The present invention relates to liquid-crystalline media (LC media) having negative or positive dielectric anisotropy, comprising a low-molecular-weight component and a polymerizable component. The polymerizable component comprises self-aligning, polymerizable mesogens (polymerizable self-alignment additives) which effect 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 LC medium without alignment layers. The invention discloses novel structures for self-alignment additives which have a certain position of the functional groups.

Provided is a liquid crystal compound satisfying at least one of physical properties such as high stability to heat and light, a high clearing point (or high maximum temperature), low minimum temperature of a liquid crystal phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, a suitable elastic constant and excellent compatibility with other liquid crystal compounds, a liquid crystal composition containing the compound and a liquid crystal display device including the composition.

A compound, represented by formula (1):

##STR00001##

wherein, in formula (1), R.sup.1 is alkoxy having 1 to 9 carbons or the like; R.sup.2 is alkenyl having 2 to 10 carbons; Z.sup.1 and Z.sup.2 are independently a single bond, —CH.sub.2CH.sub.2—, —CH═CH— or the like; and a and b are independently 0 or 1.

An object of the present invention is to provide a liquid crystal display element using a liquid crystal composition having negative dielectric anisotropy, which is capable of realizing excellent display properties by being used in an FFS mode liquid crystal display element without deteriorating various properties, as a liquid crystal display element, such as dielectric anisotropy, viscosity, a nematic phase upper limit temperature, nematic phase stability at low temperature, and γ.sub.1, and burn-in characteristics of the display element.

Provided is an FFS mode liquid crystal display element using an n-type liquid crystal composition so as to achieve the above object.

There is provided a liquid crystal composition having the following properties without suffering reductions in refractive index anisotropy (Δn) and nematic phase-isotropic liquid phase transition temperature (T.sub.m): sufficiently low viscosity (η), sufficiently low rotational viscosity (γ1), a large elastic constant (K.sub.33), and a negative dielectric anisotropy (Δ∈) with a large absolute value. There is also provided a liquid crystal display device of, for example, a VA type that uses such a liquid crystal composition and that has a high response speed and excellent display quality with defective display being eliminated or reduced. In particular, a liquid crystal composition having a negative dielectric anisotropy is provided, the composition containing a first component that is at least one compound represented by General Formula (i) and a second component that is at least one compound selected from compounds represented by General Formula (L).

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 polymerizable compound having at least one monovalent group (A), a polymerizable composition containing the polymerizable compound, a liquid crystal composite prepared from the polymerizable composition, and a liquid crystal device having the polymerizable composition. ##STR00001## In monovalent group (A), R.sup.1 and R.sup.2 are independently hydrogen, halogen or alkyl having 1 to 20 carbons, and in the alkyl, at least one piece of —CH.sub.2— may be replaced by —O— or —S—, and at least one piece of —(CH.sub.2).sub.2— may be replaced by —CH═CH—, and in the groups, at least one hydrogen may be replaced by halogen.

A compound having the structure of general formula I is useful as a liquid crystal composition and as a photoelectric display device including the liquid crystal composition. The compound having the structure of general formula I is chemically and physically stable, and has higher clearing point, and both large dielectric anisotropy and large optical anisotropy at the same time. The compound having the structure of general formula I is well compatible with other liquid crystal compounds when applied in a liquid crystal composition, the composition has good stability especially in a low-temperature environment, the characteristic of fast response and a wide range of applicabilities, especially applicable to the IPS-type and TN-TFT-type liquid crystal display devices. ##STR00001##

Polyfluorinated additives for use as components in liquid-crystal mixtures. Liquid-crystal mixtures which comprise these compounds. And liquid-crystal displays based on these liquid-crystal mixtures.

A liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of each of formulae T and L ##STR00001##
in which the parameters have the meanings given in the claims and in the text. The use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type. Also, the compounds of formulae T and L and their use for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

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.