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

Central Research Laboratories Limited

Other

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

Lawrence Kam Chan

George W Gray

Kenneth J Toyne

David Lacey

David Coates

Richard M Scrowston

Adam Jackson

Madeline J Bradshaw

Daniel J Young

Peter A Gemmell

Victoria Brimmell

Edward P Raynes

Amarjit Kaur Samra

Jennifer Constant

Ibrahim G Shenouda

Ian Charles Sage

Simon Greenfield

Michael Hird

Matthew F Bone

Chuan Chu Dong

Peter Styring

John William Goodby

A liquid crystal composition having a high order, tilted ferro-electric achiral Smectic I phase exhibiting a relaxed cone angle of greater than 20.degree. in the absence of high surface tilt alignment layers at temperatures in the range of 5.degree. C. to 40.degree. C. and includes from 90% to 99.9% by weight of a mixture of at least two achiral host compounds and from 0.1% to 10% by weight of a chiral dopant compound.

Liquid crystal compositions

Dioxane derivatives

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

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

Fluorinated 4'-cyano substituted terphenyls of general formula (I), wherein R.sub.1 is selected from alkenyl, H, R, RO and RCO where R is alkyl or perfluoroalkyl containing up to 12 carbon atoms, n is 1, 2 or 3 and the lateral fluorosubstituent(s) may be in any of the available substitution positions are provided. These have liquid crystalline properties and may be used as components of liquid crystal materials.

Fluorinated 4'-cyano substituted terphenyls

Compounds which may be used as a dopant or host in a ferroelectric chiral smectic liquid crystal mixture. The compounds are characterized in that they are derivates of an X-hydroxy carboxylic acid and contain the chiral unit (I), in which Ro may be alkyl, alkoxy, halogen, formula (II), where b may be 0 to 3 and the phenyl ring may be substituted, and a is 0 or 1. The chiral unit is combined with a range of mesogenic combinations of groups. Lactic acid derivatives are described in detail (i.e. Ro.dbd.methyl) together with various preparative routes, for example the compound formula (III), which has dopant properties in a range of hosts.

Alpha-hydroxy carboxylic acid derivates suitable for use in liquid

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

19 -hydroxy carboxylic acid derivatives suitable for use in liquid

##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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Northolt, United Kingdom

Lawrence Kam Chan