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.

Compounds of the formula I,

##STR00001##

in which Y.sup.1 denotes O or CH.sub.2, and the groups R.sup.1, L.sup.1 to L.sup.6 and X.sup.1 have the meanings indicated in claim 1. A process for the preparation thereof, and liquid-crystalline media comprising at least one compound of the formula I and electro-optical displays containing a liquid-crystalline medium this type. The compounds of the formula I include, as structural element, a combination of a 1,4-substituted cyclohexene ring besides a dioxane or tetrahydropyran ring and a substituted biphenyl group.

Provided are a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light and high stability to heat, or has a suitable balance regarding at least two of the characteristics; and an AM device having characteristics such as a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio and a long service life. The liquid crystal composition may contain a specific compound having large negative dielectric anisotropy as a first component, a specific compound having high maximum temperature as a second component, a specific compound having negative dielectric anisotropy as a third component, or a specific compound having a polymerizable group as an additive component.

A liquid-crystalline medium, preferably having a nematic phase and exhibiting a dielectric anisotropy of 0.5 or more, which contains compounds of formula B and formula S ##STR00001## in which ##STR00002##
denotes ##STR00003##
denotes ##STR00004##
the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, displays of this type which contain a liquid-crystalline medium of this type, and the use of the compounds of formula S for the improvement of the transmission and/or response times of a liquid-crystalline medium which contains one or more additional mesogenic compounds.

A liquid crystal display device in which a good voltage holding ratio is retained for a long period of time and occurrence of image sticking and stain in a display screen is prevented by using a photo-alignment film. The liquid crystal display device includes an active matrix liquid crystal panel and a backlight. The liquid crystal panel includes a liquid crystal layer, a pair of substrates that sandwich the liquid crystal layer in between, and an alignment film disposed on a liquid crystal layer side surface of each of the substrates. The alignment films are photo-alignment films formed from a material that exhibits a photo-alignment characteristic, and contain carboxyl groups on the liquid crystal layer side. The liquid crystal layer contains a liquid crystal material and at least one kind of quinone derivative selected from the group consisting of benzoquinone derivatives and anthraquinone derivatives.

A liquid crystal composition that satisfies at least one of characteristics such as a high maximum temperature, a low minimum temperature, a small viscosity, a suitable optical anisotropy and a large negative dielectric anisotropy, or that has a suitable balance between at least two of these characteristics, and an AM device including this composition. The nematic liquid crystal composition includes a specific compound having a large negative dielectric anisotropy as a first component and a specific compound having a small viscosity as a second component, and may include a specific compound having a negative dielectric anisotropy as a third component, and a specific compound having a high maximum temperature or a small viscosity as a fourth component, or a specific compound having a polymerizable group as an additive.

The invention relates to a liquid crystal mixture characterised in that it comprises one or more photoreactive mesogens of formula I

##STR00001##

wherein the parameters and groups occurring are defined as indicated in claim 1, to a process for the fabrication of liquid crystal displays using these liquid crystal mixtures and to a liquid crystal display obtainable by this process. The invention further relates to new compounds of formula I.

A light modulation element comprising, preferably consisting of a cholesteric liquid crystalline medium sandwiched between two opposing substrates, an electrode arrangement, which is capable to allow the application of an electric field, which is substantially perpendicular to the main plane of substrate or the layer of the cholesteric liquid-crystalline medium, characterized in that one of the substrates is provided with a processed alignment layer adjacent to the cholesteric liquid crystalline medium and the other substrate is either provided with an unprocessed alignment layer adjacent to the cholesteric liquid crystalline medium or is not provided with an alignment layer. The invention is further related to a method of production of said light modulation element and to the use of said light modulation element in various types of optical and electro-optical devices, such as electro-optical displays, liquid crystal displays (LCDs), non-linear optic (NLO) devices, and optical information storage devices.

The present invention relates to polymerizable compounds, to processes and intermediates for the preparation thereof, to liquid-crystal media comprising them, and to the use of the polymerizable compounds and liquid crystalline media for optical, electro-optical and electronic purposes, in particular in liquid crystalline displays, especially in liquid crystalline displays of the polymer sustained alignment type.

The present disclosure relates to a liquid crystal composition, and a liquid crystal display element or liquid crystal display comprising the liquid crystal composition, and belongs to the field of liquid crystal display, said liquid crystal composition comprises a compound represented by formula I, a compound represented by formula II, one or more compounds represented by formula III, and at least one polymerizable compound, wherein the liquid crystal composition simultaneously has a low rotary viscosity, a large refractive index, and a fast response speed.

##STR00001##