Patent number: 5578242
Abstract: Liquid crystal compounds of the formula:R.sup.1 --Z.sup.1).sub.m --(Z.sup.2)--X--(Z.sup.3)--(Z.sup.4).sub.n --R.sup.2These compounds may be mixed with other liquid crystal compounds to give liquid crystal mixtures which may then be used in liquid crystal devices. In the formula X is COS, CSS and CSO; each of Z.sup.1, Z.sup.2, Z.sup.3, and Z.sup.4 are independently phenyl, substituted phenyl, where substitution is lateral substitution selected from F, Cl, Br, NO.sub.2, CN, NCS; naphthalene, substituted naphthalene, where substitution is lateral substitution selected from F, Cl, Br, NO.sub.2, CN, NCS, CH.sub.3 ; thiophene, pyridine and pyrimidine; each of A.sup.1 and A.sup.2 is independently selected from single bond, C.tbd.C, CH.dbd.CH; A.sup.3 is selected from C.tbd.C and single bond; each of R.sup.1 and R.sup.2 are independently selected from CN, NCS, CH.dbd.C(CN).sub.2, C.tbd.C--CN, C.tbd.C--CF.sub.
Type:
Grant
Filed:
April 12, 1995
Date of Patent:
November 26, 1996
Assignee:
The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland of Defence Research Agency
Inventors:
John W. Goodby, Michael Hird, Kenneth J. Toyne, Alexander J. Seed, Damien G. McDonnell, Amarjit K. Samra