Abstract: A liquid crystal device comprises a layer of nematic or long pitch cholesteric liquid crystal material contained between two cell walls. One wall (A) carries a surface treatment giving a first azimuthal alignment direction with or without a surface pretilt to liquid crystal molecules. The other wall (B) carries a surface treatment (17) capable of separately providing both a preferred, substantially homeotropic alignment of the adjacent liquid crystal, and a defined azimuthal second alignment direction to the adjacent liquid crystal dependent upon liquid crystal molecular arrangement. The first and second alignment directions are approximately orthogonal. Polarisers may be arranged on either side of the cell walls with their polarisation axes parallel or perpendicular to the two azimuthal directions. Alternatively an amount of dichroic dye may be incorporated in the liquid crystal material, and the device operated with one or two polarisers.

Abstract: This invention describes a method for the loading and alignment of elastomers in electro-optic and electro-active devices. It comprises the in-situ polymerization between substrates of liquid crystal monomers in the presence of cross-linking reagents. It also describes the production of free-standing elastomer films.

Abstract: A tunable filter in particular for use in the visible or near infrared wavelength region, comprising a nano dispersed composite material contained within a resonant cavity structure comprising dielectric mirrors (15, 16), where the material is polarizable by means of an applied electric field. In particular, the polarizable material may be a nano phase polymer dispersed liquid crystal (PDLC) material where the diameter of liquid crystal droplets (2) within the material (3) is less than 0.1 &mgr;m, and for use in the visible wavelength region is typically between 10 nm and 50 nm. The filter also comprises structure for applying a variable electric field across the faces of the material. The transmission-wavelength characteristic of the filter is such that maxima and minima are shifted in wavelength by varying the electric field.

Abstract: Ferroelectric liquid crystal devices having two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, and a layer of a smectic liquid crystal material enclosed between the cell walls, exhibits a minimum in its response time versus voltage curve. The crystal material has two components, A and B.

Abstract: Compounds of formula ##STR1## are provided which may be used in a variety of devices including liquid crystal devices, piezoelectric devices, pyroelectric devices and in optical recording media, where m=at least 5; and R.sub.x, R.sub.y and R.sub.z are independently from formula (IA), ##STR2## where Y is selected from COO, OCO, O, S, CHOH, CHF, CH.sub.2 ; Q=(CH.sub.2).sub.n wherein one or more non-adjacent methylenes may be replaced by O and n=1-20; Z is selected from O, S, a single covalent bond, COO, a OCO; when Y is CH.sub.2 then n may also be 0; formula (IB) is ##STR3## and represents any mesogenic group; and R.sub.x, R.sub.y and R.sub.z are also independently selected from H, OH, OCOR.sup.1, COOH, CO.sub.2 R.sup.1 (CH.sub.2).sub.p OH, (CH.sub.2).sub.p CO.sub.2 H, --(CH.sub.2).sub.p OR.sup.1 or --(CH.sub.2).sub.p CO.sub.2 R.sup.1 and p=1-20, R.sup.1 =H or C.sub.1-16 alkyl, when R.sup.1 =C.sub.2-16 alkyl the terminal CH.sub.3 group may be replaced by Br or Cl; provided that at least one of and R.sub.x, R.

Abstract: Methods for loading and alignment of liquid crystal polymers in electro-optic and electro-active devices comprise in-situ polymerisation between substrates of monomer material in the presence of a cationic initiator. This allows for the synthesis of liquid crystal polymers containing polyether backbones.

Abstract: A method of aligning liquid crystal material by bringing into contact with a thin layer of polymer which contains the anthracenyl group, the polymer having previously been treated with plane polarised ultraviolet light. A liquid crystal cell is described wherein each of the substrates defining two opposing cell walls are coated on their inner surface with a suitable polymer for carrying out the invention. A typical embodiment of the invention would have repeat unit (II).

Abstract: A damage sensor for detecting damage within a structure such as aircraft wings or fuselage, or a bridge. The sensor comprises a small piece of a triboluminescent material connected via light guiding fibres or layers to one or more detectors. The sensor may be embedded within the structure or mounted on its surface. Impact of objects on the structure causes a physical damage to the triboluminescent material. Such damage causes light emission which is detected and recorded for later observation. The intensity of emission may be measured to give an indication of amount of damage received by the structure. Several different triboluminescent materials may be arranged in different location within the structure so that location of damage may be detected by a single detector sensitive to the different wavelengths of light emitted by the several materials. Light from the triboluminescent material may be detected directly by the detectors.

Abstract: Ferroelectric liquid crystal devices are described which contain liquid crystal mixtures comprising components A and B. Component A consists of one or more optically active compounds capable of imparting a spontaneous polarization to the material. Component B is selected as one or more compounds having formula (I), wherein a, b and c are independently 0, 1, 2; R.sub.1 and R.sub.2 are C.sub.1-15 straight or branched chain alkyl or alkoxy, preferably C.sub.3-12. In the above (for component B) CH=CH linking groups may be replaced by C.sub.2 H.sub.4 and CH.sub.2 O linking groups may be replaced by OCH.sub.2.

