The present invention relates to a liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy (), which is distinguished by the fact that it has a value for the ratio .sub.1/n.sup.2 in the range 6-45 with a clearing point of >60 C. and a of 2.3. Media of this type are particularly suitable for electro-optical displays having active-matrix addressing based on the ECB, PA LCD, FFS or IPS effect.

A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH, ##STR00001##
in which Z.sup.1 denotes a single bond, CH.sub.2CH.sub.2, CH?CH, CH.sub.2O, OCH.sub.2, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, (CH.sub.2).sub.4, CHFCHF, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, C?C, CF?CF, CH?CHCHO or CH.sub.2CF.sub.2O,
and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.

A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH, ##STR00001##
in which Z.sup.1 denotes a single bond, CH.sub.2CH.sub.2, CH?CH, CH.sub.2O, OCH.sub.2, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, (CH.sub.2).sub.4, CHFCHF, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, C?C, CF?CF, CH?CHCHO or CH.sub.2CF.sub.2O,
and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.

The present invention relates to a liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy (), which is distinguished by the fact that it has a value for the ratio .sub.1/n.sup.2 in the range 6-45 with a clearing point of >60 C. and a of 2.3. Media of this type are particularly suitable for electro-optical displays having active-matrix addressing based on the ECB, PA LCD, FFS or IPS effect.

Provided is a polar compound having high chemical stability, high capability of aligning liquid crystal molecules, high solubility in a liquid crystal composition, and a large voltage holding ratio when used in a liquid crystal display device. The compound is represented by formula (1): ##STR00001##
in which, for example, R.sup.1 is alkyl having 1 to 15 carbons; MES is a mesogen group having at least one ring; Sp.sup.1 is a single bond or alkylene having 1 to 10 carbons; M.sup.1 and M.sup.2 are hydrogen; and R.sup.2 is a group represented by formulas (1a) to (1c): ##STR00002##
in which, Sp.sup.2 and Sp.sup.3 are a single bond or alkylene having 1 to 10 carbons; S.sup.1 is >CH; S.sup.2 is >C<; and X.sup.1 is OH.

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.

The present invention relates to liquid crystalline (LC) medium, to a method of its production and to the use of such LC media in polymer network liquid crystalline (PNLC) light modulation elements operated in the normally transparent mode. Furthermore, the present invention relates to such light modulation elements, as such, to the use of such light modulation elements as light shutters for transparent OLED displays, to the use of such light modulation elements in smart windows, and to a method of production of such light modulation elements according to the present invention.

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.

A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH,

##STR00001##

in which Z.sup.1 denotes a single bond, CH.sub.2CH.sub.2, CH?CH, CH.sub.2O, OCH.sub.2, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, (CH.sub.2).sub.4, CHFCHF, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, C?C, CF?CF, CH?CHCHO or CH.sub.2CF.sub.2O,
and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.

The present invention relates to a liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy (), which is distinguished by the fact that it has a value for the ratio .sub.1/n.sup.2 in the range 6-45 with a clearing point of >60 C. and a of 2.3. Media of this type are particularly suitable for electro-optical displays having active-matrix addressing based on the ECB, PA LCD, FFS or IPS effect.