Liquid crystal ester compounds exhibiting a low or negative dielectric anisotropy and liquid crystal materials and devices incorporating such compounds

Abstract

Novel liquid crystal ester compounds exhibiting a low or negative dielectric anisotropy have a structural formula: ##STR1## where R.sub.1 is an alkyl group, R.sub.2 is an alkyl or alkoxy group, ##STR2## is a 1,4-disubstituted bicyclo(2,2,2) octane ring and ##STR3## is a 1,4-disubstituted ring selected from the following: (i) a 1,4-disubstituted bicyclo(2,2,2) octane ring; (ii) a trans-1,4-disubstituted cyclohexane ring; (iii) a laterally substituted benzene ring ##STR4## where of the two groups Y and Z one is a halogen or a cyano group and the other is hydrogen or a halogen or a cyano group such that Y is the same as Z. These esters may be used in a number of known applications including liquid crystal materials for multiplexed twisted nematic devices. The esters may be made by preparative methods involving known steps.

Dependencies are inferred from the claim text.