LIGHT DIFFUSION PLATE, OPTICAL ELEMENT, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a light diffusion plate and an optical element which hardly reduce visibility owing to decreases in front-directional contrast and luminance and hardly cause blurring and defocusing of an image due to interference of display light even when applied to a transmission or reflection type liquid crystal display device, etc. and to provide a liquid crystal display device which uses them and has superior display performance such as a field angle and visibility. SOLUTION: This light diffusion plate 1 is used, which is formed of a double refraction film 11 in which fine areas (a) different in thickness-directional double refraction characteristic are dispersed and distributed and has refractive index differencesΔn<1> andΔn<2> of >=0.03 (Δn<1> ) in the thickness direction of the film and <=80% of theΔn<1> (Δn<2> ) in the plane direction of the film between the fine areas and other parts of the double refraction film. Consequently, diffusion is suppressed for vertically incident light and large diffusibility is obtained for oblique incident light, thereby obtaining the light diffusion plate which diffuses the oblique incident light selectively and preferentially and is easily manufactured.