Abstract: A power outage indicator utilizes a smectic liquid crystal display cell, capable of storing information indefinitely, to provide a visual indication, of predetermined form, that power to a given installation has been interrupted. Prior to installation, the smectic liquid crystal display of the power outage indicator is heated and an appropriate voltage placed between the display electrodes to cause the liquid crystal material to align homeotropically, as the liquid crystal material cools to the smectic state; a clear stable texture results. Upon loss of power, stored charge, as in a storage capacitor, is enabled to flow through at least a portion of at least one of the display electrodes, reheating the liquid crystal material therebetween and, upon cooling without an applied field, converts a portion of the liquid crystal layer to a state having differing light-propagation properties than the remainder of the display.

Abstract: Novel asymmetric tris-azo dye compositions and a liquid crystal composition containing the asymmetric tris-azo dye compositions are disclosed. The asymmetric dye compositions having asymmetric terminal groups have the general formula: ##STR1## wherein R.sub.1 is one of the three following groups: ##STR2## 5-nitrothiazolyl group, 4-cyanophenyl group, and 4-nitrophenyl; wherein R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are selected from the group consisting of hydrogen, alkyl, halogen and alkoxy, and R.sub.6 is selected from the group consisting of N,N-diethylamino-3-methylphenyl; N,N-diethylamino-3-methylphenyl; N,N-diethylamino-3,5-dimethylphenyl; 2-pentylperimidyl; N-ethylamino-1-naphthyl; N,N-dimethylamino-1-naphthyl; and N,N-diethylamino-1-naphthyl. When the asymmetric tris-azo dichroic dyes are used as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays.

Abstract: A transflective liquid crystal display is viewable by either reflected or transmitted light. The display utilizes at least one display cell of the guest dichroic dye-host liquid crystal material type, wherein the molecules are substantially parallel to the cell walls and have a helical twist in the unactivated state and are oriented substantially perpendicular to the cell walls in the activated state. A partially-reflective, partially-transmissive transflector element, which is non-depolarizing, is placed adjacent to the rear of the display cell and is followed by a light-retarding element, having its retardation axis placed at an angle, typically 45.degree. to the polarization axis of a subsequent linear-polarizing element. A light source, for use in the transmissive mode, is placed beyond the linear-polarizing element.

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.

Abstract: Novel tris-azo dyes and a liquid crystal composition containing the tris-azo dyes. The tris-azo dyes are of the general formula: ##STR1## wherein R.sub.1 and R.sub.2 are various aromatic groups including aromatic amines, substituted aromatic amines, hydroxy-substituted aromatic groups and substituted hydroxy-containing aromatic groups. When the tris-azo dichroic dyes are used as a guest dye in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays.

Abstract: Liquid crystal compositions having guest anthraquinone-based dyes dissolved therein, are disclosed. The anthraquinone-based dyes have the general formula: ##STR1## wherein at least one of X and X' is a 5-membered ring connected to the lateral positions of the lateral benzene rings in the anthraquinone molecule, the five membered ring having the structure: ##STR2## wherein R is an alkoxy alkyl radical, a straight chain or branched chain alkyl radical, a phenyl radical, a benzyl radical and/or substituted derivatives of the foregoing radicals. The anthraquinone-based dyes of the invention may be used alone or with other compatible dyes as guest dyes to form various colors for coloring the host liquid crystal compositions. One preferred class of guest anthraquinone-based dyes which are dissolved in the host liquid crystal material, are various derivatives of 1,4-diamino-2,3-anthraquinone-dicarboximide.

Abstract: Homeotropic surface alignment is provided in liquid crystal display cells, utilizing high temperature peripheral sealing material, by fabricating the empty cell prior to introducing a solution of a homeotropic-aligning surfactant dissolved in a volatile solvent. The solvent is evaporated to provide a surfactant film on the cell cavity interior surfaces. The cell is then filled with the liquid crystal material and the cell is sealed.

Abstract: Novel tris-azo dye compositions and a liquid crystal composition containing the tris-azo dye compositions are disclosed. The tris-azo dye composition having terminal aromatic groups has the general formula: ##STR1## wherein R.sub.1 and R.sub.2 are various aromatic compounds including aromatic amines, substituted aromatic amines, hydroxy-substituted aromatic compounds and substituted hydroxy-containing aromatic compounds. When the tris-azo dichroic dyes are used as a guest dye in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. Examples of R.sub.1 and R.sub.2 include organic radicals of aminoquinoline, tetrahydroquinoline, N-ethyl-1-naphthylamine and 1,8-diaminonaphthalene.

