Twisted pneumatic or supertwisted pneumatic liquid crystal display contains a pneumatic liquid crystal mixture comprising compounds of different dielectric anisotropy and an optically active component

摘要

Twisted pneumatic or supertwisted pneumatic liquid crystal display contains a pneumatic liquid crystal mixture comprising compounds of different dielectric anisotropy and an optically active component to give low switching times and good contrast and angle dependence. Twisted pneumatic or supertwisted pneumatic liquid crystal display comprises two support plates to form a cell, a pneumatic liquid crystal mixture with positive dielectric anisotropy, electrodes with orientation layers, and angle of incidence between the length axis of the molecules on the surface of the support plates and the support plates of 0-30 deg , a twisting angle of 22.5-600 deg and a pneumatic liquid crystal mixture comprising 0-90 wt.% liquid crystal component (A) containing compounds of formula (IA), (IB) and/or (IC) and of dielectric anisotropy above +1.5, 15-80 wt.% liquid crystal component (B) comprising a compound(s) of dielectric anisotropy between -1.5 and +1.5, 0-20 wt.% liquid crystal component (C) comprising a compound(s) of dielectric anisotropy below -1.5 and an optically active component (D) used in such an amount that the ratio of film thickness and natural pitch of the Chiral pneumatic liquid crystal mixture is 0.2-1.3: Ra - Rc = 2-7C alkyl or 2-7C alkenyl or alkenyloxy; Rd and Re = 1-12C alkyl or alkoxy or 2-12C alkenyl optionally substituted via O, CH=CH, CO, OCO or COO; Z = CH2CH2 or a single bond; L = H or F; and c and q = 0 or 1.