A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH, ##STR00001##
in which Z.sup.1 denotes a single bond, CH.sub.2CH.sub.2, CH?CH, CH.sub.2O, OCH.sub.2, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, (CH.sub.2).sub.4, CHFCHF, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, C?C, CF?CF, CH?CHCHO or CH.sub.2CF.sub.2O,
and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.

The present invention relates to liquid-crystalline media comprising one or more compounds of formula C

##STR00001##

as defined in claim 1, and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas (e.g. phased array antennas).

A ferroelectric liquid crystal (FLC) material in a vertically aligned liquid crystal cell, comprising at least one chiral compound and at least one non-chiral liquid crystal compound, with a sub-micron scale helix pitch less than 300 nm, spontaneous polarization greater than 100 nC/cm2, and a tilt angle greater than 38 degrees. The ferroelectric liquid crystal (FLC) material provides an extremely large Kerr constant in a vertically aligned liquid crystal cell at the communication band of the light and therefore reduces the driving voltage and response time.

The invention relates to bimesogenic compounds of formula I ##STR00001##
wherein R.sup.11, R.sup.12, MG.sup.11, MG.sup.12, X.sup.11, X.sup.12 and Sp.sup.1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula l in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.

The invention relates to a light modulation element as comprising, preferably consisting of a cholesteric liquid crystalline medium sandwiched between two opposing substrates, an electrode arrangement, which is capable to allow the application of an electric field, which is substantially perpendicular to the main plane of substrate or the layer of the cholesteric liquid crystalline medium, characterized in that one of the substrates is provided with a planar alignment layer adjacent to the cholesteric liquid crystalline medium and the other substrate is provided with a homeotropic alignment layer adjacent to the cholesteric liquid crystalline medium. The invention is further related to a method of production of said light modulation element and to the use of said light modulation element in various types of optical and electro-optical devices, such as electro-optical displays, liquid crystal displays (LCDs), non-linear optic (NLO) devices, and optical information storage devices.

A compound represented by General Formula (I), A.sup.1 to A.sup.4 each independently represent a non-aromatic ring group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group, which may have a substituent, Z represents O, S, CHRCHR, OCHR, CHRO, CO, SO, SO.sub.2, COO, OCO, COS, SCO, OCOO, SCHR, CHRS, SOCHR, CHRSO, SO.sub.2CHR, CHRSO.sub.2, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, OCHRCHRO, SCHRCHRS, SOCHRCHRSO, SO.sub.2CHRCHRSO.sub.2, CH?CHCOO, CH?CHOCO, COOCH?CH, OCOCH?CH, COOCHRCHR, OCOCHRCHR, CHRCHRCOO, CHRCHROCO, COOCHR, OCOCHR, CHRCOO, CHROCO, CR?CR, CR?N, N?CR, N?N, CR?NN?CR, CF?CF, C?C, or a single bond, R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and m1 represents an integer of 2 to 7.

##STR00001##

The present invention relates to an LC medium comprising and a liquid-crystalline host consisting of an LC component H) comprising one or more mesogenic or liquid-crystalline compounds and an optically active component D) and optionally a polymerizable component P) comprising one or more polymerizable compounds; and to the use of the polymerizable compounds and LC media for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the polymer sustained alignment type.

A liquid crystal medium that has stability to heat, light and so forth, a wide temperature range of a liquid crystal phase and significantly large dielectric anisotropy to develop an optically isotropic liquid crystal phase is required. Moreover, various optical devices that can be used in a wide temperature range, and have a short response time, a large contrast ratio and a low drive voltage are required. A liquid crystal composition contains an achiral component T containing at least one compound (1) represented by formula (1) and a chiral agent to develop an optically isotropic liquid crystal phase, wherein in formula (1), R.sup.1 is alkyl having 1 to 12 carbons, L.sup.1, L.sup.2 and L.sup.3 are each independently hydrogen, fluorine or chlorine; and Y.sup.1 is fluorine, CF.sub.3, or OCF.sub.3. ##STR00001##

A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH,

##STR00001##

in which Z.sup.1 denotes a single bond, CH.sub.2CH.sub.2, CH?CH, CH.sub.2O, OCH.sub.2, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, (CH.sub.2).sub.4, CHFCHF, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, C?C, CF?CF, CH?CHCHO or CH.sub.2CF.sub.2O,
and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.

There is provided a polymerizable liquid crystal composition that enables a film formed through application of the composition and exposure thereof to heat or active energy rays to have an excellent molecular alignment and reduced haze. There is also provided an optically anisotropic body that is produced by using such a polymerizable liquid crystal composition and that has a good transparency. In particular, the present invention provides a polymerizable liquid crystal composition containing a polymerizable haze-reducing agent and a polymerizable liquid crystal compound. Furthermore, the present invention also provides an optically anisotropic body produced by using the polymerizable liquid crystal composition of the present invention. Using the polymerizable liquid crystal composition of the present invention enables production of an optically anisotropic body having a good transparency; hence, the polymerizable liquid crystal composition is usefully applied to optical materials used in, for example, retardation films.