| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical lens used for a tunnel lighting device, which can restrain light unevenness by controlling distribution of light emitted from a light source in a designated direction. <P>SOLUTION: The optical lens 3 includes an incident surface 31 where the light emitted from the light source is incident, and an emitting surface 32 for emitting the light incident to the incident surface 31. The emitting surface 32 takes on a convex outline shape, and a cross-section shape of the emitting surface 32 is made of a plurality of curved lines C1, C2 having different curvature radii. The first curved line C1 having a larger curvature radius is arranged at a location facing to a center part of the incident surface 31, and the second curved lines C2 having a smaller curvature radius each are respectively arranged on both sides of the first curved line C1. According to this structure, part of light from the portion covered with the first curved line C1 of the emitting surface 32 is restrained, and part of light from the portion covered with the second curved lines C2 of the emitting surface 32 can be accelerated, and thus, emitted light from the optical lens 3 can be made uniform. <P>COPYRIGHT: (C)2013,JPO&INPIT |
