| 摘要 |
PURPOSE:To eliminate the relative position dislocation of a light emitting part and a light receiving part and to miniaturize a device by arranging two light detectors at an area where a backward light in a header is not synthesized and arranging a light adsorption element at the area where it is synthesized. CONSTITUTION:Two light detectors 15a and 15b are arranged in parallel to the light axis of a backward light or inclined at the area in a header 5 where backward lights 13a and 13b emitted from two light sources of a semiconductor laser array 6 are not synthesized. Thus, a part of a backward light 13a is made incident on a detector 15a and a part of a backward light 13b is made incident on a detector 15b respectively and individually. The backward light not received by the detectors 15a and 15b is made incident on a color glass filter 17 arranged vertical to the light axis and absorbed without reflection. The light output of forward lights 12a and 12b to emit from the above-mentioned light source is controlled by the output signal of the detectors 15a and 15b. |
