Birefringent liquid crystal structure

• US 3,876,287 A
• Filed: 06/29/1973
• Issued: 04/08/1975
• Est. Priority Date: 06/29/1973
• Status: Expired due to Term

• Current Assignee: Gerard J. Sprokel
• Original Assignee: Gerard J. Sprokel
• Inventors: Sprokel, Gerard J.
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Godwin, Paul K.
• Application Number:
  US05/375,193
• Time in Patent Office: 648 Days
• Field of Search: 350/16LC
• US Class Current: 349/177
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence

Abstract

A field-effect liquid crystal structure having birefringent properties controlled by crossed electric fields in conjunction with crossed polarizing units.

Claims

1. A LIQUID CRYSTAL CELL COMPRISING:

A. A BODY OF LIQUID CRYSTAL MATERIAL HAVING POSITIVE DIELECTRIC ANISOTROPY;

B. MUTUALLY ORTHOGONAL ELECTRICAL CROSS-FIELD MEANS FOR SELECTIVELY ORIENTING SAID MATERIAL IN ISOTROPIC AND ANISOTROPIC MODES ALONG AN OPTICAL PATH;

AND C. MEANS FOR DIFFERENTIATING ISOTROPIC AND ANISOTROPIC LIGHT TRANSMISSION THROUGH SAID MATERIAL ALONG SAID PATH, D. WHEREIN SAID DIFFERENTIATING MEANS COMPRISES CROSSPOLARIZING MEANS DISPOSED ALONG SAID PATH, WHEREIN SAID CROSS-POLARIZING MEANS COMPRISES E. A POLARIZING ELEMENT AND A QUARTER WAVE PLATE INTERMEDIATE THERETO AND ONE-SIDE OF SAID MATERIAL AND F. REFLECTING MEANS ADJACENT AN OPPOSITE SIDE OF SAID MATERIAL.

2. A liquid structure comprising a cell defined by:

A. a body of nematic liquid crystal material having positive dielectric anisotropy;

B. means for forming mutually orthogonal electrical cross-fields across said material;

C. means for selectively inducing dominance in one of said cross-fields to selective orient said material in optional isotropic and anisotropic modes along an optical path; and

D. means to differentiate isotropic and anisotropic transmission of light through said material along said path, E. wherein said differentiating means comprises cross-polarizer means disposed along said path, wherein said cross-polarizer means comprises F. a polarizing element and G. a quarter wave plate intermediate thereto and on one side of said material, and H. a reflecting means adjacent an opposite side of said material.

3. A LIQUID CRYSTAL STRUCTURE COMPRISING CELLS DEFINED OF:

A. A LAYER OF NEMATIC LIQUID CRYSTAL MATERIAL HAVING POSITIVE DIELECTRIC ANISOTROPY;

B. FIRST AND SECOND TRANSPARENT AND OPPOSED ELECTRODES ENCLOSING SAID LIQUID CRYSTAL LAYER, C. FIRST AND SECOND TRANSPARENT DIELECTRIC FILMS ON THE INNER FACES OF RESPECTIVE ONES OF SAID FIRST AND SECOND ELECTRODES IN INSULATING RELATIONSHIP TO SAID LIQUID CRYSTAL LAYER;

D. THIRD AND FOURTH SPACED ELECTRODES A. DISPOSED BETWEEN SAID DIELECTRIC FILMS AND B. CONFINING A PORTION OF SAID LIQUID CRYSTAL LAYER THEREBETWEEN, E. FIRST MEANS FOR COUPLING SAID THIRD AND FOURTH ELECTRODES TO A VOLTAGE SOURCE FOR GENERATING A FIRST ELECTRIC FIELD IN A FIRST DIRECTION TO AN ISOTROPICALLY ORIENT SAID LIQUID CRYSTAL MATERIAL THEREBETWEEN IN A FIRST DIRECTION PARALLEL THERETO AND F. SECOND MEANS FOR COUPLING SAID FIRST AND SECOND ELECTRODES TO A SECOND VOLTAGE SOURCE FOR GENERATING A SECOND FIELD TO ISOTROPICALLY ORIENT SAID LIQUID CRYSTAL MATERIAL THEREBETWEEN IN A SECOND DIRECTION PARALLEL THERETO AND TRANSVERSE SAID FIRST DIRECTION.

4. The liquid crystal structure of claim 3 wherein said first coupling means is adapted to connect said second and third electrodes in permanent relationship to said first voltage source during operation of said structure for generating a fixed field in said first direction to anistropicality orient said nematic material along an optical path therethrough;

and said second coupling means is to selectively connect said first and second electrodes to said second voltage source generating a dominating field in said second direction to isotropical orient said material along said optical path.

5. The liquid crystal structure of claim 3 including cross-polarizer means for controlling passage of light through said liquid crystal material transverse said first direction.

6. The liquid crystal structure of claim 5 wherein said cross-polarizer means are laminated to said structure.

7. The liquid structure of claim 6 wherein said cell comprises one of a plurality in a liquid crystal display.

8. The liquid crystal structure of claim 5 wherein said cross-polarizer means for transmissive operating modes comprises a polarizer element adjacent said first electrode and cross-polarizing element adjacent said second electrode along an optical path transverse said first direction.

9. The liquid structure of claim 8 wherein said cell comprises one of a plurality in a liquid crystal display.

10. The liquid crystal structure of claim 8 wherein both said polarizing elements are laminated to said structure.

11. The liquid structure of claim 10 wherein said cell comprises one of a plurality in a liquid crystal display.

12. The liquid crystal structure of claim 5 wherein said cross-polarizer means comprises a quarter wave plate adjacent said first electrode;

polarizer means adjacent said plate; and

reflecting means adjacent said second electrode.

13. The liquid structure of claim 12 wherein said cell comprises one of a plurality in a liquid crystal display.

14. The liquid cell structure of claim 12 wherein the said quarter wave plate and said polarizer and reflecting means are laminated on said structure.

15. The liquid structure of claim 14 wherein said cell comprises one of a plurality in a liquid crystal display.

16. The liquid structure of claim 5 wherein said cell comprises one of a plurality in a liquie crystal display.

17. The liquid crystal structure of claim 3 including front and back transparent support having said first and second electrodes coated on respective inner-opposed faces thereof.

18. The liquid structure of claim 17 wherein said cell comprises one of a plurality in a liquid crystal display.

19. The liquid crystal structure of claim 18 including cross-polarizer means for controlling passage of light through said liquid crystal material transverse said first direction.

20. The liquid crystal cell structure of claim 19 wherein said cross-polarizer means comprises a quarter wave plate adjacent said front electrode;

a polarizing means adjacent said plate; and

a reflecting surface adjacent said back support.

21. The liquid cell structure of claim 20 wherein said quarter wave plate and said polarizing element are laminated to said front support, and said reflecting means comprises a laminate on said back support.

22. The liquid crystal cell structure of claim 19 wherein said cross-polarizer means comprises a polarizing element adjacent said front support and a cross-polarizing element adjacent said back support.

23. The liquid cell structure of claim 22 wherein both said polarizing elements are laminated to respective ones of said front and back supports.

24. The liquid cell structure of claim 19 wherein said cross-polarizer means is laminated to said supports.