| 摘要 |
PURPOSE: To ensure, to some extent, visibility from a short distance without deteriorating visibility from a long distance, by dividing a condenser lens into a base adjacent to a substrate and a lens main part occupying the residual part, and making the direction angle of the base part larger than that of the lens main part. CONSTITUTION: The center of the lens main part 3a of a condenser lens 3 is positioned to exactly face an LED 2. A base part 3b of the condenser lens 3 is adjacent to a substrate 1. The direction angle of the lens main part 3a is set smaller than that of the base part 3b. The lens main part 3a and the base part 3b may be constituted by using convex lenses different in degree. In another case, the lens main part 3a is constituted by using a convex lens, and the base part 3b is constituted by using a concave lens. Out of the light emitted from the LED 2, the light introduced to the lens main part 3a is converged in a range of small direction angle wherein an optical axis is set as the reference, because the directivity is small. Thereby visibility from a long distance can be kept high. The light introduced to the base part 3b is emitted in a range of large direction angle of this part, so that visibility from a short distance can be attained to some extent. |
