Image stabilization and shifting in a liquid crystal lens

Patent metadata

Field	Value
Publication number	US-9036102-B2
Application number	US-201013517189-A
Country	US
Kind code	B2
Filing date	Dec 23, 2010
Priority date	Dec 23, 2009
Publication date	May 19, 2015
Grant date	May 19, 2015

Abstract

Variable liquid crystal devices for controlling the propagation of light through a liquid crystal layer use a frequency dependent material to dynamically reconfigure effective electrode structures in the device. The frequency of a drive signal that generates an electric field in the device can be varied, and the frequency dependent material has different charge mobilities for the different frequencies. At a low charge mobility, the frequency dependent material has little effect on the existing electrode structures. However, at a high charge mobility, the frequency dependent material appears as an extension of the fixed electrodes, and can be used to change the effective electrode structure and, thereby, the spatial profile of the electric field. This, in turn, changes the optical properties of the liquid crystal, thus allowing the optical device to be frequency controllable.

First claim

What is claimed is:

1. A tunable lens optical device for controlling the propagation of light passing through the device using a dynamically-configured effective electrode geometry, said optical device comprising:
a liquid crystal layer configured to pass said light therethrough, optical properties of the liquid crystal layer controlling said light propagation;
an electrode system arranged to generate an electric field acting on said liquid crystal layer the electrode system including a segmented ring electrode; and
an electrical signal generator for generating a drive signal at a plurality of different frequencies and applying the drive signal to the electrode system to generate said electric field, the electrical signal generator being further configured to apply a separate drive signal component of the drive signal to each electrode segment of the segmented ring electrode, each drive signal component having a corresponding frequency;
wherein:
said electrode system comprises a frequency dependent material interacting with the electric field, the frequency dependent material having a charge mobility therein that varies with a frequency of the drive signal such that a spectral content of said drive signal dynamically configures an effective electrode geometry of said electrode system whereby a spatial profile of the electric field varies as a function of said spectral content to alter the optical properties of the liquid crystal layer; and
said electrode system is configured to controllably move an optical axis of the lens created in said liquid crystal layer by said electric field, driving said segmented ring electrode providing a parametric lens.

2. The device as claimed in claim 1 , further comprising a controller for dynamically adjusting said electrical signal generator.

3. The device as claimed in claim 2 , further comprising a vibration sensor, wherein said controller adjusts optical axis position in response to vibration.

4. The device as claimed in claim 3 , wherein said vibration sensor is an accelerometer.

5. The device as claimed in claim 3 , wherein said vibration sensor is an image analyzer for analyzing a position of an image captured by an image sensor.

6. The device as claimed in claim 1 , the segmented ring electrode comprising six or more electrode segments.

7. The device as claimed in claim 1 , each drive signal component further having a corresponding voltage, wherein different voltages are applied to different electrode segments, driving said segmented ring electrode providing a parametric lens.

8. The device as claimed in claim 1 , said electrode system further comprising an arrangement of strip electrodes coupled to the frequency dependent material, wherein said electrical signal generator generates a drive signal component having a frequency and a voltage, said electrical signal generator being configured to apply to each strip electrode said drive signal component.

9. The device as claimed in claim 8 , said arrangement of strip electrodes is configured to operate in combination with said ring electrode via the same frequency dependent material.

10. The device as claimed in claim 9 , said arrangement of strip electrodes and corresponding frequency dependent material operate as a planar uniform electrode when substantially similar low frequency drive signal components are applied by the electrical signal generator.

11. The device as claimed in claim 9 , said arrangement of strip electrodes and corresponding frequency dependent material operate as a potential ramp electrode when dissimilar drive signal components of moderate to high frequencies are applied by the electrical signal generator, said potential ramp electrode altering said spatial profile of the electric field to provide beam steering.

12. The device as claimed in claim 8 , said arrangement of strip electrodes is configured to operate independently of said ring electrode, said arrangement of strip electrodes being coupled to an additional frequency dependent material.

13. The device as claimed in claim 12 , wherein said additional frequency dependent material and said arrangement strip electrodes are not involved in modulating said electric field to provide lensing.

14. A tunable lens optical device for controlling the propagation of light, said optical device comprising:
a liquid crystal layer containing a liquid crystal;
an electric field source configured to generate a spatially non-uniform electric field acting on said liquid crystal layer via an electrode system including a segmented ring electrode, such that an optical axis position of the lens can be controlled; and
a variable frequency electrical drive signal having a plurality of different frequencies that can be applied by said electric field source to the electrode system to generate said electric field, the electrical field source being further configured to apply a separate drive signal component of the drive signal to each electrode segment of the segmented ring electrode, each drive signal component having a corresponding frequency such that a spectral content of said drive signal dynamically configures an effective electrode geometry of said electrode system;
wherein the liquid crystal layer has a charge mobility that varies as a function of a frequency of said drive signal, and said liquid crystal shapes said electric field to be more spatially uniform so as to provide a desired light propagation behaviour.

Assignees

• Galstian Tigran
• Presniakov Vladimir
• Asatryan Karen
• Zohrabyan Armen
• Lensvector Inc

Inventors

• Galstian Tigran
• Presniakov Vladimir
• Asatryan Karen
• Zohrabyan Armen

Classifications

• G02F1/13471

  in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells (G02F1/13475 takes precedence) · CPC title

• G02F1/134309 Primary

  characterised by their geometrical arrangement · CPC title

• G02F2203/06

  Polarisation independent · CPC title

• G02F2001/294

  Physics · mapped topic

• G02F1/135

  Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied {(G02F1/133348 takes precedence)} · CPC title