Low voltage actuated field effect liquid crystals compositions and method of synthesis

Claim 2

A liquid crystal composition suitable for use in twisted nematic display systems consisting essentially of the following liquid crystal constituents: Constituent One -- one or more low molecular weight negative dielectric anisotropy non-Schiff base liquid crystal compounds, comprising from about 20 to about 90 mole percent of the composition; Constituent Two -- one or more positive dielectric anisotropy non-Schiff base liquid crystal compounds, comprising from about 10 to about 80 mole percent of the composition; and Constituent Three -- one or more cholesteric liquid crystal compounds, comprising a minor constituent in the composition and being present in an operational range of concentration effective to bring about a short decay time not more than about 350 milliseconds with saturation voltages of less than about 3.3 Vrms in a 12.5 micron thick cell, said concentration being less than that which results in the predominance of cholesteric properties in the composition, said composition being nematic in its electro-optical properties.

Claim 3

The liquid crystal composition defined in claim 1 wherein the concentration of constituent three is at least about 0.05 and not greater than about 5.0 mole percent.

Claim 4

The liquid crystal composition defined in claim 1 wherein constituent three consists essentially of an ester of cholesterol and the concentration is between about 0.05 and 0.8 mole percent.

Claim 5

The liquid crystal composition defined in claim 3 wherein constituent three consists essentially of cholesteryl nonanoate.

Claim 6

The liquid crystal composition defined in claim 2 wherein the concentration of constituent three is at least about 0.5.

Claim 7

The liquid crystal composition defined in claim 5 wherein constituent three consists essentially of one or more compounds selected from the group having the general formula: ##SPC11## wherein R is a lower alkyl radical having from 2 to 4 carbon atoms and R' is a lower alkyl radical having from 1 to 7 carbon atoms, the center of asymmetry being shown by the asterisk.

Claim 8

The liquid crystal composition defined in claim 6 wherein constituent three consists essentially of (S)-4-(2"-methylbutoxy)-phenyl-4-n-pentylbenzoate.

Claim 9

The liquid crystal composition defined in claim 1 wherein the positive dielectric anisotropy non-Schiff base liquid crystals include one or more of the following compounds: A. compounds selected from the group having the general formula: ##SPC12## wherein R is a lower alkyl or alkoxy group having from 1 to 7 carbon atoms; B. compounds selected from the group having the general formula: ##SPC13## wherein R is a lower alkyl or alkoxy group having from 1 to 7 carbon atoms; and the negative dielectric anisotropy non-Schiff base liquid crystals include one or more of the following compounds: a. compounds selected from the group having the general formula: ##SPC14## in eutectic mixture with corresponding compounds having the general formula: ##SPC15## wherein, in each of said classes of compounds, R and R' are lower alkyl groups having from 1 to 4 carbon atoms, corresponding compounds being those compounds in which R is the same in both compounds and R' is the same in both compounds; b. combinations of eutectic mixtures as set forth in preceding paragraph (a) wherein R and R' in one such eutectic mixture is different from R and R' in another of such eutectic mixture, the two eutectic mixtures being combined; c. compounds selected from the group having the general formula: ##SPC16## wherein R is lower alkyl having from 1 to 7 carbon atoms and R' is lower alkoxy having from 1 to 7 carbon atoms and wherein R is lower alkoxy having from 1 to 7 carbon atoms and R' is lower alkyl having from 1 to 7 carbon atoms; and d. compounds selected from the group having the general formula: ##SPC17## wherein R and R' are lower alkyl groups having from 1 to 7 carbon atoms and a and b may both be H- and wherein either a or b, but not both, may be Cl-.