| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a light distribution pattern suitable for a lighting device for a tunnel which has improved light distribution characteristics of the lighting device for a tunnel that uses an LED with a simple structure, using a simple constitution. <P>SOLUTION: There is provided the lighting device for a tunnel which includes an instrument container (14); a translucent cover (12), provided with a lens element portion (17) covering a front, and an internal space (18) formed with both, wherein an LED light source unit (11) is included in the internal space (18); the LED light source unit (11) is arranged so that a plurality of LED elements (1) are dispersed in a non-dot-matrix form; an incident side lens cut (5) is constituted of a parallel cross-sectional triangle-shaped prisms group (6); an emission side lens cut (7) is made of a convex prism (8); and the cross-sectional triangle-shaped prism group is made to have a plane (5a) that is substantially identical to and has an acute angle with respect to a reference plane (L). As a result, the light distribution pattern with reduced luminance unevenness is obtained, even if a reflecting mirror is not actively installed. <P>COPYRIGHT: (C)2011,JPO&INPIT |
