The present invention relates to liquid-crystalline (LC) media and to LC displays (LCDs) containing these media, in particular to LCDs of the twisted nematic (TN) mode, preferably to displays of the LCOS (LC on silicon) mode.

A liquid-crystalline medium having a nematic phase containing one or more compounds of formula D ##STR00001##
the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, displays of this type which contain a liquid-crystalline medium of this type and the use of the compounds of formula D for improvement of the contrast and/or response times of a liquid-crystalline medium which contain one or more additional mesogenic compounds, as well as certain compounds of formula D.

Liquid-crystalline media which can be used, in particular, for electro-optical displays having active-matrix addressing based on the ECB effect and for IPS (in-plane switching) displays or FFS (fringe field switching) displays.

The invention relates to 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 YX

##STR00001## in which
the parameters have the meanings given in the text,
to 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 use of the compounds of formula YX for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

The present invention provides a liquid crystal composition, containing: one kind or two or more kinds of a first monomer having a first mesogenic skeleton, at least one polymerizable group represented by the general formula (PG1) linked to the first mesogenic skeleton, and at least one polar group linked to the mesogenic skeleton or the polymerizable group; and one kind or two or more kinds of a second monomer having a second mesogenic skeleton and a polymerizable group represented by the general formula (PG2) linked to the second mesogenic skeleton, and having a chemical structure different from that of the first monomer, in an amount of more than 0.4% by mass, which is excellent in vertical alignment, burn-in characteristics (change with time of pretilt angle), and compatibility, and provides a liquid crystal display element using the liquid crystal composition.

The present invention relates to a liquid crystal display device. The liquid crystal display device of the present invention comprises a first substrate, a second substrate, and a liquid crystal composition disposed between said first substrate and said second substrate, wherein said first substrate and said second substrate are disposed in parallel and opposite to each other; alignment layers are disposed on the sides of said first and second substrates that are close to said liquid crystal composition; and said alignment layers are provided with vertical alignment films that allow liquid crystal molecules in said liquid crystal composition to be arranged roughly perpendicular to said first and second substrates, with said liquid crystal molecules having a pretilt angle of 88.5° to 89.5°.

The invention relates to a liquid-crystalline medium, characterised in that it comprises one or more compounds of the formula IA, ##STR00001##
and
one or more compounds of the formula IB, ##STR00002##
in which R.sup.A, R.sup.B, X.sup.A, X.sup.B and Y.sup.1-13 have the meanings indicated in Claim 1, and to the use thereof for electro-optical purposes, in particular for shutter glasses, 3D applications, in TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, PS-FFS and PS-VA-IPS displays.

The invention relates to a compound of formula I,

##STR00001##

wherein R.sup.11, R.sup.21, A.sup.11, A, Z, X.sup.11, X.sup.21, Y.sup.11, Y.sup.12, Sp.sup.11, Sp.sup.21, o and p have one of the meanings as given in claim 1. The invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I. Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, and to LC device comprising a LC medium according to the present invention. The present invention further relates to a process for the fabrication such liquid crystal display and to the use of the liquid crystal mixtures according to the invention for the fabrication of such liquid crystal display.

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 the compound is used in a liquid crystal display device; and a composition containing the compound. The compound is represented by formula (1). In formula (1), for example, P.sup.1 is a group represented by any one of formulas (1b) to (1i), P.sup.2 is a group represented by formula (1d), Sp.sup.1 and Sp.sup.2 are a single bond, Z.sup.1, Z.sup.2, Z.sup.3, Z.sup.4 and Z.sup.5 are —COO—, and ring A.sup.1, ring A.sup.2, ring A.sup.3 and ring A.sup.4 are 1,4-phenylene: ##STR00001##

The present invention provides a liquid crystal composition comprising: at least one compound of general Formula I; at least one compound of general Formula II; at least one compound of general Formula M and at least one compound of general Formula N. The present invention also provides a liquid crystal display device comprising the liquid crystal composition. The liquid crystal composition provided in the present invention has a higher optical anisotropy, a higher clearing point, a higher dielectric anisotropy, a high transmittance and a larger average elastic constant. When the liquid crystal composition is used in the IPS liquid crystal display device, the transmittance of the display device can be effectively improved, so that the display device has a good display performance while also having good energy-saving and environment-friendly characteristics. ##STR00001## ##STR00002## ##STR00003## ##STR00004##