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.

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.

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##

The present invention relates to liquid-crystalline media comprising one or more mesogenic compounds of formula I as set forth hereinafter, wherein the one or more compounds of formula I are contained in the medium in an amount, based on the overall contents of the medium, of at least 15% by weight. The present invention further relates to a switching layer, a switching element and a window element containing the liquid-crystalline medium.

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.

##STR00001##

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.

##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.

Liquid-crystalline media containing one or more mesogenic compounds, one or more chiral compounds, and one or more polymerizable mesogenic compounds, wherein the media exhibit a pitch of 0.55 μm or more and a clearing point of 80° C. or more and wherein the one or more polymerizable mesogenic compounds are contained in an amount, based on the overall contents of the media, of 5% by weight or less, are suitable as modulation materials. Such modulation materials can be used in switching layers and window elements.

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 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.