| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lighting device of constant-brightness illumination, high directivity in light beam, and high utilization of the light beam. <P>SOLUTION: The lighting device comprises a light source 201, a lightguide plate 202, and a reflecting plate 203. The lightguide plate 202 is provided with multiple grooves 207 on its rear surface 202a which directs the light from an incident surface toward an exit surface. The multiple grooves 207 at the part closer to the incident surface and the part closer to the end on the side opposite to the incident surface have a narrow pitch P2 compared to a central part. The light quantity advancing toward the exit surface becomes larger at the lightguide plate at the part closer to the incident surface and the part closer to the tip end, thus brightness distribution is constant over the entire light emission surface. <P>COPYRIGHT: (C)2004,JPO |
