Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Patent
1999-02-02
2000-10-03
Parker, Kenneth
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
349 88, 349 92, G02F 11333
Patent
active
061280569
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a liquid crystal display element, and more particularly, to a polymer dispersed liquid crystal display element in which liquid crystal is dispersed in polymer compound and a producing method therefor.
BACKGROUND ART
A polymer dispersed liquid crystal display element, which is a display system utilizing the light scattering effects of the composite material comprising liquid crystal and polymer compound, requires no polarizers to produce linearly polarized light, unlike general type liquid crystal display elements such as Twisted Nematic (TN), and thus has a high light availability efficiency. Accordingly, attention is being given to the polymer dispersed liquid crystal display element as the coming generation of liquid crystal display element, and the research and development are being lively made.
The polymer dispersed liquid crystal display element can be classified under the following structure. First is the structure of Nematic liquid crystal being micro-encapsulated with polyvinyl alcohol and the like, which is called NCAP (Nematic Curviliner Aligned Phase); Second is the structure of liquid crystal droplets of a generally spherical or ellipsoid-of-revolution form being each separately dispersed in polymer matrix, which is called PDLC (Polymer Dispersed Liquid Crystal) (e.g. Society for information display international symposium digest '90 P.227-230); Third is the structure of the liquid crystal droplets existing in the form of being partly contacting with and connecting with each other, not in the form of being separate from each other (e.g. 22.sup.nd liquid crystal symposium digest 1996 P403-404); and Fourth is the structure of polymer resin spreading in the form of a three dimensional network in a continuous phase of liquid crystal, which is called PNLC (Polymer Network Liquid Crystal) (e.g. U.S. Pat. No. 5,304,323 and 15.sup.th liquid crystal symposium digest 1989 P190).
Usually, only one of these kinds of structure was adopted in these conventional type of polymer dispersed liquid crystal display elements.
Take the polymer dispersed liquid crystal display element of the conventional type having the structure of the liquid crystal droplets being dispersed in the form of a part thereof being contacting with and connecting with each other (see FIG. 31(a)) for instance, it was produced by the following technique.
First, opposing upper and lower substrates 1001 and 1002 were bonded together through a sealant 1006 so that an uniform gap could be formed therebetween. Then, a mixture including liquid crystal material and polymerizable monomer was filled in between the upper and lower substrates 1001 and 1002. After polymerization temperature and irradiation intensity of ultraviolet was so set as to be prescribed conditions,. the mixture was irradiated with ultraviolet, so that the monomer is polymerized to cause a phase separation of the liquid crystal material. The irradiation of ultraviolet was so controlled as to be uniform in the panel surface.
As a result of this, the state of the liquid crystal material being dispersed in the polymer matrix or the state of the liquid crystal material being dispersed in continuation in the polymer matrix was presented between the two substrates in accordance with the prescribed conditions (cf. e.g. Flat panel display '91, NIKKEI BP Co., Ltd., Page 221).
However, the polymer dispersed liquid crystal display element having the structure of the liquid crystal droplets being completely separated from each other, which is in actual use in the TFT liquid crystal panel, is low in light scattering, thus presenting problems of low contrast and high driving voltage.
The reduction of scattering of light is caused for the following reason. In the case of liquid crystal droplets being separated from each other, their particle size is about 0.8 .mu.m, which corresponding to about 69% of the percentage of the liquid crystal. If the particle size and percentage of the liquid crystal exceed these values, the liquid crystal drople
REFERENCES:
patent: 3872050 (1975-03-01), Benton et al.
patent: 5200845 (1993-04-01), Crooker et al.
patent: 5243451 (1993-09-01), Kanemoto et al.
patent: 5304323 (1994-04-01), Arai et al.
patent: 5327271 (1994-07-01), Takeuchi et al.
patent: 5353133 (1994-10-01), Bernkopf
patent: 5401437 (1995-03-01), Im
patent: 5427828 (1995-06-01), Park
patent: 5519519 (1996-05-01), Nakajima et al.
patent: 5559615 (1996-09-01), Takei et al.
patent: 5729312 (1998-03-01), Yamagishi et al.
patent: 5738804 (1998-04-01), Cao et al.
patent: 6017468 (2000-01-01), Chung et al.
Tahara et al., Structure Analysis of LCPC by Conocal Fluorescence Microscopy and its Application, 1996, pp. 403-404.
Kobayashi et al., Light Switching Properties and mechanism of Electro-Optical Effect for (Polymer)/(Liquid crystal) Composite Film, 1989, pp. 190-191.
Flate Panel Display, 1991, pp. 219-224.
Kunigita et al., A Full-Color Projection TV Using LC/Polymer Composite Light Valves, 1990, pp. 227-230.
Tahara et al., Structure Analysis of LCPC by Confocal Fluorescence Microscopy and its Application, 1996, pp. 403-404 with partial translation.
Kobayashi et al., Light Switching Properties and Mechanism of Electro-Optical Effect for (Polymer)/(Liquid Crystal) Composite Film, 1989, pp. 190-191 with partial translation.
Flat Panel Display, 1991, pp. 219-224, with partial translation.
Kunigita et al., A Full-Color Projection TV Using LC/Polymer Composite Light Valves, 1990, pp. 227-230.
Kubota Hirofumi
Nakao Kenji
Uemura Tsuyoshi
Matsushita Electric - Industrial Co., Ltd.
Parker Kenneth
Qi Mike
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