The present invention relates to liquid-crystalline media (LC media) having negative or positive dielectric anisotropy comprising self-alignment additives (SAMs) with an at least one bifunctional or polyfunctional anchor group, which effects the homeotropic (vertical) alignment of the LC media at a surface or the cell walls of a liquid-crystal display (LC display). The invention therefore also encompasses LC displays having homeotropic alignment of the liquid-crystalline medium (LC medium) without conventional imide alignment layers. The LC media may be supplemented by a polymerizable or polymerized component, which serves for stabilization of the alignment, for adjustment of the tilt angle and/or as passivation layer.

This invention provides an FFS type liquid crystal display containing one type or two or more types of compounds selected from the group of compounds represented by General Formula (i), General Formula (ii), and General Formula (iii) and one type or two or more types of compounds selected from compounds represented by General Formula (II). This display makes it possible to realize excellent display characteristics without deteriorating various liquid crystal display characteristics such as dielectric anisotropy, viscosity, nematic-phase maximum temperature, nematic-phase stability at low temperatures, or γ.sub.1 and the display burn-in characteristics.

The present invention relates to a liquid crystal display device including a pair of a substrate arranged opposite to each other, an electrode group disposed on one side or both sides of the pair of substrates facing each other, a plurality of active devices connected to the electrode group, a liquid crystal alignment film disposed on each facing side of the pair of substrates, and a liquid crystal layer interposed between the pair of substrates, wherein the liquid crystal alignment film is manufactured by irradiating linearly polarized light to a film obtained from polyamic acid or a derivative thereof having a photoisomerization structure in the main chain or a film being subject to heat-baking so as to provide alignment-controlling capability, and the liquid crystal layer is a liquid crystal composition having negative (−) dielectric anisotropy. By the present invention, a liquid crystal display device having improved image sticking characteristics and good alignment stability is provided.

Provided are a liquid crystal composition containing a dibenzo derivative and a liquid crystal display device. The liquid crystal composition includes at least one compound of general formula I and at least one compound of general formula II. The liquid crystal compositions have the characteristics of high clearing point, large optical anisotropy, large dielectric anisotropy, large ε.sub.⊥, large ε.sub.⊥/|Δε|, and large K.sub.ave. The liquid crystal display devices containing these liquid crystal compositions have the effects of good transmittance and high contrast. The liquid crystal composition can meet the requirements of the liquid crystal display device on low power consumption and good display effect and has high application value in liquid crystal displays of in-plane switching (IPS) mode, fringe field switching (FFS) mode, and vertical alignment (VA) mode.

##STR00001##

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.

A liquid crystal composition includes at least one compound of general formula I and at least one compound selected from a group consisting of the compounds of general formula II-1 and general formula II-2. The liquid crystal composition provided by the present invention has suitable optical anisotropy, high clearing point, high elastic constants K.sub.11 and K.sub.33, and relatively low dielectric anisotropy. When the liquid crystal composition is applied to a liquid crystal display device, the liquid crystal display device may have better weather resistance and higher contrast ratio. ##STR00001##

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 disclosure provides a liquid crystal device including a liquid crystal composition containing a dichroic dye (dye-containing liquid crystal composition) that is in a light transmissive state when no voltage is applied to the transparent electrode and in a light scattering state when voltage is applied. The liquid crystal composition exhibits a negative dielectric constant anisotropy. The haze value of the liquid crystal device is 10% or less when no voltage is applied at 25° C., and the haze value is 50% or more when a rectangular wave voltage (AC 50 V, 60 Hz) is applied. The voltage holding ratio of the dye-containing liquid crystal composition is 60% or less at 25° C. The liquid crystal device provided by the disclosure is used as a component to provide a liquid crystal display apparatus, a light control apparatus, or a light transmitting apparatus with a high contrast.

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 liquid crystal composition, a liquid crystal display element and a liquid crystal display including the liquid crystal composition, belonging to the field of liquid crystal display. The liquid crystal composition includes a compound represented by formula I and one or more compounds represented by formula II. The liquid crystal composition can increase the dielectric anisotropy and improve the voltage retention rate. ##STR00001##