The invention relates to a medium comprising one or more compounds of formula I,

R.sup.11-A.sup.11-A.sup.12-(CH.sub.2).sub.s-A.sup.13-A.sup.14-R.sup.12I

in a concentration of up to 30% or less,
and one or more compounds of formula II,

R.sup.21-A.sup.21-A.sup.22-(A.sup.23).sub.u-Z.sup.21(CH.sub.2).sub.tZ.sup.22-A.sup.24-A.sup.25-A.sup.26-R.sup.22II

in a concentration of 10% or more,
wherein R.sup.11 to R.sup.22, A.sup.11 to A.sup.26, Z.sup.21, Z.sup.22, s, t, and u have one of the meanings as given in claim 1, to a method of production of such a media, to the use of such media in liquid crystal devices, in particular in flexoelectric liquid crystal devices, and to a flexoelectric liquid crystal device comprising a medium according to the present invention.

The present invention relates to a nematic liquid crystal composition containing a polymerizable compound and having a negative dielectric anisotropy () and PSA or PSVA liquid crystal display element produced by using the same. The liquid crystal composition according to the present invention can provide PSA or PSVA liquid crystal display element, in which a sufficient pretilt angle is included, the amount of remaining monomer is small, there are no or almost no problems, e.g., alignment defects and display defects, arisen from a low voltage holding rate (VHR) and the like, and excellent response performance is exhibited. A liquid crystal display element using the liquid crystal composition according to the present invention is useful for an active-matrix-drive liquid crystal display element and can be applied to PSA, PSVA, and other liquid crystal display elements.

There is provided a liquid crystal composition that exhibits a sufficiently low viscosity (), a sufficiently low rotational viscosity (1), and a large elastic modulus (K.sub.33) without decreasing the refractive index anisotropy (n) 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 provides a liquid crystal composition comprising one or more compounds of general formula I and one or more compounds of general formula II; the liquid crystal composition of the present invention can work at very high and very low temperatures, has a very short response time and a better reliability to light and heat, and particularly exhibits no image retention or a significantly reduced image retention after a long time operation.

[Object] An object to be achieved by the present invention is to provide a liquid crystal display device that uses a liquid crystal composition having negative dielectric anisotropy, in which the liquid crystal composition can realize excellent display properties when used in the liquid crystal display device without degrading the image-sticking properties of the display device while realizing various liquid crystal display properties such as dielectric anisotropy, viscosity, nematic phase upper limit temperature, low-temperature nematic phase stability, .sub.1, etc. [Solution] A liquid crystal composition is characterized in that it contains, as a first component, at least one compound selected from the group consisting of compounds represented by general formula (i), and, as a second component, at least one compound selected from the group consisting of compounds represented by general formula (ii).

A nematic liquid crystal composition according to the invention is used for a liquid crystal display element for an active matrix drive for TV applications or the like for which a high speed and a wide viewing angle are required. The liquid crystal composition has a negative dielectric anisotropy having a large absolute value and also has a sufficiently low viscosity. Therefore, the liquid crystal composition has excellent characteristic properties, that is, a high speed response, good display quality and a suppressed display defect, and is therefore suitable as a practical liquid crystal composition. Further, a liquid crystal display element produced using the liquid crystal composition can be used favorably as a liquid crystal display element of a VA type or the like.

There is provided a liquid crystal display device in which a decrease in the voltage holding ratio (VHR) of a liquid crystal layer and an increase in the ion density (ID) are prevented and problems of display defects such as white streaks, alignment unevenness, and image sticking are overcome. In the liquid crystal display device, a decrease in the voltage holding ratio (VHR) of a liquid crystal layer and an increase in the ion density (ID) are prevented and display defects such as image sticking are suppressed. Therefore, the liquid crystal display device is useful for active matrix liquid crystal display apparatuses that use a VA mode or a PSVA mode and can be applied to liquid crystal display apparatuses of liquid crystal televisions, monitors, cellular phones, smart phones, and the like.

The present invention provides a liquid crystal composition having a sufficiently low viscosity (), a sufficiently low rotational viscosity (1), a high elastic constant (K.sub.33), and a negative dielectric anisotropy () with a high absolute value without decreasing the refractive index anisotropy (n) and the nematic phase-isotropic liquid phase transition temperature (T.sub.ni); and a liquid crystal display device with a VA mode that uses the liquid crystal composition and has high display quality and high response speed. The liquid crystal display device that uses the liquid crystal composition of the present invention has a distinguished feature of high-speed response and is particularly useful as an active matrix driving liquid crystal display device. The liquid crystal display device is applicable to a VA mode, PSVA mode, PSA mode, IPS mode, or ECB mode liquid crystal display device.

The present invention relates to a liquid crystal display device including a particular liquid crystal composition and a cured product of a particular curable resin composition serving as a sealant.

The present invention provides a liquid crystal display device that does not suffer from a decrease in the voltage holding ratio (VHR) or increase in the ion density (ID) of the liquid crystal layer or the problem of display defects such as white spots, alignment unevenness, and image-sticking.

Since the liquid crystal display device according to the present invention does not suffer from a decrease in the voltage holding ratio (VHR) of the liquid crystal layer or display defects such as alignment unevenness and image-sticking, the liquid crystal display device is particularly useful as an active-matrix-driven liquid crystal display device such as a VA, PSVA, IPS, or FFS liquid crystal display device and can be used as a liquid crystal display device for products such as liquid crystal display televisions, monitors, cell phones, and smartphones.

The present invention relates to a nematic liquid crystal composition containing a polymerizable compound and having a negative dielectric anisotropy () and PSA or PSVA liquid crystal display element produced by using the same. The liquid crystal composition according to the present invention can provide PSA or PSVA liquid crystal display element, in which a sufficient pretilt angle is included, the amount of remaining monomer is small, there are no or almost no problems, e.g., alignment defects and display defects, arisen from a low voltage holding rate (VHR) and the like, and excellent response performance is exhibited. A liquid crystal display element using the liquid crystal composition according to the present invention is useful for an active-matrix-drive liquid crystal display element and can be applied to PSA, PSVA, and other liquid crystal display elements.