Liquid crystal medium for electro-optical applications contains compounds with difluoromethylene linking groups, e.g. perfluoroalkane derivatives, and compounds with linked benzene and cyclohexane rings

摘要

A liquid crystal medium containing compounds (I) with optionally fluorinated and/or otherwise-substituted groups linked by a difluoro-methylene group and compounds (II) with an optionally fluorinated and/or otherwise-substituted phenyl group linked to a cyclohexane, bicyclohexyl or tercyclohexyl system. A liquid crystal (LC) medium based on a mixture of polar compounds with positive dielectric anisotropy contains compound(s) of formula (I) and compound(s) of formula (II), in which R1, R2 = H, CN, F, Cl, OCHF2, OCF3, SF5, OCHFCF3, OCH2CF3, OCF2CF3, CH3, OCH3, CF3, CH2F, CHF2 or 1-12C alkyl (optionally substituted at least once with halogen or CN and optionally with one or more CH2 groups replaced by -O-, -S-, -CO-, cyclobutane-1,3-diyl, -COO-, -OCO-, -OCOO- or -CH=CH-, with no directly linked hetero-atoms); A = (a) trans-1,4-cyclohexylene (optionally with one or more non-adjacent CH2 replaced by -O- and/or -S-), (b) 1,4-phenylene (optionally with one or two CH replaced by N), (c) 1,4-bicyclo(2.2.2)octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl or its decahydro and 1,2,3,4-tetrahydro derivatives or (d) 1,4-cyclohexenylene, where types (a), (b) and (d) may also be substituted with CN, Cl or F; Z1, Z2 = -CH2-, -CF2-, -CHF-, -O-, -S-, -CH=CH-, -C equivalent to C- or -SF4-; n, m = 0-20; q = 0 or 1; R3 = H or 1-12C alkyl (optionally substituted with one CN or CF3 group or with at least one halogen and optionally with one or more non-adjacent CH2 groups replaced by groups as listed for R1 and R2; X = 1-10C alkyl or alkoxy (optionally substituted at least once with halogen), 2-10C alkenyl or alkenyloxy (optionally substituted at least once with CN, CF3 or F), F, Cl, CF3, OCHF2, OCF3, OCHFCF3 or OCF2CF3; L1-L3 = H or F; p = 0, 1 or 2 . Independent claims are also included for (a) electro-optical LC displays containing this LC medium; (b) compounds of formula (IA)-(ID), in which v = 1-20; R4, R5 = 1-10C alkyl; X1 = as for X above; L1-L3 = H or F .