CELLULOSE ESTER FILM, POLARIZING PLATE AND DISPLAY

摘要

Disclosed is a cellulose ester film characterized by having a free volume radius of 0.25-0.310 nm as determined by positron annihilation lifetime technique, a half bandwidth of 0.04-0.1 nm, and an Ro of 0-10 nm and an Rt of from -30 to +20 nm as determined by the formulae below. Formula (a): Ro = (nx - ny) × d Formula (b): Rt = ((nx + ny)/2 - nz) × d (In the formulae, Ro represents the in-plane retardation of the film; Rt represents the retardation in the thickness direction of the film; nx represents the in-plane refractive index in the slow axis direction of the film; ny represents the in-plane refractive index in the fast axis direction of the film; nz represents the refractive index in the thickness direction of the film (the refractive indexes are measured at a wavelength of 590 nm); and d represents the thickness (nm) of the film.)