Capacitively coupled electric field control device

1. A liquid crystal lens or optical device comprising:

a liquid crystal cell having:

planar cell walls;

alignment coatings on the cell walls;

a liquid crystal material in contact with the cell walls;

an electrode structure having:

a plurality of capacitively coupled electrode segments separated by at least one insulating layer;

an opposed electrode;

wherein an electric field can be provided between the electrode segments and the opposed electrode within the liquid crystal cell;

wherein a voltage applied to a first segment of the plurality of segments induces a reduced voltage in subsequent capacitively coupled segments of said plurality of segments;

wherein the arrangement of said segments corresponds to a desired electric field spatial profile across an aperture of the liquid crystal cell.

2. A liquid crystal lens or optical device comprising:

a liquid crystal cell having:

planar cell walls;

alignment coatings on the cell walls;

a liquid crystal material in contact with the cell walls;

an electrode structure having:

a plurality of capacitively coupled electrode segments separated by at least one intermediate layer, at least neighboring capacitively coupled electrode segments being configured to at least partially overlap; and

an opposed electrode across the liquid crystal layer from said plurality of capacitively coupled electrode segments;

wherein an electric field can be provided between the electrode segments and the opposed electrode within the liquid crystal cell;

wherein a voltage applied to a first segment of the plurality of segments induces a reduced voltage in subsequent electrically floating capacitively coupled segments of said plurality of segments; and

wherein the arrangement of said segments corresponds to a desired electric field spatial profile across an aperture of the liquid crystal cell.

3. A device as claimed in claim 2 , wherein said optical device is a cylindrical lens, said electrode structure comprising strips of substantially parallel electrode segments and said first capacitively coupled electrode segment comprising outer ones of said parallel electrode segment strips.

4. A device as claimed in claim 2 , wherein said optical device is a liquid crystal lens, said electrode structure comprising a substantially circular aperture, said plurality of capacitively coupled electrode segments comprising a plurality of substantially concentric capacitively coupled electrode segments, and said first capacitively coupled electrode segment comprising an outer hole patterned electrode.

5. A device as claimed in claim 2 , wherein each capacitively coupled electrode segment further comprises circumferential subsegments for providing wavefront control via said optical device, preferably further comprising a controller configured to provide time-varying adjusted voltages to said subsegments for optical image stabilization.

6. A device as claimed in claim 2 , wherein said plurality of capacitively coupled electrode segments is divided into first group of segments and second group of segments on corresponding layers separated by one of: an insulation layer and a high dielectric constant layer, applied over said first group of capacitively coupled electrode segments.

7. A device as claimed in claim 6 , wherein each electrode segment of the second group of electrode segments partially overlaps adjacent neighboring electrode segments of the first group of electrode segments.

8. A device as claimed in claim 2 , said electrode structure comprising one of:

a dielectric substrate over a substantially flat transparent electrically conductive electrode layer; and

an insulation layer over a substantially flat transparent conductive electrode layer.

9. A device as claimed in claim 2 , said electrode structure comprising one of:

a butterfly shaped connected transparent electrode partially overlapping each electrode segment, said partial overlap increasing gradually with aperture position; and

a first Maltese-cross shaped connected transparent electrode partially overlapping each electrode segment.

10. A device as claimed in claim 9 , said electrode structure comprising a second Maltese-cross oriented complimentary to said first Maltese-cross.

11. A device as claimed in claim 2 , said electrode structure comprising one of:

a plurality of electrically floating conductive transparent capacitive bridges, each capacitive bridge partially overlapping adjacent electrode segments.

12. A device as claimed in claim 2 , comprising:

a pair of said liquid crystal cells arranged to act on corresponding orthogonal polarizations of light, each liquid crystal material being sandwiched between a corresponding pair alignment layers between planar and substantially parallel liquid crystal cell walls, each said pair of alignment layers selecting a predetermined liquid crystal molecular orientation in the corresponding liquid crystal material defining a corresponding director orientation, said directors in the pair of liquid crystal material layers being substantially orthogonal to one another for providing polarization independent operation of said liquid crystal optical device; and

said electrode structure being arranged on said liquid crystal cell walls being separately provided for each of said pair of liquid crystal cells.

13. A device as claimed in claim 2 , wherein said intermediate layer allows said desired electric field spatial profile to be essentially invariant as a function of a frequency of a control signal applied to said first segment.

14. A device as claimed in claim 13 , further comprising an electrode covering at least a central part of said aperture for creating an electric field separately from said electrode segments.

15. A device as claimed in claim 2 , wherein said intermediate layer provides a small amount of conductivity and allows said desired electric field spatial profile to be essentially controlled as a function of a frequency of a control signal applied to said first segment.

16. A device as claimed in claim 14 , further comprising a drive signal controller configured to provide at least one variable electrical signal of a predetermined voltage and frequency selected according to a desired variable optical property of the device, wherein preferably frequency is used to control the optical property.

17. A device as claimed in claim 2 , wherein the device is a tunable lens.

18. A device as claimed in claim 2 , wherein said device has a flat planar geometry.

19. A device as claimed in claim 2 , wherein said neighboring capacitively coupled electrode segments are configured to overlap such that an electrode segment is always present opposite said opposed electrode providing a smoother change in said electric field spatial profile across said aperture.

20. A liquid crystal lens or optical device comprising:

a liquid crystal cell having:

planar cell walls;

alignment coatings on the cell walls;

a liquid crystal material in contact with the cell walls;

an electrode structure having:

a plurality of electrically coupled electrode segments separated by at least one intermediate layer, said plurality of electrode segments including at least two neighboring electrically floating electrode segments; and

an opposed electrode across the liquid crystal layer from said plurality of electrically coupled electrode segments;

wherein an electric field can be provided between the electrode segments and the opposed electrode within the liquid crystal cell;

wherein a voltage applied to a first segment of the plurality of segments induces a reduced voltage in subsequent electrically floating electrically coupled electrode segments of said plurality of electrode segments; and

wherein the arrangement of said segments corresponds to a desired electric field spatial profile across an aperture of the liquid crystal cell.

21. A device as claimed in claim 20 , said electrically coupled electrode segments being configured provide gradual step by step coupling between electrically floating neighboring electrode segments.