Hoechst Aktiengesellschaft

Displaytech, Inc.

Claus Escher

Dieter Ohlendorf

Rainer Wingen

Gerhard Illian

Hans-Rolf Dubal

Wolfgang Hemmerling

Ingrid Muller

Takamasa Harada

Mikio Murakami

Norbert Rosch

Gerd Illian

Yoshio Inoguchi

Hubert Schlosser

Gunter Scherowsky

Anke Kaltbeitzel

Heinz Rieger

Jurgen Gay

Tsuyoshi Uemura

Mark A Handschy

Michael D Wand

Shozo Fujiwara

Gerd Heppke

Rohini T Vohra

Karsten Blatter

Dietmar Jungbauer

Michael Feldhues

Kazuya Nagao

Detlef Lotzsch

Thomas Mecklenburg

Hiroyuki Ohnishi

Christian Bahr

Peter Harnischfeger

Armin De Meijere

Heinz-Joachim Rieger

Karl Pampus

Electrical addressing of ferroelectric liquid-crystal displays

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

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

Optically active 1,3-dioxolane derivatives which carry a mesogenic radical in the 4-position and have the general formula (I) ##STR1## are suitable for use as doping agents in liquid-crystal mixtures--in particular ferroelectric liquid-crystal mixtures. The symbols in the general formula have the following meanings:

Optically active 1,3-dioxolane derivatives carrying a mesogenic radical

Optically active, mesogenic 1,3-dioxolane-4-carboxylates are suitable as dopes in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases having short switching times and in electroclinic phases having large electroclinic coefficients. Their particular advantage is that they induce a helix of very large pitch, meaning that helix compensation by further dopes is unnecessary. In addition, the 1,3-dioxolane-4-carboxylates exhibit high UV stability.

Use of optically active 1,3-dioxolane-4-carboxylates as dopes in

2-Fluoropyridines, processes for their preparation and their use in ferroelectric liquid crystal mixtures

2-Fluoropyridines, their preparation and their use in liquid crystal

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

Fast response, high contrast Ferroelectric Liquid Crystal (FLC) electro-optic devices in which the FLC retains a helical director structure stable to unwinding are provided. In particular, high contrast distorted helix FLC electro-optic devices including half-wave plates in the visible wavelength region are provided. The FLC cells of this invention incorporate chiral FLCs which exhibit a ferroelectric phase and a chiral nematic phase at temperatures above the ferroelectric phase. The natural helix pitch of the FLC in the ferroelectric phase is sufficiently tighter than the thickness of the FLC layer such that it is not surface-stabilized. The chiral nematic phase has a natural helix pitch sufficiently greater than the cell thickness to facilitate alignment of the FLC in the device to achieve high contrast.

High contrast distorted helex effect electro-optic devices and tight

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.

Use of optically active tetrahydrofuran-2-carboxylic acid esters as

Ferroelectric liquid-crystalline mixtures

Ferroelectric liquid crystal display comprising outer substrates, electrodes, polarizer(s), ferroelectric liquid crystalline material and alignment layer(s), in which the ferroelectric liquid crystalline material has a spontaneous polarization of Ps&gt;20 nC.cm.sup.-2 and a natural helical pitch of less than half of the cell thickness, and the alignment layer comprises at least one lipophilizing, lipophilic and/or amphiphilic compound. The liquid crystal display according to the invention exhibits a short switching time and a significantly reduced surface memory effect, and thus achieves an improved display contrast.

Ferroelectric liquid crystal display with liquid crystal mixtures having

Chiral alkenylaryl 2,3-epoxyalkyl ethers, and the use thereof in

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Muhltal, Germany

Claus Escher