| 摘要 |
<p>PURPOSE:To improve temperature characteristics, by changing a distance between a monitoring photodetector and a light emitting element 1 and/or an angle formed between the monitoring photodetector and the light emitting element in response to the change in ambinet temperature. CONSTITUTION:A photodetector 2 such as a germanium PIN type photodiode, which receives part of light emitted from a light emitting element 1, is attached to a bimetal and the like 4, which are supported with a supporting body 5. The bimetal and the like 4 are attached so that the distance between the photodetector and the light emitting element is shortened and/or the facing angle between the photodetector and the light emitting diode is made parallel, when ambient temperature is increased and the sensitivity of the photodiode is decreased. An automatic control circuit 3 receives the light received in the photodetector and keeps the intesity of the output light of the light emitting element constant. Even if the ambient temperature is changed, errors are not yielded in the signal inputted into the automatic control circuit 3. The error based on the change in ambient temperature is completely compensated. The constant light can be accurately outputted regardless of the change in ambient temperature.</p> |
