Liquid-crystalline (LC) media having positive dielectric anisotropy and liquid-crystal displays (LCDs) containing these media, especially displays addressed by an active matrix and in particular to LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS PS-FFS, SA-HB-FFS, polymer stabilised SA-HB-FFS, positive VA or positive PS-VA type.

The present invention relates to a liquid-crystal (LC) medium comprising polymerizable compounds, to its use for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the PSA (polymer sustained alignment) or SA (self-aligning) mode, to an LC display of the PSA or SA mode comprising the LC medium, and to a process of manufacturing the LC display using the LC medium, especially an energy-saving LC display and energy-saving LC display production process.

The present invention belongs to the technical field of liquid crystal materials, and in particular relates to a liquid crystal composition and a liquid crystal display element or liquid crystal display containing the liquid crystal composition. The present invention discloses 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. The liquid crystal composition of the present invention has a large optical anisotropy and a small ratio of γ.sub.1/K.sub.11, and can be used for developing a liquid crystal display element or liquid crystal display with a low cell thickness and a fast response.

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A compound is represented by general formula (I), a liquid-crystal composition contains this compound, and devices are made using this liquid-crystal composition.

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Having a large refractive-index anisotropy Δn and a sufficiently high Tni, highly compatible with liquid-crystal compositions, and exhibiting a high dielectric anisotropy in the radiofrequency range, the compound is a useful material for RF phase shifters, phased-array antennae, image recognition devices, distance meters, liquid-crystal displays, liquid-crystal lenses, and birefringent lenses for 3D image display, among other devices.

A liquid crystal composition and a liquid crystal display device including the liquid crystal composition include at least one compound of general formula I and at least one compound of general formula II. Compared with the prior art, the liquid crystal composition has a smaller voltage change rate at high and low temperatures and a shorter low temperature response time, while maintaining an appropriate optical anisotropy, an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, such that the liquid crystal display device having the liquid crystal composition has a better display and a faster response speed.

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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.

A liquid crystal composition, a liquid crystal display element and a liquid crystal display comprising the liquid crystal composition belong to the field of liquid crystal display. The liquid crystal composition of the present disclosure comprises a compound represented by formula I, a compound represented by formula II, one or more compounds represented by formula III, one or more compounds represented by formula IV and more than three compounds represented by formula V. The liquid crystal composition has low rotational viscosity γ.sub.1 and high stability to heat and light on the basis of maintaining appropriate optical anisotropy Δn, which can realize fast response of liquid crystal display.

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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##

Compounds of the formula I, liquid-crystalline media which contain at least one compound of the formula I and electro-optical displays which contain the LC mixtures, especially for the self-aligning VA, PSA, PS-VA, PVA, MVA, PM-VA, HT-VA or VA-IPS mode ##STR00001##
in which R.sub.1, R.sub.2, ring A.sub.1, Z.sub.1, Z.sub.2, Sp, P, L.sub.1, L.sub.2, r1, r2, r3, m, n, p1 and p2 have the meanings indicated above.

The present invention relates to a liquid-crystal material (LC media) comprising thiophene derivatives which are stabilised by sterically hindered amines or amine derivatives (HALS, hindered amine light stabilisers), and to liquid-crystal displays (LC displays) which contain these LC materials.