Patent ID: 7026020

Claim:
Liquid-crystalline medium comprising a mixture of polar compounds of positive dielectric anisotropy, wherein the medium comprises: one or more compounds of formula Ia in which R is H, an alkyl or alkenyl radical having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where one or more CH 2 groups in these radicals are optionally, in each case independently of one another, replaced by —O—, —S—, —CO—, —CO—O—, —O—CO— or —O—CO—O in such a way that O atoms are not linked directly to one another, and one or more compounds selected from the group consisting of compounds of the formulae III and V to VIII: in which the individual radicals have the following meanings: R 0 : n-alkyl, oxoalkyl, fluoroalkyl or alkenyl, in each case having 1 to 7 carbon atoms; X 0 : F, Cl, halogenated alkyl, alkenyl or alkoxy having 1 to 6 carbon atoms; Z 0 : —C 4 H 8 —, —CF 2 O—, —OCF 2 —, —C 2 F 4 —, —CH 2 O—, —OCH 2 — or —COO—; Y 1 , Y 2 , Y 3 and Y 4 : each, independently of one another, H or F, and r: 0 or 1.