Patent ID: 8308862
Filing Date: 2012-11-13
Classification: C08J,C08K,C09K,G02B,G02F,Y10T

Abstract:
1. An optical cellulose acylate film comprising a polymer component which is a cellulose acylate obtained by substituting hydroxyl groups of a cellulose by an acetyl group and an acyl group having 3 or more carbon atoms, wherein (i) a substitution degree A of the acetyl group and a substitution degree B of the acyl group having 3 or more carbon atoms satisfy the following formulae (I) and (II): and (ii) an elastic modulus E(MD) in a casting direction and an elastic modulus E(TD) in a casting width direction satisfy the following formulae (III) and (IV): wherein Re(λ) and Rth(λ) defined by the following formulae (IX) and (X) satisfy the following formulae (XI) and (XII): wherein Re(λ) is a front retardation value (unit: nm) at a wavelength of λ nm, Rth(λ) is a retardation value (unit: nm) in a film thickness direction at a wavelength of λ nm, nx is a refractive index in a slow axis direction in a film plane, ny is a refractive index in a fast axis direction in a film plane, nz is a refractive index in a film thickness direction, and d is a thickness of the film, and wherein Re