Liquid crystal mixture

Abstract

Liquid crystal mixtures comprising one or more compounds of formula (I), wherein R 1 is H or a straight chain or branched chain alkyl group of 1 to 20 carbon atoms or a straight chain or branched chain alkenyl group of 2 to 20 carbon atoms, wherein in both cases, optionally one -CH 2 -group replaced by cyclohexa-1,4-diyl, or 1 or 2 -CH 2 -group, if not adjacent to nitrogen (N), optionally replaced by -O-, or by -C(=O)-, -Si(CH 3 ) 2 - replace; and / or one or more H on the alkyl or alkenyl is optionally replaced by F or CH 3 alternative, R 2 Represents a) H or F; b) straight-chain or branched-chain alkyl of 1 to 20 carbon atoms or straight-chain or branched alkenyl of 2 to 20 carbon atoms, wherein in both cases, 1 or 2 -CH 2 - optionally replaced by -O-, -C(=O)O-, -Si(CH 3 ) 2 - Replacement, and / or one or more H on the alkyl or alkenyl group is replaced by F or CH 3 Replacement; c) group (a), wherein independently of the meanings of formula (I), R 3 , R 4 , R 5 , R 6 independently of each other is an alkyl group of 1-8 carbon atoms, M 1 , M 2 Each independently represents a single bond, -OC(=O), -C(=O)O-, -OCH 2 -, -NH-, A is a) a straight-chain or branched alkane-α, ω-diyl group of 1 to 20 carbon atoms or a straight-chain or branched alkene-α, ω of 2 to 20 carbon atoms - Diyl group, if not with M 1 / 2 Adjacent, optional 1 or 2 non-adjacent -CH 2 -may be replaced by -O-; b) a group -C(=Y)-, wherein Y is CH-Z, and Z is benzene-1,4-diyl optionally substituted by 1 to 3 halogen atoms, An alkyl or alkoxy group of 1 to 4 carbon atoms, with the proviso that M 1 and M 2 is -C(=O)O- and -OC(=O)-; c) the group -CHY, wherein Y is CH 2 -Z, and Z is benzene-1,4-diyl optionally substituted by 1 to 3 halogen atoms, an alkyl or alkoxy group of 1 to 4 carbon atoms, with the proviso that M 1 and M 2 Be -C(=O)O- and -OC(=O)-; d) group (b), wherein p, q are 0, 1 or 2, p+q≥1; M 3 is a single bond or -OC(=O)-, -C(=O)O-, -OCH 2 -, -CH 2 O-, -C≡C-, -CH 2 CH 2 -, -CH 2 CH 2 CH 2 CH 2 -, groups (c) and (d) independently of each other are benzene-1,4-diyl optionally substituted by 1, 2 or 3 F, or optionally substituted by 1 CN, CH 3 Or cyclohexa-1,4-diyl substituted by F, or pyrimidine-2,5-diyl optionally substituted by 1 F, pyridine-2,5-diyl optionally substituted by 1 F , or naphthalene-2,6-diyl optionally substituted by 1, 2 or 3 Fs, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl (the aromatic ring is optionally substituted by 1, 2 or 3 F), or decalin-2,6-diyl, or indane-2,5(6)-diyl, or fluorene-2,7-diyl, Or phenanthrene-2,7-diyl, or 9,10-dihydrophenanthrene-2,7-diyl, or (1,3,4)-thiadiazole-2,5-diyl, or (1, 3) Thiazole-2,5-diyl, or (1,3) thiazole-2,4-diyl, or thiophene-2,4-diyl, or thiophene-2,5-diyl, or (1, 3) Dioxane-2,5-diyl, or piperidine-1,4-diyl, or piperazine-1,4-diyl; X is H, OH, a straight chain of 1 to 20 carbon atoms Or branched chain alkyl or alkoxy, of which 1 or 2 -CH 2 - can be replaced by -O-, -C(=O)O-, -Si(CH 3 ) 2 - Replacement, optionally one or more hydrogens are replaced by F or CH 3 Substitution; m is 0 or 1, X and M 1 -(A) m -M 2 -R 2 Together they can constitute a) a 4-16-membered ring optionally substituted by an alkyl group of 1-15 carbon atoms, b) a combination of two directly connected or spiro-connected 4-16-membered rings independently connected to each other, optionally substituted by Alkyl substitution of 1 to 15 carbon atoms, regardless of which of the three cases, the rings can be independently of each other carbocycles or carbocycles containing boron, nitrogen, oxygen or sulfur heteroatoms.

Description

technical field [0001] The present invention relates to a novel liquid crystal mixture. More specifically, the present invention relates to a chiral smectic or ferroelectric liquid crystal mixture, which has high thermal and photochemical stability and is therefore especially suitable for active matrix display screens. Another aspect of the invention is the use of such liquid crystal mixtures in displays, especially active matrix displays. A further aspect of the invention is an active matrix display comprising such a mixture. Background technique [0002] Since the discovery of surface-stabilized ferroelectric liquid crystals (SSFLCs) by Clark and Lagerwall in 1980 [N.A. Clark and S.T.LagerwaH, Appl. A lot of related research work has been carried out. [0003] Ferroelectric liquid crystal (FLC) displays have two main advantages: first, the "pixel speed" is easily 100 or even 1000 times faster than nematic liquid crystals, and second, due to bistability, the resolution o...

AI Technical Summary

Problems solved by technology

Therefore, the application of fast-switching smectic liquid crystals to TFTs is greatly limited if not prohibited, and the range of potentially usable nematic liquid crystals is greatly reduced.

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