Abstract: An electroclinic device having two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, where the liquid crystal material contains one or more of the compounds described by formula I as defined in the specification.

Abstract: An electroclinic device having two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, where the liquid crystal material contains one or more of the compounds described by formula I as defined in the specification.

Abstract: An electoclinic device having two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, where the liquid crystal material contains one or more of the compounds described by formula I as defined in the specification.

Abstract: In order to reduce the effects of impact on liquid crystal devices a polymer network is introduced into ferroelectric liquid crystal cells. A liquid crystal device comprises two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, characterised in that the liquid crystal material contains a small amount of monomer. The liquid crystal material may also contain a photoinitiator. The monomer material may be cured to produce the polymer networks the curing many be carried out in the presence of an electric or magnetic field. Further, the monomer may be cured in an isotropic or liquid crystal phase.

Abstract: A mixture of a ferroelectric or anti-ferroelectric liquid crystal material and a monomer having a single photopolymeric functional group is injected in the space between two electrode substrates while heat is applied. After cooling of the mixture it is irradiated with ultraviolet light at a temperature at which the liquid crystal material remains in the smectic phase so as to polymerise the monomer. Areas of liquid crystal material requiring different threshold voltages for switching are thereby produced. Alternatively such areas can be produced by changing the conditions applied to a mixture of liquid crystal material with a suitable dopant so as to cause separation of the dopant out of the liquid crystal material in order to provide a polarity of nucleation points for controlling domain formation within the liquid crystal material. Such control of domain formation can be used to provide greyscale in a liquid crystal device.

Abstract: A liquid crystal device is provided with a pair of substrates (12, 16) containing a liquid crystal material (22). A wall structure comprising, for example, a plurality of walls (14) is provided between the two substrates. The wall structure provides mechanical strength to the device and resistance to flow of liquid crystal material which can cause deterioration in the device performance. The walls may extend in two mutually different directions (FIG. 8, 40) to provide mechanical strength and resistance to flow in two directions while the device can still be readily filled. The device is particularly applicable to a ferroelectric liquid crystal device.

Abstract: In order to the effects of impact on liquid crystal devices a polymer network is introduced into ferroelectric liquid crystal cells. A liquid crystal device comprises two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, characterised in that the liquid crystal material contains a small amount of monomer. The liquid crystal material may also contain a photoinitiator. The monomer material may be cured to produce the polymer network; the curing may be carried out in the presence of an electric or magnetic field. Further, the monomer may be cured in an isotropic or liquid crystal phase.

Abstract: A compound of formula I ##STR1## wherein n=3-30; X and Y are independently chosen from C.sub.1-6 alkyl, phenyl or formula II:(CH.sub.2).sub.p O--M IIwherein p=1-20 and M is a group of formula III: ##STR2## wherein a, b and g are independently chosen from 0 and 1; G is selected from CO.sub.2, OCO and is a single bond when g=0; j=0-4; F indicates that one or more of the phenyl rings may be laterally fluorinated; Z is chosen from R, OR, CO.sub.2 R, OCOR or CN wherein R is selected from chiral C.sub.4-20 branched chain alkyl, provided that at least one of X and Y is selected from formula II and that the positions of X and Y relative to each other provide stereo-isomers.

Abstract: A liquid crystal device is provided with a pair of substrates (12, 16) containing a liquid crystal material (22). A wall structure comprising, for example, a plurality of walls (14) is provided between the two substrates. The wall structure provides mechanical strength to the device and resistance to flow of liquid crystal material which can cause deterioration in the device performance. The walls may extend in two mutually different directions (FIG. 8, 40) to provide mechanical strength and resistance to flow in two directions while the device can still be readily filled. The device is particularly applicable to a ferroelectric liquid crystal device.

Abstract: This invention describes compounds of formula (I) ##STR1## wherein R is C.sub.1-16 alkyl or alkoxy; X is selected from F and Cl and indicates that one or more of the phenyl rings may be laterally substituted; x is selected from 0-3; A and B are independently selected from CO.sub.2, OCO, .tbd.C and single bond; R.sub.1 and R.sub.2 are independently selected from H and C.sub.1-16 alkyl provided that R.sub.1 and R.sub.2 are different; n is 0 or 1 provided that if n is zero then B is single bond. These compounds may be used as dopants suitable for use in ferroelectric liquid crystal mixtures.

Abstract: A liquid crystal display cell comprises two cell walls spaced apart to enclose a layer of liquid crystal material. The cell walls carry electrode structures, e.g. arranged in rows and columns to give an x, y matrix of addressable elements or pixels. The liquid crystal material is aligned by a grating (grooved) structure on one or both cell walls. This grating structure is a bigrating with one symmetrical grating and an asymmetric grating which may be orthogonal to the symmetric grating. The grooves of the asymmetric grating varying their depth or asymmetry along the lengths to give a locally varying pretilt whose longer range average provides a pretilt in a preferred range, e.g. about 2-24 degrees.

