| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polymer film which has excellent viewing field angle characteristics and is not likely to affect display color tone when used for a liquid crystal display as a protective layer of a polarizing plate, because the polymer film has small optical anisotropy and small wavelength dispersion in the optical anisotropy, and furthermore, which has a controlled laminating property to be suitably used in an image display device such as a liquid crystal display device. <P>SOLUTION: The polymer film has a front retardation value Re<SB POS="POST">(λ)</SB>and a retardation value Rth<SB POS="POST">(λ)</SB>in the film thickness direction, where represents a wavelength (nm), satisfying expressions (i):0≤Re<SB POS="POST">(630)</SB>≤10 and ¾Rth<SB POS="POST">(630)</SB>¾≤25 and expressions (ii):¾Re<SB POS="POST">(400)</SB>-Re<SB POS="POST">(700)</SB>¾≤10 and ¾Rth<SB POS="POST">(400)</SB>-Rth<SB POS="POST">(700)</SB>¾≤35. At least one surface of the film has a surface energy of 50 mN/m or more and 80 mN/m or less. The polymer film contains a compound that suppresses orientation of cellulose acylate in the film in a plane direction and in the film thickness direction and decreases optical anisotropy. The compound that decreases the optical anisotropy is distributed in such a manner that an average content of the compound in a portion from a surface in at least one side to a depth corresponding to 10% of the whole film thickness is 80 to 99% of the average content of the compound in a center portion of the cellulose acylate film. <P>COPYRIGHT: (C)2012,JPO&INPIT |
