Brominated phenoxy:carbonyl-phenyl benzoate liq. crystal cpds. - with positive or negative dielectric anisotropy depending on frequency

摘要

Liq. crystal, within the scope of claim 1 of the parent patent, is of formula (I). In (I) (R1=C7H15O(Ia) or C8H17O(Ib) (I) may be combined with other nematic liq. crystals, esp a mixt. comprises cpds (II) with 18 mole% Q=C8H17;24 mole % Q-C6H13;25 mol% Q=C7H15 and 33 mole% (Ia). Electro-optical devices contg these liq crystals are also claimed. (I) show positive dielectric anisotropy at low frequency but negative anisotropy at high frequency. They are useful in e.g. display devices operating by dynamic light diffusion or memory-field effects, and in double-frequency devices.