Optical film, manufacturing method of the same, and polarizing plate and liquid crystal display using the optical film

摘要

An optical film having an inner portion exhibiting an N value defined by the following equation smaller than an N value at a surface of the optical film: N=(nx+ny)/2−nz wherein nx represents an in-plane refractive index in a slow axis direction of the optical film, ny represents an in-plane refractive index in a fast axis direction of the optical film, and nz represent a refractive index in a thickness direction of the optical film.