BEAM IRRADIATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a beam irradiation apparatus capable of smoothly monitoring the position of irradiation with a laser beam while reducing an electric power consumption and lengthening the life of semiconductor lasers. SOLUTION: A semiconductor laser 100 emits spontaneous emission light of a laser oscillation threshold value or less during the period of pulse emission. The spontaneous emission light is split by a beam splitter 400 and received by a PSD 600. An output current from the PSD 600 is converted into a voltage signal by an I/V conversion circuit 60. A PSD signal processing circuit 70 outputs a position voltage signal corresponding to the position of light reception of split light on a PSD light reception surface on the basis of the voltage signal. An ADC 80 samples position voltage signals during the light emission period of spontaneous emission light and outputs sampled data to a DSP 10. The DSP 10 detects the position of irradiation with a leaser beam at each timing of pulse emission on the basis of the sampled data. COPYRIGHT: (C)2008,JPO&INPIT