Japan Display Inc.

Panasonic Liquid Crystal Display Co., Ltd.

Hitachi Displays, Ltd.

Hitachi, Ltd.

Masaki Matsumori

Yasushi Tomioka

Noboru Kunimatsu

Hidehiro Sonoda

Chikae Matsui

Yuko Matsumoto

Shoichi Uchino

Toshiki Kaneko

Yasuo Imanishi

Shigeru Matsuyama

Jun Tanaka

Shuji Imazeki

Shintaro Takeda

Kotaro Araya

Katsumi Kondo

Tetsuya Nagata

Osamu Itou

Shinichiro Oka

Yoshiro Mikami

Takeshi Sato

Shoichi Hirota

Katsuyuki Funahata

Ayami Ohsato

The present invention prevents the shaving of an alignment film caused by a columnar spacer in a liquid crystal display device of an IPS method using photo-alignment. A plinth higher than a pixel electrode is formed at a part where a columnar spacer formed over a counter substrate touches a TFT substrate. When an alignment film of a double-layered structure is applied over the pixel electrode and the plinth, the thickness of the alignment film over the plinth reduces by a leveling effect. When photo-alignment is applied in the state, a photodegraded upper alignment film over the plinth disappears and a lower alignment film having a high mechanical strength remains. As a result, it is possible to prevent the shaving of the alignment film.

Liquid crystal display device and manufacturing method thereof

A liquid crystal display device includes a TFT substrate having a first alignment film and an opposing substrate having a second alignment film with liquid crystals sandwiched therebetween. One of the first and second alignment films, comprises a first polyimide produced via polyamide acid ester containing cyclobutane as a precursor and a second polyimide produced via polyamide acid as a precursor. The polyamide acid has a higher polarity than that of the polyamide acid ester. The one of the first and second alignment films is responsive to photo-alignment. A first side of the one of the first and second alignment films is adjacent to the liquid crystals, and a second side thereof is closer to one of the TFT substrate and the counter substrate than the first side. The first side contains more of the first polyimide and less of the second polyimide than the second side.

Liquid crystal display device

An IPS type liquid crystal display device superior in mass productivity and improved in image quality with a higher contrast ratio by decreasing the occurrence of defective display due to the disorder of the initial liquid crystal alignment by the liquid orientation control film and realizing stable alignment of liquid crystals comprises: a pair of substrates, at least one which is transparent; a liquid crystal layer disposed between the pair of substrates; a group of electrodes formed on at least one of the pair of substrates to apply an electric field to the liquid crystal layer; plural active elements connected to the group of electrodes; and an orientation control film disposed on at least one of the pair of substrates, wherein said orientation control film is made of a photosensitive polyimide and a polyamide acid ester and is given orientation control ability by being irradiated with substantially linearly polarized light.

Various layer separation states are generated by the combination of a polyamide acid ester and a polyamide acid and a long residual image characteristic cannot be further improved merely by combining them. A liquid crystal display device comprises a substrate, a liquid crystal layer, and an orientation film placed between the substrate and the liquid crystal layer. The orientation film comprises a polyimide precursor having two or more components. In the polyimide precursor, an octanol-water partition coefficient is defined as log P and the difference in log P (&#x394; log P) between the two components having most distant log Ps is set so as to fall within a prescribed range.

Orientation film materials and liquid crystal display device using it

An object of the present invention is to enhance transmissivity and the luminance of a screen in an IPS liquid crystal display device. To achieve the object, in the IPS liquid crystal display device according to the present invention, a counter electrode is formed flatly and solidly on an organic passivation film, a pixel electrode having a slit is formed on the counter electrode via an interlayer insulation film, and an alignment film the orientation of which is controlled by optical orientation is formed on the pixel electrode. The transmissivity is enhanced by also making the inside of the contact hole function as a transmissible area for image formation by applying optical orientation to the alignment film in the contact hole to result in enhancement of the luminance of the screen.

An image retention phenomenon and black unevenness generated after long-time operation in the liquid crystal device are prevented. By using a material having a polyamide acid ester as a precursor less likely to adsorb impurities on a boundary for an alignment film and a material having a dielectric constant anisotropy &#x394;&#x2208; of 5 or less for liquid crystals, adsorption of an antioxidant dispersed in the liquid crystals is suppressed to prevent oxidation of the liquid crystals. The extent that impurities are intruded into the liquid crystals is reduced by restricting the dielectric constant anisotropy &#x394;&#x2208; of the liquid crystals to 5 or less, thereby capable of preventing the image retention phenomenon and the black unevenness.

Growing community of inventors

Tokai, Japan

Masaki Matsumori