| 摘要 |
PURPOSE:To reduce load of a high-voltage switch, lengthen a life, heighten reliability and simplify constitution by incorporating a preparatory ionization means into a circuit for starting discharge. CONSTITUTION:A capacitor 1 for excitation is charged in advance at low voltage to a degree not to break down laser gas between main electrodes, while a first capacitor 11 is charged at high-voltage fully capable of causing breakdown. And, when a high-voltage switch 4 is turned on, the voltage impressed on the capacitor 31 is impressed on a gap 8 for preparatory ionization to break down the gap 8 for preparatory ionization and generate ultraviolet rays so as to perform preparatory ionization of laser gas between the main electrodes 5 and 6. At the same time, load of the capacitor 11 is shifted to a second capacitor 12 and a high-voltage pulse to be impressed between the main electrodes 5 and 6 becomes overvoltage sufficient to cause breakdown for a time to an extent of a time constant of a circuit 10 for starting discharge. Accordingly, uniform glow-shaped discharge 7 is generated between the main electrodes 5 and 6 combined with preparatory ionization by the gap 8 for preparatory ionization. Thereby, load of the high-voltage switch can be reduced simultaneously obtaining a long life of the switch, high-reliability and simplification of device constitution. |
