| 摘要 |
PURPOSE:To maintain the preliminary ionization in an optimum state and to prevent the reduction of the laser output by controlling the outputs of a high-frequency pulse power supply and a main power supply for generating preliminary ionizations on the basis of the value of the discharge load impedance. CONSTITUTION:From a main power supply 5 a voltage is applied between main electrodes 1, 2, whereby a discharge occurs between preliminary ionization electrodes 3a, 3b to generate ultraviolet rays, and on the other hand, a high-frequency, high-voltage pulse train is applied from a high-frequency pulse power supply 11 to pulse preliminary ionization electrodes 10a, 10b, whereby a discharge occurs to generate ultraviolet rays; thus, two preliminary ionizations proceed concurrently. Further, the load impedance of the main discharge space is inputted to an operation control block 12 connected to the high-frequency pulse power supply 11 and the main power supply 5 to control the number of high-frequency pulses applied between the main electrodes 1, 2, whereby an optimum preliminary ionization state is maintained: furthermore the voltage value of the main power supply 5 is controlled to prevent the reduction of the laser output. |
