Patent ID: 7497598

Claim:
A light diffusion film comprising: a transparent substrate, and a light-diffusing layer provided at least on one surface of the transparent substrate either directly or through another layer, the light-diffusing layer comprising an ionizing radiation curing resin and an ultraviolet light absorber and having, on its surface, fine irregularities that have a function of diffusing light, wherein when being incorporated in a 21-type (21-inch) surface light source unit having a direct-type surface light source member that contains, as a light source, 12 cold cathode ray tubes arranged in parallel, the light diffusion film makes the center portion of the surface of the surface light source unit show a change in hue (b*), based on the L*, a*, b* color system according to JIS-Z-8729, of not more than 2.0 as a difference between the hue values determined right after the incorporation of the light diffusion film to the surface light source unit and after 5000-hour lighting of the light source.