Abstract: Novel yellow azo dye compositions and novel liquid crystal compositions containing the yellow azo dye composition. The yellow azo dye composition, having terminal ester groups, has the general formula: ##STR1## wherein R and R' are alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used alone, or in combination with other dyes, as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. An invention method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dye, as described above, is added to a host liquid crystal material.

Abstract: Novel yellow azo dye compositions and a liquid crystal composition containing the yellow azo dye composition are disclosed. The yellow azo dye composition, having terminal ester groups has the general formula: ##STR1## wherein R and R' are acyl groups having the formula: ##STR2## and R.sub.2 is an alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, or R.sub.2 is an aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. The disclosure also embraces a method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dyes as described above is added to a host liquid crystal material.

Abstract: Novel yellow azo dye compositions and a liquid crystal composition containing the yellow azo dye composition are disclosed. The yellow azo dye composition, having terminal ester groups, has the general formula: ##STR1## wherein R and R' are acyl groups having the formula: ##STR2## and R.sub.2 is an alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, or R.sub.2 is an aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used alone, or in combination with other dyes, as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. The disclosure also embraces a method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dye, as described above, is added to a host liquid crystal material.

Abstract: Novel yellow azo dye compositions and a liquid crystal composition containing the yellow azo dye composition are disclosed. The yellow azo dye composition, having terminal ester groups has the general formula: ##STR1## wherein R and R' are acyl groups having the formula: ##STR2## and R.sub.2 is an alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, or R.sub.2 is an aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. The disclosure also embraces a method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dye as described above is added to a host liquid crystal material.

Abstract: Novel liquid crystal compositions having extended temperature ranges, without sacrifice of stability, are provided by mixing 10-25%, by weight, of a terphenyl liquid crystal material with 75-90%, by weight, of a four-component liquid crystal composition of cyclohexanes.

Abstract: Dichroic liquid crystal compositions for use in displays are mixtures of a liquid crystal host material and at least one of a plurality of dyes each having a plurality of azo (--N.dbd.N--) bonding groups and a high order parameter. The dichroic liquid crystal compositions each provide a contrast ratio on the order of 10:1.

Abstract: A method for improving the decay time of a display device utilizing a twisted nematic liquid crystal composition by the addition of a controlled amount of optically active material to produce a natural pitch, under field-free conditions, shorter than four times the thickness of the display device cell.

Abstract: A dichroic liquid crystal display of the parallel-nematic type is caused to have a bright background, indicative of the light-transmissive state, and dark characters, in the unactivated condition, by treatment of the display electrodes to cause boundaries of the dichroic liquid crystal material to be normally homeotropic except in those areas defining a character, in which areas a pattern of silicon oxide or other parallel alignment surfactant is deposited by masking techniques.

Abstract: Dichroic liquid crystal compositions, for use in liquid crystal displays, have a host liquid crystal material in which is dissolved one of a plurality of guest dichroic dyes, each having at least one Schiff-base ##STR1## bonding group. The dichroic liquid crystal compositions have a high order parameter, for providing contrast ratios on the order of 10:1 and imparting a yellow color to the display.

Abstract: Dichroic liquid crystal compositions for use in displays are mixtures of a liquid crystal host material and at least one of a plurality of dyes each having a plurality of azo (--N.dbd.N--) bonding groups and a high order parameter. The dichroic liquid crystal compositions each provide a contrast ratio on the order of 10:1.

Abstract: Dichroic dyes of the 4,4'-Bis-(substituted naphthylazo)azobenzene type, each having three azo (--N.dbd.N--) bonding groups, provide a high order parameter in excess of 0.70, when dissolved in liquid crystal mixtures to provide contrast ratios on the order of 10:1.

Abstract: Dichroic liquid crystal compositions for use in displays are mixtures of a liquid crystal host material and at least one of a plurality of stilbene-derivative dichroic dyes each having a vinylidene (--CH.dbd.CH--) group and a high order parameter. The dichroic liquid crystal compositions each provide a contrast ratio on the order of 10:1.