Patent ID: 7292047
Filing Date: 2007-11-06
Classification: H01J,H03H,H05H

Abstract:
1. A high-frequency power source for supplying high-frequency power to a load in which a reflection characteristic for the high-frequency power varies with time, the power source comprising: a frequency-variable power generator for generating the high-frequency power; a power detector for detecting a high-frequency power which goes into the load and a high-frequency power which is reflected by the load; a reflection coefficient calculator for calculating a reflection coefficient based on the detection by the power detector of the power which goes into the load and the power which is reflected by the load; a power supply controller for causing the power generator to generate high-frequency powers at various frequencies within a predetermined frequency range for obtaining a frequency that gives a minimum value to the reflection coefficient calculated by the reflection coefficient calculator; the power supply controller also causing the power generator to generate a high-frequency power of the obtained frequency for supply to the load; wherein the power supply controller includes: a detection range setting unit for setting a detection range narrower than the predetermined frequency range, with respect to a predetermined initial frequency selected from the predetermined frequency range; a frequency setting unit for setting two frequencies within the detection range set by the detection range setting unit; a frequency determining unit for causing the power generator to generate high-frequency powers at the two frequencies set by the frequency setting unit, and selecting one from the two frequencies whose reflection coefficient is smaller than the other, based on the reflection coefficients calculated by the reflection coefficient calculator; and a detection process controller for repeating a cycle of: setting the detection range by the detection range setting unit for a frequency determined by the frequency determining unit; setting the two frequencies by the frequency setting unit; and selecting a frequency having a smaller reflection coefficient, by the frequency determining unit until a smallest reflection coefficient is found.