| 摘要 |
PROBLEM TO BE SOLVED: To provide a planar lighting device which aims at improving the effective use of light from a light source. SOLUTION: A reflecting plate 14 is fitted on a face 6a opposite to a transparent substrate of a light guide body 6 (the rear face of the light guide body 6). On a first face 14a of the reflecting plate which faces a light guide body 6 of the reflecting plate 14, triangular prism convex parts 17 extending toward the direction orthogonal to the light guide body (the direction of crossing the optical axis A) are arrayed in plural number in the longitudinal direction of the reflecting plate 14, to form a convex part row. A reflecting layer 16 is formed on the surface of the convex part row. Light, transmitting the slanted wall of the light guide body 6, is readily reflected in the direction of the light axis A by the reflecting layer 16, easily to become an effective light. With reflecting materials of the conventional technology, much non-effective light is generated radiating toward directions with large angle of sight and, therefore the effective use of light from the light source is limited by that much; but since generation of non-effective light is restrained to be minimum, improvement can aim at in effective use of light from the light source 4. |
