Patent ID: 6419999
Filing Date: 2002-07-16
Classification: C09K

Abstract:
A liquid-crystalline medium of positive dielectric anisotropy, comprising: one or more compounds of formula I whereinR1 is alkyl or alkoxy having in each case 1 to 12 carbon atoms, or alkenyl, alkoxyalkyl or alkenyloxy having in each case 2 to 12 carbon atoms, and L is H or F; and one or more compounds of formula II â€ƒwherein R21 is alkyl or alkoxy having in each case 1 to 7 carbon atoms, alkenyl, alkoxyalkyl or alkenyloxy having in each case 2 to 7 carbon atoms, F, Cl, OCF3 or OCF2H, R22 is H or alkyl having 1 to 10 carbon atoms, Y21 and Y22 are each, independently of one another, H or F, n is from 0 to 5, and m is 0 or 1, and said medium having a frequency of the inflection point of &Dgr;âˆˆ as a function of the frequency (f(&Dgr;âˆˆâ€²max, T) at the temperature of 20Â° C. of 250 kHz or more, wherein the amount of ester compounds of formulae VIIf and VIIj â€ƒin which R7 is alkyl or alkoxy having 1 to 12 carbon atoms or alkenyl or alkenyloxy having 2 to 12 carbon atoms and Y71 and Y72 are each independently H or F, is not sufficient to lower said inflection point to less than 250 kHz.