| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a retardation film containing cellulose acylate, which is thin, has in-plane retardation Ro showing reverse wavelength dispersion and a high retardation value Rth in a thickness direction that is necessary for optical compensation, and shows no variation in the retardation value and no decrease in contrast even in a saponification process. <P>SOLUTION: The retardation film includes a core layer containing a cellulose acylate satisfying an acyl substitution degree of a formula (1):2.0<Z1<2.5 and a skin layer containing a cellulose acylate satisfying an acyl substitution degree of a formula (2):2.7<Z2<3.0 disposed on both sides of the core layer, and is subjected to an orientation process. The retardation film has a surface orientation degree Sth of 3.3/1000 or more, and the retardation value Ro in an in-plane direction shows reverse wavelength dispersion. The viscosity (ND<SB POS="POST">C</SB>) of a composition for the core layer and the viscosity (ND<SB POS="POST">S</SB>) of a composition for the skin layer satisfy ND<SB POS="POST">S</SB>/ND<SB POS="POST">C</SB><0.96. <P>COPYRIGHT: (C)2012,JPO&INPIT |
