Nitto-denko Corporation

Naotaka Kinjo

Nao Murakami

Takashi Shimizu

Kentarou Yoshida

Amane Mochizuki

Masaki Hayashi

Takahiro Fukuoka

Toshihiko Omote

Shinobu Nagano

Naoki Kurata

There is provided a liquid crystal display panel having a high contrast ratio in a front direction. A liquid crystal panel of the present invention includes: a liquid crystal cell; a first polarizing plate placed on one side of the liquid crystal cell; and a second polarizing plate placed on another side of the liquid crystal cell. A transmittance (T) of the first polarizing plate is higher than a transmittance (T) of the second polarizing plate. Preferably, a difference (&#x394;T=T&#x2212;T) between the transmittance (T) of the first polarizing plate and the transmittance (T) of the second polarizing plate is 0.1% to 6.0%.

Liquid crystal panel and liquid crystal display apparatus

It is an object of the present invention to provide a liquid crystal display panel having a high contrast ratio in a front direction. A liquid crystal panel according to an embodiment of the present invention includes: a liquid crystal cell; a first polarizing plate placed on one side of the liquid crystal cell; a second polarizing plate placed on the other side of the liquid crystal cell; and a retardation layer placed between the liquid crystal cell and the second polarizing plate. A refractive index ellipsoid of the retardation layer exhibits a relationship of n&#x2267;ny&#x3e;nz; and a light transmittance (T) of the second polarizing plate is larger than a light transmittance (T) of the first polarizing plate. Such a liquid crystal panel has a remarkably higher contrast ratio in a front direction than that of a conventional liquid crystal panel (for example, a liquid crystal panel in which the light transmittances of two polarizing plates placed on both sides of a liquid crystal cell are the same), and shows excellent display properties.

The polyamic acid of the invention can be obtained by the reaction of an acid anhydride component comprising pyromellitic anhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane with 2,2&prime;-di-substituted-4,4&prime;-diaminobiphenyls as a first aromatic diamine and any aromatic diamine component, as a second aromatic diamine, of 2,2-bis(4-aminophenoxyphenyl)propanes, 1,1-bis(4-(4-aminophenoxy)-3-t-butyl-6-methylphenyl)butane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane and &agr;,&agr;&prime;-bis(4-aminophenyl)diisopropylbenzenes in an organic solvent. The polyimide resin of the invention can be obtained by heating such a polyamic acid solution. In the production of a circuit board, by using a photosensitive polyamic acid having a sensitizer incorporated in such a polyamic acid solution, a patterned polyimide resin layer can be provided as an insulation layer on a metal foil.

Polyamic acid, polyimide resin obtained therefrom and application thereof to circuit board

Growing community of inventors

Osaka, Japan

Naotaka Kinjo