Abstract: An integrated electro-optical device according to the invention comprises a pixellated liquid crystal modulation layer superimposed over an electronic detection layer. Modulator pads for the liquid crystal layer may be formed as electrically conductive combs to achieve optical polarization. Where the liquid crystal layer provides selective absorption of unpolarized light, and separate polarizers between the liquid crystal and detection layers are therefore unnecessary, the device comprises such a liquid crystal layer superimposed over the electronic detector layer. Further, an integrated electro-optical device, optionally of the above type, has a plurality of pixels of the liquid crystal layer for each pixel of the detector array. This allows optical shuttering of the detector pixels by electrically modulating the pixellated liquid crystal layer.

Abstract: A liquid crystal display comprises a nematic liquid crystal layer disposed between alignment layers. The alignment layers are formed on substrates which also carry display control electrodes connected to a drive circuit. Polarisers are provided on opposite sides of the substrates. The alignment layers are arranged such that the liquid crystal molecule pretilt angles at the surfaces of the alignment layers are parallel. The liquid crystal layer has a retardance equal to (M+1).lambda./2 at a first operating voltage and M.lambda./2 at a second operating voltage, where M is an integer greater than zero or less than minus one and .lambda. is a wavelength of visible light.

Abstract: Liquid crystal compounds of formula (I) are described, where formula (I) is given as R.sub.1 --A--(X.sub.m --(B).sub.n --R.sub.2 where A is selected from nathyl, flourinated naphthyl, brominated naphthyl, B is selected from phenyl, methylated phenyl, brominated phenyl, fluorinated phenyl, thiophene, pyrimidine and pyridine, R.sub.1 and R.sub.2 are independently selected from alkyl, alkoxy, alkynyl, thioalkyl, Br, CN, SCN, NCS, perfluoroalkyl, perfluoroalkoxy and hydrogen, X is selected from C.tbd.C, COO and C.tbd.C, m is 0 or 1, n is 0 or 1 where m is 1 and n is 0 where m is 0; provided that where A is naphthyl, n is 1 and m is 0 then B is selected from methylated phenyl, brominated phenyl, thiophene, pyrimidine and pyridine; and further provided that where A is naphthyl, X is C.tbd.C, m is 1 and n is 1, then B is selected from thiophene, pyrimidine and pyridine.

Abstract: Optically active compounds of formula (I), where X has a structure (II) and B is C.sub.1-12 alkyl, a chiral group or a group having a general structure (III), where R and R' are H, C.sub.1-12 alkyl, alkoxy, alkylcarbonyloxy, or alkoxycarbonyl, each ring (IV) and (V) is the same or different, A and D are single bonds or bridging groups, each a and d is 0 or 1; Z, Z' are CN, Cl, F, Br or CF.sub.3 ; provided when Z is CN or Cl, then when B is alkyl X-Y is not (VI) or (VII). Ferroelectric smectic liquid crystal mixtures containing these compounds are also described.

Abstract: This invention relates to novel chiral cyano-containing compounds suitable for use in ferroelectric smectic liquid crystal mixtures.

Abstract: A color display formed of information of one color on a different color background is projected onto a screen. Light from the bulb is passed serially through a neutral polarizer, a smectic liquid crystal cell, and a further polarizer. The cell comprises a smectic liquid crystal material incorporating an amount of a cholesteric material and a dye contained between two cell walls carrying electrodes and surface treated to give a molecular twist and alignment to the liquid crystal material. Information is written into the cell by scanning the laser beam over the cell, causing localized heating, in combination with or without an applied electric field to form selected areas with a twisted structure on a background of homeotropic structure, or vice versa. Thus plane polarized light is passed through the cell with its plane selectively rotated or non rotated. This provides a two color display of information of one color on a background of the other color.

Abstract: A method, device, and material for providing a fast switching liquid crystal display employs the ferro electric effect of chiral smectic liquid crystal material. To provide a uniform appearance the liquid crystal material is arranged to have a long cholesteric pitch at a temperature close to a smectic/cholesteric phase transistion temperature. This long cholesteric pitch allows liquid crystal molecules to cool from the cholesteric to smectic phase with a uniform alignment. The smectic material is contained in a cell between walls (2, 3) bearing electrodes (5, 6) and surface treated to provide homogeneous alignment of liquid crystal material (7).

