Liquid crystal on silicon imager

• US 8,319,915 B2
• Filed: 08/03/2010
• Issued: 11/27/2012
• Est. Priority Date: 08/03/2009
• Status: Active Grant

• Current Assignee: XI'AN Yisheng Optoelectronics Technology Co., Ltd.
• Original Assignee: Shanghai Lexvu Opto Microelectronics Technology Co., Ltd.
• Inventors: Huang, Herb He
• Primary Examiner(s): Stahl, Mike
• Application Number:
  US12/849,216
• Publication Number:
  US 20110025957A1
• Time in Patent Office: 847 Days
• Field of Search: None
• US Class Current: 349/97
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133548 Wire-grid polarisers
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 2203/02 reflective

Abstract

The present invention relates to a liquid crystal on silicon imager. The imager includes a backplane substrate, a reflective polarization electrode array, a planar liquid crystal cell, a transparent conductive film and a transparent plate. The reflective polarization electrode array is placed onto the backplane substrate, consists of a plurality of reflective polarization electrodes, and a pattern of each of the reflective polarization electrodes is configured in a planar arrangement having regularly spaced and electrically isolated gaps in parallel to each other. The planar liquid crystal cell is placed above the reflective polarization electrode array. The transparent conductive film is placed above the planar liquid crystal cell. The transparent plate is placed on the transparent conductive film and facing incident light. Through embedding the reflective polarization electrodes, only one polarization portion could be reflected back, while the residual polarization portion is let pass but not reflected back as desired, thereby decreasing the loss in contrast ratio of the imager.

Claims

1. A liquid crystal on silicon imager, comprising:

a backplane substrate;

a reflective polarization electrode array, placed onto the backplane substrate, wherein the reflective polarization electrode array consists of a plurality of reflective polarization electrodes, and a pattern of each of the reflective polarization electrodes is configured in a planar arrangement having regularly spaced and electrically isolated gaps in parallel to each other;

a planar liquid crystal cell, placed above the reflective polarization electrode array;

a transparent conductive film, placed above the planar liquid crystal cell; and

a transparent plate, placed on the transparent conductive film and facing incident light;

wherein the reflective polarization electrodes are spatially regrouped into several groups, which have different micro structural patterns.

2. The liquid crystal on silicon imager according to claim 1, wherein the reflective polarization electrode array is coated with a first alignment layer, the transparent conductive film is coated with a second alignment layer, and the planar liquid crystal cell is sandwiched between the first alignment layer and the second alignment layer.

3. The liquid crystal on silicon imager according to claim 1, wherein the reflective polarization electrode array is deposited with a transparent protective dielectric coating and the planar liquid crystal cell is placed on the transparent protective dielectric coating.

4. The liquid crystal on silicon imager according to claim 3, wherein the transparent protective dielectric coating is formed into gaps between the reflective polarization electrodes, and the reflective polarization electrodes are electrically isolated from each other by the transparent protective dielectric coating.

5. The liquid crystal on silicon imager according to claim 1, wherein the liquid crystal on silicon imager further includes a driving circuitry connected to the reflective polarization electrodes respectively, and providing electrical charge onto and discharge from the reflective polarization electrodes, individually and independently.

6. The liquid crystal on silicon imager according to claim 1, wherein the reflective polarization electrode array further includes a plurality of pixel isolators, and the pixel isolators are placed between the reflective polarization electrodes to electrically isolate the reflective polarization electrodes each to other.

7. The liquid crystal on silicon imager according to claim 1, wherein the transparent conductive film is made of indium tin oxide.

8. The liquid crystal on silicon imager according to claim 1, wherein the backplane substrate is made from semiconductors including any one or combination of silicon, germanium, gallium and arsenic.

9. The liquid crystal on silicon imager according to claim 1, wherein the backplane substrate is made from glass, polymers or combination thereof.

10. The liquid crystal on silicon imager according to claim 2, wherein the first alignment layer and the second alignment layer are made of any one or combination of polyimide, oxides, nitrides and carbon.

11. The liquid crystal on silicon imager according to claim 3, wherein the transparent protective dielectric coating is made from any one or combination of polyimide, silicon oxide, silicon nitride and carbon.

12. The liquid crystal on silicon imager according to claim 1, wherein each of the reflective polarization electrodes comprises a plurality of parallel elongated conductive elements electrically connected each other and configured in parallel to the planar liquid crystal cell.

13. The liquid crystal on silicon imager according to claim 12, wherein the elongated conductive elements are made of any or combination of reflective metals and their alloys including aluminum, titanium, copper, platinum, silver and gold.

14. The liquid crystal on silicon imager according to claim 1, wherein the reflective polarization electrodes are divided into three groups, a first group of reflective polarization electrodes is configured to have a first polarization reflection spectrum, a second group of reflective polarization electrodes is configured to have a second polarization reflection spectrum and a third group of reflective polarization electrodes is configured to have a third polarization reflection spectrum, and the first, second and third groups of reflective polarization electrodes have different polarization reflection spectrum from each other.

15. The liquid crystal on silicon imager according to claim 14, wherein the first polarization reflection spectrum, the second polarization reflection spectrum and the third polarization reflection spectrum are corresponding to band pass spectra of blue, green and red, respectively;

or the first polarization reflection spectrum, the second polarization reflection spectrum and the third polarization reflection spectrum are corresponding to band block spectra of yellow, magenta and cyan, respectively.

16. The liquid crystal on silicon imager according to claim 14, wherein the first group of reflective polarization electrodes, the second group of reflective polarization electrodes and the third group of reflective polarization electrodes are spatially configured individually in a regularly interwoven planar pattern.

17. The liquid crystal on silicon imager according to claim 15, wherein the first group of reflective polarization electrodes, the second group of reflective polarization electrodes and the third group of reflective polarization electrodes are spatially configured individually in a regularly interwoven planar pattern.

18. The liquid crystal on silicon imager according to claim 1, wherein the several groups of reflective polarization electrodes have different polarization reflection spectrum.