| abstract |
Liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, characterized in that it contains one or more compounds of the general formula I contains wherein R is an unsubstituted, an alkyl or alkenyl radical having 1 to 15 C atoms which is monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where one or more CH 2 groups in these radicals are each independently of one another denoted by -O- . -CO-, -CO-O-, -O-CO- or -O-CO-O- may be replaced so that O atoms are not directly linked to one another, A 1 (a) trans-1,4-cyclohexylene radical, in which also one or more non-adjacent CH 2 groups may be replaced by -O- and / or -S-, or a 1,4-cyclohexenylene radical, (b) radical from the group consisting of 1,4-bicyclo- (2,2,2) -octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2 , 3,4-tetrahydronaphthalene-2,6-diyl, where the radical (a) may be mono- or polysubstituted by CN, CH 3 or F, Z 1 is a single bond, YF or Cl, LH or F, and ... |