Abstract: A liquid crystal display is arranged to provide very low minimum light trmission in one of its two switchable states. This makes it useful for a shutter (FIG. 1) and for high contrast digital displays (FIG. 2). A layer of a chiral smectic liquid crystal material is contained between two cell walls carrying electrode structures. The liquid crystal material has the following phases with temperature: isotropic.revreaction.cholesteric.revreaction.chiral smectic.revreaction.solid. The cholesteric pitch is large. The cell walls are surface treated to provide a parallel alignment of liquid crystal molecules. Crossed polarizers are arranged either side of the cell walls, one aligned with its optical axis parallel to the surface alignment of the adjacent cell wall. The device is switched by means of .+-.-d.c. voltage pulses and utilizes the ferro electric effect.

Abstract: Biphenyl egters of formula (I), ##STR1## wherein formula (II) represents formula (III) or formula (IV), R.sub.1 represents C.sub.3 -C.sub.12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is O or 1 R.sub.2 represents C.sub.3 -C.sub.12 alkyl or alkoxy, one of Q.sub.1 or Q.sub.2 is fluorine and the other is hydrogen, provided that when j is O and formula (II) is formula (III) and both R.sub.1 and R.sub.2 are n-alkyl, then the total number of carbon atoms in R.sub.1 and R.sub.2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.

Abstract: Biphenyl esters of formula (I), wherein formula (II) represents formula (III) or formula (IV), R.sub.1 represents C.sub.3 -C.sub.12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is 0 or 1, R.sub.2 represents C.sub.3 -C.sub.12 alkyl or alkoxy, one of Q.sub.1 or Q.sub.2 is fluorine and the other is hydrogen, provided that when j is 0 and formula (II) is formula (III) and both R.sub.1 and R.sub.2 are n-alkyl, then the total number of carbon atoms in R.sub.1 and R.sub.2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.

Abstract: Novel compounds for use in ferroelectric smectic liquid crystal mixtures are provided, having a general formula: ##STR1## where R.sub.1 is alkyl, alkoxy, alkylcarbonyloxy or alkoxy-carbonyl, ##STR2## are cyclic groups, A and B are a single bond, COO, OOc, CH.sub.2 CH.sub.2, CH.sub.2 O or OCH.sub.2, (a+b+c) is 2 or 3 and R.sub.2 is an optically active alkyl group. Ferroelectric smectic liquid crystal mixtures containing these compounds, and a suitable ferroelectric liquid crystal device are also described.

Abstract: A liquid crystal device comprises a layer of long pitch cholesteric liquid crystal material incorporating a pleochroic dye. The layer is contained between two cell walls surface treated to align liquid crystal molecules in a tilted homogeneous structure. The surface alignment and natural pitch of the cholesteric material are matched to provide a progressive molecular twist of between .pi. and 2.pi., preferably about 3.pi./2, with a uniform tilt direction. The ratio natural pitch P divided by thickness d of the liquid crystal layer is arranged to lie between 0.5 and 1.0, with a value of d less than 20 .mu.m. Both low tilt and high tilt surface alignment may be used separately or in combination. Polarizers may be used to enhance between ON and OFF states. The device has a sharp transmission/voltage characteristic which enables it to be used in large multiplex addressed matrix displays.

Abstract: A touch sensitive switch with a liquid crystal cell and a circuit for measuring capacitive changes when the cell is deformed by touch. The cell has a layer of a liquid crystal material between slides bearing electrodes. Capacitive changes are detected for example by a comparator or by a bridge circuit which includes one or more cells. Touching one cell unbalances the bridge. The area of cell that is touched may be coincident with or separate from a display area. For some types of cells extra sensitivity is achieved by maintaining a voltage across the cell between a critical and saturation value.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye characterized in that the dye comprises at least one anthraquinone compound free from water-solubilizing and ionic substituents and having the formula: ##STR1## wherein each of R and R.sup.1 independently represents an n-alkyl group having from 4 to 7 carbon atoms inclusive and wherein each of R.sup.2 and R.sup.3 is independently selected from hydrogen and alkyl groups having from 1 to 4 carbon atoms inclusive.

