OPTICAL FILM, POLARIZING FILM AND METHOD FOR IMPROVING VISIBILITY ANGLE OF POLARIZING FILM

摘要

PROBLEM TO BE SOLVED: To reduce the leakage of light occurring when an observing direction is tilted from a front in a direction different from absorbing axis directions in the case that the absorbing axis directions of a polarizing plate are disposed perpendicular to each other. SOLUTION: The optical film is prepared by laminating a first phase contrast film having a requirement of (ne-no>0) where an average reflective index in the surface of at least one sheet of film is (no) and a refractive index in the thickness direction thereof is (ne) and a second phase contrast film having a requirement of (nx>ny>=nz) where a refractive index in the surface of at least one sheet of film in the direction providing the maximum refractive index is (nx), a refractive index in the direction perpendicular to that direction is (ny) and a refractive index in the thickness direction thereof.