Patent ID: 6251301
Filing Date: 2001-06-26
Classification: C09K

Abstract:
A ferroelectric liquid crystal device comprising two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, a minimum in its response time versus voltage curve, wherein crystal material consists of two components; A and B, where the two components are given by:Component A present in a range of 0.1-50 wt % is one or more optically active compounds capable of imparting a spontaneous polarization to the material and is given by the following general formula: ##STR64##in which X is a group having a general structure: ##STR65##and B is alkyl containing 1-12 carbons, a chiral group, or a group having a general structure ##STR66##where R and R.sup.1 are independently hydrogen or C.sub.1-12 alkyl, alkoxy, alkylcarbonyloxy or alkoxycarbonyl, each of the rings (A) and (D) may be the same or different and are each independently selected from optionally alkyl-, cyano- or halogen- substituted phenyl, transcyclohexyl, pyridyl, pyrimidyl, bicyclo (2,2,2) octyl or dioxan each A and D may be the same or different and is independently selected from a single bond, COO, OOC, CH.dbd.N, N.dbd.CH, CH.sub.2 O, OCH.sub.2, CH.sub.2, CH.sub.2 CH.sub.2, CH(CH.sub.3) or a combination of two of such groupsin which each a and d is independently 0 and 1,in which Y is selected from --COO--, --OOC--, --O-- or a single bond, in which W is selected from a single bond, --(--CH.sub.2 --)--.sub.n or --(CH.sub.2).sub.m CH(Z).sup.1)-- --(CH.sub.2).sub.p -- where n, m and p are independently 0 to 10;in which Z or Z.sup.1 are independently selected from CN, Cl, F, Br and CF.sub.3 ; provided that when Z is Cl or CN, then when B is alkyl, X--Y-- is not ##STR67##Component B is present in an amount sufficient to enable A+B=100 wt %, wherein Component B is at least two compounds selected from: ##STR68##wherein a, b and c are independently 0, 1 or 2 and R.sub.1 and R.sub.2 are C.sub.1-15 straight or branched chain alkyl or alkoxy provided that in component B the CH.dbd.CH linking groups may be replaced by C.sub.2 H.sub.4 and CH.sub.2 O linking groups may be replaced by OCH.sub.2.