| 摘要 |
PURPOSE: To obtain such a phase difference plate that when it is used for a liquid crystal display panel, changes of local retardation in the plane of the panel can be decreased so that the obtd. liquid crystal display panel has no irregularity in colors or contrast, by specifying the difference of thickness between any one point and a point with specified distance in the plane of a polymer film showing double refraction. CONSTITUTION: This phase difference plate consists of a polymer film having double refraction and is formed in such a manner that the difference of thickness between any one point and a point with 1cm distance in the film plane is <=0.3μm. The polymer film having double refraction is obtd. by uniaxially stretching a transparent film having little orientation, or may be biaxially oriented according to the polymer material used. A transparent polymer film having little orientation means such a film that has >=70% transmittance of light and is formed by a soln. casting method. As for the polymer film, any material can be used as far as it is transparent is made of an amorphous polymer. However, it is preferable to use a film excellent in stretching property and transparency.
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