Patent ID: 9377571
Filing Date: 2016-06-28
CPC Classification: G02B,G02F

Claim Text:
1. An optical film, comprising: a laminate comprising a positive biaxial phase retardation layer, and an optical anisotropic layer selected from the group consisting of a positive uniaxial phase retardation layer, a negative uniaxial phase retardation layer, a positive biaxial phase retardation layer, and a negative biaxial phase retardation layer; wherein the positive biaxial phase retardation layer and the optical anisotropic layer are in direct contact, separated by an adhesive, or separated by a pressure-sensitive adhesive, wherein an optical axis of the positive biaxial phase retardation layer is perpendicular to an optical axis of the optical anisotropic layer, and wherein “perpendicular” includes an error within approximately ±15 degrees and “optical axis” refers to a slow axis; wherein the positive uniaxial phase retardation layer satisfies following Expression 1, the negative uniaxial phase retardation layer satisfies following Expression 2, the positive biaxial phase retardation layer satisfies following Expression 3, and the negative biaxial phase retardation layer satisfies following Expression 4: wherein Nx, Ny and Nz respectively refer to a refractive index of an x-axis direction, a refractive index of a y-axis direction, and a refractive index of a z-axis direction of the positive uniaxial phase retardation layer, the negative uniaxial phase retardation layer, the positive biaxial phase retardation layer, or the negative biaxial phase retardation layer, and “z-axis”refers to a thickness direction of the optical anisotropic layer, “x-axis” refers to a direction parallel to the slow axis of the optical anisotropic layer, and “y-axis” refers to a direction parallel to the fast axis of the optical anisotropic layer; wherein the laminate satisfies Expressions 5 to 7: wherein |R wherein R(550) is in a range from 100 nm to 250 nm.