Disclosed is a liquid crystal composition comprising one or more compounds represented by formula I, one or more compounds represented by formula II, and one or more compounds represented by formula III: ##STR00001##
The liquid crystal composition has simultaneously a lower rotary viscosity, a better photoelectric performance, a higher clearing point, a good low temperature performance, and less display defects. Further disclosed is a liquid crystal display element or device comprising the liquid crystal composition.

The invention relates to a liquid-crystalline medium comprising one or more compounds of the formula CC

##STR00001##

in which the groups occurring have the meanings indicated in Claim 1, and to the use of the liquid-crystalline medium for electro-optical purposes, in particular in liquid-crystal light valves for lighting devices for vehicles, and to liquid-crystal light valves which comprise this medium and lighting devices for vehicles which contain liquid-crystal light valves of this type.

A liquid crystal composition includes one or more compounds of general Formula I in an amount of 1%-30% by weight of the total weight of the liquid crystal composition, one or more compounds of general Formula II in an amount of 5%-35% by weight of the total weight of the liquid crystal composition, and one or more compounds of general Formula III in an amount of 1%-35% by weight of the total weight of the liquid crystal composition. The liquid crystal composition has an appropriate clearing point, an appropriate optical anisotropy, an appropriate dielectric anisotropy, as well as a higher voltage holding ratio, a higher transmittance, a good high-temperature resistant performance and a faster response speed, thus being suitable for display modes, such as VA, IPS and FFS. A photoelectric display device includes the liquid crystal composition.

##STR00001##

A vertical alignment liquid crystal display includes a first substrate, a second substrate, a liquid crystal layer located between the first substrate and the second substrate, a first and a second passivation layers respectively located at inner sides of the first and the second substrates, a common electrode layer and a pixel electrode layer respectively located on the first and the second passivation layers. The liquid crystal layer includes liquid crystal molecules, auxiliary alignment agent and a polymer network penetrating the entire liquid crystal layer. The auxiliary alignment agent makes the liquid crystal molecules in the liquid crystal layer vertically aligned on the surfaces of the first and the second substrates. The polymer network stabilizes alignment of the liquid crystal molecules and enhances vertical alignment effect of the auxiliary alignment agent to the liquid crystal molecules.

Disclosed is a liquid crystal composition comprising one or more compounds represented by formula I and/or formula II and one or more compounds represented by formula III: ##STR00001##
wherein the definition of each substituent is given. The composition involved in the present invention has a low viscosity .sub.1, a high clearing point Tni and a large optical anisotropy n, and can realize a rapid response of liquid crystal display.

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.

A negative dielectric anisotropy liquid crystal composition having one or more A-R.sub.0B compounds represented by formula I above as a first component, and one or more compounds represented by formula II above as a second component: ##STR00001##
The liquid crystal composition has a good stability against light and heat, a lower viscosity, a wider refractive index that may be achieved by adjusting the monomer ratio, and a higher clearing point (a very wide service temperature range). The liquid crystal composition has a higher light transmittance, thus allowing a display device to have a higher brightness or an energy saving effect.

A liquid crystal composition and the use thereof are provided. The liquid crystal composition comprises 15-30% by weight of three or more compounds of general formula I; the general formula I must comprises at least two compounds of general formula I-1; wherein, by weight of the total amount of the liquid crystal composition, the total amount of the compounds of general formula I-1 is no lower than 10%, and the content of each of the compounds of general formula I-1 is no higher than 8%. The liquid crystal composition has appropriately high optical anisotropy, higher dielectric anisotropy, lower threshold voltage, suitable elastic constant, suitable temperature range of nematic phase, good reliability and heat stability, and good low-temperature intersolubility. ##STR00001##

A liquid crystal composition without requiring an alignment film or alignment treatment on a substrate. The problem is solved by a low molecular weight polar compound capable of homogeneously aligning a liquid crystal medium relative to the substrate, for example, a low molecular weight polar compound represented by formula (1):
M-P(1) In formula (1), M is a nonpolar group having 1 or more carbons, and P is a polar group.

Disclosed are a liquid crystal composition and a liquid crystal display device. The liquid crystal composition comprises at least one compound of general formula I, at least one compound of general formula II, at least one compound of general formula III, and at least one compound of general formula IV. By compounding the four compounds, the composition can have advantages of a wide temperature range of nematic phase, a low viscosity and a low threshold voltage, and the liquid crystal display element can have a short response time and great power saving performance.