Red perylene dichroic dye containing liquid crystal formulations
AssigneeGeneral Electric Company
InventorsSiegfried Aftergut, Herbert S. Cole, Jr.
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Abstract
Liquid crystal compositions having guest perylene-based dichroic dyes dissolved therein. The perylene dichroic dyes have symmetrically-disposed substituents which are preferably a group forming with the 3,4 and 9, 10 carbons, respectively, a 5 or 6 membered cyclic ring which is substituted by, or fused to, a phenyl ring. The perylene-based dyes of the invention can be used alone or with other compatible dyes as guest dyes to form various colors for coloring the host liquid crystal compositions.
Claims15
A dichroic liquid crystal composition comprising a host liquid crystal material and a dye composition having a solubility in said host liquid crystal material which is sufficient to produce a mixture having about 0.05% by weight to about 1% by weight, based on the weight of the liquid crystal host material, where said dye composition contains as an essential ingredient a red dichroic dye having the formula, ##STR18## where the R and R' groups each forms a 5 or 6 membered cyclic ring which is substituted by or fused to a phenyl ring or each forms a group ##STR19## with the 3, 4, or 9, 10 carbons of the perylene nucleus and where X is substituted or unsubstituted alkyl or aryl.
A method of improving the color of dichroic dyes for use in liquid crystal displays comprising the step of:
- adding to a host liquid crystal material, a dye composition which contains at least one dichroic dye in a proportion to absorb radiation in at least a part of the spectral range of about 400-700 nm, where said dye composition is sufficiently soluble in said host liquid crystal material to produce a display composition having about 0.05% by weight to about 1.0% by weight of the dye composition in the host liquid crystal material wherein at least one of the dichroic dyes is a red guest dye having the formula ##STR24## where the R and R' groups each forms a 5 or 6 membered cyclic ring which is substituted by or fused to a phenyl ring or each forms a group ##STR25## with the 3, 4 of 9, 10 carbons of the perylene nucleus and where X is substituted or unsubstituted alkyl or aryl.
Dependencies are inferred from the claim text.