BACK LIGHT, LIGHT GUIDING PLATE, METHOD FOR MANUFACTURING DIFFUSION PLATE AND LIGHT GUIDING PLATE, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

There are provided a backlight, a light guiding plate, a method for manufacturing a diffusion plate and a light guiding plate, and a liquid crystal display device capable of reducing the number of parts and eliminating unnecessary production steps, thereby reducing the cost. The diffusion plate (261) includes a light orientation layer (181) composed of a prism surface having stripe grooves and convex/concave portions arranged in parallel, a diffuser (191) arranged inside, a diffusion layer (182) for diffusing the incident light, and an incident light control layer (271) composed of a prism surface having stripe grooves and convex/concave portions arranged in parallel at the side of a fluorescent tube (131). The diffusion layer (182) is made by the same resin while the diffuser (191) alone is made of a different resin. The prism of the incident light control layer (271) is optimized so as to increase the ratio of the light which has not entered the incident light control layer (271) but has been reflected and re-irradiated to the other portion of the surface of the incident light control layer (271), so that the incident light is effectively guided to the diffusion layer (182). The present invention can be applied to the backlight of the liquid crystal display device.