The present invention provides a liquid crystal alignment agent having high thermal stability and high solvent solubility, and a liquid crystal panel in which occurrence of ghosting and stain and a decrease in contrast are suppressed even under environments at high temperatures long period of time. The present invention is a liquid crystal alignment agent including a copolymer including a structure represented by a chemical formula (1) below, and a solvent. In the formula, X is a specified structure including a cyclic hydrocarbon group, Y.sup.1 is a specified structure including a cyclic hydrocarbon group, R.sup.1 represents a homogeneous alignment group, a homeotropic alignment group, or a photoreactive functional group, and Z.sup.1 and Z.sup.2 are the same or different, and represent an NH group, an O group, or a S group.

##STR00001##

The present invention relates to siloxane polymer, copolymer or oligomer for the photoalignment of liquid crystals, especially for the planar orientation of liquid crystals, and which derives from at least one monomer of formula (I), to compositions thereof, to a process for the preparation of the linear, branched or crosslinked siloxane polymer, and to its use for optical and electro optical devices, such as liquid crystal devices (LCDs): ##STR00001##

A liquid crystal display capable of reducing the occurrence of defective display due to variations in the initial alignment direction of a liquid crystal alignment control film in a liquid crystal display of an IPS scheme, realizing the stable liquid crystal alignment, providing excellent mass productivity, and having high image quality with a higher contrast ratio. The liquid crystal display has a liquid crystal layer disposed between a pair of substrates, at least one of the substrates being transparent, and an alignment control film formed between the liquid crystal layer and the substrate. At least one of the alignment control films 109 comprises photoreactive polyimide and/or polyamic acid provided with an alignment control ability by irradiation of substantially linearly polarized light.

The present invention is a liquid crystal display device including a liquid crystal layer containing a liquid crystal material, a sealing member surrounding the liquid crystal layer in a plan view, a pair of substrates sandwiching the liquid crystal layer, and an alignment control layer being in contact with the liquid crystal layer in a region surrounded by the sealing member in a plan view. The alignment control layer aligns a liquid crystal compound in the liquid crystal material in a direction horizontal to faces of the substrates, and contains a polymer formed by polymerization of at least one monomer, and the at least one monomer contains a monomer represented by the following Chemical formula (1):

##STR00001##

wherein at least one hydrogen atom of the phenylene group may be the same or different and may be substituted with a halogen atom, a methyl group, an ethyl group, or a propyl group.

The present, invention provides a liquid crystal display device that can exhibit excellent retardation stability against heat and that can prevent reduction in contrast ratio due to scattering even when the liquid crystal display device includes a retardation layer formed by polymerization of a reactive monomer, and a method for producing a liquid crystal display device suitable for production of the liquid crystal display device. The liquid crystal display device of the present invention includes paired substrates and a liquid crystal layer provided between the paired substrates. At least one of the paired substrates includes a retardation layer formed from a polymer of at least one type of monomer. The at least one type of monomer includes a photo-aligning monomer that is to be aligned by polarized light.

Provided is a reverse mode light scattering type liquid crystal device that is capable of withstanding practical use, has a low driving voltage, and shows a high haze when voltage is applied and a low haze when no voltage is applied. A reverse mode liquid crystal device includes a light control layer and at least a pair of electrodes, wherein the light control layer includes a polymerization product of a polymerizable material including: (A) a liquid crystal composition, (B) a perpendicular alignment agent, and (C) at least one polymerizable compound selected from polymer forming monomers and polymer forming oligomers.

The present invention relates to a liquid crystal aligning agent composition for producing a liquid crystal alignment film having improved film strength together with liquid crystal alignment properties, a method for producing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the same.

The present application relates to a liquid crystal aligning agent, a liquid crystal alignment film and a method for producing the same, as well as a liquid crystal display device. The liquid crystal aligning agent comprises (i) a first polyamic acid having a photoreactive group without a liquid crystal group; (ii) a second polyamic acid having a liquid crystal group without a photoreactive group; (iii) a third polyamic acid having both a liquid crystal group and a photoreactive group; (iv) a fourth polyamic acid having neither a photoreactive group nor a liquid crystal group. The liquid crystal display device using the liquid crystal alignment film formed by the liquid crystal aligning agent provided by the present disclosure has a high display contrast and an improved AC residual image.

The present invention relates to novel photoaligning polymer materials, to their use as orienting layer for liquid crystals, which are used for the production of non-structured and structured optical elements, electro-optical elements, multi-layer systems or in nanoelectronics.

A polymer having excellent liquid crystal alignment and electrical properties and thus is suitable for use as a liquid crystal alignment agent, a liquid crystal alignment agent including the same, a liquid crystal alignment film formed from the liquid crystal alignment agent, and a liquid crystal display device including the liquid crystal alignment film are provided.