Liquid crystal display having a fine particle-dispersion layer on at least one side of the liquid crystal layer

• US 5,552,914 A
• Filed: 05/26/1995
• Issued: 09/03/1996
• Est. Priority Date: 07/30/1992
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tsukamoto, Takeo, Kaneko, Tetsuya, Shinjo, Katsuhiko, Kaneko, Shuzo
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): MILLER, CHARLES LELAND
• Application Number:
  US08/452,002
• Time in Patent Office: 466 Days
• Field of Search: 359/87, 359/100, 359/54, 359/56, 359/74
• US Class Current: 349/139
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/141 using ferroelectric liquid crystals
• CPC Class Codes: G02F 2203/30 Gray scale

Abstract

A liquid crystal display device is constituted by a pair of oppositely disposed substrates each having a plurality of opposing electrodes, and a ferroelectric liquid crystal disposed between the substrates so as to form a plurality of pixels each composed by a combination of a pair of the opposing electrodes and the ferroelectric liquid crystal disposed therebetween. Each pixel is provided with regions of different polarity inversion threshold voltages, and at least one of the pair of opposing electrodes is provided with a plurality of regions having unevennesses at different densities including a region with a higher density of unevennesses corresponding to a region of a lower polarity inversion threshold voltage and a region with a lower density of unevennesses corresponding to a region of a higher polarity inversion threshold voltage.

Claims

1. A liquid crystal optical device:

comprising a plurality of pixels each comprising a pair of opposing electrodes and a ferroelectric liquid crystal layer disposed between the opposing electrodes, wherein at least one opposing electrode is coated with a fine particle-dispersion layer containing electroconductive ultrafine particles having an average particle size of 30-300 Å and

further an alignment control layer disposed to allow a local direct contact of the fine particle dispersion layer with the ferroelectric liquid crystal layer.

2. A device according to Claim 1, wherein said alignment control layer has an average thickness at its film-retaining portion which is smaller than the average particle size of the ultrafine particles.

3. A device according to Claim 1 or 2, wherein said alignment control layer has an average thickness at its film-retaining portion of 20-100 Å

.

4. A device according to Claim 1 or 2, wherein said pair of opposing electrodes are respectively provided with alignment control layers which have substantially anti-parallel alignment control directions.

5. A device according to Claim 1 or 2, wherein said fine particles-dispersion layer comprises a matrix polymer.

6. A device according to Claim 1 or 2, wherein said ferroelectric liquid crystal is provided with an apparently increased tilt angle by application of an AC electric field after disposing the liquid crystal between the opposing electrodes.

7. A liquid crystal optical device comprising a plurality of pixels each comprising a pair of opposing electrodes and a chiral smectic liquid crystal layer disposed in a thickness between the opposing electrodes, wherein:

each pixel comprises projections and a film covering the projections and containing particles having an average particle size of 30-300 Å

on at least one of the opposing electrodes;

the projections have a height larger than the average particle size of the particles; and

the projections are disposed at a pitch which is substantially equal to or larger than the thickness of the liquid crystal layer.

8. A device according to Claim 7, wherein the particles are electroconductive.

9. A device according to Claim 7, wherein the particles are unevenly dispersed.

10. A device according to Claim 9, wherein the particles have a self-aligning property at a time of dispersion application.

11. A liquid crystal optical device comprising a plurality of pixels each comprising a pair of opposing electrodes and a chiral smectic liquid crystal layer disposed between the opposing electrodes, wherein at least one opposing electrode is coated with a fine particle-dispersion layer, containing electroconductive ultrafine particles having an average particle size of 30-300 Å

and an alignment control layer disposed to allow a local direct contact of the fine particle dispersion layer with the chiral smectic liquid crystal layer.