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.

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.

An object of the present invention is to provide a composition that has positive Δ∈, exhibits a liquid crystal phase over a wide temperature range, has low viscosity, excellent solubility at low temperatures, and high resistivity and voltage holding ratio, and is stable against heat and light. By using this composition, IPS or TN liquid crystal display devices and the like that have excellent display quality and suppress display failures such as image-sticking and drop marks are provided in high yield.

Provided is a composition that contains at least one selected from the group consisting of compounds represented by general formulae (i) and (ii) and at least one selected from compounds represented by general formula (iii). Moreover, a liquid crystal display device using the composition and an IPS or FFS device that uses the composition are provided.

An object of the present invention is to provide a composition that has positive Δ∈, exhibits a liquid crystal phase over a wide temperature range, has low viscosity, excellent solubility at low temperatures, and high resistivity and voltage holding ratio, and is stable against heat and light. By using this composition, IPS or TN liquid crystal display devices and the like that have excellent display quality and suppress display failures such as image-sticking and drop marks are provided in high yield.

Provided is a composition that contains at least one selected from the group consisting of compounds represented by general formulae (i) and (ii) and at least one selected from compounds represented by general formula (iii). Moreover, a liquid crystal display device using the composition and an IPS or FFS device that uses the composition are provided.

There is provided a polymerizable compound-containing liquid crystal composition having strong alignment regulating force of a liquid crystal compound. The polymerizable compound-containing liquid crystal composition includes: a polymerizable compound; and a liquid crystal compound, in which the polymerizable compound includes at least one polymerizable compound represented by General Formula (I), and in which the liquid crystal compound includes at least one component selected from the group consisting of at least one compound represented by General Formula (II) as a second component, at least one compound represented by General Formulae (IIIa), (IIIb), and (IIIc) as a third component, and at least one compound represented by General Formulae (IVa), (IVb), and (IVc) as a fourth component.

An optical film of the present invention includes a positive A-plate and a positive C-plate, in which the Re(450), Re(550), and Re(650) of the positive A-plate satisfy the relationship of Re(450)≦Re(550)≦Re(650), the positive A-plate is formed of a cured product of a composition including the liquid crystal compound A, and the positive C-plate is formed of a cured product of a composition including the liquid crystal compound C.

There is provided a liquid crystal composition containing at least one compound represented by General Formula (a). There is also provided a liquid crystal display device using such a liquid crystal composition. The liquid crystal composition of the present invention has the following properties without suffering reductions in refractive index anisotropy (Δn) and nematic phase-isotropic liquid phase transition temperature (T.sub.ni): sufficiently low viscosity (η), sufficiently low rotational viscosity (γ.sub.1), a large elastic constant (K.sub.33), a high voltage holding ratio after UV exposure (VHR (UV)), and a negative dielectric anisotropy (Δ∈) with a large absolute value. A liquid crystal display device of, for example, a VA type that uses such a liquid crystal composition has a high response speed and excellent display quality with defective display being eliminated or reduced.

##STR00001##

The present invention relates to a liquid crystal display that incorporates a particular liquid crystal composition and a sealant in which a cured form of a particular curable resin composition is used. The present invention provides a liquid crystal display that prevents reduced voltage holding ratio (VHR) and increased ionic density (ID) in the liquid crystal layer and solves the problems of display defects such as voids, alignment irregularities, and image-sticking. Liquid crystal displays according to the present invention, featuring the ability to prevent reduced voltage holding ratio (VHR) in the liquid crystal layer and reduce the occurrence of display defects such as alignment irregularities and image-sticking, are useful particularly to liquid crystal displays in the IPS and FFS modes for active matrix drive and applicable to liquid crystal displays of equipment such as liquid crystal TVs, monitors, mobile phones, and smartphones.

The present invention provides a liquid crystal composition including at least one compound represented by General Formula (1), at least one compound represented by General Formula (2), and at least one compound represented by General Formula (LC1).

##STR00001##

The liquid crystal composition of the present invention has high refractive index anisotropy (Δn) and sufficiently low viscosity (η), achieves a wide nematic phase temperature range by suppressing a decrease in nematic phase-isotropic liquid phase transition temperature (T.sub.ni), and exhibits high compatibility. By using the liquid crystal composition of the present invention in a liquid crystal display element, a liquid crystal display element having a high response speed and high practical reliability can be obtained.

The present invention provides a liquid crystal composition including at least one compound represented by General Formula (1), at least one compound represented by General Formula (2), and at least one compound represented by General Formula (LC1).

##STR00001##

The liquid crystal composition of the present invention has high refractive index anisotropy (Δn) and sufficiently low viscosity (η), achieves a wide nematic phase temperature range by suppressing a decrease in nematic phase-isotropic liquid phase transition temperature (T.sub.ni), and exhibits high compatibility. By using the liquid crystal composition of the present invention in a liquid crystal display element, a liquid crystal display element having a high response speed and high practical reliability can be obtained.