Circuit for preventing destruction of semiconductor laser element, and optical disc device provided with the circuit

An optical disc device, comprising:

• an optical pickup part having a semiconductor laser element;
• an optical-output-controlling circuit part for controlling an optical output of the semiconductor laser element;
• a power source for the semiconductor laser element, the power source supplying to the optical-output-controlling circuit part a light-emitting voltage for causing the semiconductor laser element to emit light;
• and
• a circuit for preventing destruction of the semiconductor laser element, the circuit having the following:
• a light-emission-directing circuit part for outputting a light-emission-directing signal for directing the semiconductor laser element to emit light;
• a voltage-monitoring circuit part for monitoring the light-emitting voltage and, when a judgment is made that the light-emitting voltage is normal, outputting a light-emission-permitting signal for permitting the semiconductor laser element to emit light, the light-emitting voltage being supplied from the power source for the semiconductor laser element to the optical-output-controlling circuit part in order to cause the semiconductor laser element to emit light;
• and
• a light-emission-permitting circuit part for using the optical-output-controlling circuit part to cause the semiconductor laser element to emit light only when the light-emission-directing signal and the light-emission-permitting signal are inputted.