Patent ID: 8852697

Claim:
A cellulose acetate film comprising: a cellulose acetate having an acetyl substitution degree of 2.0 to 2.5; and at least one compound having a structure represented by Formula (1) and having a mixing ratio of a component exhibiting m=0:a component exhibiting m>0 of 45:55 through 0:100, a content of the compound being 5 to 15% by mass based on a mass of cellulose acetate, (HO) m -G-(X 1 —R 1 ) n Formula (1) wherein G represents a residue of a mono- or di-saccharide, X 1 represents —O—, R 1 represents —CO—R 2 , R 2 represents an aliphatic group or an aromatic group, m represents a total number of a hydroxyl group directly bonded to the mono- or di-saccharide, n represents a total number of OR′ group directly bonded to the mono- or di-saccharide, 3≦m+n≦8, and n is not zero, wherein the compound represented by Formula (1) exhibits an average log P value of 7.5 or more, wherein an in-plane retardation Ro of the film defined by the following Equation (I) is in the range of 30 to 200 nm, and a thickness direction retardation Rt of the film defined by the following Equation (II) is in the range of 70 to 300 nm, Ro =( nx−ny )× d, Equation (I) Rt ={( nx+ny )/2 −nz}×d, Equation (II) and in the equations, nx is an in-plane refractive index in the slow axis direction of the film, ny is an in-plane refractive index in the fast axis direction perpendicular to the slow axis direction of the film, nz is a refractive index in the film thickness direction of the film, and d is a thickness (nm) of the film, wherein the cellulose acetate film comprises 5 to 15% by mass based on the mass of the cellulose ester of a compound represented by Formula ( 1 ) and exhibiting an average log P value of 7.5 or more.