The present invention relates to a liquid crystal (LC) medium comprising a compound of formula I

##STR00001## and one or more compounds of formula II

##STR00002## as defined in claim 1, and to the use thereof for optical, electro-optical and electronic purposes, in particular in LC displays, especially in IPS, FFS, VA or PS-VA 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 liquid crystal display device. The liquid crystal display device of the present invention comprises a first substrate, a second substrate, and a liquid crystal composition disposed between said first substrate and said second substrate, wherein said first substrate and said second substrate are disposed in parallel and opposite to each other; alignment layers are disposed on the sides of said first and second substrates that are close to said liquid crystal composition; and said alignment layers are provided with vertical alignment films that allow liquid crystal molecules in said liquid crystal composition to be arranged roughly perpendicular to said first and second substrates, with said liquid crystal molecules having a pretilt angle of 88.5° to 89.5°.

The present invention provides a liquid crystal composition comprising: at least one compound of general Formula I; at least one compound of general Formula II; at least one compound of general Formula M and at least one compound of general Formula N. The present invention also provides a liquid crystal display device comprising the liquid crystal composition. The liquid crystal composition provided in the present invention has a higher optical anisotropy, a higher clearing point, a higher dielectric anisotropy, a high transmittance and a larger average elastic constant. When the liquid crystal composition is used in the IPS liquid crystal display device, the transmittance of the display device can be effectively improved, so that the display device has a good display performance while also having good energy-saving and environment-friendly characteristics. ##STR00001## ##STR00002## ##STR00003## ##STR00004##

The invention relates to a liquid crystal composition, a liquid crystal display element and a liquid crystal display comprising the liquid crystal composition, belonging to the field of liquid crystal display. The liquid crystal composition of the present disclosure comprises a compound of formula I and one or more compounds of formula II. The liquid crystal composition can increase the dielectric anisotropy and improve the voltage retention rate.

##STR00001##

Provided are a polymerizable compound represented by formula I and a liquid crystal composition formed by combining such a polymerizable compound with a specific liquid crystal component, particularly a PSVA liquid crystal composition for displays or TV applications and a PSA-IPS liquid crystal composition for an IPS mode; in particular, the polymerizable compound has a faster polymerization rate, and a “material system” formed from the selected polymerizable component and liquid crystal component has a low rotary viscosity and good photoelectric properties, and has a high VHR after (UV) photoradiation, this avoiding the problem of the occurrence of residual images to final displays. ##STR00001##

Provided are a polymerizable compound represented by formula I and a liquid crystal composition comprising the polymerizable compound, particularly a PSVA liquid crystal composition for displays or TV applications and a PSA-IPS liquid crystal composition for an IPS mode; in particular, the polymerizable compound has a faster polymerization rate, and a “material system” formed from the selected polymerizable component and liquid crystal component has a lower rotary viscosity and better photoelectric properties, and has a high VHR after (UV) photoradiation, this avoiding the problem of the occurrence of residual images to final displays. ##STR00001##

The invention relates to a liquid-crystalline medium, in particular based on a mixture of polar compounds, and to the use thereof for an active-matrix display, in particular based on the VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB-FFS effect.

The present invention relates to a liquid crystal display device. The liquid crystal display device of the present invention comprises a first substrate, a second substrate, and a liquid crystal composition disposed between said first substrate and said second substrate, wherein said first substrate and said second substrate are disposed in parallel and opposite to each other, with the distance between said first substrate and said second substrate being 2.5 μm to 3.2 μm; alignment layers are disposed on the sides of said first and second substrates that are close to said liquid crystal composition; and said alignment layers are provided with vertical alignment films that allow liquid crystal molecules in said liquid crystal composition to be arranged roughly perpendicular to said first or second substrate.

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##