A liquid crystal display device having a liquid crystal composition, requiring neither an alignment film nor alignment treatment on a substrate. The problem is solved by a low molecular weight polar compound for homogeneously aligning a liquid crystal medium relative to the substrate, for example, the low molecular weight polar compound represented by formula (1).
Formula 95
M-P(1) In formula (1), M is a nonpolar group having 1 or more carbons, and P is a polar group.

The problem is to provide a polymerizable compound having suitable polymerization reactivity, a high conversion ratio, low polymerization starting temperature, and high solubility in a liquid crystal composition; a liquid crystal composition containing the compound; and a liquid crystal display device including the composition.

A means thereof includes a compound represented by formula (1) and a liquid crystal composition containing the compound.

##STR00001##

In formula (1), R.sup.1, R.sup.2 and R.sup.3 are independently alkyl or the like; n is 0 or the like; ring A.sup.1 is phenyl or the like, and ring A.sup.2 and ring A.sup.3 are independently 1,4-phenylene or the like; Z.sup.1 and Z.sup.2 are independently a single bond or the like; Sp.sup.1 to Sp.sup.4 are a single bond or the like; a is 1 or the like; c, d and e are independently 0 or 1, and a sum of c, d and e is 1 or the like; and P.sup.1 to P.sup.4 are a polymerizable group, and at least one of P.sup.1 to P.sup.4 is a polymerizable group represented by formula (P-1).

##STR00002##

The subject is to provide liquid crystal display device having a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, a long service life and a small flicker rate. The liquid crystal display device having a liquid crystal alignment film formed on the opposing surfaces of a pair of substrates, and a liquid crystal composition therebetween, wherein the liquid crystal alignment film includes a polymer derived from a polyamic acid having a photodegradable group, and the liquid crystal composition includes at least one compound represented by formula (1) as a first component: ##STR00001## R.sup.1 is alkyl having 1 to 12 carbons or the like; ring A is 1,4-cyclohexylene, 1,4-phenylene or the like; Z.sup.1 is a single bond or the like; X.sup.1 and X.sup.2 are hydrogen or fluorine; Y.sup.1 is fluorine or the like; and a is 1, 2, 3 or 4.

Provided are a liquid crystal composition satisfying 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 high stability to heat, or has a suitable balance regarding at least two of the characteristics; and an AM device having characteristics such as a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio and a long service life. The liquid crystal composition may contain a specific compound having large negative dielectric anisotropy as a first component, a specific compound having high maximum temperature as a second component, a specific compound having negative dielectric anisotropy as a third component, or a specific compound having a polymerizable group as an additive component.

Provided is a liquid crystal compound containing 2,3,4-trisubstituted benzene, a liquid crystal composition thereof, and a liquid crystal display element or a liquid crystal display comprising the liquid crystal compound or the liquid crystal composition, wherein the liquid crystal composition has a lower viscosity, can achieve a quick response, and further has a moderate dielectric anisotropy , a moderate optical anisotropy n, and high stability to heat and light. The liquid crystal display element or liquid crystal display comprising the liquid crystal composition has the properties of a wider nematic phase temperature range, an appropriate birefringence anisotropy, a very high electrical resistivity, a good ultraviolet resistant property, a high charge retention rate, a low vapor pressure etc., and particularly, the liquid crystal compound or the liquid crystal composition has the advantage of a high light transmittance.

Disclosed is a polymerizable compound having a structural formula as represented by the following formula I: ##STR00001##
The polymerizable compound disclosed in the present invention has a plurality of ring systems, and the entire molecular structure thereof is curved and twisted. The present invention further discloses a liquid crystal medium comprising the polymerizable compound, the polymerizable compound provided by the present invention has an appropriate polymerization rate in the liquid crystal medium, and the liquid crystal medium can be well applied to a PS-(polymer stabilized)- or PSA-(polymer stabilized alignment)-type liquid crystal display device. Further disclosed is a liquid crystal display device prepared from the liquid crystal medium.

A liquid crystal composition that satisfies at least one of characteristics such as a high maximum temperature, a low minimum temperature, a wide temperature range of a liquid crystal phase, a small viscosity, a large optical anisotropy, a large positive or negative dielectric anisotropy, a large specific resistance, a high stability to light, a high stability to heat and a large elastic constant or that is suitably balanced between at least two of these characteristics. The means is use of a liquid crystal composition that includes a specific compound having a high maximum temperature or a small viscosity as a first component, and that may include a specific compound having a large positive dielectric anisotropy as a second component, or a specific compound having a large negative dielectric anisotropy as a third component or a specific compound having a polymerizable group as a first additive.

A liquid crystal composition that satisfies at least one of characteristics such as a high maximum temperature, a low minimum temperature, a small viscosity, a suitable optical anisotropy and a large negative dielectric anisotropy, or that has a suitable balance between at least two of these characteristics, and an AM device including this composition. The nematic liquid crystal composition includes a specific compound having a large negative dielectric anisotropy as a first component and a specific compound having a small viscosity as a second component, and may include a specific compound having a negative dielectric anisotropy as a third component, and a specific compound having a high maximum temperature or a small viscosity as a fourth component, or a specific compound having a polymerizable group as an additive.

The present application relates to a liquid-crystalline material comprising a sterically hindered N-oxide and a dye. The invention furthermore relates to the use of the liquid-crystalline material in an optical switching device for regulation of the passage of sunlight.

A complex (10) includes a liquid crystal component (13) and a support (11, 12) of the liquid crystal component (13), in which a lubricating interface derivation region (16) is formed between the liquid crystal component (13) and the support (11, 12). An optical element includes a pair of substrates (11, 12) having electrodes (18, 19) on at least one substrate (11), and a liquid crystal component (13) with which a space between the pair of substrates (11, 12) is filled, in which a lubricating interface derivation region (16) is formed between the pair of substrates (11, 12) and the liquid crystal component (13). It is preferable that the lubricating interface deriving agent (14) is present in the lubricating interface derivation region.