| 摘要 |
PURPOSE:To eliminate the need to adjust a control part and also to give interchangeability by providing a temperature detecting element near the light emitting element of a light emitting unit with a temperature control element for keeping a temperature constant and by connecting a resistance element to it in series or parallel. CONSTITUTION:Near laser diode 1-1 inside of light emitting unit 1, thermistor 1-3 as a temperatute detecting element is arranged and by correcting resistance 1-2 connected to it and resistor 4, power voltage Vcc is divided to obtain voltage VT. Next, voltage Vcc is divided by resistors 5 and 6 to reference voltage VR against a desirable temperature, which is amplified by error amplifier 3 and then applied to Peltier element 1-4 serving as a temperature control element via driving part 2. In this way, the surface temperature of diode 1-1 is controlled by element 1-4 and at the same time, output VT of thermistor 1-2 is applied to window comparator 7, where it is compared with reference voltage VS1 of reference signal generator 14, thereby controlling the output of element 1-4. |
