Abstract: There is provided a light diffusive plate and a light guide plate, in which the generation of deflection, a cause of defective imaging, can be prevented. On both surfaces and/or end surfaces of a light diffusive plate 1 made of synthetic resin, a moisture proof layer 2 made of a material having lower vapor permeability than that of the light diffusive plate 1 is formed to produce a light diffusive plate 3. On both surfaces and/or end surfaces of a light guide plate 1 made of synthetic resin, which has at least on end as a light incident surface and a surface almost orthogonal with it as a light emergent surface, a moisture proof layer 2 made of a material having lower vapor permeability than that of the light guide plate 1 is formed to produce a light guide plate 3.

Abstract: A light-diffusing sheet which can prevent generation of scratches on the surface of the light-diffusing sheet or a surface of another member contacting with the light-diffusing sheet at the time of being used as a constituent member of a backlight unit of a liquid crystal display or transportation thereof, and also can exhibit the light-diffusing performance is provided. The light-diffusing sheet of the present invention has a light-diffusing layer comprising microparticles, wherein the light-diffusing layer has a surface showing a maximum peak height (Rp) of 8.0 ?m or higher in a roughness curve determined by three-dimensional surface profilometry, and mean particle size (?) of the microparticles contained in the light-diffusing layer and thickness (d) of the light-diffusing layer satisfy the relationship: ?/d?0.7.

Abstract: A direct type backlight unit 1 comprising a light source 13, a diffusing plate 14 disposed over the light source, and an optical member 15 disposed on the diffusing plate, or an edge light type backlight unit comprising a light conducting plate and an optical member disposed on the light conducting plate, wherein the surface of the optical member 15 contacting with the diffusing plate or the light conducting plate (henceforth referred to as optical element) is formed from a material containing a thermosetting resin and/or a thermoplastic resin, and polyethylene type wax particles having a mean particle diameter of 4 to 10 ?m. The content of the polyethylene type wax particles is 0.20 to 0.50 part by weight based on 100 parts by weight of resin component of the resin layer.

Abstract: An optical film enhances provide brightness in the frontal direction and light diffusing without using a prism sheet or a lens sheet. Two laminates each produced by providing a light diffusing layer formed from acrylic resin particles and a styrene acrylic copolymer resin binder on a transparent support are superimposed to form the optical film. The styrene acrylic copolymer resin binder preferably has a glass transition temperature of 40° C. or higher. The light diffusing layer 12 preferably contains an acrylic resin binder having a glass transition temperature of 30° C. or lower.

Abstract: Because light diffusing plates constituting backlight units have high moisture absorbency, light diffusing plates cause deformation such as warp, swell and flexure and adversely affect other members such as liquid crystal cells to cause defective images. A backlight unit that does not generate defective images due to such deformation of light diffusing plate is provided. This backlight unit is a backlight unit 1 comprising light sources 13, a light diffusing plate 14 comprising a synthetic resin and disposed on the light sources, and one or more kinds of optical members 15 and 16 for backlight unit disposed on the light diffusing plate, wherein both surfaces of the light diffusing plate 14 shall have an arithmetical mean deviation (Ra) of 0.1 ?m or less according to JIS B0601:1994.