| 摘要 |
PURPOSE:To thin a device by providing diffusing patterns, where the diffusion/ scattering becomes larger as a distance from a light source becomes larger, on at least either of the reflecting layer side of a transparent photoconductive layer and the transparent photoconductive layer side of the reflecting layer. CONSTITUTION:A light diffusing layer 1 is disposed all over the surface between tubular light sources 5, 5. Under the light diffusing layer 1, a transparent photoconductive layer 2 and a reflecting layer 4 are superposed in order. Acryl resin or polyester resin is used as the light diffusing layer 1 for the purpose of uniformly diffusing light emitted from the transparent photoconductive layer 2 over the whole surface. Grid-like diffusing/scattering patterns are screen-printed on one surface of the reflecting layer side of the acryl resin plate in such a manner that the area of a grid-like square becomes larger at every pitch proceding from the light receiving surface toward the center of the photoconductive layer, to be used for the transparent photoconductive layer 2. Therefore, the disposition of the diffusing/scattering patterns can be varied density, or a quantity of the light permeating in the direction of a visual field can be controlled. Consequently, the transparent photoconductive layer thinner than a conventional one can provide a plane luminance equal to or more than that of the conventional one as well as uniformity of the plane luminance, and additionally, a device can be formed thinly. |
