Liq. crystal medium used for electro-optical applications - contains mixts. of cpds. with linked 1,4-phenylene, trans-1,4-cyclohexylene and trans-1,3-di:oxan-1,4-di:yl units

摘要

A liq. crystal (LC) medium (I) is claimed, contg. mainly (a) 5-65 wt.% component (A), consisting of two or more cpds. of formula R-Cyce-Ar-X (A1), R-Diox-Ar-X (A2), R-Phe-Ar-X (A3) and/or R-Ar-Phe-X (A4), (b) 20-95 wt.% component (B) consisting of two or more cpds. of formula R-Cyc-Cyc-Ar'-X (B1), R-Cyc-Diox-Ar-X (B2), R-Diox-Cyc-Ar-X (B3), R-Cyce-Ar-Phe-X (B4) and/or R-Cyc-Phe-Ar'-X (B5), and (c) 0-40 wt.% component (C) consisting of one or more cpds. with clearing pt. above 170 deg.C; R = 1-7C alkyl, oxa-alkyl, halo-alkyl or alkenyl; X = F, Cl, CHF2, CF3, OCHF2 or OCF3; e = trans-1,4-cyclohexylene; Diox = trans-1,3-dioxan-1,4-diyl; Phe = 1,4-phenylene; Ar = a gp. of formula (II); Ar' = a gp. of formula (III); Y = H, F or Cl. USE/ADVANTAGE - (I) is useful for electro-optical applications (claimed); electro-optical LC displays contg. (I) are also claimed. LC compsns. contg. (I) (esp. matrix LC displays) have low viscosity, low threshold voltage (pref. not above 1.65 V), clearing pt. above 60 (pref. above 80) deg.C and high specific resistance.