To solve the problem that, though a polarizing film obtained by flow-expanding a coating liquid including an azo compound on a base material such as a glass board and a resin film and drying the same is known, regarding the conventional polarizing film obtained by flow-expanding a coating liquid including an azo compound, fine crystals are precipitated in a drying stage, thus haze (light diffusion) is increased, and a dichroic ratio is made low.
By using an azo compound expressed by general formula containing an amino naphthol skeleton in which a lithium sulfonate group is substituted into a specified position, a polarizing film having reduced haze can be obtained. By introducing a lithium sulfonate group into the specified position of an amino naphthol skeleton poor in solubility in the structure of the azo compound and increasing the solubility of the azo compound, the precipitation of fine crystals in a drying stage can be prevented or reduced.
MATSUDA SHOICHI
KAMEYAMA TADAYUKI
Takanobu Nakaetsu
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