The Secretary of State for Defence in Her Britannic Majesty's Government

Merck Patent Gesellschaft MIT Beschrankter Haftung

Akzo N.v.

The Secretary of State for Defence in Her Majesty'3 S Government of the

Richard M Scrowston

George W Gray

David Lacey

Kenneth J Toyne

Adam Jackson

Lawrence Kam Chan

Madeline J Bradshaw

Victoria Brimmell

David Coates

Edward P Raynes

Amarjit Kaur Samra

Jennifer Constant

Ibrahim G Shenouda

Eike Poetsch

Joachim Krause

Georg Weber

Andreas Wachtler

Thomas Geelhaar

Matthew F Bone

Daniel J Young

Peter A Gemmell

David Holmes

Andrew M McRoberts

Raymond Denman

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. ##STR1##

Chiral liquid crystal compounds

The invention relates to the use of chiral and/or achiral compounds, containing at least one structural element from the group comprising

Media containing thiazole derivatives and thiadiazole derivatives and

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

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.

Liquid crystalline polyesters for optical data storage

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).

Cyano-alicyclic esters in liquid crystal compositions

Liquid crystal compounds, mixtures and devices

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

Amide liquid crystal compounds: mixtures and devices using them

N-substituted amino acid derivatives for use in liquid crystal materials

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.

Liquid crystal compounds containing two or more chiral centers

##STR1## Ferroelectric smectic liquid crystal mixtures are provided consisting of two constituents; a smectic host and another containing a chiral compound in which rotation of the chiral center relative to the molecular core is sterically hindered, so that the chiral compound induces a high Ps in the mixture. A preferred class of chiral compounds is those derived from naturally occurring compounds with chiral groups, especially .alpha.-hydroxycarboxylic acids, amino acids and terpenoids, e.g. with chiral groups (I), (II), (III). The chiral group is incorporated into a compound containing a mesogenic combination of groups, e.g. with chains of cyclic groups and some mesogenic combinations are described.

Compounds for ferroelectric liquid crystal devices

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North Humberside, United Kingdom

Richard M Scrowston