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: The invention relates to the use of chiral and/or achiral compounds, containing at least one structural element from the group comprisingthiazole-2,4-diylthiazole-2,5-diyl1,2,4-thiadiazole-2,5-diyl1,2,4-thiadiazole-3,5-diylas components of media having a smectic liquid-crystalline phase.

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

Abstract: The invention comprises liquid crystalline polyesters suited to be used as a medium for optical data storage, especially reversible (or erasable) optical data storage. The polyesters comprise the polycondensation product of an aliphatic dicarboxylic acid or a derivative thereof and propane diol which on its center carbon bears a mesogenic substituent comprising two rings, either alicyclic or aromatic. Preferably also the dicarboxylic acid or derivative thereof is mesogenically substituted. The invention further comprises a medium for optical data storage containing polyesters of the above type.

Abstract: Compounds suitable for use as constituents of ferroelectric smectic liquid crystal compositions, which are esters of formula (I), where R.sub.2 and R.sub.3 together represent the residue of an alicyclic hydrocarbon ring system where .degree.C. is an asymmetric carbon atom and X is a chain of up to three linked aromatic or alicyclic six-membered organic cyclic groups, laterally and/or terminally substituted. Preferred compounds have a formula (II), where R.sub.1 is alkyl or alkoxy, A, B, and D are phenyl, fluoro or chloro substituted phenyl or cyclohexyl, n is 0 or 1, Y is a bond or CH.sub.2 CH.sub.2 if n is 0, or a bond CH.sub.2 CH.sub.2 COO or COO if n is 1. Preferred groups C(CN)R.sub.2 R.sub.3 are formula (III) and (IV).

Abstract: Compounds for use in ferroelectric smectic liquid crystal mixtures of general formula (I), where R.sub.1 is alkyl, Y is COO or OOC, m, n and p are 0 or 1 provided m+n is 2 or less and when Y is OOC, p is 0, X is a mesogenic group, especially 4.sup.1 -alkyl- or alkyl-biphenyl or bicyclohexyl. Methods for preparation of these compounds are given, and ferroelectric smectic liquid crystal mixtures containing them are described.

Abstract: Amides having the following structure: ##STR1## used in ferroelectric smectic liquid crystal mixtures, especially as pitch compensators and liquid crystal compositions containing them.

Abstract: Novel compounds suitable for use as chiral dopants in ferroelectric smectic liquid crystal materials comprising an optically active derivative of an .alpha.-amino acid of the formula ##STR1## wherein R.sub.1 is selected from the group consisting of C.sub.1-20 alkyl or alkoxy, R is C.sub.1-20 n-alkyl and Y is C.sub.1-20 alkyl. A liquid crystal mixture and a device using these compounds are also described.

Abstract: A compound suitable for use in a ferroelectric smectic liquid crystal composition having a structure which contains two chiral centers derived from alpha hydroxy carboxylic acid groups and having the formula: ##STR1## wherein R.sub.1 is n-alkoxy containing 1-12 carbo atoms and R.sub.2 is n-alkyl containing 1-12 carbon atoms. Methods of preparation and details of liquid crystal mixtures containing these compounds are described.