| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a retardation film having excellent wavelength dispersion property and a small photoelastic coefficient and suitable for application to optical compensation. <P>SOLUTION: The retardation film includes an at least two-layer structure of an A layer comprising a thermoplastic resin A and a B layer comprising a thermoplastic resin B, wherein the ratio of an in-plane retardation of the A layer at 480.4 nm wavelength Re(480.4) (nm) to an in-plane retardation of the A layer at 548.3 nm wavelength Re (548.3) (nm) satisfies expression (1): 0.65≤Re(480.4)/Re(548.3)≤0.98, and the ratio of a thickness-direction retardation of the A layer at 480.4 nm wavelength Rth(480.4) (nm) to an in-plane retardation of the A layer at 548.3 nm wavelength Rth(548.3) (nm) satisfies expression (2): 0.65≤Rth(480.4)/Rth(548.3)≤0.98. The thermoplastic resin B includes a photoelastic coefficient Cσ(B) satisfying expression (3):-10×10<SP>-12</SP>/Pa≤Cσ(B)≤-2×10<SP>-12</SP>/Pa. <P>COPYRIGHT: (C)2010,JPO&INPIT |
