LIGHT-DIFFUSION PLATE

A light diffusion plate is provided to prevent the longitudinal variation of the light diffusion plate even if exposed to an optical source for a long time by improving optical characteristics, such as a transmittance ratio, of the light diffusion plate. A light diffusion plate includes a base layer and a surface layer. The base layer contains at least one kind of first base resin, which is selected from the group consisting of acryl-group resin, styrene-acryl-group copolymer resin, and styrene-group resin, and optical diffusion agent. The surface layer is formed on at least one surface of the base layer and contains at least one kind of second base resin, which is selected from the group consisting of acryl-group resin, styrene-acryl-group copolymer resin, and styrene-group resin, and glass bead. The average diameter of the glass bead lies between 10 address 70mum. The refractive index of the glass bead lies between 1.8 and 2.5.