| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-quality surface light source by eliminating various luminance nonuniformities accompanied by use of a small number of primary point light sources to reduce the power consumption of surface light sources. <P>SOLUTION: A photo conductive plate 4 guides light from LEDs 2, and has a light incident end surface 41 through which the light from the LEDs enters, and a light outgoing surface 43 from which the guided light goes out. In the plate 4, a plurality of lens rows, arranged in parallel with each other and extending in the direction (X direction) of directivity of the incident light into the photo conductive member in the plane parallel with the light outgoing surface 43, are formed on the back surface 44. In the vicinity of the LEDs 2, the cross-sectional shape perpendicular to the extending direction of the plural lens rows is such that the distribution proportion of the absolute values of the tilting angles of ≥20°and ≤50° made by the tangent in every infinitesimal region of the cross-sectional shape and the surface on which the lens rows are formed, is designed to be ≥10%. A light deflection element 6 disposed adjacently on the light outgoing surface 43 is provided with a plurality of lens rows 61a on the light incident surface 61 thereof which lens rows extend in the direction parallel with the light incident end surface 41 and are parallel with each other. <P>COPYRIGHT: (C)2004,JPO |
