Patent ID: 6790488
Filing Date: 2004-09-14
Classification: C09K

Abstract:
A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, said medium comprising one or more compounds of formula I, and one or more compounds of the general formula I* in whichR, R1* and R2* are in each case, independently of one another, H, an alkyl or alkenyl radical having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, wherein optionally one or more CH2 groups in the alkyl or alkenyl radical are replaced by, in each case independently of one another, â€”Câ‰¡Câ€”, â€”COâ€”, â€”COâ€”Oâ€”, â€”Oâ€”COâ€”, â€”Sâ€” or â€”Oâ€”COâ€”Oâ€” in such a way that O atoms are not linked directly to one another, A1(a) is a trans-1,4-cyclohexylene radical in which, in addition, one or more non-adjacent CH2 groups are each optionally replaced by â€”Oâ€” or â€”Sâ€”, or is a 1,4-cyclohexenylene radical, (b) is a 1,4-phenylene radical, in which, in addition, one or two CH groups are each optionally replaced by N, (c) is a radical selected from 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 radicals (a) and (b) may be monosubstituted, disubstituted or polysubstituted by CN, CH3 or F, Z1 is â€”COâ€”Oâ€”, â€”Oâ€”COâ€”, â€”CH2Oâ€”, â€”OCH2â€”, â€”CH2CH2â€”, â€”CH&boxH;CHâ€”, â€”CF2Oâ€”, â€”OCF2â€”, â€”Câ‰¡Câ€”, â€”(CH2)4â€”, â€”CH&boxH;CHâ€”CH2CH2â€” or a single bound, Y is F, Cl, or halogenated alkyl, alkenyl, alkenyloxy, alkoxyalkyl or alkoxy, each having up to 6 carbon atoms, L is H or F, L1* and L2* are in each case independently of one another H or F, x and y are in each case independently of one another 0, 1, 2, 3 or 4, and m is 0 or 1.