| 摘要 |
PURPOSE:To enhance reliability of an auxiliary discharger by connecting a resonance coil between an auxiliary electrode and a ground or between the electrode and a power source, and providing a resonance circuit in which a frequency of a high frequency power source to be applied between main electrodes is set to a resonance frequency by an equivalent capacity between the main and auxiliary electrodes. CONSTITUTION:An oscillator 1 has a discharge tube 2, and main electrodes 3a, 3b are attached oppositely thereto. Wirings for connecting the electrode 3a, an auxiliary electrode 4 and a resonance coil 8 therebetween constitute an auxiliary discharger. Inductive reactance of the coil 8 and capacitive reactance of an equivalent capacity between the electrodes 3a and 4 are so set that resonance frequency is substantially equal to that of a high frequency power source to be applied between the electrodes 3a and 3b. Even if an auxiliary discharge is cut OFF, resonance of the resonance circuit is restarted, a voltage between the electrodes 3a and 4 is raised, and the auxiliary discharge 7 is immediately recovered. |
