Patent ID: 7054049
Filing Date: 2006-05-30
Classification: G02B,G02F

Abstract:
1. An optical film comprising a birefringent layer (a) and a transparent film(b), wherein the birefringent layer is laminated on the transparent film, satisfying all the following formulae (I), (II) and (III): Δn(a) is a birefringent index of the birefringent layer (a) and Δn(b) is a birefringent index of the transparent film (b), respectively represented by the following equations: in the above formulae (II) and the above-stated equations, nx, ny and nz indicate respectively refractive indexes in an X-axis direction, a Y-axis direction and a Z-axis direction in the birefringent layer (a); nx′, ny′ and nz′ indicate respectively refractive indexes in an X-axis direction, a Y-axis direction and a Z-axis direction in the transparent film (b); and the X-axis corresponds to an axial direction exhibiting a maximum refractive index within a plane of the birefringent layer (a) and the transparent film (b), the Y-axis corresponds to an axial direction perpendicular to the X-axis within the plane, and the Z-axis corresponds to a thickness direction perpendicular to the X-axis and the Y-axis.