| 摘要 |
PROBLEM TO BE SOLVED: To improve productivity, heat radiating property, convenience of use and so on. SOLUTION: Plural LEDs(light emitting diodes) 14 are directly attached to the lower surface of a fixing plate 11. The productivity and the positioning accuracy are improved because thereby conventional fixing of the LEDs with lead wires and fixing members are not necessary any more. Also the fixing plate 11 radiates the heat generated by the LEDs 14. However, as the direct attachment of the respective LEDs 14 to the lower surface of the fixing plate 11 like this results in the directional angle of the optical signal turning out to be limited within a vertically downward narrow range, a diffusion lens 12 diffusing the optical signal with specified light distribution is arranged so as to ensure a wide directional angle for the transmission range of the optical signal and to obtain nearly uniform intensity of the optical signal within a specified range. |
