| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical compensation sheet having a cellulose acetate film improved in the expansion of an angle of visibility and greatly improved in productivity and an optically compensated liquid crystal display device. <P>SOLUTION: The optical compensation sheet has optically biaxial cellulose ester and satisfies all conditions of all of the following (A) to (D): (A) The degree of acetyl group substitution of the cellulose ester, defined as A, and the degree of propionyl group substitution thereof, defines as B, are required to be 2.5≤(A+B)≤2.8 and 0≤B≤1.0. (B) The retardation (R0) at a wavelength 590 nm expressed by R0=(Nx-Ny)×d is required to be 20 to 70 nm (where Nx denotes the maximum reflective index within face, Ny denotes a refractive index in a direction orthogonal with Nx within face and (d) denotes a film thickness). (C) The retardation (Rt) at a wavelength 590 nm expressed by Rt=((Nx+Ny)/2-Nz) is required to be 70 to 400 nm (where Nx and Ny denote the maximum reflective index within face, Ny denotes a refractive index in a direction orthogonal with Nx within face and Nz denotes a refractive index in the thickness direction of the sheet). (D) The sheet is required to have a tacky adhesive layer having an average refractive index 1.40 to 1.55. <P>COPYRIGHT: (C)2004,JPO |
