductive layer between the liquid crystal layer and the inward-facing surface of the second transparent substrate; and

an electrical control electrically connected to the electrode zones and the conductive layer;

(b) determining the desired focal length (f′

);

(c) calculating the area of the mth zone of the Fresnel zone patterned electrode using the equation;

r_m²+f′

²=(f′

+mλ

)²,

where f′

is the design focal length and λ

is the design wavelength;

(d) dividing the calculated area of the mth zone by L or a larger integer to determine the number of individually addressable electrodes that form a design subzone;

(e) applying the same voltage to the number of individually addressable electrodes in a design subzone.

23. The method of claim 22, further comprising before step (a):

determining one or more design focal lengths;

calculating the maximum ring size in the Fresnel zone patterned electrode that allows all design focal lengths to be formed in a design subzone.

24. The method of claim 22, further comprising determining the design focal length using a range-finding device to determine the distance between the lens and a desired object.

25. The method of claim 22, wherein the voltage applied is between negative 3 volts and positive 3 volts.