| 摘要 |
PURPOSE:To detect an arc discharge with a high resolution, by detecting pulse waveforms of a current detection voltage between the electrodes for laser oscillation, comparing said pulse waveforms with pulse waveforms delayed by several cycles, and detecting the occurrence of the arc discharge based on the difference. CONSTITUTION:A circuit 9 in a laser discharge section is provided with a DC current transformer 10 for detecting the total discharge current between discharge electrodes 1 and converting in into a current detecting voltage. The voltage is inputted into a comparator 13 through a circuit 11 while it is also inputted into a comparator 13 via a delay circuit 12. The voltage waveforms 2 and 3 of these inputs are compared so that an arc is detected based on the difference therebetween and an arc detection signal 14 is outputted. |
