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 a liquid crystal alignment composition comprising first liquid crystal alignment polymer; second liquid crystal alignment polymer; and a cross-linking agent compound, a method for preparing a liquid crystal alignment film using the same, a liquid crystal alignment film and a liquid crystal display using the same.

Provided are a polarizing plate including a polarizing layer containing a lyotropic liquid crystal compound and capable of achieving uniform polarization properties over a large area, and a display device equipped with the polarizing plate. The polarizing plate includes: an alignment film; and a polarizing layer on the alignment film. The alignment film contains an alignment film polymer, has a static contact angle with water of 60° or smaller, and has a slow axis. The polarizing layer contains a lyotropic liquid crystal compound and has an absorption axis parallel to the above slow axis. The lyotropic liquid crystal compound is preferably dichroic.

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 thermally stable diamine compound of formula (I′) is proposed as well as polymers, copolymers, polyamic acids, polyamic acid esters, or polyimides based on such compound. Also, a process of preparing orientation layers for liquid crystals including preparing orientation layers for liquid crystals from thermally stable alignment materials comprising diamine compounds of formula (I′).

In the step of curing a resin for bonding a TFT substrate and a counter substrate each having an alignment film that has been optically aligned by using UV-light, damage to the alignment film due to the UV-light can be prevented without using a light shielding mask. A UV-light absorption layer is formed between each black matrix on the counter substrate. The TFT and counter substrates are sealed at their periphery by a resin that is cured by UV-light radiated from the counter substrate side. Since the absorption layer has a high absorbability to UV-light at a wavelength of 300 nm or less that degrades the alignment film, damage to the alignment film due to the UV-light for curing the resin can be prevented. Thus, provision of a light shielding mask for shielding the UV-light for the display region can be saved.

A liquid crystal display includes: a first substrate, a second substrate overlapping the first substrate, a liquid crystal layer positioned between the first substrate and the second substrate and including a plurality of liquid crystal molecules, a first alignment layer positioned between the first substrate and the liquid crystal layer, a second alignment layer positioned between the second substrate and the liquid crystal layer, and a plurality of protrusions positioned at at least one of between the first alignment layer and the liquid crystal layer and between the second alignment layer and the liquid crystal layer, wherein at least one among the plurality of protrusions includes a polymer of a reactive mesogen, and the reactive mesogen is represented by Chemical Formula 1:

P.sub.a-A.sub.1-OCH.sub.2.sub.nO-A.sub.2-P.sub.b  Chemical Formula 1

To provide a liquid crystal display device, whereby transparency when no voltage is applied and scattering properties when a voltage is applied, are good, adhesion between a liquid crystal layer and a vertical liquid crystal alignment film is high, and its lifespan is long even in a severe environment. The liquid crystal display device has a liquid crystal layer formed by disposing a liquid crystal composition containing a liquid crystal and a polymerizable compound between a pair of substrates provided with electrodes, and irradiating and curing the composition with ultraviolet rays by an ultraviolet irradiation apparatus, and at least one of the substrates is provided with a liquid crystal alignment film to vertically align a liquid crystal, wherein the ultraviolet irradiation apparatus is an ultraviolet irradiation apparatus capable of controlling the irradiation light intensity and wavelength of the ultraviolet rays to be irradiated and the surface temperature of the pair of the substrates, the liquid crystal composition contains a compound represented by the formula [1], and the liquid crystal alignment film is a liquid crystal alignment film obtained from a liquid crystal alignment treating agent containing a polymer having a side chain structure represented by the formula [2-1] or formula [2-2].

X.sup.1-X.sup.2-X.sup.3-X.sup.4-X.sup.5-X.sup.6X.sup.7.sub.pX.sup.8  [1]

(X.sup.1 is a specific side chain structure; X.sup.2, X.sup.3, X.sup.4 and X.sup.6 are each a single bond, etc.; X.sup.5 and X.sup.7 are each a benzene ring, etc.; p is an integer of from 0 to 4; and X.sup.8 is a C.sub.1-18 alkyl group, etc.),

—Y.sup.1-Y.sup.2-Y.sup.3-Y.sup.4Y.sup.5.sub.nY.sup.6  [2-1]

(Y.sup.1, Y.sup.2 and Y.sup.3 are each a single bond; Y.sup.4 and Y.sup.5 are each a benzene ring, etc.; n is from 0 to 4; and Y.sup.6 is a C.sub.1-18 alkyl group, etc.,

—Y.sup.7-Y.sup.8  [2-2]

(Y.sup.7 is a single bond; and Y.sup.8 is a C.sub.8-22 alkyl group, etc.).

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.

A liquid crystal display including a first substrate; a second substrate on the first substrate; a liquid crystal layer between the first substrate and the second substrate; a first alignment layer between the first substrate and the liquid crystal layer and including a first polymer; a second alignment layer between the second substrate and the liquid crystal layer and including a second polymer; and protrusions between the first alignment layer and the liquid crystal layer, wherein at least one of the protrusions includes an alignment polymer polymerized with a reactive mesogen, the first polymer includes a first main chain and a plurality of first side chains connected to the first main chain, and at least one of the plurality of first side chains includes a photoreactive group and a photoreactive derivative, and wherein the photoreactive group has an absorbance that is greater than that of the reactive mesogen.