| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to increase the quantity of light radiated from a light guide to the external by simple structure and to uniform the distribution of luminance. SOLUTION: One end part of a light guide 3 is opened in a state opposed to a light source 1 and the end face of the other end part 4 forms a reflection face 3a for reflecting light advanced in the guide 3. The reflection face 3a is inclined to the lower part (side for radiating light to the external) of the guide 3. Therefore the quantity of light to be radiated from the guide 3 downward can be increased and the luminance distribution of the guide 3 can be uniformed. In addition, there are some merits capable of realizing these improvement by simple structure only for inclining the reflection face 3a on the other end part of the guide 3 without almost increasing the number of parts and the number of manufacturing processes and cost up can be suppressed to a minimum. |
