Citizen Watch Company, Ltd.

Asahi Denka Kogyo Kabushiki Kaisha

L.c.c. Consultants Co., Ltd.

Tomijiro Naito

Yumiko Sakamaki

Katsuji Niino

Kikuo Yamamoto

Hisato Sato

Toshiro Yukinari

Toshihiro Shibata

Masaki Kimura

Yukari Shinada

Yasunobu Tuji

Yumiko Sato

A novel tolan compound of the formula (I):

Tolan compound and liquid crystal composition containing the same

A novel tolan compound of the formula (I): ##STR1## wherein A is C.sub.1-10 alkyl, C.sub.1-10 alkoxy, cyclohexyl substituted by C.sub.1-10 alkyl at 4 position, cyclohexyl substituted by C.sub.1-10 alkoxy group at 4 position or a group of the formula: ##STR2## wherein Y is hydrogen or halogen and Z is C.sub.1-10 alkyl or halogen; B is a single bond or --CO--O-- or --O--CO--; D is hydrogen, C.sub.1-10 alkyl, cyclohexyl substituted by C.sub.1-10 alkyl at 4 position; and Z represents a hydrogen atom or a halogen atom. The tolan compound can increase the N-I point, decrease the viscosity, and increase the double refractive index of a liquid crystal composition without affecting the viscosity and threshold voltage Vth, and is mutually soluble with various other liquid crystal compounds, so that the compound can be used as a constituent of a liquid crystal composition in combination with these other liquid crystal materials to improve the properties of the composition.

A novel tolan compound of the formula (I): ##STR1## wherein A is a substituted or unsubstituted cyclohexyl or phenyl group; B is --CO--O-- or --O--CO--; X is a hydrogen atom, a halogen atom, a cyano group, a C.sub.1 -C.sub.10 alkyl group, or a C.sub.1 -C.sub.10 alkoxy group; Y is a hydrogen atom or a halogen atom; and m and n are an integer of 0 or 1, provided that m+n=0 or 1. The tolan compound can raise the N-I point and increase the double refractive index (.DELTA.n) of liquid crystal compositions. The liquid crystal composition containing this tolan compound has excellent characteristics as a liquid crystal material, and the liquid crystal display device using this liquid crystal composition has a wide temperature range and a wide visible angle and can be operated at a low driving voltage.

Benzyl ether derivative and composition containing the same

An ester derivative represented by the following formula (I). ##STR1## In the formula, V, W, X, Y and Z represent a hydrogen atom or a halogen atom, respectively. The present invention also comprises a liquid crystal composition containing the ester derivative. The ester derivative can optimize the n value, lower the viscosity and reduce the threshold voltage Vth of the liquid crystal composition.

Ester derivatives

Particular 1,4-substituted dihydrobenzene derivatives are useful as liquid crystalline materials. They are represented by the following formula (I): ##STR1## wherein A means a 1,4-dihydrophenylene group, R denotes a hydrogen atom or an alkyl or trans-4-alkylcyclohexyl group, R' represents a hydrogen or halogen atom, a trifluoromethyl, trifluoromethoxy, cyano, alkyl, alkoxyl or carboxyl group or a group --COO--B--R' in which B stands for an unsubstituted or halogen-substituted 1,4-phenylene or 1,4-cyclohexenylene group and R' represents a halogen atom or a cyano, alkyl or alkoxyl group, and X, Y and Z individually mean a hydrogen or halogen atom.

1,4-substituted dihydrobenzene derivatives

A nematic liquid crystal composition comprising at least one member selected from 4-alkyl- or 4-alkoxy-benzoic acids represented by the following general formula (I) , particularly a nematic liquid crystal composition comprising a carboxylic acid mixture composed of at least one member selected from 4-alkyl- or 4-alkoxy-benzoic acids represented by the following general formula (I) and at least one member selected from 4-alkylcyclohexanecarboxylic acids represented by the following general formula (IV): ##STR1## wherein R.sub.1 stands for an alkyl or alkoxy group having 1 to 12 carbon atoms and R.sub.4 stands for an alkyl group having 1 to 12 carbon atoms.

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Tokyo, Japan

Tomijiro Naito