METHOD FOR MANUFACTURING SEQUENTIAL BIAXIALLY STRETCHED RETARDATION FILM AND UNIAXIALLY STRETCHED CAST FILM TO BE USED FOR THE METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a retardation film which has little variance of the retardation and the optical axis in the plane direction of the film comprising polycarbonate, which has excellent display quality such as contrast in a wide viewing field range in the front and oblique viewing directions, and which can be directly stuck with a polarizing plate so that a liquid crystal display having uniform display in the plane without having speckles of leaked light in a black display screen can be formed. SOLUTION: The method for manufacturing a retardation film includes: a step of preparing a cast film from polycarbonate by a solution casting method; a longitudinal stretching step to stretch the cast film in the casting direction; and a transverse stretching step to stretch the film in the direction orthogonal to the casting direction. The variance of the film thickness in the plane direction of the longitudinally (or transversely) uniaxially stretched cast film in the longitudinal (or transverse) stretching step is within 5μm. The uniaxially stretched cast film containing a solvent by 0.1 to 1.0 wt.% in the film is stretched in a direction almost orthogonal to the first stretching direction. COPYRIGHT: (C)2005,JPO&NCIPI