Electro-optical liquid crystal display element

Claim 1

An electro-optical liquid crystal display element, based on an effect from the group consisting of the twisted cell, guest-host, deformation of aligned phase, dynamic scattering, SBE and STN effects, containing a dielectric with at least two liquid-crystalline components, characterized in that, for shortening the switching times, the dielectric contains at least one fluorine-containing compound of the formula I R.sup.1 --(A.sup.1 --Z.sup.1).sub.m --A.sup.2 --R.sup.2 I wherein one of the radicals R 1 and R 2 is H, F, Cl, Br, --CN, --NCS or an unsubstituted straight-chain alkyl group having 1-15 C atoms, in which one or two CH 2 groups can also be replaced by a grouping selected from the group comprising --O--, --CO--, --O--CO--, --CO--O--, --C.tbd.C-- and --CH═CH--, no 2 heteroatoms being directly linked to one another, the other radical R 1 or R 2 has the formula --X'--Q'--Y'--R.sup.5 in which X' is --CO--, --O--CO--, --O--, or a single bond, Q' is alkylene having 2 to 5 C atoms, Y' is perfluoroalkylene having 2 to 15 C atoms, in which one or more CF 2 groups can also be replaced by --CHF-- or --CF═CF--, and R 5 is H, F, or an alkyl group having 1 to 5 C atoms, with the proviso that the group of the formula --X'--Q'--Y'--R 5 does not contain more than 15 C atoms in total and contains at least two CF 2 groups, A 1 and A 2 independently of one another are each 1,4-phenylene which is unsubstituted or substituted by one or two F and/or Cl atoms and/or CH 3 groups and/or CN groups and in which one or two CH groups can also be replaced by N atoms, 1,4-cyclohexylene in which one or two non-adjacent CH 2 groups can also be replaced by O atoms and/or S atoms, piperidine-1,4-diyl, 1,4-bicyclo-[2.2.2]octylene, unsubstituted or CN-substituted decahydronaphthalene-2,6-diyl or 1,2,3,4,-tetrahydronaphthalene-2,6-diyl, and A 2 is optionally a single bond, m is 0, 1, 2 or 3 and Z 1 is --CO--O--, --O--CO--, --OCH 2 --, --CH 2 O--, --CH 2 --CH 2 --, substituted ethylene or a single bond, it being possible for the groups A 1 to be identical or different and the groups Z 1 to be identical or different in the case of m=2 or 3, with the proviso that, in the case of m=0, the sum of the number of C atoms in the two groups R 1 and R 2 is at least 8.