| 摘要 |
PURPOSE:To detect the abnormal temperature of the dielectric of a dielectric electrode securely and prevent the dielectric from being damaged by a method wherein a temperature detecting means composed of a temperature sensor and an optical fiber is provided on the dielectric. CONSTITUTION:When the temperature of a dielectric 3a or 3b rises, the temperature of a temperature sensor part 20 rises. The temperature rise is supplied to an optical transmitter/receiver 23 through an optical fiber 21 and the output voltage V1 of the optical transmitter/receiver 23 is elevated. If the output voltage V1 exceeds a certain threshold voltage V2 inputted (-) to the input terminal of a comparator 24, a high level output voltage V3 is outputted to an electric source 9. When the level of the output voltage V3 is high, the application of a radio frequency voltage V4 which is the output of the source 9 to a dielectric electrode 4a or 4b is discontinued. |
