Optical film having low chromaticity variation and quarter wavelength plate, and liquid crystal display using the same

An optical film comprising:

• a polarizing plate;
• and
• a brightness enhancement film comprising a layer having a circularly polarized light separating function, and a quarter wavelength plate;
• wherein the quarter wavelength plate comprises
• a retardation film satisfying nxr>nyr=nzr, and
• a liquid crystal layer satisfying nzc>nxc≧nyc,
• where “nxr, nyr, nzr” and “nxc, nyc, nzc” indicate refractive indices in an X-axis direction, a Y-axis direction and a Z-axis direction in the retardation film and the liquid crystal layer, respectively, with the X-axis direction being an axial direction exhibiting a maximum refractive index within a plane of the retardation film or the liquid crystal layer, the Y-axis direction being an axial direction perpendicular to the X axis within the plane and the Z-axis direction being a thickness direction perpendicular to the X axis and the Y axis, and
• wherein a maximum chromaticity difference Δxy(max) of in-plane transmitted light of the optical film is about 0.008 or smaller after the optical film is attached to a glass plate and allowed to stand at 70° C. for 120 hours.