The present invention provides a compound represented by general formula (1) as well as a liquid crystal composition containing this compound and a liquid crystal display using this liquid crystal composition. Using the compound represented by general formula (1) as a component of a liquid crystal composition makes it possible to obtain a liquid crystal composition having a low viscosity (η), a high Δn, suitable T.sub.-i, high miscibility with other liquid crystal compounds, and presenting a liquid crystal phase over a wide temperature range. This is therefore extremely useful as a structural component of a liquid crystal composition for a liquid crystal display requiring a high speed response.

The compounds of the formula I, and a liquid-crystalline medium, preferably having a nematic phase and negative dielectric anisotropy, which comprises a) one or more compounds of the formula I ##STR00001## and b) one or more compounds of the formulae II-1 to II-4, ##STR00002##
in which the parameters have the meanings defined herein, are suitable for use in an electro-optical display, particularly in an active-matrix display based on the VA, ECB, PALC, FFS or IPS effect.

There is provided a liquid crystal composition that exhibits a sufficiently low viscosity (η), a sufficiently low rotational viscosity (γ1), and a large elastic modulus (K.sub.33) without decreasing the refractive index anisotropy (Δn) and the nematic phase-isotropic liquid phase transition temperature (T.sub.ni) and without increasing the solid phase-nematic phase transition temperature (T.sub.cn). The liquid crystal display element that uses this liquid crystal composition satisfactorily obtains a pretilt angle and has a high voltage holding ratio (VHR) and high-speed response. Thus, a liquid crystal display element that has no or less alignment defects and display defects such as image sticking, and has high display quality and high response speed is obtained.

The present invention is to find appropriate manufacturing conditions for obtaining a homogeneous scattering state, a homogeneous transparent state, and a homogeneous driving voltage state and to obtain a polymer dispersed liquid crystal display element that has homogeneous properties. A polymer dispersed liquid crystal display element having excellent homogeneity can be obtained by irradiating a light control layer-forming material containing a liquid crystal material and a polymerizable composition with ultraviolet light under specific ultraviolet irradiation conditions to polymerize the polymerizable composition.

The present invention belongs to the technical field of liquid crystal materials, and in particular relates to a negative liquid crystal composition and a liquid crystal display element or liquid crystal display containing the liquid crystal composition. The present invention discloses a negative dielectric nematic liquid crystal composition, comprising a compound 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 has a relatively low rotational viscosity (γ.sub.1), a high clearing point (Cp), a good solubility and a high stability to heat and light (VHR) on the basis of maintaining an appropriate optical anisotropy (Δn), and can be used for developing a liquid crystal display element or liquid crystal display with a low cell thickness, a wide temperature for display, and a fast response.

##STR00001##

A liquid crystal composition containing a benzochromene compound and the use thereof in a liquid crystal display element or liquid crystal display. The liquid crystal composition comprises one or more compounds represented by Formula I and one or more compounds represented by Formula II. The liquid crystal composition has the characteristics of a small rotational viscosity, a large elastic constant, a high transmittance, a fast response speed, a strong resistance to ultraviolet light irradiation, and a high long-time light stability, and is particularly suitable for the field of TV display.

##STR00001##

The present invention provides a novel liquid crystal material composition comprising one or more compound, in order to achieve the properties of low viscosity, high resistivity, good low-temperature mutual solubility, fast response, excellent transmission, and which can be used for a variety of fast response display modes. Since the working temperature of a LCD material is subjected to the temperature range of individual LC molecules, information can only be displayed in a specific temperature range of the specific liquid crystal macro-alignment phase. At low temperature, the viscosity of liquid crystal increases exponentially, which in turn substantially reduces the response speed and overall performances of the display system. The liquid crystal composition according to the present invention overcomes these problems with balanced chemical composition by achieving low viscosity, good low-temperature performance and excellent transmission in a wide range of LCD applications including TN, IPS or FFS displays, thus improving display performance.

The present invention relates to a liquid crystal composition for a light-scattering liquid crystal device shown in FIG. 1 containing a polymerizable compound selected from the group consisting of compounds represented by the following general formula (1) as a first component and containing a compound having a negative dielectric anisotropy as a second component, a light-scattering liquid crystal device using the liquid crystal composition, and a smart window using the light-scattering liquid crystal device. A reverse mode type light-scattering liquid crystal device can have excellent transparency when no voltage is applied and a reduced driving voltage by the liquid crystal composition of the present invention.

An object of the present invention is to provide a composition that has positive Δε, exhibits a liquid crystal phase over a wide temperature range, has low viscosity, excellent solubility at low temperatures, and high resistivity and voltage holding ratio, and is stable against heat and light. By using this composition, IPS or TN liquid crystal display devices and the like that have excellent display quality and suppress display failures such as image-sticking and drop marks are provided in high yield. Provided is a composition that contains at least one selected from the group consisting of compounds represented by general formulae (i) and (ii) and at least one compound represented by general formula (iii). Also provided is a liquid crystal display device that uses the composition and an IPS or FFS device that uses the composition.

The invention relates to a liquid-crystalline medium and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PM-VA, SS-VA, PALC, IPS, PS-IPS, FFS or PS-FFS effect.