The invention relates to a liquid-crystalline medium having a nematic phase comprising one or more compounds of formula X

##STR00001##

wherein the parameters have the meaning 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 X for improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds, as well as to certain compounds of formula X, as specified in the text.

The invention relates to a liquid crystal device comprising at least two opposing transparent substrates, at least one liquid crystal switching layer sandwiched between said opposing substrates comprising one or more polymerised photoreactive mesogens of formula I,

R.sup.11-Sp.sup.11-X.sup.11[-A-Z].sub.o-A.sup.11-CY.sup.11═CY.sup.12[—C═O].sub.x[—O].sub.y-A[-Z-A].sub.p—X.sup.21-Sp.sup.21-R.sup.21  I

wherein R.sup.11, R.sup.21, A.sup.11, A, Z, X.sup.11, X.sup.21, Y.sup.11, Y.sup.12, Sp.sup.11, Sp.sup.21, o, p, x and y have one of the meanings as given in claim 1, and one or more nematogenic compounds, an electrode structure provided on one or both of the opposing substrates, wherein one or more of said substrates are additionally provided with an optical grating or a lens structure adjacent to the LC switching layer. The invention is further related to a method of production of said liquid crystal device, to the use of said Liquid Crystal device in various types of optical and electro-optical devices, and to electro-optical devices comprising the liquid crystal device.

To provide a liquid crystal composition having at least one or a suitable balance regarding two of characteristics such as high maximum or low minimum temperature of a nematic phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet light or heat and a large elastic constant; and an AM device including the composition and having a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio, a long service life and so forth. The liquid crystal composition contains a quencher as an additive component and a specific compound having large positive dielectric anisotropy as a first component, and a liquid crystal display device includes the composition. The composition may contain a specific compound having high maximum temperature or small viscosity as a second component, or a specific compound having negative dielectric anisotropy as a third component.

Provided is a polar compound having high chemical stability, high capability of aligning liquid crystal molecules, high solubility in a liquid crystal composition, and a large voltage holding ratio when used in a liquid crystal display device. The compound is represented by formula (1):

##STR00001##

in which, for example, R.sup.1 is alkyl having 1 to 15 carbons; MES is a mesogen group having at least one ring; Sp.sup.1 is a single bond or alkylene having 1 to 10 carbons; M.sup.1 and M.sup.2 are hydrogen; and R.sup.2 is a group represented by formulas (1a) to (1c):

##STR00002##

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

The present invention relates to polymerisable compounds, to processes and intermediates for the preparation thereof, to liquid-crystal (LC) media comprising them, and to the use of the polymerisable 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 (PS, PSA) and self-aligning (SA) type.

The present invention relates to liquid-crystalline media comprising one or more pleochroic dyes and one or more compounds selected from the group of compounds of formulae I, II and III,

##STR00001##

in which the parameters have the meaning indicated in Claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.

Disclosed is a novel stabilizer represented by formula I,

##STR00001##

Further disclosed is a liquid crystal composition comprising a compound of formula I. The liquid crystal composition disclosed in the present invention has a low viscosity γ.sub.1, a moderate dielectric anisotropy Δ∈, a moderate optical anisotropy Δn, and most principally a high reliability, and can achieve a quick response of liquid crystal display.

The present invention relates to the technical field of liquid crystal displays, and particularly relates to a liquid crystal composition containing a 2-methyl-3,4,5-trifluorobenzene liquid crystal compound and use thereof, wherein the liquid crystal composition of the present invention comprises, in percentages by weight, 1-50% of one or more compounds represented by general formula I and 10-70% of one or more compounds represented by general formula II, and may further comprise 0-30% of compounds represented by general formula III and/or 6-45% of one or more compounds represented by general formulas IV to XIII The liquid crystal composition provided by the present invention has a low rotational viscosity and a large elastic constant, is presented as having a shorter response time, and can significantly improve the display effect of a liquid crystal display when applied to TN, IPS and FFS mode displays.

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 (Δ∈), i.e. (∈.sub.⊥/Δ∈), 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.

A liquid-crystalline medium, in particular based on a mixture of polar compounds, having compounds of formulae Y, CY, PY and/or LY, and compounds of formula S1 and/or S2:

##STR00001##