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 invention relates to a liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, characterised in that it comprises one or more compounds of the formula I in a total concentration of 40%,

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in which the parameters have the meanings indicated in claim 1, and 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.

Shown is a liquid crystal composition satisfying at least one or having suitable balance regarding at least two of characteristics such as high maximum or low minimum temperature of a nematic phase, large optical anisotropy, large positive dielectric anisotropy and high stability to ultraviolet light, a liquid crystal display device including such a composition, particularly including an encapsulated composition, and a liquid crystal display device including the composition serving as a constituent of 3D lens. The liquid crystal composition contains a specific compound having large optical anisotropy as a first component, and a specific compound having large optical anisotropy and positive dielectric anisotropy as a second component; a specific compound having large positive dielectric anisotropy as a third component; and a specific compound having large optical anisotropy and further having high maximum or low minimum temperature as a fourth component, and the liquid crystal display device includes the composition.

The present invention relates to liquid-crystalline media (LC media) having negative or positive dielectric anisotropy, comprising a low-molecular-weight component and a polymerisable component. The polymerisable component comprises self-aligning, polymerisable mesogens (polymerisable 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 polymerisable self-alignment additives which have a certain position of the functional groups.

A liquid crystal compound is represented by formula (1):

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In formula (1), R.sup.1 is alkyl or the like; ring A.sup.1 and ring A.sup.2 are independently 1,4-cyclohexylene, 1,4-phenylene or the like; Z.sup.1, Z.sup.2 and Z.sup.3 are independently a single bond, CF.sub.2O or the like; X.sup.1 is fluorine, chlorine, CF.sub.3 or the like; L.sup.1 and L.sup.2 are independently hydrogen, fluorine or the like; a and b are independently 0, 1, 2 or 3; and W is a group represented by formula (1a) or formula (1b);

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In formula (1a) and formula (1b), L.sup.3 to L.sup.8 are independently hydrogen, fluorine or the like.

Provided are a compound having an effect on preventing photolysis of a liquid crystal composition, and high solubility in the liquid crystal composition, a liquid crystal composition containing the compound and a liquid crystal display device including the composition.

A compound is represented by formula (1), a liquid crystal composition contains the compound and a liquid crystal display device uses the composition.

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In formula (1), for example, R1 is alkyl having 1 to 10 carbons; R2 is hydrogen, hydroxy, oxy radical or alkyl; ring A1, ring A2 and ring A3 are independently 1,4-cyclohexylene, 1,4-phenylene or pyridine-2,5-diyl; Z1 and Z2 are independently a single bond or alkylene; and a and b are independently 0 or 1.

Provided are a liquid crystal compound satisfying at least one of physical properties such as high stability to heat or light, a high clearing point (or high maximum temperature), low minimum temperature of a liquid crystal phase, small viscosity, large optical anisotropy, large negative dielectric anisotropy, a suitable elastic constant and good compatibility with other liquid crystal compounds, a liquid crystal composition containing the compound and a liquid crystal display device including the composition.

A compound is represented by formula (1):

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wherein, R.sup.1 and R.sup.2 are alkyl having 1 to 15 carbons; A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are 1,4-cyclohexylene and 1,4-phenylene; Z.sup.1, Z.sup.2, Z.sup.3 and Z.sup.4 are a single bond; Y.sup.1, Y.sup.2 and Y.sup.3 are fluorine; and a, b, c and d are 0 or 1, and a sum of a, b, c and d is an integer from 0 to 3, or the like.

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.

Provided are a liquid crystal compound having larger dielectric anisotropy and superb heating reliability in comparison with a similar compound, a liquid crystal composition containing the compound and a liquid crystal display device including the composition. A compound is represented by formula (1).

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In formula (1), for example, R.sup.1 is alkyl having 1 to 15 carbons, ring A.sup.1 is 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is replaced by halogen or tetrahydropyran-2,5-diyl; Z.sup.1 is a single bond or CF.sub.2O; L.sup.1 and L.sup.2 are hydrogen or halogen; Y.sup.1 and Y.sup.2 are hydrogen or halogen; and a is an integer from 1 to 4.

Shown are a liquid crystal compound satisfying at least one of physical properties such as high stability to heat and light, a high clearing point (or high maximum temperature), low minimum temperature of a liquid crystal phase, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, a suitable elastic constant and satisfactory compatibility with other liquid crystal compounds, a liquid crystal composition containing the compound and a liquid crystal display device including the composition. A compound is represented by formula (1), a liquid crystal composition contains the compound, or the like.

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