Patent ID: 8477275

Claim:
An optical film comprising: a cellulose acylate film; and at least two layers of an optically anisotropic layer A and an optically anisotropic layer B, wherein the cellulose acylate film satisfies the following formulae (I) and (II), Re(548) of the optically anisotropic layer A is from 80 to 190 nm and the slow axis of the optically anisotropic layer A is at 45°±10° with respect to the film conveying direction, and the optically anisotropic layer B satisfies the following formulae (III) and (IV): 0.1≦DSA≦2.0 Formula (I): 1.0≦DSB≦2.9 Formula (II): (wherein DSA represents the acetyl substitution degree, and DSB represents the benzoyl substitution degree); −10 nm≦Re(548)≦10 nm Formula (III): Nz≧10 Formula (IV): (wherein Re(λ) represents the in-plane retardation at a wavelength of λ, and Nz=(nx−nz)/(nx−ny), wherein nx, ny and nz represent the refractive indexes in the film conveying direction, the direction perpendicular to the film conveying direction, and the thickness direction, respectively).