| 摘要 |
PURPOSE: To suppress the rise of the temperature of the assembly of light emitting elements for optical space transmission of the data transmission by a hand- shaking. CONSTITUTION: The assembly 5 of light emitting elements is provided with a thermistor 8 for temperature detection and a pulse signal 39 with a duty cycle reduced as a temperature 9 becomes higher is obtained by a voltage control pulse generator 30. When a set temperature 19 and the temperature 9 are compared and the temperature 9 exceeds the set temperature, a comparator output 29 is obtained from a comparator 20. In a power limit signal generator 50, the pulse signal 39 is used as a power limit signal 54 for a period when the comparator output 29 exists. When the temperature 9 is low, no power limit is applied. When the temperature 9 is high and exceeds the set temperature 19, a transmission can be performed for only a period of the pulse having small duty cycle. Also the fluctuation of an ambient temperature can be coped with. |
