Abstract: A liquid crystal display device comprising: a liquid crystal display element formed by holding, between two substrates at least one of which has a light-permeable electrode, a liquid crystal layer in which liquid crystal molecules of a nematic liquid crystal having positive dielectric anisotropy and containing an optically active substance has a helical axis perpendicular to the substrates between the substrates and are helically oriented, and the liquid crystal molecules between the substrates have a twist angle of 180 to 270 degrees, and a phase plate formed by stacking water surface development films of an organic polymer with changing the orientation axes thereof at a constant angle, wherein the contrast ratio, a ratio between brightness in white display and brightness in black display, is remarkably excellent over that of a device obtained by stacking plastic films, and the transmissivity, a quotient of background brightness and light source brightness, is equivalent to that of a conventional double laye

Abstract: A liquid crystal display cell, wherein orientation films are made of an organic polymer such as polyimide, polyamide, liquid crystal polymer having one or more mesogen groups in a main chain or side chain and produced by spreading an organic polymer solution on a water surface, is excellent in memory properties and contrast and generates no static electricity, no short circuit between electrodes and no breaking of electrodes.

Abstract: In a liquid crystal display device, light transmitting through a liquid crystal layer is colored depending on the structural conditions of the liquid crystal display device. The phase of the transmission light is corrected by means of a phase correction plate to make the transmission light approximate achromatic color, thereby permitting monochromatic display or color display.

Abstract: A liquid crystal display device including a nematic liquid crystal composition having a twist angle of 160.degree. to 260.degree. of liquid crystal molecules and at least one compound of the formula: ##STR1## (m, n=1-7) further improved in time-multiplexability and display quality.

Abstract: A liquid crystal display element comprising a pair of substrates, a pair of electrodes provided on the respective substrates, at least one of which is transparent and a liquid crystal layer disposed between said substrates, the liquid crystal layer comprising a nematic liquid crystal, which exhibits a positive dielectric constant anisotropy and contains an optically active substance, the liquid crystal moleccule orientation direction in the liquid crystal layer is twisted in the range of 200.degree. to 250.degree. from the one substrate surface toward the other substrate surface so as to form a helical structure therein. A polyimide orientation film is provided between the electrodes and the liquid crystal layer. The polyimide orientation film is one made of a polyimide prepared by reacting a diamine compound having a long-chain hydrocarbon group or a diamine compound having a trifluoromethyl group with a tetracarboxylic dianhydride and causes a pretilt angle of at least 3.degree.

Abstract: A liquid crystal display device comprises a liquid crystal layer sandwiched between upper and lower electrode substrates subjected to aligning treatment. The liquid crystal layer includes a nematic liquid crystal added with a chiral material and has a 160.degree.-360.degree. twisted helical structure. A pair of polarizers are disposed adjacent to the electrode substrates with their polarization or absorption axes inclined by respective predetermined angles with respect to the aligning directions of the electrode substrates. At least one of the polarizers is formed by a color polarizer for compensating a wavelength dependence of transmittance (or the coloring due to birefringence) resulting from the anti-coincidence between the polarization or absorption axis of the polarizer and the aligning direction of the electrode substrate, i.e. an optical axis of liquid crystal molecules adjacent to the substrate, so that light emerging from the device becomes approximately achromatic or colorless.

Abstract: The element comprises a pair of transparent substrates, a pair of light-transmitting electrodes each provided on the respective substrates, a ferroelectric liquid crystal layer disposed between the pair of substrates and orientation control films for the molecules of the ferroelectric liquid crystal provided between the electrodes and the ferroelectric liquid crystal layer. The orientation control film controls a tile angle of a biphenyle series nematic liquid crystal having biphenyl ring system below 1.5.degree. and causes a uniform molecule orientation characteristic and a memory property for the ferroelectric liquid crystal element of smectic C* liquid crystal and having a liquid crystal layer thickness of even more than 4 .mu.m.

Abstract: A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 96.degree. and 108.degree. along a direction of thickness thereof, absorption axes of a pair of polarizing plates disposed on the upper and lower substrates constitute an angle between 63.degree. and 73.degree., and a product .DELTA.n.multidot.d of a thickness d (.mu.m) and an optical anisotropy .DELTA.n of a liquid crystal layer falls within a range from 0.69 .mu.m to 0.79 .mu.m.

