Merck Patent Gesellschaft MIT Beschrankter Haftung

Other

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

Merck Patent Gesellschaft MIT Beschr&auml;nkter Haftung

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

David I Bishop

Ian Charles Sage

David Coates

Edward P Raynes

John A Jenner

Madeline J Bradshaw

Volker Reiffenrath

Eike Poetsch

Herbert Plach

Reinhard Hittich

George W Gray

Andreas Wachtler

Simon Greenfield

Damien Gerard McDonnell

Kenneth J Toyne

David Lacey

Volker Meyer

Anthony Bernard Davey

Robert Hammond-Smith

Klaus P Stahl

Stephen J Lewis

Peter H Balkwill

Andrew D Pearson

The invention relates to a thermochromic liquid crystalline medium comprising a liquid crystalline host component and an active component, to a thermochromic ink comprising such a thermochromic liquid crystalline medium encapsulated in a light transmissive polymeric material, to the use of a thermochromic medium or ink in decorative applications like pigments, inks and paints, cosmetics, thermodiagnostic applications like medical thermography, thermometry, optical and electrooptical applications, and security applications and devices, to a security marking or device comprising a thermochromic liquid crystalline medium or thermochromic ink and to a document of value comprising such a security marking.

Thermochromic liquid crystalline medium

Biphenylylethanes

Biphenyl egters of formula (I), ##STR1## wherein formula (II) represents formula (III) or formula (IV), R.sub.1 represents C.sub.3 -C.sub.12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is O or 1 R.sub.2 represents C.sub.3 -C.sub.12 alkyl or alkoxy, one of Q.sub.1 or Q.sub.2 is fluorine and the other is hydrogen, provided that when j is O and formula (II) is formula (III) and both R.sub.1 and R.sub.2 are n-alkyl, then the total number of carbon atoms in R.sub.1 and R.sub.2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.

Biphenyl esters and liquid crystal materials and devices containing them

Smectic A liquid crystal compositions

A fluorinated compound having a formula: ##STR1## R.sub.1 is hydrogen or alkyl having up to 12 carbon atoms; R.sub.2 is selected from hydrogen, alkyl having up to 12 carbon atoms, alkoxy having up to 12 carbon atoms, ##STR2## wherein R.sub.3 is hydrogen or alkyl having up to 12 carbon atoms, and wherein R.sub.4 is hydrogen, alkyl having up to 12 carbon atoms or alkoxy having up to 12 carbon atoms; ##STR3## represents a cyclohexane ring which is in the trans configuration if 1, 4-disubstituted; ##STR4## represents a benzene ring; each of X, Y and Z independently represents hydrogen or fluorine in one or more of the lateral benzene ring positions, provided that at least one of X, Y and Z is present representing fluorine;

Disubstituted ethanes and their use in liquid crystal materials and

Growing community of inventors

Dorset, United Kingdom

David I Bishop