Color liquid crystal display device using birefringence

• US 5,570,211 A
• Filed: 05/31/1994
• Issued: 10/29/1996
• Est. Priority Date: 03/02/1994
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Fujitsu Limited
• Inventors: Tsuda, Hideaki, Hanaoka, Kazutaka, Yoshida, Hidefumi, Nakamura, Kimiaki, Chida, Hideo
• Primary Examiner(s): Gross, Anita Pellman
• Assistant Examiner(s): Abraham, Fetsum
• Application Number:
  US08/251,865
• Time in Patent Office: 882 Days
• Field of Search: 359/53, 359/73, 359/76, 359/75, 359/78
• US Class Current: 349/74
• CPC Class Codes: G02F 1/133636 with twisted orientation, e.g. comprising helically oriented LC-molecules or a plurality of twisted birefringent sublayers
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

A color liquid crystal display device includes a compensation liquid crystal panel having a first thickness and a first predetermined twist angle of liquid crystal molecules in a first direction, a driver liquid crystal panel having a second thickness identical to the first thickness and a second predetermined twist angle of liquid crystal molecules in a second, opposite direction such that the second predetermined twist angle is identical with the first predetermined twist angle in terms of magnitude, a first polarizer provided on the compensation liquid crystal panel, and a second polarizer provided on the driver liquid crystal panel.

Claims

1. A color liquid crystal display device, comprising:

a first liquid crystal panel having upper and lower major surfaces for accommodating liquid crystal molecules, said first liquid crystal panel having a first thickness and a first predetermined twist angle of liquid crystal molecules in a first direction;

a second liquid crystal panel having upper and lower major surfaces for accommodating liquid crystal molecules, said second liquid crystal panel having a second thickness identical to said first thickness and a second predetermined twist angle of liquid crystal molecules in a second, opposite direction such that said second predetermined twist angle is identical with said first predetermined twist angle in terms of magnitude;

one of said first and second liquid crystal panels carrying electrode means for applying an electric field to said liquid crystal molecules therein;

said first and second liquid crystal panels being stacked such that said first liquid crystal panel is provided on said second liquid crystal panel to form a liquid crystal panel assembly;

a first polarizer provided on said first liquid crystal panel with a first polarization plane; and

a second polarizer provided on said second liquid crystal panel with a second polarization plane;

said first and second polarizers being disposed to form one of a first state wherein said first and second polarization planes are parallel with each other and a second state wherein said first and second polarization planes intersect with each other perpendicularly;

said first and second thicknesses being set such that a retardation larger than 1600 nm is obtained in each of said first and second liquid crystal panels.

2. A color liquid crystal display device as claimed in claim 1, wherein said first and second predetermined twist angles have a common absolute magnitude of 180 degrees.

3. A color liquid crystal display device as claimed in claim 2, wherein each of said first liquid crystal panel and second liquid crystal panel has an upper alignment layer and a lower alignment layer sandwiching therebetween a liquid crystal layer, for aligning liquid crystal molecules contacting thereto, said upper and lower alignment layer forming said first liquid crystal panel causing an alignment of said liquid crystal molecules that contact thereto in a first orientation, each of said upper and lower alignment,layers forming said second liquid crystal panel causing an alignment of said liquid crystal molecules that contact thereto in a second orientation that is substantially perpendicular to said first orientation.

4. A color liquid crystal display device as claimed in claim 3, wherein said first and second polarizers are,disposed such that said first and second polarization planes are parallel to each other, said polarization planes having a third orientation that generally bisects an angle formed between said first and second orientations.

5. A color liquid crystal display device as claimed in claim 4, wherein said third orientation forms an angle of substantially 45 degrees with respect to an elongating direction of said liquid crystal molecules.

6. A color liquid crystal display device as claimed in claim 4, wherein said first and second polarizers are disposed such that said first and second polarization planes intersect with each other perpendicularly, wherein each of said polarization planes bisects an angle formed between said first and second orientations.

7. A color liquid crystal display device as claimed in claim 1, wherein said first and second thicknesses fall in a range between 10-30 μ

m.

