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 compound represented by Formula (1):

##STR00001## R.sup.1 is hydrogen or an alkyl group that may be substituted; rings A.sup.1 to A.sup.2 are cyclohexylene or phenylene that may be substituted; a is 0 to 4; Z.sup.1 is a single bond or an alkylene group that may be substituted; Sp.sup.1 to Sp.sup.3 are a single bond or an alkylene that may be substituted; M.sup.1 to M.sup.4 are H, F, Cl, or an alkyl group that may be substituted; R.sup.2 and R.sup.3 are hydrogen, a group represented by Formula (1-a), or an alkyl group having 1 to 5 carbon atoms that may be substituted; and at least one of R.sup.2 and R.sup.3 is a group represented by Formula (1-a);

##STR00002## Sp.sup.4 is a single bond or an alkylene group that may be substituted; R.sup.4 and R.sup.5 are hydrogen or an alkyl group; and at least one of R.sup.4 and R.sup.5 is an alkyl group.

The present invention relates to liquid-crystalline media (LC media) having negative or positive dielectric anisotropy, comprising a low-molecular-weight component and a polymerizable component. The polymerizable component comprises self-aligning, polymerizable mesogens (polymerizable self-alignment additives) which effect homeotropic (vertical) alignment of the LC media at a surface or the cell walls of a liquid-crystal display (LC display). The invention therefore also encompasses LC displays having homeotropic alignment of the LC medium without alignment layers. The invention discloses novel structures for self-alignment additives which have a certain position of the functional groups.

The present invention relates to a liquid crystal (LC) medium comprising a compound of formula I ##STR00001## and one or more compounds selected from the group of compounds of the formulae IIA, IIB, IIC and IID, ##STR00002## as defined in claim 1, and to the use of the LC medium for optical, electro-optical and electronic purposes, in particular in LC displays, especially in IPS, FFS, VA or PS-VA displays.

Liquid crystal compound satisfying at least one of physical properties such as high stability to heat or light, high maximum temperature, high clearing point, low minimum temperature of liquid crystal phase, small viscosity, suitable optical-anisotropy, large negative dielectric-anisotropy, suitable elastic constant and good compatibility with other liquid crystal compounds; liquid crystal composition containing the compound; and liquid crystal display device including the composition. Compound represented by formula (1), wherein R.sup.1 is alkyl having 1 to 15 carbons; R.sup.2 is alkyl having branched-chain and 3 to 15 carbons; A.sup.1, A.sup.2 are independently 1,2-cyclopropylene; Z.sup.1, Z.sup.2 are independently single bond or alkylene having 1 to 15 carbons; L.sup.1, L.sup.2 are fluorine, chlorine, OCF.sub.3 or OCH.sub.2F; X.sup.1, X.sup.2 are oxygen or sulfur; and a is 0 or 1, b is 0 or 1, and sum of a and b is 0, 1 or 2.

##STR00001##

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.

The present invention relates to liquid-crystalline media (LC media) having negative or positive dielectric anisotropy, comprising a low-molecular-weight component and a polymerizable component. The polymerizable component comprises self-aligning, polymerizable mesogens (polymerizable self-alignment additives) which effect homeotropic (vertical) alignment of the LC media at a surface or the cell walls of a liquid-crystal display (LC display). The invention therefore also encompasses LC displays having homeotropic alignment of the LC medium without alignment layers. The invention discloses novel structures for polymerizable self-alignment additives which have a certain position of the functional groups.

The invention relates to a liquid-crystalline medium which comprises one or more compounds of the formula BO

##STR00001##

in which the parameters have the meanings indicated in Claim 1, to the use of the liquid-crystalline medium for electro-optical purposes, in particular in liquid-crystal light valves for lighting devices for motor vehicles, and to liquid-crystal light valves which comprise this medium and lighting devices for motor vehicles which contain such liquid-crystal light valves and to compounds of the formula BO.

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.

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.