Abstract: Disclosed are compounds of formula I ##STR1## wherein R is C.sub.1-12 -alkyl or halogenoalkyl wherein one or two non-adjacent CH.sub.2 groups are optionally replaced by --O--,A is ##STR2## Q is a bivalent radical of formula (2), and L.sup.0, L.sup.1 and L.sup.2 are each independently H or F, with the proviso that at least one of L.sup.0, L.sup.1 and L.sup.2 present in the molecule denotes F.

Abstract: Multiplex addressed ferroelectric liquid crystal devices containing liquid crystal mixtures composed of components A, B and C. Component A consists of one or more optically active compounds capable of imparting a spontaneous polarization to the material. Component B is a compound or compounds of the formula: ##STR1## where R.sub.1 and R.sub.2 independently represent straight or branched chain C.sub.3 -C.sub.12 alkyl or alkoxy groups, a, b and c are independently 0, 1 or 2 and the total of a+b+c is not greater than 4. Component C is selected from a range of liquid crystal components.

Abstract: The invention relates to fluoro-chloro-benzene derivatives of the formula I ##STR1## wherein R denotes an alkyl or halogenoalkyl residue of up to 12 C atoms wherein one or two non-adjacent CH.sub.2 groups may also be replaced by -0- and/or -HC=CH-,the radical A is a ring of the formula (1) or (2): ##STR2## Q is a bivalent radical of the formula (1) or (2) or a single bond or--if radical A denotes trans-1,4-cyclohexylene--is also a bivalent radical of the formulae (3), (4) or (5): ##STR3## and L.degree., L.sup.1 and L.sup.2 are each independently H or F, with the proviso that at least one of L.degree., L.sup.1 and L.sup.2 present in the molecule denotes F.

Abstract: The invention relates to an improved surface coating medium comprising:a thermochromic liquid crystal,a binder polymer being capable of film formation or sufficiently adhesive to allow handling of in a dry uncured state,the improvement wherein the medium further comprises a fusible polymer being capable of melting below 300.degree. C. to form a viscous fluid, and to form a nontacky film on cooling. The invention also relates to a method of coating a substrate with the medium and to a substrate, in particular fabric, coated with the medium.

Abstract: Mesogenic compounds with a .omega.-CF.sub.3 -alkyl, .omega.-CF.sub.3 -alkenyl or .omega.-CF.sub.3 -alkinyl terminal group of formula I ##STR1## with the meaning of R, Z, Q, ##STR2## m, n and o being indicated in claim 1.

Abstract: The invention relates to dihalogenobenzene derivatives of the formula IR.sup.1 --A.sup.1 --Z.sup.1 --A.sup.2 --(Z.sup.2 --A.sup.3).sub.n --R.sup.2wherein R.sup.1, R.sup.2, A.sup.1, A.sup.2, A.sup.3, Z.sup.1, Z.sup.2 and n are as defined in the specification.

Abstract: 2,3-difluorohydroquinone compounds of the formula I ##STR1## in which R.sup.1 and R.sup.2, in each case independently of one another, are alkyl having 1 to 15 C atoms or alkenyl having 3 to 15 C atoms which are unsubstituted, monosubstituted by cyano or at least monosubstituted by fluorine or chlorine, it also being possible for one CH.sub.2 group in these radicals to be replaced by --O--, --CO--, --CO--O--, --O--CO-- or --O--CO--O--,A.sup.1, A.sup.2 and A.sup.3, in each case independently of one another, are(a) trans-1,4-cyclohexylene, in which, in addition, one or two non-adjacent CH.sub.

Abstract: The invention relates to pyridine derivatives of the formula I ##STR1## wherein R.sup.1, A.sup.1, E.sup.1, n, A.sup.2, Z.sup.2, X and Y have the meaning given in claim 1.

Abstract: 4-Q.sup.1 -4'-Q.sup.2 -2,3-Difluorobiphenyls whereinQ.sup.1 and Q.sup.2 independently of one another are each R or R-A.sup.1 -A.sup.2 -Z in whichR (sic) alkyl having 1-15 C atoms or alkenyl having 3-15 C atoms each of which is unsubstituted or monosubstituted by cyano or at least monosubstituted by fluorine or chlorine, and in which in each case one or two non-adjacent CH.sub.2 groups can also be replaced by --O--, --CO--, --O--CO, --CO--O-- or --O--COO--, (sic) --COO--, --O--CO--, --CH.sub.2 O, --O--CH.sub.2 --, --CH.sub.2 CH.sub.2 -- or a single bond, andA.sup.1 and A.sup.2 independently of one another . . (sic) each 1,4-phenylene which is unsubstituted or substituted by one or two fluorine atoms, and in which one or two CH groups can also be replaced by N, or trans-1,4-cyclohexylene wherein one or two non-adjacent CH.sub.2 groups can also be replaced by --O--, and one of the two groups A.sup.1 and A.sup.2 can also be a single bond,subject to the proviso that Z is --CO--O, --O--CO--, --CH.sub.2 O--, --OCH.

Abstract: This invention relates to liquid crystalline mixtures with at least two liquid-crystalline compounds which are free of perfluoro alkylene groups and at least one partially fluorinated additive of formula IR.sup.1 --(CH.sub.2).sub.m --(CF.sub.2).sub.n --R.sup.2 Iwherein R.sup.1, R.sup.2, m and n have the meanings indicated in patent claim 1, and to a means of reducing the refractive indices of a liquid crystalline mixture by adding one or more partially fluorinated additives of formula I.