Liquid crystalline medium, useful in electrooptical indicator, comprises a mixture of fluorinated phenanthrene compounds

Abstract

The invention relates to a liquid-crystal medium based on a mixture of polar compounds, the medium containing at least one compound of formula (I), in which R<11>, R<12>, A<1>, A<2>, Z<1>, Z<2>, m and n are defined as cited in claim 1. The invention also relates to the use of the medium in an active matrix display based on the ECB, PALC or IPS effect.

Description

Technical field [0001] The present invention relates to a liquid-crystalline medium based on a mixture of polar compounds, which contains at least one compound of formula I [0002] [0003] among them [0004] R 11 And R 12 Independently of each other, each represents H, an alkyl or alkenyl group having up to 15 carbon atoms, the alkyl or alkenyl group is unsubstituted and is composed of CN or CF 3 Monosubstituted or at least monosubstituted by halogen, here, in addition, one or more CH in these groups 2 The group can be -O-, -S-, -C≡C-, -OC-O- or -O-CO- are replaced by the way O atoms are not directly connected to each other, [0005] A 1 And A 2 Independently of each other [0006] a) 1,4-cyclohexenylene or 1,4-cyclohexylene, one or two non-adjacent CH 2 The group can be replaced by -O- or -S-, [0007] b) 1,4-phenylene, where one or two CH groups can be replaced by N, [0008] c) A group selected from the following groups: piperidine-1,4-diyl, 1,4-bicyclo[2.2.2]octyl, napht...

AI Technical Summary

Problems solved by technology

[0027] Disadvantages of MLC-TN displays disclosed so far are due to their relatively low contrast ratio, relatively high viewing angle dependence and difficulty in producing gray scales in these displays

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