| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light guide element for illumination which has a high utilization efficiency of light and has less restrictions on size and uniformly illuminate and has less light mixed in reflected light from an illumination object. <P>SOLUTION: A lightguide (20) has an upper face (21) having prism-like protrusions repeatedly formed and a plane lower face (22) and reflects light going in an inside thereof by each protrusion and emits the light from the lower face, and each protrusion has a shape having a first surface (23a) descending along the going direction of light, a second surface (23B) ascending along this direction, and a third surface (23c) ascending along this direction, in order from the leaving side of light. Light emitted from the lower face is generated by the first surface, and progress of light is made to continue by the second surface, and light having transmitted the first surface is made incident again by the third surface. <P>COPYRIGHT: (C)2004,JPO |
