Kabushiki Kaisha Toshiba

Toshiba Techno Center Inc.

Masumi Okamoto

Hitoshi Hatoh

Masahito Ishikawa

Takeshi Yamamoto

Rei Hasegawa

Kazuyuki Sunohara

Hiroyuki Nagata

Yasuharu Tanaka

Yasuhiro Yamamoto

Nobuko Fukuoka

Yuzo Hisatake

Atsuyuki Manabe

Makiko Sato

Masato Shoji

Toshihiro Ninomiya

Norihiro Yoshida

Tsuyoshi Ohyama

In a liquid crystal display device having a driving liquid crystal cell interposed between two polarizers and , the cell having a liquid crystal layer held between two substrates and , the layer having a twisted molecular alignment when no voltage is applied, and the liquid crystal cell performing optical control, using the optical anisotropy of liquid crystal, there is provided with an optical anisotropic element between the polarizer and the driving liquid crystal cell, the optical anisotropic element comprising an optical anisotropic substance layer in which the optical rotatory power is minimal in the direction of layer thickness and the optical anisotropy is negative. The angle of the optical axis of the optical anisotropic element varies continuously or in stages in the direction of layer thickness of the optical anisotropic element as against the surface of the optical anisotropic element. Furthermore, optical anisotropic element with negative optical anisotropy can be combine to the anisotropically negative element.

Liquid crystal display device with compensation for viewing angle dependency and optical anisotropic element used therein

In an electooptical liquid crystal device comprising an OCB mode liquid crystal cell and an optically anisotropic element compensating a viewing angle characteristics of the cell, the optically anisotropic element satisfies the elliptical coefficient Z of the index ellipsoid of the optically anisotropic element,

Electrooptical liquid crystal device

A liquid crystal display device comprising a liquid crystal cell including a pair of substrates each having an alignment film on the surface thereof, and a liquid crystal filled in a space between the substrates, which is provided with a plurality of alignment regions, each region having the direction of alignment or the rise direction of liquid crystal molecule different from another region within a display region. The alignment film comprises a polyimide having a glass transition point of 300.degree. to 400.degree. C., a skeleton having no two-revolution axis, non-conjugated carbon occupying 10 to 60% of the total number of carbon excluding carbon atoms directly connected to imido group, a relative dielectric constant of 4 to 7 at a frequency of 1kH and at a temperature of 20.degree. C., or an imidization degree of not less than 90%, or a polyimide obtained by reacting tetracarboxylic acid di-anhydride with a di-amine compound, or a polyimide obtained by imidizing a polyimide, the tetracarboxylic acid di-anhydride moiety being prohibited of the free rotation thereof.

Liquid crystal display device

A liquid crystal display device comprising a liquid crystal cell including a pair of substrates each having an alignment film on the surface thereof, and a liquid crystal filled in a space between the substrates, which is provided with a plurality of alignment regions, each region having the direction of alignment or the rise direction of liquid crystal molecule different from another region within a display region. The alignment film comprises a polyimide having a glass transition point of 300.degree. to 400.degree. C., a skeleton having no two-revolution axis, non-conjugated carbon occupying 10 to 60% of the total number of carbon excluding carbon atoms directly connected to imido group, a relative dielectric constant of 4 to 7 at a frequency of 1 kH and at a temperature of 20.degree. C., or an imidization degree of not less than 90%, or a polyimide obtained by reacting tetracarboxylic acid di-anhydride with a di-amine compound, or a polyimide obtained by imidizing a polyimide, the tetracarboxylic acid di-anhydride moiety being prohibited of the free rotation thereof.

Between the substrates with electrodes arranged to face each other, there is held a neamtic liquid crystal layer having a molecular arrangement capable of obtaining two or more directions of the tilt direction when an electric field is applied. The electrode structure is formed by a region having the conductive sections the width of which is 50 .mu.m or less in the widest part and the non-conductive sections the width of which is 50 .mu.m or less in the widest part per pixel. Between the substrates arranged to face each other, the conductive sections and non-conductive sections are opposed to each other at least per pixel in a part of the region in the pixel, and given the width of the narrowest part of the non-conductive sections as S, and the distance between the electrodes of the substrates arranged to face each other as D, the relationship of D.gtoreq.S/2 is satisfied. With this structure, it is possible to obtain a liquid crystal display device having a high light scattering characteristic at a low driving voltage, and also, with a high gradation having a bright contrast ratio. There is no inverted display even when a gradation display is executed, and a liquid crystal display device can be obtained with an extremely wide viewing angle. These characteristics can be sufficiently maintained in practice in a state of a voltage being applied.

Liquid crystal device with pixel electrodes in an opposed striped form

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Yokohama, Japan

Masumi Okamoto