The present disclosure relates to a polyimide-based resin film which is synthesized by the reaction of an acid anhydride compound and a diamine compound having a specific structure, thereby capable of ensuring excellent flatness even under high temperature heat treatment conditions, and stably maintaining flatness even during further heat treatment, a substrate for display device, and an optical device using the same.

The present disclosure relates to a polyimide-based resin film which is synthesized by the reaction of an acid anhydride compound and a diamine compound having a specific structure, a substrate for display device, and an optical device using the same.

Provided is a liquid crystal aligning agent composition including a liquid crystal polymer together with a polyimide-based (co)polymer, a method for preparing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the same.

With the use of a photoalignment film, the present invention provides a liquid crystal display device capable of maintaining a favorable voltage holding ratio and reducing or preventing image sticking, stains, and a decrease in contrast ratio for a long time not only in a room-temperature environment but also in a high-temperature environment; and a method for producing such a liquid crystal display device. The liquid crystal display device of the present invention includes paired substrates; a liquid crystal layer disposed between the substrates; a photoalignment film disposed between at least one of the substrates and the liquid crystal layer; and a polymer layer disposed between the photoalignment film and the liquid crystal layer, wherein the polymer layer has a structure derived from a specific epoxy-based monomer and a structure derived from a specific curing agent.

An alignment film is given a 2-layer structure comprising a photoalignment film that is photoalignable and a low-resistivity alignment film whose resistivity is smaller than that of the photoalignment film. The photoalignment film is formed by a polyimide whose precursor is polyamide acid alkyl ester, the number molecular weight of the photoalignment film is large, and the stability of alignment of the photoalignment film by photoalignment is excellent. The low-resistivity alignment film is formed by a polyimide whose precursor is polyamide acid, the number molecular weight of the low-resistivity alignment film is small, and the resistivity of the low-resistivity alignment film is small. The 2-layer structure alignment film can be maintaining an excellent photoalignment characteristic, so DC afterimages can be controlled.

The present invention provides a liquid crystal display device capable of maintaining a favorable voltage holding ratio for a long period of time and thereby reducing generation of image sticking not only at room temperature but also at high temperatures. The liquid crystal display device includes: paired substrates; a liquid crystal layer that is held between the paired substrates and contains liquid crystal molecules; and an alignment film disposed between at least one of the paired substrates and the liquid crystal layer, the alignment film containing quantum dots.

A liquid crystal display device includes: a TFT substrate formed with an alignment film on a pixel; a counter substrate disposed opposite to the TFT substrate and formed with an alignment film on a top surface on the TFT substrate side; and a liquid crystal sandwiched between the TFT substrate and the counter substrate. In the liquid crystal display device, the alignment film is configured of a first alignment film layer contacting the liquid crystal layer and having at least one kind of polyimide and a second alignment film layer formed below the first alignment film layer and having at least one kind of polyimide, the first alignment film layer is a material that is enabled to provide liquid crystal alignment regulating force by applying polarized light, and the first alignment film layer and the second alignment film layer contain a common polyimide structure.

The present invention provides: (A) a liquid crystal alignment agent containing a polyamic acid which is a polymer of a tetracarboxylic dianhydride represented by a predetermined formula and any one of diamines represented by predetermined formulas, or a derivative of the polyamic acid; (B) a liquid crystal alignment film containing a polyimide compound represented by a predetermined formula, which is an imidization product of the polymer in the liquid crystal alignment agent; and (C) a liquid crystal display device including a pair of substrates, a liquid crystal layer held between the substrates, and the liquid crystal alignment film disposed between at least one of the substrates and the liquid crystal layer.

Provided is a liquid crystal display device including a first substrate; a second substrate; a liquid crystal layer sandwiched between the first substrate and the second substrate and containing a negative liquid crystal material; a first alignment film provided on the surface of the first substrate on the liquid crystal layer side; a first phase difference layer having birefringence provided between the first substrate and the first alignment film; and a second alignment film disposed on the surface of the second substrate on the liquid crystal layer side, wherein at least one of the first alignment film and the second alignment film is a photo-alignment film being in contact with the liquid crystal layer and imparting a pretilt angle of 75 or more and less than 90 to the liquid crystal material; the first phase difference layer is formed of a first polymer material having a first photofunctional group; the photo-alignment film is formed of a second polymer material having a second photofunctional group; and the first photofunctional group and the second photofunctional group are each a group causing at least one reaction selected from the group consisting of isomerization reaction, dimerization reaction, Fries rearrangement reaction, and cleavage reaction.

A liquid crystal display device of the present invention includes a thin-film transistor substrate, a counter substrate facing the thin-film transistor substrate, a liquid crystal layer provided between the thin-film transistor substrate and the counter substrate, an alignment film provided on the thin-film transistor substrate; a sealing material which bonds together the thin-film transistor substrate and the counter substrate at the periphery of the liquid crystal layer, and a polymerized layer provided on the liquid crystal layer-side surface of the alignment film. The alignment film contains a first polymer and a second polymer of a different type from that of the first polymer and is chemically bonded to the sealing material, the first polymer and the second polymer contained in the alignment film are mixed in a surface layer in contact with the liquid crystal layer, and the first polymer and the second polymer have different photo-functional groups.