Liquid crystal materials and devices

Abstract

A novel liquid crystal material contains a compound having a molecular structure such that the material exhibits a liquid crystal phase, the molecular structure of the compound being ##SPC1## Or an orthosubstituted derivative thereof, where X and Y are different parasubstituents of the kind which promote liquid crystal behaviour, where the para substituent is a group selected from the following list; an alkyl group, an acyloxy group, an unsaturated group or an alkoxy group having more than one carbon atom; and where the para-substituent Y is a group selected from the following list; a cyano group, a nitro group, a group which includes a terminal cyano group, a group which includes a terminal nitro group and an acyloxy group. The material may be the said compound or it may be a multi-component solution or mixture containing it. The liquid crystal material may be nematic, smectic or cholesteric depending on the selection of the substituents X and Y. A device such as a twisted nematic effect device, incorporating the material may be operated at low temperatures. The material does not suffer from significant chemical and/or photochemical decomposition when used in a liquid crystal device.

Dependencies are inferred from the claim text.