Provided are a liquid crystal composition that contains a polar compound having a polymerizable group, in which vertical alignment of liquid crystal molecules can be achieved by action of the compound (or polymer), and a liquid crystal display device including the composition. The composition satisfies at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light and heat. The composition is a nematic liquid crystal composition that has negative dielectric anisotropy and contains the polar compound as a first additive, and may contain a specific liquid crystal compound having large negative dielectric anisotropy as a first component, a specific liquid crystal compound having high maximum temperature or small viscosity as a second component and a polymerizable compound as a second additive, and the liquid crystal display device includes the composition.

Provided are a liquid crystal composition that contains a polar compound having a polymerizable group, in which vertical alignment of liquid crystal molecules can be achieved by action of the compound (or polymer), and a liquid crystal display device including the composition. The composition satisfies at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light and heat. The composition is a nematic liquid crystal composition that has negative dielectric anisotropy and contains the polar compound as a first additive, and may contain a specific liquid crystal compound having large negative dielectric anisotropy as a first component, a specific liquid crystal compound having high maximum temperature or small viscosity as a second component and a polymerizable compound as a second additive, and the liquid crystal display device includes the composition.

A problem to be solved by the present invention is to provide a liquid crystal composition having negative dielectric anisotropy (), large refractive index anisotropy (n), a high nematic phase-isotopic liquid phase transition temperature (T.sub.NI), a low solid phase-nematic phase transition temperature (T.sub.CN), sufficiently low rotational viscosity (.sub.1), and large elastic constant (K.sub.33), and also to provide a VA-mode, FFS-mode, or IPS-mode liquid crystal display device using the liquid crystal composition, satisfying a high response speed, high VHR, and excellent low-temperature storage stability, and having no or very few display defects. According to the liquid crystal composition of the present invention, the problem is solved by a liquid crystal composition containing compounds represented by general formula (S1), general formula (S2), and general formula (S3).

A liquid crystal display device includes a pair of substrates, a negative liquid crystal layer held between the pair of substrates, a seal portion held between the pair of substrates and disposed around the liquid crystal layer, and a pair of alignment layers each of which is disposed on a surface, adjacent to the liquid crystal layer, of a corresponding one of the substrates. The negative liquid crystal layer includes a liquid crystal composition including a compound having a functional group represented by the formula (A) below, the seal portion includes a radical polymerization initiator, the alignment layers include a polymer including polyimide, the polyimide is prepared from polyamic acid as a precursor, and the imidization ratio of the polyimide is not less than 60% with respect to the whole polymer.

##STR00001##

(where X: oxygen radical, hydroxyl group, C.sub.1-20 linear alkyl group, or C.sub.3-20 branched alkyl group, Y1 to Y4: C.sub.1-4 linear alkyl group or C.sub.3-4 branched alkyl group)

A liquid crystal display device includes a pair of substrates, a negative liquid crystal layer held between the pair of substrates, a seal portion held between the pair of substrates and disposed around the liquid crystal layer, and a pair of alignment layers each of which is disposed on a surface, adjacent to the liquid crystal layer, of a corresponding one of the substrates. The negative liquid crystal layer includes a liquid crystal composition including a compound having a functional group represented by the formula (A) below, the seal portion includes a radical polymerization initiator, the alignment layers include a polymer including polyimide, the polyimide is prepared from polyamic acid as a precursor, and the imidization ratio of the polyimide is not less than 60% with respect to the whole polymer.

##STR00001##

(where X: oxygen radical, hydroxyl group, C.sub.1-20 linear alkyl group, or C.sub.3-20 branched alkyl group, Y1 to Y4: C.sub.1-4 linear alkyl group or C.sub.3-4 branched alkyl group)

A liquid crystal compound is represented by formula (1): ##STR00001## 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); ##STR00002## In formula (1a) and formula (1b), L.sup.3 to L.sup.8 are independently hydrogen, fluorine or the like.

A liquid crystal compound is represented by formula (1): ##STR00001## 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); ##STR00002## In formula (1a) and formula (1b), L.sup.3 to L.sup.8 are independently hydrogen, fluorine or the like.

The present invention relates to liquid-crystalline media comprising one or more polymerisable compounds, preferably of formula P
P.sup.a-(Sp.sup.a).sub.s1-(A.sup.1-Z.sup.1).sub.n1-A.sup.2-Q-A.sup.3-(Z.sup.4-A.sup.4).sub.n2-(Sp.sup.b).sub.s2-P.sup.bP
and one or more compounds selected from the group of compounds of formulae I, II, and III, ##STR00001##
in which the parameters have the meaning indicated in Claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.

A liquid crystalline compound, a liquid crystal composition, and a liquid crystal display element are provided. The liquid crystalline compound satisfying at least one physical property among high stability against heat and light, high transparency, low minimum temperature of the liquid crystal phase, low viscosity, proper optical anisotropy, negatively large dielectric anisotropy, proper elastic constant, good compatibility with other liquid crystalline compounds at room temperature and low temperature. The liquid crystalline compound represented by formula (1).

##STR00001##

There are provided a liquid crystal composition containing one or two or more compounds represented by general formula (L) and three or four or more dichroic dyes selected from azo compounds, and a guest-host liquid crystal display device or light-controlling device that uses the liquid crystal composition. The liquid crystal composition according to the present invention contains dichroic dyes that satisfy high contrast, high solubility, high nematic-isotropic transition temperature (T.sub.NI), and low birefringent anisotropy (n) effective for high light resistance and high thermal resistance at the same time. The use of the liquid crystal composition according to the present invention provides a liquid crystal display device or a light-controlling device that exhibits a good-looking black color and has high contrast, high display quality, and high practicality.