Mitsubishi Chemical Industries Limited

Hitachi, Ltd.

Sony Corporation

Junko Iwanami

Akio Mukoh

Shuji Imazeki

Masaharu Kaneko

Mikio Sato

Tomio Yoneyama

Tetsuo Ozawa

Konoe Miura

Tetsuya Morita

Tetsuo Urabe

Kunihiko Arai

A squarilium compound represented by the following formula (I) and a liquid crystal composition containing the same are disclosed: ##STR1## wherein X and Y each represents ##STR2## wherein R.sup.1 represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group; R.sup.2, R.sup.3 and R.sup.4 each represents a hydrogen atom, an alkyl group or a substituted or unsubstituted alkoxy group; R.sup.5 represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group; ring A represents a cyclic alkylene; ring B represents a substituted or unsubstituted aromatic ring; and ring C represents a heterocyclic ring containing one or two of a nitrogen atom, an oxygen atom and a sulfur atom; with proviso that X and Y are not the same when either one of them represents ##STR3## and a liquid crystal composition containing the squarilium compound of the formula (I). The squarilium compound (I) are soluble in a wide variety of solvents and resistant to light, and their maximum absorption wavelengths in these solvents are in the ranges of from 700 to 900 nm.

Squarilium compound and liquid crystal composition containing the same

A liquid crystal display device of the type in which thermo-writing is performed by means of irradiation of laser beams, the display device including a laser-sensitive liquid crystal composition exhibiting a maximum absorption at or near the wavelength of the impinging laser beam with which the display device is to be used. The specific improvement of the present invention comprises including in the liquid crystal composition at least two types of laser-responsive dyes, each being present in an amount less than its solubility limit in the liquid crystal composition, and each of the dyes evidencing a maximum absorption at or near the wavelength of the laser beam. In an embodiment, the dyes are chosen from the class of squarilium dyes.

Liquid crystal display device

A liquid crystal composition containing azo dyes represented by the formula (I.sub.0) ##STR1## wherein X represents ##STR2## A.sup.1 represents --O-- or --NH--; R.sup.1 represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an aryloxyalkyl group, a dialkylaminoalkyl group, an arylaminoalkyl group, a cycloalkyl group, an alkoxy group, an alkoxyalkoxy group, an arylalkoxy group, an aryl group, a halogen atom or a group of ##STR3## D.sup.1 and D.sup.2 each represents an aromatic group which does not contain an ionic group;

Liquid crystal composition containing azo dyes

A liquid crystal composition containing azo dyes represented by the formula (I.sub.0) ##STR1## wherein X represents ##STR2## A.sup.1 represents --O-- or --NH--, R.sup.1 represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an aryloxyalkyl group, a dialkylaminoalkyl group, an arylaminoalkyl group, a cycloalkyl group, an alkoxy group, an alkoxyalkoxy group, an arylalkoxy group, an aryl group, a halogen atom or a group of ##STR3## D.sup.1 and D.sup.2 each represents an aromatic group which does not contain an ionic group; U.sup.1 and U.sup.2 each represents a hydrogen atom, a halogen atom, a methyl group, a methoxy group or an ethoxy group;

Liquid crystal composition

The description is concerned with a liquid crystal composition of the guest-host type which contains a pleochroic dye dissolved therein. The dye molecule has an end group or end groups in the molecule represented by the general formula: ##STR1## where Ro designates a straight chain of alkyl group, in which methylene group not adjacent to the nitrogen atom may be substituted by oxygen atom or sulfer atom; R1 designates an alkyl group having a chain length different from that of the alkyl group of Ro or a group ##STR2## in R1 a methylene group not adjacent to the nitrogen atom may be substituted by oxygen atom or sulfur atom, and R2 designates hydrogen atom, alkyl group, alkoxy group, cycloalkyl group or dialkylamino group.

Growing community of inventors

Kanagawa, Japan

Junko Iwanami