Patent ID: 7390538

Claim:
A liquid-crystalline medium comprising a mixture of polar compounds of positive or negative dielectric anisotropy, including one or more compounds of formula I in which R 1 and R 2 are each, independently of one another, identically or differently, H, an alkyl radical having from 1 to 12 carbon atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may each, independently of one another, be replaced by —O—, —S—, —CH═CH—, —C≡C—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that atoms are not linked directly to one another, and further comprising one or more compounds of the formulae XI to XVII: in which the individual radicals have the following meanings: R 1 and R 2 : independently of one another, identically or differently, n-alkyl, n-alkoxy or alkenyl, each having up to 9 carbon atoms; and Z 1 and Z 2 : independently of one another, identically or differently, a single bond, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CH═CH—, —C 2 H 4 —, —C 2 F 4 —, —CH 2 CF 2 —, —CF 2 CH 2 — or —C 4 H 8 —.