Liquid crystal dyestuffs and electro-optic devices incorporating same
AssigneeRCA Corporation
InventorsAllen Bloom, Ling K. Hung
Life of this patent
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Abstract
Novel dyes of the formula ##STR1## wherein X is --NH, --NCH.sub.3, --S or --O; R.sub.1, R.sub.2, R.sub.3 and R.sub.4 independently at each occurrence can be hydrogen, fluoro, chloro, bromo, alkoxy, cyano, nitro, --N(R).sub.2 wherein R is alkyl or two of R.sub.1 to R.sub.4 together can be part of an aromatic ring; R.sub.5 and R.sub.6 are hydrogen, fluoro, chloro, bromo or lower alkyl; and R.sub.7 is hydrogen, fluoro, chloro, bromo, alkoxy, cyano, nitro, --N(R.sub.2), ##STR2## HYDROGEN, FLUORO, CHLORO, BROMO, ALKOXY, CYANO, NITRO, DI-ALKYLAMINO, ##STR3## can be added to known liquid crystal compositions to impart color to the mixtures and to improve contrast of a liquid crystal electro-optic device containing such mixtures.
Claims6
In an electro-optic device field effect liquid comprising a crystal neamtic liquid crystal composition havng positive dielectric anistropy between two electrodes, the improvement which comprises a dyestuff dissolved in said composition of the formula ##STR12## wherein R.sub.1 to R.sub.4 independently at each occurrence can be hydrogen, fluoro, chloro, bromo, alkoxy, cyano, nitro or dialkylamino or any adjacent two of R.sub.1 to R.sub.4 together can be part of an aromatic ring;
- X can be NH, NCH.sub.3, S or O;
- R.sub.5 and R.sub.6 independently can be hydrogen, fluoro, chloro, bromo, or lower alkyl;
- and R.sub.7 can be alkoxy, dialkylamino, ##STR13##
A nematic liquid crystal composition comprising a nematic liquid crystal having positive dielectric anistropy having dissolved therein a compound of the formula ##STR14## wherein R.sub.1 to R.sub.4 independently at each occurrence can be hydrogen, fluoro, chloro, bromo, alkoxy, cyano, nitro or dialkylamino or any adjacent two of R.sub.1 and R.sub.4 together can be part of an aromatic ring;
- X can be NH, NCH.sub.3, S or O;
- R.sub.5 and R.sub.6 independently can be hydrogen, fluoro, chloro, bromo or lower alkyl;
- and R.sub.7 can be alkoxy, dialkylamino, ##STR15##
Dependencies are inferred from the claim text.