8. A color liquid crystal display device as claimed in claim 1, wherein said color liquid crystal display device further includes a retardation film between said first polarizer and said first liquid crystal panel, said retardation film having an optical axis perpendicular to a plane of said first liquid crystal panel.

9. A color liquid crystal display device as claimed in claim 8, wherein said retardation film has a birefringence .sub..increment. n'"'"', when viewed from a direction offset from said optical axis by 30 degrees, that satisfies a relationship

10. A color liquid crystal display device as claimed in claim 1, wherein one of said first and second liquid crystal panels carries thereon pixel electrodes and corresponding thin-film transistors such that each of said thin-film transistors energizes a corresponding pixel electrode.

11. A color liquid crystal display device comprising:

a first liquid crystal panel having upper and lower major surfaces for accommodating liquid crystal molecules, said first liquid crystal panel having a first thickness and a first predetermined twist angle crystal molecules in a first direction;

a second liquid crystal panel having upper and lower major surfaces for accommodating liquid crystal molecules, said second liquid crystal panel having a second thickness identical to said first thickness and a second predetermined twist angle of liquid crystal molecules in a second, opposite direction such that said second predetermined twist angle is identical with said first predetermined twist angle in terms of magnitude;

one of said first and second liquid crystal panels carrying electrode means for applying an electric field to said liquid crystal molecules therein;

said first and second liquid crystal panels being stacked such that said first liquid crystal panel is provided on said second liquid crystal panel to form a liquid crystal panel assembly;

a first polarizer provided on said first liquid crystal panel with a first polarization plane; and

a second polarizer provided on said second liquid crystal panel with a second polarization plane;

said first and second polarizers being disposed to form one of a first state wherein said first and second polarization planes are parallel with each other and a second state wherein said first and second polarization planes intersect with each other perpendicularly;

said first and second thicknesses being set such that a retardation larger than 1000 nm is obtained in each of said first and second liquid crystal panels;

wherein each of said first and second liquid crystal panels include an upper molecular alignment layer and a lower molecular alignment layer that sandwich a liquid crystal layer therebetween, each of said upper and lower molecular alignment layers being formed of areas corresponding to pixels, each of said areas being formed of a first region having a first rubbing direction and a second region having a second, opposite rubbing direction, wherein said first region of said upper molecular alignment layer faces said first region of said lower molecular alignment layer across said liquid crystal layer, and wherein said second region of said upper molecular alignment layer faces said second region of said lower molecular alignment layer across said liquid crystal layer.

12. A color liquid crystal display device as claimed in claim 11 wherein said first and second regions of said upper molecular alignment layer provide respectively a low pretilt angle and a high pretilt angle to said liquid crystal molecules in said liquid crystal layer, and wherein said first and second regions of said lower molecular alignment layer provide respectively a high pretilt angle and a low pretilt angle to said liquid crystal molecules in said liquid crystal layer.

13. A color liquid crystal display device as claimed in claim 12 wherein said first region of said upper molecular alignment layer and said second region of said lower molecular alignment layer are formed of an inorganic material that provides said low pretilt angle, and wherein said second region of said upper molecular alignment layer and said first region of said lower molecular alignment layer are formed of an organic material that provides said high pretilt angle.

14. A color liquid crystal display device as claimed in claim 13, wherein said second region of said upper molecular alignment layer comprises a pattern of said organic material provided on a layer of said inorganic material, and wherein said second region of said lower molecular alignment layer comprises a pattern of said organic material provided on a layer of said inorganic material, wherein said pattern of said organic material exposes, in said upper molecular alignment layer, said layer of inorganic material as said second region, and wherein said pattern of said organic material exposes, in said lower molecular alignment layer, said layer of inorganic material as said first region.

15. A color liquid crystal display device as claimed in claim 12, wherein each of said areas further includes, in each of said upper and lower molecular alignment layers, third and fourth regions having third and fourth rubbing directions such that said third rubbing direction-is opposite to said fourth rubbing direction and such that each of said third and fourth rubbing directions is perpendicular to any of said first and second rubbing directions, wherein said upper and lower molecular alignment layers are disposed such that said third region of said upper molecular alignment layer faces said third region of said lower molecular alignment layer and such that said fourth region of said upper molecular alignment layer faces said fourth region of said lower molecular alignment layer.