Liquid crystal compositions including pleochroic dye
AssigneeMinnesota Mining and Manufacturing Company
InventorJudith L. Benham
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Abstract
Liquid crystal compositions containing pleochroic dyes. The pleochroic dyes are substituted anthraquinones useful in guest-host combinations with nematic liquid crystal compositions having positive dielectric anisotropy. Electro-optic devices containing these guest-host combinations are employed.
Claims14
A composition having positive dielectric anisotropy comprising at least one nematic liquid crystal material having positive dielectric anisotropy and a pleochroic dye in an amount effective to provide a pleochroic character having the general formula:
- ##STR7## wherein Q is independently --NH.sub.2, --NO.sub.2, --OH, --Cl or --F;
- R is --CH.sub.3, --OCH.sub.3 or --H;
- and
- m is an integer from 1 to 4.
An electro-optic device comprising a transparent envelope having electrodes on a portion of the opposed surfaces thereof and containing in said envelope a nematic liquid crystal composition having a pleochroic dye dissolved therein in an amount effective to provide a pleochroic character, wherein the improvement comprises a liquid crystal composition comprising at least one nematic liquid crystal material having positive dielectric anisotropy and a pleochroic dye compound having the general formula:
- ##STR8## wherein Q is independently --NH.sub.2, --NO.sub.2, --OH, --Cl or --F;
- R is --CH.sub.3, --OCH.sub.3 or --H;
- and
- m is an integer from 1 to 4.
Dependencies are inferred from the claim text.