Patent ID: 7335404

Claim:
In a method of achieving an electrooptical effect comprising applying a voltage to a bistable liquid crystal device containing a liquid crystal composition, the improvement wherein said composition comprises: from 1 to 30 weight %, based on the total weight of the composition, of a component (αα) containing one or more compounds having a dielectric anisotropy Δε of at least 40; and a component (ββ) comprising at least one compound of formula I and/or of formula II and/or of formula III and/or of formula IV in which a is 0 or 1; R 11 , R 12 , R 21 , R 22 , R 31 , R 32 , R 41 and R 42 are independently of each other C 1 -C 15 alkyl which is unsubstituted or mono- or poly-substituted with CN or halogen and in which one or more of the CH 2 groups may be replaced independently of each other by —O—, —S—, —CH═CH—, —C≡C—, —CO—O—, —OC—O— such that there are no hetero atoms adjacent to each other, with the proviso that R 41 has no —CH═CH— moiety if Z 41 is a single bond; L 11 and L 12 are independently of each other H or F; Z 21 and Z 41 are independently of each other a single bond, —CO—O—, —CH 2 O—, —OCH 2 — —CF 2 O—, —OCF 2 — —CH 2 CH 2 —, —CF 2 CF 2 —, —CH 2 CF 2 —, —CF 2 CH 2 —, —CH═CH— or —C≡C—; are independently of each other and L 13 , L 14 , L 15 , L 16 , L 17 and L 18 are independently of each other H or F.