Nippon Electric Co., Ltd.

Sumitomo Chemical Company, Limited

Nec Corporation

Sanyo Chemical Industries, Ltd.

Chizuka Tani

Hirohito Kenmochi

Toshihiko Ueno

Yasutaka Shimidzu

Masahiro Satoh

Toyokazu Nakamura

Kunikiyo Yoshio

Hiroshi Kishiki

Shohei Naemura

Hiroshi Hoshino

Fumihiro Ogawa

Yuzi Kato

Liquid Crystal compounds represented by the following formula are disclosed. ##STR1## wherein R and R' are independently selected from alkyl groups containing 1.about.20 carbon atoms; X is --O--, --O--CO--O-- or direct bond; A.sub.1 and A.sub.2 are independently cyclic groups (such as phenylene and biphenylene), said cyclic groups may be substituted with 1.about.4 fluorine, chlorine or bromine atoms, or 1 or 2 substituent groups selected from the group consisting of cyano, nitro and trifluoromethyl groups; Y is --CO--O--, --O--CO--, --C.tbd.C--, --CH.sub.2 O--, --OCH.sub.2 --, --CH.dbd.N--, --N.dbd.CH--, --N.dbd.N--, --CH.sub.2 S--, --SCH.sub.2 -- or direct bond; and * represents asymmetric atom providing optical activity.

Liquid crystal compounds and compositions

A liquid crystal display device comprising a liquid crystal composition filled between one pair of electrode substrates at least one of which is transparent, said liquid crystal composition containing one or more blue dye(s) represented by the following general formula: ##STR1## wherein one of X and Y is amino group and the other is hydroxyl group; and R is alkyl group, alkoxy group, alkylthio group, aryl group, aralkyl group, aryloxy group, arylthio group, aralkyloxy group, aralkylthio group, halogen atom, piperidino group, piperazino group, morpholino group, pyrrolidino group or a group ##STR2## in which R.sub.1 and R.sub.2 are hydrogen atom, alkyl group, aryl group or aralkyl group; provided that the alkyl chain and the aryl ring in substituents R, R.sub.1 and R.sub.2 may optionally be substituted.

Liquid crystal dye compound

Liquid crystal display device

A liquid crystal cell includes a nematic liquid crystal of negative dielectric anisotropy is disposed between a pair of transparent electrode substrates. The electrode substrates have on their inner surfaces small grooves formed parallel to each other, the grooves on one surface being perpendicular to those on the other surface. In the absence of a voltage applied between the substrates, the long axes of the liquid crystal molecules are perpendicular to the inner surfaces of the electrode substrates. The addition of a small amount of a cholesteric liquid crystal material markedly improves the contrast of the display.

Growing community of inventors

Tokyo, Japan

Chizuka Tani