| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a retardation film, having front retardation and optical biaxial properties, suitable as an optical compensating member, having high durability without substantial deterioration of optical compensating physical properties even in a heating condition, and maintaining a display image of high quality in a liquid crystal display device over a long period of time. <P>SOLUTION: The retardation film is obtained by drawing a film formed of amorphous resin (A) and thermoplastic elastomer resin (B) substantially presenting phase separation form to the amorphous resin (A) at least either in the longitudinal direction or in the width direction. A change rate of front retardation R0 defined by the following formula (1) to an initial value before heat treatment after the film is treated at 80°C for 1,000 hours is within 2%, a change rate of thickness retardation Rth defined by the following formula (2) to an initial value before heating treatment similarly after the heat treatment is within 3%, the front retardation R0 ranges from 20 to 200 nm, and the thickness retardation Rth ranges from -200 to 300 nm. In the formulas R0=(nx-ny)×d (1), Rth=((nx+ny)/2-nz)×d (2), nx: maximum refractive index in plane of film, ny: refractive index in the direction orthogonal to nx direction in plane of film, nz: refractive index in thickness direction of film, and d: average thickness of retardation film. <P>COPYRIGHT: (C)2010,JPO&INPIT |
