The present invention relates to liquid-crystal (LC) media as defined in claim 1, having negative dielectric anisotropy and to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays.

The present invention provides a compound represented by formula (i), a liquid crystal composition using the compound, and a liquid crystal display device using the liquid crystal composition. The compound represented by formula (i) has a partial structure K.sup.i1 represented by any of general formulas (K-1) to (K-17) and further has ring B having at least two P-Sp- groups. Therefore, when used for a liquid crystal composition, the compound adsorbs to substrates sandwiching the liquid crystal composition (liquid crystal layer) and allows liquid crystal molecules to be held such that they are aligned in a vertical direction without a PI layer, and improved alignment stability and low-temperature storage stability can be achieved.

The present invention relates to a mixture comprising a not fully aromatic polymerisable compound and a polymerisable photoinitiator, 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 type.

A liquid crystal composition includes at least one compound of general Formula I, at least one compound of general Formula II and at least one compound of general Formula M. The polymerizable liquid crystal composition provides a higher VHR (especially an excellent VHR after UV irradiation), a lower surface roughness of the polymer layer, a faster polymerization rate, a lower residual amount of the polymerizable compound and a better pretilt angle stability, which enables the production of a liquid crystal display device with a better voltage stability and a faster response speed, and can effectively reduce or prevent the occurrences of problems such as “burn-in”, “image sticking”, “Zara Particle” and “uneven display” in the liquid crystal display device. A liquid crystal display includes the liquid crystal composition.

##STR00001##

The present invention provides a compound represented by formula (i), a liquid crystal composition using the compound, and a liquid crystal display device using the liquid crystal composition. The compound represented by formula (i) has a partial structure K.sup.i1 represented by any of general formulas (K-1) to (K-17) and further has ring B having at least two P-Sp- groups. Therefore, when used for a liquid crystal composition, the compound adsorbs to substrates sandwiching the liquid crystal composition (liquid crystal layer) and allows liquid crystal molecules to be held such that they are aligned in a vertical direction without a PI layer, and improved alignment stability and low-temperature storage stability can be achieved.

The problem is to provide a polymerizable compound having suitable polymerization reactivity, a high conversion ratio, low polymerization starting temperature, and high solubility in a liquid crystal composition; a liquid crystal composition containing the compound; and a liquid crystal display device including the composition.

A means thereof includes a compound represented by formula (1) and a liquid crystal composition containing the compound.

##STR00001##

In formula (1), R.sup.1, R.sup.2 and R.sup.3 are independently alkyl or the like; n is 0 or the like; ring A.sup.1 is phenyl or the like, and ring A.sup.2 and ring A.sup.3 are independently 1,4-phenylene or the like; Z.sup.1 and Z.sup.2 are independently a single bond or the like; Sp.sup.1 to Sp.sup.4 are a single bond or the like; a is 1 or the like; c, d and e are independently 0 or 1, and a sum of c, d and e is 1 or the like; and P.sup.1 to P.sup.4 are a polymerizable group, and at least one of P.sup.1 to P.sup.4 is a polymerizable group represented by formula (P-1).

##STR00002##

The subject is to provide liquid crystal display device having a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, a long service life and a small flicker rate. The liquid crystal display device having a liquid crystal alignment film formed on the opposing surfaces of a pair of substrates, and a liquid crystal composition therebetween, wherein the liquid crystal alignment film includes a polymer derived from a polyamic acid having a photodegradable group, and the liquid crystal composition includes at least one compound represented by formula (1) as a first component: ##STR00001## R.sup.1 is alkyl having 1 to 12 carbons or the like; ring A is 1,4-cyclohexylene, 1,4-phenylene or the like; Z.sup.1 is a single bond or the like; X.sup.1 and X.sup.2 are hydrogen or fluorine; Y.sup.1 is fluorine or the like; and a is 1, 2, 3 or 4.

The present invention relates to a mixture comprising a not fully aromatic polymerisabe compound and a polymerisable photoinitiator, 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 type.

The present application relates to mixtures which have liquid-crystalline properties. The application furthermore relates to the use of the mixtures in devices which regulate the transmission of light through an area element.

The invention relates to a medium comprising one or more compounds of formula I,

R.sup.11-A.sup.11-A.sup.12-(CH.sub.2).sub.s-A.sup.13-A.sup.14-R.sup.12I

in a concentration of up to 30% or less,
and one or more compounds of formula II,

R.sup.21-A.sup.21-A.sup.22-(A.sup.23).sub.u-Z.sup.21(CH.sub.2).sub.tZ.sup.22-A.sup.24-A.sup.25-A.sup.26-R.sup.22II

in a concentration of 10% or more,
wherein R.sup.11 to R.sup.22, A.sup.11 to A.sup.26, Z.sup.21, Z.sup.22, s, t, and u have one of the meanings as given in claim 1, to a method of production of such a media, to the use of such media in liquid crystal devices, in particular in flexoelectric liquid crystal devices, and to a flexoelectric liquid crystal device comprising a medium according to the present invention.