Patent ID: 7303791

Claim:
A liquid-crystalline medium comprising a mixture of polar compounds of positive or negative dielectric anisotropy, including: one or more compounds of the formula I in which are a) a 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non-adjacent CH 2 groups are optionally replaced by —O— or —S—, b) a 1,4-phenylene radical, in which one or two CH groups are optionally replaced by N, c) a radical selected from the group consisting of piperidine-1,4-diyl, 1,4-bicyclo[2.2.2]octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, where the radicals a), b) and c) are optionally monosubstituted or polysubstituted by halogen atoms, x, y and z are each, independently of one another, 0, 1 or 2, Z 1 , Z 2 and Z 3 are each, independently of one another, —CO—O—, —O—CO—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CH 2 CH 2 —, —(CH 2 ) 4 —, —C 2 F 4 —, —CH 2 CF 2 —, —CF 2 CH 2 —, —CF═CF—, —CH═CH—, —C≡C— or a single bond, X is F, Cl, CN, NCS, CF 3 , C 2 F 5 , n-C 3 F 7 , SF 5 , CF 2 H, OCF 3 , OCF 2 H, OCFHCF 3 , OCFHCFH 2 , OCFHCF 2 H, OCF 2 CH 3 , OCF 2 CFH 2 , OCF 2 CF 2 H, OCF 2 CF 2 CF 2 H, OCF 2 CF 2 CFH 2 , OCFHCF 2 CF 3 , OCFHCF 2 CF 2 H, OCF 2 CF 2 CF 3 , CF 2 CHFCF 3 , CF 2 CH 2 CF 3 , OCH 2 CF 2 CHFCF 3 , OCF 2 CHFCF 3 , OCClFCF 2 CF 3 , CH 3 , C 2 H 5 and n-C 3 H 7 , provided that, when the A 4 ring is unsubstituted phenyl, X is not CN, CH 3 , C 2 H 5 or n-C 3 H 7 , a is 0, 1 or 2, b is 0, 1 or 2, and c is 0, 1 or 2, where a+b+c is from 1 to 3; and additionally comprising one or more compounds of the formula RI to RII, RIV to RVIII, RX to RXII and RXIV: in which R 0 is n-alkyl, oxaalkyl, fluoroalkyl, alkenyloxy or alkenyl, each having from 2 to 8 carbon atoms, d is 0, 1 or 2, Y 1 is H or F, alkyl and alkyl* are each, independently of one another, a straight-chain or branched alkyl radical having from 2 to 8 carbon atoms, alkenyl and alkenyl* are each, independently of one another, a straight-chain or branched alkenyl radical having from 2 to 8 carbon atoms.