Patent ID: 7294368

Claim:
Bistable liquid crystal device comprising two outer substrates which, together with a frame, form a cell; a liquid crystal composition present in said cell; electrode structures with alignment layers on the inside of said outer substrates whereby at least one alignment layer comprises an alignment grating that permits the compounds of said liquid crystal composition to adopt at least two different stable states whereby the assembly of said electrode structures with said alignment layers being such that a switching between the said at least two different stable states is achieved by applying suitable electric signals to said electrode structures; whereby said liquid crystal composition comprises at least 30 weight % (based on the total weight of the composition) of a component (α) containing one or more compounds having a dielectric anisotropy Δε of at least 25, whereby at least 25 weight % (based on the total weight of the composition) of said compounds have a dielectric anisotropy Δε of at least 40; and at least 5 weight % (based on the total weight of the composition) of a component (β); whereby said component (β) comprises at least one compound of formula III and/or at least one compound of formula IV and/or at least one compound of formula V and/or at least one compound of formula VI and/or at least one compound of formula VII in which a and b are independently of each other 0 or 1; R 31 , R 32 , R 41 , R 42 , R 51 , R 52 , R 61 , R 62 , R 71 and R 72 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; and L 31 is H or F; Z 41 is —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 in which L 32 and L 33 are independently of each other H or F.