Retardation film

Abstract

A retardation film which has few foreign matter defects and small retardation nonuniformity and meets the required quality of a retardation film is provided with high productivity at a low cost by melt extruding a polycarbonate. The retardation film obtained by stretching and orienting a melt extruded film of a polycarbonate is characterized in that: (1) the polycarbonate constituting the film has a viscosity average molecular weight of 1.3×104 to 1.8×104; (2) the retardation R(589) within the plane of the film measured at a wavelength of 589 nm is 50 to 800 nm; (3) the retardation R (589) nonuniformity within the plane of the film is ±5 nm; (4) the average thickness of the film is 10 to 150 μm; and (5) the number of film defects as large as 100 μm or more is 2 or less/m2.

Dependencies are inferred from the claim text.