| 摘要 |
The invention relates to a liquid-crystalline medium comprising a mixture of at least two compounds of the general formula (I) <?in-line-formulae description="In-line Formulae" end="lead"?>R<SUP>1</SUP>-A<SUB>m</SUB>-B<SUB>n</SUB>-Z<SUP>1</SUP>-C-Z<SUP>2</SUP>-D-R<SUP>2</SUP> (I)<?in-line-formulae description="In-line Formulae" end="tail"?> in which R<SUP>1 </SUP>is H, an alkyl or alkenyl radical having 1 to 15 carbon atoms and 2 to 15 carbon atoms, respectively, which is unsubstituted, monosubstituted by CN or CF<SUB>3 </SUB>or at least monosubstituted by halogen, where one or more CH<SUB>2 </SUB>groups in these radicals may also, in each case independently of one another, be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that O atoms are not linked directly to one another; A, B, C and D are each, independently of one another, in which Y, Y<SUP>1</SUP>, Y<SUP>2</SUP>, Y<SUP>3</SUP>, Y<SUP>4</SUP>, Y<SUP>5 </SUP>and Y<SUP>6 </SUP>are each, independently of one another, H or F; C is, in addition to the abovementioned meanings, Z<SUP>1 </SUP>and Z<SUP>2 </SUP>are each, independently of one another, a single bond, -CH<SUB>2</SUB>O-, -OCH<SUB>2</SUB>-, -CH<SUB>2</SUB>-CH<SUB>2</SUB>-, -CH-CH-, -C≡C-, -CF<SUB>2</SUB>-CF<SUB>2</SUB>-, 13 CF<SUB>2</SUB>O-, -OCF<SUB>2</SUB>- or -CO-O-; R<SUP>2 </SUP>is, in addition to the abovementioned meanings of R<SUP>1</SUP>, F, CF<SUB>3</SUB>, OCF<SUB>3</SUB>, OCHF<SUB>2</SUB>, OCH<SUB>2</SUB>CF<SUB>2</SUB>H; and m and n are each, independently of one another, 0 or 1, with the proviso that Z<SUP>1 </SUP>is a single bond when m and n are 0, characterized in that the mixture comprises a) from 30 to 90% by weight of compounds of the general formula (I) having Delta∈>=9(=highly polar compounds); b) from 0 to 30% by weight of compounds of the general formula (I) having 1<=Delta∈<=9(=polar compounds); c) from 10 to 40% by weight of compounds of the general formula (I) having -1<=Delta∈<=1(=neutral compounds); the sum of a), b) and c) being 100% by weight. |
