Laser processing apparatus

摘要

When an IGBT (insulated gate bipolar transistor (32)) turns on, a current from a laser power supply unit (102) is supplied via a switching element (32) to an excitation lamp (20) of a laser oscillation unit (100) so that the excitation lamp (20) lights to oscillatorily output a laser beam LB. A switching control unit (50) uses as a main feedback signal a measured-value-of-laser-output signal SL from a laser output measurement unit (38) and uses as a sub-feedback signal for correction an AC component SPc (SIc) of a lamp measured-value-of-power signal SP from a power computing circuit (44) or of a measured-value-of-lamp-current signal SI from a current measuring circuit (46). The switching control unit (50) compares the feedback signals SL, SPc (SIc) with a reference signal Sref having a desired pulse waveform from a CPU (34) to obtain a comparison error. The switching control unit (50) then generates a switching control signal SW for e.g., PWM so as to nullify the comparison error and provides a switching control of the IGBT (32) via a drive circuit (52) in response to the switching control signal SW.