| 摘要 |
PURPOSE:To stabilize the light amount of a light emitting element in luminous wavelength by a method wherein the light emitting element and a photo detecting element arranged on the same base are temperature-controlled at the same time and light-amount-controlled. CONSTITUTION:A semiconductor laser generator 1 and the photo detecting element 11 are mounted on the base 2 excellent in thermal conductivity. When the temperature of the base 21 is low, the resistance of a temperature-detecting element 23 increases, and the voltage of an input terminal 25 increases. When this voltage becomes higher than a referance voltage determined by divided resistors 28 and 29, an operational amplifier 30 of a temperature control circuit 24 acts so as to increase the collector current of a transistor 33, resulting in the increase in current of a heater 22, and in temperature of the base 21. On the other hand, when the temperature of the base 21 is high, the collector current decreases as compared with the case of low temperature. As a result, the temperature of the base 21 is kept constant. Therefore, at the time of light amount control, the variation in sensitivity due to the change in temperature of the photo detecting element can be prevented; accordingly, the light amount can be stabilized and at the same time the variation in luminous wavelength of the light emitting element can be prevented. The resistor 29 is made variable 29, and the resistance value can be switched according to regions for device use, so as to switch the control temperature. |