Abstract: A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 200.degree. and 260.degree. along a direction of thickness thereof, and polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are angularly displaced by a predetermined angle or predetermined angles from major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively.

Abstract: A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 160.degree. and 200.degree. along a direction of thickness thereof, and polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are inclined by a predetermined angle with respect to major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively.

Abstract: A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 140.degree. and 250.degree. along a direction of thickness thereof, and polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are angularly displaced by a predetermined angle or predetermined angles from major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively, and a ratio of thickness of the nematic liquid crystal to a natural molecular helical pitch of the nematic liquid crystal added with a chiral material falls within a range of from 0.14 to 0.60 inclusive.

Abstract: A liquid crystal display device wherein a nematic liquid crystal having a positive dielectric anisotropy and added with a chiral material is sealed between a pair of upper and lower substrates so as to constitute a helical structure twisted within a range between 90.degree. and 160.degree. along a direction of thickness thereof, polarizing axes or absorption axes of a pair of polarizing plates disposed on the upper and lower substrates are inclined by a predetermined angle falling within a range between 25.degree. and 65.degree. with respect to major axes of liquid crystal molecules adjacent to the upper and lower substrates, respectively, and in the direction of the twist of the liquid crystal, and a product .DELTA.n.multidot.d of a thickness d (.mu.m) and an optical anisotropy .DELTA.n of a liquid crystal layer falls within a range from 0.8 .mu.m to 1.2 .mu.m.

Abstract: A liquid crystal display element which may have a multi-layer structure comprising substrates having electrodes and liquid crystal orientation controlling films on the sides thereof facing a liquid crystal layer and one or more liquid crystal layers interposed between said substrates, characterized in that the liquid crystal orientation controlling film is made from a copolymer produced by reacting a dibasic acid dihydrazide, a diamine and a tetracarboxylic acid dianhydride, followed by ring closure and dehydration with heating, is excellent in transparency and the electrode (partially reflected) pattern is hardly observable.

Abstract: A process for the manufacture of a liquid crystal container for a liquid crystal display element, which process comprises the steps of applying a low-melting glass frit paste to at least one of a pair of glass substrates, subjecting this glass substrate to primary firing in an open condition in which the paste is in no contact with any matters, and while holding the pair of the glass substrates in their accurate relative positions, subjecting the glass substrates to secondary firing to seal the pair of the glass substrates with the glass frit. The process preferably comprises the step of applying, prior to the step of secondary firing, a low-melting glass frit paste to one of the glass substrates so as to reliably hold the pair of the glass substrates in the accurate relative positions.

Abstract: In a liquid crystal display element having a twisted structure wherein the periphery of two transparent glass substrates having electrodes according to desired display patterns is sealed with a sealing medium and a liquid crystal is enclosed in the space thus produced, the one characterized by having an undercoating film of metal oxide on the inner surface of each glass substrate, having a transparent electrode on each undercoating film of metal oxide and having an orientation controlling film made from an organic polymer and having abrasion grooves along a certain direction on each electrode can give a liquid crystal display element excellent in heat resistance of the orientation controlling film, excellent in adhesion to the glass substrates, and the like without causing a voltage drop, or without damaging rising of voltage-brightness property and response property.

Abstract: A liquid crystal display element comprising a pair of substrates, a pair of electrodes provided on the respective substrates, at least one of which is transparent and a liquid crystal layer disposed between said substrates, the liquid crystal layer comprising a nematic liquid crystal, which exhibits a positive dielectric constant anisotropy and contains an optically active substance, the liquid crystal moleccule orientation direction in the liquid crystal layer is twisted in the range of 200.degree. to 250.degree. from the one substrate surface toward the other substrate surface so as to form a helical structure therein. A polyimide orientation film is provided between the electrodes and the liquid crystal layer. The polyimide orientation film is one made of a polyimide prepared by reacting a diamine compound having a long-chain hydrocarbon group or a diamine compound having a trifluoromethyl group with a tetracarboxylic dianhydride and causes a pretilt angle of at least 3.degree.