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 energy efficient LC displays of the TN, PSTN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer stabilised SA-HB-FFS, polymer stabilised SA-XB-FFS, positive VA or positive PS-VA type. The media have an improved long-term stability against UV radiation and elevated temperatures.

The present invention relates to a liquid crystal (LC) medium comprising a terphenyl compound and at least two polymerisable compounds, to a process for its preparation, to its use for optical, electro-optical and electronic purposes, in particular in LC displays, especially in an LC display of the polymer sustained alignment (PSA) type, and to an LC display, especially a PSA display, comprising it.

A liquid crystal (LC) medium containing a polymerisable compound, a process for its preparation, its use for optical, electro-optical and/or electronic purposes, in particular in LC displays, especially in an LC display of the polymer sustained alignment (PSA) type, and an LC display, especially a PSA display, containing the LC medium.

Provided are a liquid crystal composition satisfying at least one of characteristics including a high maximum temperature, a low minimum temperature, small viscosity, suitable optical anisotropy and large negative dielectric anisotropy, or the liquid crystal composition having a suitable balance regarding at least two of the above characteristics; and an AM device including the composition. The liquid crystal composition contains a specific compound having large negative dielectric anisotropy as a first component, and a specific compound having small viscosity as a second component, and may contain a specific component having high maximum temperature or small viscosity as a third component, a specific component having negative dielectric anisotropy as a fourth component, or a specific compound having a polymerizable group as an additive.

A liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of formula T

##STR00001## in which

##STR00002##

denotes

##STR00003##

and the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the compounds of formula T and their use for the improvement of the transmission and/or response times of a liquid-crystalline medium which contains one or more additional mesogenic compounds.

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.

Compounds of the formula I ##STR00001## in which R.sup.1 is alkyl or alkoxy in which CH.sub.2 groups are optionally replaced, and X.sup.1 is alkyl OCF.sub.3, CF.sub.3, CHF.sub.2, OCF.sub.2CF.sub.3, CCF.sub.2CHFCF.sub.3, OCFCF.sub.2, OCHCF.sub.2 or F, a liquid-crystalline medium containing a compound of formula I, and use thereof in electro-optical liquid-crystal displays, in particular in TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS or PS-FFS-, positive VA displays and in shutter spectacles for 3D effects and LC lenses.

A liquid-crystalline medium having least one compound of the formula I, ##STR00001## and at least one compound of the formulae ST-1 to ST-17, ##STR00002## ##STR00003## ##STR00004## in which R.sup.1 and R.sup.1*, A.sup.1 and A.sup.1*, Z.sup.1 and Z.sup.1*, X, L.sup.1 and L.sup.2, R.sup.ST, ring A, Z.sup.ST, p and q have the meanings indicated in claim 1, and the use thereof for an active-matrix display, in particular based on the VA, PSA, PA-VA, SS-VA, SA-VA, PS-VA, PALC, IPS, PS-IPS, UB-FFS, U-IPS, FFS or PS-FFS effect.

Disclosed are a liquid crystal composition and a display element or display using the liquid crystal composition, wherein the liquid crystal composition contains one or more compounds of general formulas I, II and III, ##STR00001##
The liquid crystal composition disclosed in the present invention has an excellent performance, an optical anisotropy in the range of 0.080 to 0.150, a low rotary viscosity, a fast response time, and good chemical, optical and thermal stabilities, and is very suitable for manufacturing liquid crystal display elements, particularly suitable for active matrix display elements, such as active matrix displays using a VA, FFS or IPS mode.

A liquid-crystalline medium and 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.