Hoechst Aktiengesellschaft

Gerhard Illian

Claus Escher

Rainer Wingen

Dieter Ohlendorf

Mikio Murakami

Takamasa Harada

Hans-Rolf Dubal

Wolfgang Hemmerling

Ingrid Muller

Norbert Rosch

Ayako Takeichi

Hubert Schlosser

Kazuya Nagao

Heinz Rieger

Yoshio Inoguchi

Tsuyoshi Uemura

Shozo Fujiwara

Dietmar Jungbauer

Michael Feldhues

Thomas Mecklenburg

Hiroyuki Ohnishi

Hidenori Fujiwara

Thoshiaki Nonaka

Karl Pampus

Armin De Meijere

Heinz-Joachim Rieger

Compounds for use in liquid-crystal composition

Electrical addressing of ferroelectric liquid-crystal displays

A ferroelectric liquid crystal mixture which does not lower the conventional transition temperature to the ferroelectric phase (60.degree. C. or above), which maintains the Sa phase within a suitable temperature range, and which is useful for reducing the cone angle is disclosed. The ferroelectric liquid crystal mixture contains at least one of the compounds represented by the following general formulae 1 to 3, and exhibits a Sa/Sc phase transition temperature of 60.degree. C. or more and a cone angle of 47 degree or less atsome temperature between 15.degree. C. and 35.degree. C.: ##STR1##

Ferroelectric liquid crystal mixture

A ferroelectric liquid crystal mixture containing two or more components, at least one of which is a complex ligand for ions, in particular for cations, is particularly suitable for use in ferroelectric liquid crystal displays.

Use of complex ligands for ions in ferroelectric liquid-crystal mixtures

A ferroelectric liquid crystal mixture which does not lower the conventional transition temperature to the ferroelectric phase (60.degree. C. or above), which maintains the Sa phase within a suitable temperature range, and which is useful for reducing the cone angle is disclosed. The ferroelectric liquid crystal mixture contains at least one of the compounds represented by the following general formula 1 to 3, and exhibits a Sa/Sc phase transition temperature of 60.degree. C. or more and a cone angle of 47 degree or less atsome temperature between 15.degree. C. and 35.degree. C.: ##STR1##

Compounds of formula I ##STR1## in which R.sup.1 and R.sup.2 are, for example, an alkyl chain,

Derivatives of 3-cyclohexylpropionic acid, and the use thereof in

Ferroelectric liquid-crystal systems having high spontaneous polarization, in particular &gt;35 nC cm.sup.-2, and good orientation properties in the ferroelectric phase, in particular the S.sub.C * phase, contain at least three different optically active compounds, preferably as dopes in a base mixture which is not itself optically active and has a nematic phase above the smectic phase. The optically active compounds are selected so that they do not all induce a helix of the same rotation sense in the nematic phase. Their relative concentrations are selected so that the total resultant pitch of the helix throughout the cholesteric phase is not less than 10 .mu.m.

Ferroelectric liquid-crystal systems having three or more chiral

Pyridylpyrimidines, a process for their preparation and their use in

A process for producing a liquid-crystal cell by using a ferroelectric liquid crystal (FLC) composition containing at least one oleophilic substance that exhibits liquid crystallinity and at least one additive having lower boiling point than said substance, characterized in that said FLC composition is charged into the cell under high-temperature and high-vacuum conditions, provided that the two conditions will not overlap, or will overlap for a sufficiently short time to effectively prevent the evaporation of said additive.

Process for producing ferroelectric liquid-crystal cells with oleophilic

Disclosed and claimed are liquid-crystalline cyclopropylalkyl or -alkenyl or heterocyclic compounds, process for their preparation, and their use in liquid-crystalline mixtures. The novel cyclopropylalkyl or -alkenyl or heterocyclic compounds are of the general formula ##STR1## In this formula A.sup.1, A.sup.2 and A.sup.3 are unsubstituted or substituted, aromatic or heteroaromatic molecular components such as 1,4-phenylene or pyrimidine-2,5-diyl which are linked via a single bond (in the case where k and m=0) or via functional groups M.sup.1 and M.sup.2, such as CO--O or CH.sub.2 --O; j, k, l, m and n are zero, 1 or 2. The radicals R.sup.2, R.sup.3 and R.sup.4 are H or alkyl/alkenyl, R.sup.1 is alkyl/alkenyl or one of the substitutents known from LC chemistry such as an .alpha.-haloalkanoic acid radical. At least one of the components A.sup.1, A.sup.2 and A.sup.3 can be heteroaromatic, and G is alkylene or alkenylene.

Cyclopropylaklyl or -alkenyl or heterocyclic compounds, process for

The use of optically active tetrahydrofuran-2-carboxylic acid esters as dopants in liquid-crystal mixtures, liquid-crystal mixtures containing same and novel optically active tetrahydrofuran-2-carboxylic acid esters. Optically active tetrahydrofuran-2-carboxylic acid esters containing a mesogenic molecular building unit are suitable as dopants in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases having short switching times and in electroclinic phases having large electroclinic coefficients. A further advantage is that they induce a helix having a very small pitch so that they are also suitable for helix compensation in LC mixtures. The compounds are symbolized by the general formula: ##STR1## in which the symbols and indices essentially denote: R.sup.1 =alkyl/alkenyl or tetrahydrofurancarbonyloxy or -thio; j, l, n=zero, 1 or 2; k, m=zero or 1; --A.sup.1, --A.sup.2, --A.sup.3 =phenylene, cycloalkylene or corresponding heterocyclates containing nitrogen, oxygen or sulfur; --M.sup.1, --M.sup.2 =bridges such as --CO--O, --OCH.sub.2 or --CH.dbd.CH; X=oxygen or sulfur.

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Frankfurt am Main, Germany

Gerhard Illian