| 摘要 |
PURPOSE: An optical film, a polarizing optical film, and an image display device are provided to widen a viewing angle and enhance durability by stretching a polymer film including a polycarbonate resin and a styrene resin. CONSTITUTION: An optical film is obtained by stretching a polymer film including a polycarbonate resin and a styrene resin. A photoelastic coefficient is 2.0x10¬-11 to 6.0x 10¬-11 m¬2/N. A three dimensional refractive index is controlled so that an Nz coefficient represented with Nz=(nx-nz)/(nx-ny) satisfies a relationship of Nz<=0.9 and a front retardation (Re)=(nx-ny)xd satisfies a relationship of Re>=80 nm, when a direction where a refractive index in a film plane gives maximum is defined as X-axis, a direction perpendicular to X-axis as Y-axis, a thickness direction of the film as Z-axis, and when refractive indexes in each axial direction are defined as nx, ny, and nz, respectively, and a thickness of the film is defined as d(nm). |