Abstract: The invention describes liquid crystal compounds of formula (I) which are suitable for use in liquid crystal devices including those devices which exploit the electroclinic effect, ##STR1## where X may be CN, NO.sub.2, CF.sub.3, CF.sub.2 H, CFH.sub.2, halogen, hydrogen, alkyl or alkoxy; X.sub.2 may be CN, NO.sub.2, CF.sub.3, CF.sub.2 H, CFH.sub.2, halogen, hydrogen, alkyl or alkoxy; X.sub.3 may be CN, NO.sub.2, CF.sub.3, CF.sub.2 H, CFH.sub.2, halogen, alkyl, alkoxy or hydrogen; X.sub.4 may be CN, NO.sub.2, CF.sub.3, CF.sub.2 H, CFH.sub.2, halogen, alkyl, alkoxy or hydrogen; provided that at lease one of X or X.sub.2 is CF.sub.3, CF.sub.2 H, CFH.sub.2, CN, NO.sub.2 or halogen; A and B are independently phenyl, mono-fluorinated phenyl, di-fluorinated phenyl or cyclohexyl; Y may be single bond, COO, OOC, C.dbd.C; q may be 0 or 1; R.sub.1 may be an end group of formula (II) wherein Z may be a single bond, O, CO.sub.2, (CH.sub.2).sub.n or (CH.sub.2).sub.

Abstract: There is disclosed a liquid crystal polyacrylate mono- or co-polymers having a repeat unit (I), wherein R.sub.1 and R.sub.2 are independently alkyl or hydrogen, R.sub.3 is alkyl, hydrogen or chlorine, m is 0 or an integer 1-20, W is a linkage group COO, OOC or O and X is a mesogenic group.

Abstract: A twisted nematic type of liquid crystal device comprises two cell walls enclosing a layer of a nematic or long pitch cholesteric liquid crystal material. The device has both an alignment direction and a surface tilt provided by an asymmetric grooves structure alignment on one or both walls. The alignment treatment may be provided by a shaped layer of a photolithographic material. Embossing, ruling, or transferred from a carrier layer material may alternatively provide the alignment. The amount of twist may be multiples of about 90.degree. and the device arranged between two polarisers.

Abstract: An electro-optic color device including a layer of polymer dispersed liquid crystal (7), with polarizers on either side (9,10), at least one being colored. By applying a voltage across the polymer dispersed liquid crystal cell (PDLC), the cell is switched from a scattering to a non-scattering state or vice-versa, and the color of the transmitted light is controlled. Applications include membrane switches.

Abstract: A ferroelectric liquid crystal device comprises a layer of a ferroelectric liquid crystal material contained between two cell walls carrying electrode structures and a surface alignment treatment. The surface alignment is provided by a profiled surface, e.g., a grating, on at least one cell wall. The grating may be a monograting or a bigrating, with a symmetric or asymmetric profile. Such a profiling enables surface tilt and alignment anchoring energy to be independently arranged to suit liquid crystal material and device type to give a required molecular arrangement and low device defect. The grating may be provided by interferography, photolithography, embossing, ruling, or carrier layer transfer. Alignment directions on the cell walls may be parallel or non-parallel. The surface tilt on both cell walls may be the same or different values. The cell walls may be relatively rigid, e.g., glass slides, or flexible, e.g.

Abstract: Liquid crystal compounds have been synthesized of general formula (I) and may be mixed with other liquid crystal compounds to give useful liquid crystal mixtures which may then be used in liquid crystal devices. Such devices include linear and non-linear electrical, optical and electro-optical devices, magneto-optical devices and devices providing responses to stimuli such as temperature changes and total or partial pressure changes. Formula (I) where each Z.sub.1-6 is given by formula (II), where Y for each of Z.sub.1-6 is independently COO, OCO, CH.sub.2 O and OCH.sub.2, m defines the number of substituents on each of Z.sub.1-6 and is independently 0-5,and X is independently for each substituent on each of Z.sub.1-6 alkyl (straight chain, branched and chiral), alkoxy (straight chain, branched or chiral), alkanoyl (straight chain, branched or chiral), alkenyl (straight chain, branched or chiral), halogen, halogenoalkyl (straight chain, branched or chiral) and CN, provided that at least one of Z.sub.

Abstract: The invention provides a liquid crystal device having an aligned and surface tilted liquid crystal layer contained between two cell walls. The cell walls carry electrodes for applying voltages across the layer thickness to provide a display. The alignment is provided by a layer of a material that undergoes optically induced ordering during cross linking. That is, a material capable of aligning liquid crystal molecules after cross linking with polarized light. One such material is polyvinylcinnamate. The aligning layer is profiled with an asymmetric grating, eg approximately sawtooth in cross section by interferometer, oblique incidence photolithography, or embossing. The shape of the grating provides the surface tilt. The liquid crystal material may be nematic, cholesteric, or smectic.

Abstract: Novel liquid crystal materials which are trans-4-alkylcyclohexane-1-carboxylic acid esters are provided having the general formula: ##STR1## where R is a normal or branched chain alkyl group, which may also contain a chiral center, containing up to ten carbon atoms and X is selected from the groups: ##STR2## where A is a cyano group, a normal or branched chain alkyl group, which may also contain a chiral center, containing up to ten carbon atoms or an alkoxy group in which the alkyl group is as defined immediately above, and where Y is a halogen, preferably chlorine, or hydrogen.

Abstract: Liquid crystal compounds are disclosed having the formula ##STR1## where p is an integer having a value from 0 to 5 inclusive. These materials are optically active and cholesterogenic and may be used in an electro-optical display device either on their own or in admixture with nematogenic materials having a formula ##STR2## where i has a value from 0 to 5 inclusive and j is 0 or 1. These last mentioned mixtures may be thermochromic and employed in a temperature sensing device.