A liquid crystal composition includes at least one compound of general formula I, at least one compound of general formula II and at least one compound of general formula III. The liquid crystal composition has a higher optical anisotropy, the relatively large elastic constants K.sub.11 and K.sub.33 while maintaining a relatively high clearing point, an appropriate dielectric anisotropy and a better low-temperature intersolubility. A liquid crystal display device which includes the liquid crystal composition has advantages of a fast response, a high contrast and a wide temperature range, thereby having a good display effect and a large range of applicability. ##STR00001##

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.

The invention relates to a liquid-crystalline medium having a nematic phase comprising one or more compounds of formula X

##STR00001##

wherein the parameters have the meaning 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 X for improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds, as well as to certain compounds of formula X, as specified in the text.

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 crystal composition contains: at least one compound of general formula I and at least one polymerizable compound of general formula II. Such a liquid crystal composition has a suitable optical anisotropy, a suitable dielectric anisotropy, and a better pretilt angle consistency while maintaining a relatively high clearing point, and the drop mura is good. When the liquid crystal composition is applied to a PSA liquid crystal display, the liquid crystal composition has an excellent display effect. ##STR00001##

The present invention relates to a liquid-crystal (LC) medium comprising polymerizable compounds, to its use for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the PSA (polymer sustained alignment) or SA (self-aligning) mode, to an LC display of the PSA or SA mode comprising the LC medium, and to a process of manufacturing the LC display.

A liquid crystal composition includes at least one compound of general formula F and at least one compound of general formula N. A liquid crystal display device includes the liquid crystal composition. The liquid crystal composition has a larger K value, a smaller rotational viscosity, a higher VHR value, a longer low temperature storage time and a shorter response time while maintaining an appropriate clearing point, an appropriate optical anisotropy, and an appropriate absolute value of dielectric anisotropy, such that the liquid crystal display device including the liquid crystal composition has a better contrast, a wider temperature range for application, a faster response speed, a better contrast and a higher reliability.

##STR00001##

An object of the present invention is to provide a liquid crystal composition suitable for producing liquid crystal display elements which reduces the risk of the formation of droplet traces during production and allows a liquid crystal material to be ejected at a constant rate during an ODF process without deteriorating the properties of the liquid crystal display element, such as dielectric anisotropy, viscosity, nematic-phase upper-limit temperature, nematic-phase stability at a low temperature, and γ.sub.1, and the image sticking resistance of the display element, and a liquid crystal display element including the liquid crystal composition. Provided are a liquid crystal composition having a negative dielectric anisotropy, the liquid crystal composition including one or more compounds represented by General Formula (I), one or more compounds represented by General Formula (II), and the compound represented by Formula (IIIb-1) and a liquid crystal display element including the liquid crystal composition.

The invention relates to a liquid-crystalline medium having negative dielectric anisotropy comprising one or more compounds of formula I ##STR00001##
and
one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00002##
wherein the groups and parameters have the meanings indicated in claim 1, to a guest-host liquid crystal medium derived therefrom comprising one or more dichroic dyes and the use of said medium in devices such as light shutters, switchable windows, switchable mirrors and guest-host displays. The invention further relates to devices containing the liquid crystalline medium according to the invention.

A positive dielectric anisotropic liquid crystal composition includes one or more compounds of formula I and one or more compounds of formula II: ##STR00001##
wherein R1 represents cyclopropyl, cyclobutyl or cyclopentyl, R2, R3 and R4 are as defined in the specification, and a liquid crystal display device. The liquid crystal composition has positive dielectric properties, a high charge retention ratio, a low rotary viscosity, a fast response time, and especially a high transmittance, and is suitable for manufacturing a TFT-LCD with a high transmittance and a fast response.