Liq. crystal mixt. with wide nematic phase range etc. - contg. one or more opt. substd. alkyl bis-(1-4-cyclohexylene) phenylene cpds. with ethylene linking gp.

摘要

The novel feature in a liq. crystal medium based on a mixt. of polar cpds. with positive dielectric anisotropy is that at least one cpd. of formula (I) is claimed. Y = H or F; X = F, Cl, CF3, OCF3 or OCHF2; one of Q1 and Q2 = -C2H4- and the other is a bond; and R = alkyl, oxa-alkyl, fluoroalkyl or alkenyl, each with up to 7C. USE/ADVANTAGE - The medium can be used in matrix-, twisted nematic- or super-twisted nematic-cells and has, compared to prior artt liq. crystal compsns., a broadened nematic phase range (eso. at low temps.), switchability at low temps. (e.g., for outdoor, automobile or avionic uses), increased UV resistance, improved clear pt., lower viscosity at low temps. and improved heat stability. Viscosity at -30 deg.C is 600 mPa.s or less and at -40 deg.C 1800 mPa.s or less, while anisotropy value (delta epsilon) is 3.5 or above and clear pt. is above 65 deg.C. Nematic phase range is -30 to +70 deg.C. (23op Dwg.No.0/0)