Liquid crystal materials containing pleochroic anthraquinone dyes
AssigneeThe Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
InventorsKenneth J. Harrison, Edward P. Raynes, Frances C. Saunders, David J. Thompson
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Abstract
A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein one of X and Y is OH and the other is NHR wherein R is H or lower alkyl; each of R.sub.1 and R.sub.2 independently represents alkyl, aryl, aralkyl, alkoxy or --NR.sub.3 R.sub.4 wherein each of R.sub.3 and R.sub.4 is independently H or lower alkyl, provided that R.sub.2 is always adjacent to an OH group.
Claims25
A material suitable for a guest-host liquid crystal device comprising a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula:
- ##STR34## wherein R is H or lower alkyl;
- and each of R.sub.1 and R.sub.2 independently represents alkyl containing between 1 and 10 carbon atoms.
A material as claimed in claim 1 in which the pleochroic dye comprises a mixture of dyes of different color, at least one comprising a compound having Formula (I) as defined in claim 33.
Dependencies are inferred from the claim text.