Patent ID: 7115307
Filing Date: 2006-10-03
Classification: C09K

Abstract:
1. A nematic liquid crystal medium with weak zenithal anchoring energy for bistable display devices, comprising: a) at least 40% by weight of compounds with strong molecular polarisability (Δε>10) and strong dipole moment (μ>1D), however with weak zenithal anchoring, the compounds including: AI compounds selected from the group consisting of 4-pentyl-4′-cyanobiphenyl, 4-heptyl-4′-cyanobiphenyl, 3-fluoro-4-cyanophenyl-4′-ethylbenzoate, 3-fluoro-4-cyanophenyl-4′-propylbenzoate, 3-fluoro-4′-cyanophenyl-4′-butylbenzoate and 3-fluoro-4-cyanophenyl-4′-pentylbenzoate; and AII or AIV compounds selected from the group consisting of 4-cyanophenyl-4′-trans-butyl-cyclohexylbenzoate, 3-fluoro-4-cyanophenyl-4′-trans-pentyl-cyclohexylbenzoate and 4-pentyl-trans-cyclohexyl-benzoate-4′-phenyl-carboxylate of 4-cyano-3-fluorobenzene b) 0 to 50% by weight of compounds with weak anchoring selected from the group consisting of 4-pentylphenyl-4′-pentylcyclohexyl-carboxylate, 4-pentylphenyl-4′-propylcyclohexylcarboxylate, 4,4′-bis(4-propyl-cyclohexyl)-3-fluorobiphenyl, 4,4′-bis(4-propyl-cyclohexyl)-biphenyl, 4-pentylphenyl-4′-propylcyclohexylcarboxylate, 4-pentylphenyl-4′-propylphenylcarboxylate, 4-pentylphenyl-4′-pentylphenylcarboxylate, 4-propylphenylethynyl-4′-butylphenyl and 4-hexylcarboxyphenylethynyl-4′-hexylcarboxylphenyl; wherein the relative proportions of the above-mentioned compounds used in the composition of the nematic liquid crystal mixture are determined to simultaneously obtain the following physical characteristics for the said mixture: