Patent ID: 6171665
Filing Date: 2001-01-09
Classification: C09K

Abstract:
Liquid-crystalline medium based on a mixture of polar compounds of positive dielectric anisotropy, characterized in that it comprises one or more compounds of the general formula I ##STR54##in whichR.sup.1 -R.sup.4 are each, independently of one another, an alkyl or alkenyl radical having up to 12 carbon atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where one or more CH.sub.2 groups in these radicals may also, in each case independently of one another, be replaced by --O--, --S--, ##STR55##--CO--, --CO--O--, --O--CO-- or --O--CO--O--in such a way that O atoms are not linked directly to one another, and--A-- is 1,4-phenylene, in which, in addition, one or two CH groups may be replaced by N, 2,3-difluoro-1,4-phenylene, 2-fluor-1,4-phenylene, 3-fluoro-1,4-phenylene or a single bond.