Patent ID: 6821580
Filing Date: 2004-11-23
Classification: C09K

Abstract:
A liquid-crystalline medium of positive dielectric anisotropy, which comprises:one or more compounds of the formula I: in whichR1 is an alkyl or alkenyl radical having 1 or 2 to 7 carbon atoms, and X1 is F, OCF3 or OCHF2; one or more compounds of the formula II in which R2 is an alkyl or alkenyl radical having 1 or 2 to 7 carbon atoms, and X2 is F, OCF3 or OCHF2; one or more compound(s) of the formulae IIIb or IIIg which R3 is an alkyl of 1 to 7 carbon atoms or alkenyl radical of 2 to 7 carbon atoms; one or more compound(s) of that formula IV in whichR4 is an alkyl or alkenyl radical having 1 to 7 carbon atoms or alkenyl radical having 2 to 7 carbon atoms, X4 is F, Cl, and k is 0 or 1; and one or more compounds of the formula V in which are each, independently of one another, R51 and R52 are each, independently of one another, an alkyl or alkoxy radical having 1 to 7 carbon atoms or alkenyl radical having 2 to 7 carbon atoms, and n and m are each, independently of one another, 0 or 1; wherein the medium exhibits a nematic phase at least down to âˆ’20Â° C. and at least above 75Â° C., birefringe value of &lE;0.090 or &gE;0.100, and a rotational viscosity, &ggr;1, at 20Â° C., of less than 160 mPaÂ·s.