Abstract: The present invention relates to improved liquid crystal compounds which contain a mesogenic core which comprises a group of sub-formula (i) wherein R3 and R4 are independently selected from hydrogen, halogen or CF3, provided at least one of R3 or R4 is selected from halogen or CF3. The sub-formula (i) group may be located at any position within the mesogenic core of the liquid crystal compound, either at the terminus of the liquid crystal core or alternatively substantially in the middle of the liquid crystal core. The compounds of the invention provide compounds which when added to LC mixtures provide increasing birefringence, lowering of melting points, lowering clearing points, and lowering viscosities. These compounds and mixtures may fmd particular use in imaging or display media, such as monitors or televisions.

Abstract: Liquid crystal compounds of Formula (I) for use in liquid crystal devices contains a dioxatetralin unit within the mesogenic liquid crystal core. The dioxatetralin unit may be located at any position within the mesogenic core of the liquid crystal compound, either at the terminus of the liquid crystal core or alternatively substantially in the middle of the liquid crystal core. The compounds of the invention exhibit fast switching and may be used in liquid crystal mixtures for particular use in imaging or display media, such as monitors or televisions.

Abstract: Liquid crystal mixtures comprising at least one of the compounds of formula (I) containing a heterocyclic five-membered ring and with a carbon-carbon double bond in the termninal group are new. RJ=CnH2n+1CH=CHCmH2mZ1; n=1-5; m=0-5; and q=0, 1 or 2; A1 and A2=2,5-disubstituted furan, 2,5-disubstituted thiophene, 2,5-disubstituted oxazole, 2,5-disubstituted thiazole, 2,5-disubstituted 1,3,4-oxadiazole, 2,5-disubstituted 1,3,4-thiadiazole, 1,4-disubstituted benzene, 2,5-disubstituted pyrimidine, 2,5-disubstituted pyridine, 2,6-disubstituted naphthalene; laterally substituted 1,4-disubstituted benzene, laterally substituted 2,5-disubstituted pyrimidine, laterally substituted 2,5-disubstituted pyridine or laterally substituted 2,6-disubstituted naphthalene (lateral substituents=F, Cl, Br or CN); A3=any A1 or 1,4-disubstituted bicyclo(2.2.

Abstract: A material of general formula I: ##STR1## where E=0 indicates a non-cyclic system, and E=1 indicates a cyclic system;G is R.sub.3 SiR.sub.1 R.sub.2 (O).sub.kR.sub.1, R.sub.2, R.sub.3 are independently selected from C.sub.1-16 alkyl which may be partly or fully halogenated, H and formula IA: ##STR2## wherein Y is a propylene group which may be partially halogenated with fluorine or chlorine and Y.sub.1 is independently selected from COO, OCO, O, S, CHOH, CHF, CO or CH.sub.2 ;Q and Q.sub.1 are independently selected from (CH.sub.2).sub.n wherein one or more non-adjacent methylenes may be replaced by O andn=0-20;Z and Z.sub.1 are independently selected from O, S, single covalent bond, COO or OCO; ##STR3## represents a mesogenic group and is given by the general structure II ##STR4## A, B, D are selected from the following rings: ##STR5## the above rings may be substituted with one or more of the following substituents in at least one of the available substitution positions: F, Cl, Br, CH.sub.