The invention relates to a liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of formula YX

##STR00001## in which
the parameters have the meanings given in the text,
to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the use of the compounds of formula YX for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

Holographic polymer dispersed liquid crystal material systems in accordance with various embodiments of the invention are illustrated. One embodiment includes a holographic polymer dispersed liquid crystal formulation, including monomers, photoinitiators, and a liquid crystal mixture including terphenyl compounds and non-terphenyl compounds, the liquid crystal mixture having a ratio of at least 1:10 by weight percentage of the terphenyl compounds to the non-terphenyl compounds, wherein the photoinitiators are configured to facilitate a photopolymerization induced phase separation process of the monomers and the liquid crystal mixture. In another embodiment, the liquid crystal mixture further includes pyrimidine compounds, and wherein the liquid crystal mixture has a ratio of at least 1:10 by weight percentage of the terphenyl compounds and pyrimidine compounds to the non-terphenyl compounds. In a further embodiment, the ratio of the terphenyl compounds to the non-terphenyl compounds is at least 1.5:10.

An object of the present invention is to provide a composition that realizes high n, has a wide liquid crystal phase temperature range, small viscosity, excellent low-temperature solubility, and high resistivity and voltage holding ratio, and is stable against heat and light, and to provide a liquid crystal composition having an excellent lens effect and excellent chemical stability using the composition, and a liquid crystal display device and a liquid crystal lens that use the liquid crystal composition. The present invention provides a liquid crystal composition that contains one or two or more compounds represented by general formula (i) and one or two or more compounds represented by general formula (ii), a liquid crystal display device using the liquid crystal composition, a liquid crystal lens using the liquid crystal composition, and a birefringence lens for stereoscopic image display using the liquid crystal composition.

The present invention relates to compounds of formula M

##STR00001##

in which R.sup.M has the meaning indicated in claim 1, to liquid crystal mixture comprising the same, to the use of these liquid-crystal media, in particular in components for high-frequency technology, and to components of this type which contain media according to the invention, and to the production and use of these components. The components according to the invention are suitable, in particular, as phase shifters in the microwave and millimetre wave region, for microwave and millimetre wave array antennae and very particularly for so-called tunable reflectarrays.

A liquid crystal composite that contains a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, large optical anisotropy and large positive dielectric anisotropy, and that is suitable for dimming, or having a suitable balance regarding at least two of the characteristics; and a liquid crystal dimming device having the liquid crystal composite. The liquid crystal composite contains a polymer and a liquid crystal composition containing a specific compound having large positive dielectric anisotropy. The liquid crystal composite may further contain a specific compound having high maximum temperature or low minimum temperature; or a specific compound having large negative dielectric anisotropy.

The new media exhibit a ferroelectric nematic phase preferably at ambient temperature. They preferably comprise one or more compounds selected from the group of compounds of formulae IA, IB and IC,

##STR00001##

in which the variable groups have the meanings indicated in the text and in the claims. Use of the media for providing ferroelectric nematic materials and a method of operation of an electro-optical device are presented. The media may be useful for energy-saving displays and electrical appliances.

Compound (1) is provided.

R.sup.1-MES-Sp.sup.1-P.sup.1(1)

In compound (1), R.sup.1 is alkyl having 1 to 15 carbons; MES is a mesogen group having an at least one ring; Sp.sup.1 is a single bond or alkylene having 1 to 10 carbons, and in the alkylene, at least one hydrogen is replaced by group (1a); P.sup.1 is group (1e) or (1f);

##STR00001##

wherein, M.sup.1, M.sup.2, M.sup.3 and M.sup.4 are hydrogen; Sp.sup.2 and Sp.sup.3 are a single bond or alkylene having 1 to 10 carbons; R.sup.2 is alkyl having 1 to 15 carbons; R.sup.3 is group (1g), (1h) or (1i);

##STR00002##

wherein, Sp.sup.4 and Sp.sup.5 are a single bond or alkylene having 1 to 10 carbons; S.sup.1 is >CH, and S.sup.2 is >C<; and X is OH.

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I, ##STR00001## in which R.sup.1, R.sup.1*, Z.sup.1, Z.sup.2 and L.sup.1-3 have the meanings defined herein, and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, PS-IPS or IPS effect.

A liquid-crystalline medium having a nematic phase, a dielectric anisotropy of 0.5 or more and a ratio of the dielectric constant perpendicular to the director (?.sub.?) to the dielectric anisotropy (??), i.e. (?.sub.?/??), of 2.0 or less and comprises one or more compounds of formula I: ##STR00001##
wherein the parameters have the meaning given in the text. An electro-optical display containing such a medium, particularly in an active-matrix display based on the IPS or FFS effect. Methods for using of the compounds of formula I for improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

An object of the present invention is to provide a dye compound-containing liquid crystal composition that has high solubility and high solubility retention for the dye compound and has high light resistance and a device including the composition. The use of a combination of one or two or more predetermined alkenyl compounds and a compound including a predetermined difluoro structure can provide a dye compound-containing liquid crystal composition that has high solubility and high solubility retention for the dye compound and has high light resistance, and the dye compound-containing liquid crystal composition is useful for devices, in particular, photochromic devices.