PHASE DIFFERENCE FILM AND ITS MANUFACTURING METHOD, OPTICAL COMPENSATING FILM, POLARIZING PLATE, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a phase difference film which has a superior field angle characteristic and a small breakage frequency in tenter drawing and its manufacturing method, an optical compensating film, a polarizing plate, and a liquid crystal display device.;SOLUTION: The phase difference film is made of at least two kinds of cellulose ester which are selected from cellulose ester of 2.50 to 2.90 in substitution degree of an an acyl group and have a ≥0.02 in difference in substitution degree of the acyl group; and nxnynz and relations shown by expressions (1) and (2) are satisfied. Here, the expression (1) is 2.5R_t/T₀≤20 and the expression (2) is 20 nm≤R₀≤70 nm, where R₀=(nx-ny)×d and R_t={(nx+ny)/2-nz}×d. In the expressions, nx is a refractive index in an in-film-surface phase delaying axis direction, ny a refractive index in an in-film-surface phase leading axis direction, nz a refractive index in a film thickness direction, and (d) the thickness (nm) of the film.;COPYRIGHT: (C)2004,JPO