Abstract: A material suitable for a guest-host liquid crystal device comprises a soion of a liquid crystal material and a pleochroic dye where in the pleochroic dye comprises at least one anthrquinone compound free from water solubilizing and ionic substituents and having the formula: ##STR1## wherein Q is NH.sub.2, OH, alkyl, aryl, NO.sub.2 or halo;n is 0 to 4;each X independently is H, --SR, --NZ.sub.1 Z.sub.2 or Q;each R independently is alkyl, aryl or cycloalkyl;Z.sub.1 and Z.sub.2 are independently H, alkyl, cycloalkyl or aryl; provided that there are at least two groups X which are different --SR groups.

Abstract: A nematic liquid crystal composition suitable for use as the liquid crystal material of a multiplexed twisted nematic electro-optical display comprising a mixture of Components A, B and C as follows:Component A: a high dielectric anisotropy component;Component B: a low dielectric anisotropy component;Component C: a high cleaning component having a clearing point greater than 80.degree. C.;wherein Component A forms from 25% to 50% inclusive by weight of the composition and consists of one or more two ringed compounds having a terminal cyano group and includes at least one compound having formula I as follows ##STR1## where R.sub.1 is an n-alkyl group having up to 7 carbon atoms and ##STR2## represents a trans-1,4 disubstituted cyclohexane ring; wherein Component B forms from 25% to 50% inclusive by weight of the composition and consists of one or more low dielectric anisotropy compounds, at least 50% of Component B being formed by one or more ester compounds having Formula II as follows: ##STR3## where R.sub.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein one of X and Y is OH and the other is NHR wherein R is H or lower alkyl; each of R.sub.1 and R.sub.2 independently represents alkyl, aryl, aralkyl, alkoxy or --NR.sub.3 R.sub.4 wherein each of R.sub.3 and R.sub.4 is independently H or lower alkyl, provided that R.sub.2 is always adjacent to an OH group.

Abstract: A liquid crystal material which comprises a mixture of compounds includes at least one low viscosity additive compound of Formula (I) as follows:A--CH.sub.2.CH.sub.2 --B Formula (I)wherein A is selected from: ##STR1## and B is selected from: ##STR2##where R.sub.1 is selected from alkyl, alkoxy, alkylcarbonyloxy and alkoxycarbonyloxy; and R.sub.2 is alkyl; and where ##STR3## is a benzene ring; ##STR4## is a cyclohexane ring, which is in the trans-configuration if di-substituted; and ##STR5## is a bicyclo(2,2,2)octane ring.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one anthraquinone compound free from water solubilizing and ionic substituents and having the formula: ##STR1## wherein P is OH or NH.sub.2 ; each group X.sup.A is independently selected from OH, NO.sub.2, SR and NZ.sub.1 Z.sub.2 provided that one group X.sup.A is SR and the other group X.sup.A is OH, NO.sub.2 or NZ.sub.1 Z.sub.2 is 1 or 2; each group Q.sub.1 is independently alkyl having from 1 to 20 carbon atoms; each group R is independently selected from alkyl having from 1 to 20 carbon atoms, aryl having up to 15 carbon atoms and cycloalkyl having from 4 to 8 carbon atoms.

Abstract: A method, device, and material for providing a fast switching liquid crystal display employs the ferro electric effect of chiral smectic liquid crystal material. To provide a uniform appearance the liquid crystal material is arranged to have a long cholesteric pitch at a temperature close to a smectic/cholesteric phase transistion temperature. This long cholesteric pitch allows liquid crystal molecules to cool from the cholesteric to smectic phase with a uniform alignment. The smectic material is contained in a cell between wells (2, 3) bearing electrodes (5, 6) and surface treated to provide homogeneous alignment of liquid crystal material (7).