Patent ID: 8652591

Claim:
An optical retardation film having an inner haze of 0.02 or less at 23° C. and 55% RH, comprising: a cellulose ester composition comprising a cellulose ester resin which has a degree of substitution of total acyl groups being 2.0 to 2.55; and a compound represented by Formula (1), wherein: R 1 to R 8 each represents a substituted or unsubstituted alkyl carbonyl group or a substituted or unsubstituted aryl carbonyl group; and R 1 to R 8 may be the same with or different from each other; the compound has an average degree of substitution of 3.0 to 6.0 and contains a component with a degree of substitution of 4 or less in an amount of 30 mass % to 80 mass %, and the retardation film has an inner haze variation amount of 0.03 or less due to a temperature and humidity change from 23° C. and 55% RH to 60° C. and 90% RH; and a retardation value Ro, defined by the following formula (i), of 30 to 90 nm with a retardation value Rt, defined by the following formula (ii), of 70 to 300 nm, Ro =( nx−ny )× d Formula (i) Rth ={( nx+ny )/2 −nz}×d Formula (ii) wherein nx represents a refractive index in a film in-plane slow axis direction; NY represents a refractive index in a film in-plane fast axis direction, nz represents a refractive index in a thickness direction, and d represents a thickness (nm) of the film, under the environment of a temperature of 23° C. and a humidity of 55% RH, at a wavelength of 589 nm.