Hitachi, Ltd.

Dainippon Ink and Chemicals, Incorporated

Tamihito Nakagomi

Shinji Hasegawa

Yasuhiko Kando

Kazuhisa Toriyama

Hisato Sato

Haruyoshi Takatsu

Makoto Sasaki

Yoshi Arai

Masatoshi Ito

Yutaka Fujita

Yoshio Hanada

Katsuhiko Morita

Tuneo Shimamura

A liquid crystal display device including a nematic liquid crystal composition having a twist angle of 160.degree. to 260.degree. of liquid crystal molecules and at least one compound of the formula: ##STR1## (m, n=1-7) further improved in time-multiplexability and display quality.

Liquid crystal display device

A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 96.degree. and 108.degree. along a direction of thickness thereof, absorption axes of a pair of polarizing plates disposed on the upper and lower substrates constitute an angle between 63.degree. and 73.degree., and a product .DELTA.n.multidot.d of a thickness d (.mu.m) and an optical anisotropy .DELTA.n of a liquid crystal layer falls within a range from 0.69 .mu.m to 0.79 .mu.m.

A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 200.degree. and 260.degree. along a direction of thickness thereof, and polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are angularly displaced by a predetermined angle or predetermined angles from major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively.

Liquid crystal display device having a chiral additive and angularly

A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 160.degree. and 200.degree. along a direction of thickness thereof, and polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are inclined by a predetermined angle with respect to major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively.

A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 140.degree. and 250.degree. along a direction of thickness thereof, and polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are angularly displaced by a predetermined angle or predetermined angles from major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively, and a ratio of thickness of the nematic liquid crystal to a natural molecular helical pitch of the nematic liquid crystal added with a chiral material falls within a range of from 0.14 to 0.60 inclusive.

A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 90.degree. and 160.degree. along a direction of thickness thereof, polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are inclined by a predetermined angle falling within a range between 25.degree. and 65.degree. with respect to major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively, and in the direction of the twist of the liquid crystal, and a product .DELTA.n.multidot.d of a thickness d (.mu.m) and an optical anisotropy .DELTA.n of a liquid crystal layer falls within a range from 0.8 .mu.m to 1.2 .mu.m.

A nematic liquid crystal composition comprising (a) at least one compound of the formula: ##STR1## wherein R.sub.1 is n--C.sub.m H.sub.2m+1, n--C.sub.m H.sub.2m+1 --O or n--C.sub.m H.sub.2m+1 --CO; R.sub.2 is n--C.sub.q H.sub.2q+1, n--C.sub.q H.sub.2q+1 --O or n--C.sub.q H.sub.2q+1 --CO; m and q are each an integer of 1 to 10 and n is a symbol indicating that carbons are linked linearly, and (b) at least one compound of the formula: ##STR2## wherein R.sub.3 is n--C.sub.r H.sub.2r+1 or n--C.sub.r H.sub.2r+1 --O; R.sub.4 is n--C.sub.s H.sub.2s+1 or n--C.sub.s H.sub.2s+1 --O; r and s are each an integer of 1 to 10 and n is as defined above, and where necessary (c) at least one nematic liquid crystal compound having positive dielectric anisotropy and/or its homologous compound, and if necessary (d) at least one nematic liquid crystal compound having negative dielectric anisotropy and/or its homologous compound. This liquid crystal composition, when used for a display device, shows excellent properties in that it is oriented with high stability over a wide temperature range, allows wide-range setting of threshold voltage and is small in temperature dependency and quick to respond to the applied voltage.

Nematic liquid crystal composition for display devices

A compound represented by the general formula ##STR1## wherein R represents a linear alkyl group having 1 to 10 carbon atoms.

4-N-Alkylbenzoyloxy-3'-fluoro-4'-cyanobenzenes

A nematic liquid crystal composition composed of (i) at least one compound of the general formula ##STR1## wherein R.sub.1 represents n-C.sub.m H.sub.2m+1, R.sub.2 represents n-C.sub.q H.sub.2q+1 -O, and m and q are integers of 1 to 10, (ii) at least one compound selected from the group consisting of nematic liquid crystalline compounds having positive dielectric anisotropy and homologs thereof, and (iii) as an optional ingredient, at least one compound selected from the group consisting of nematic liquid crystalline compounds having negative dielectric anisotropy and homologs thereof. This liquid crystal composition is colorless and chemically stable and has superior multiplexing drive characteristics. These properties render it useful as a display element.

Growing community of inventors

Mobara, Japan

Tamihito Nakagomi