| 摘要 |
PROBLEM TO BE SOLVED: To provide the long service life by using a detector capable of supplying a signal corresponding to the detected lamp operation parameter to a control circuit, having a six-port directional coupler connected between an RF power supply source and a lamp, and detecting the forward and reflected power, and allowing them to be corresponded to the lamp operation parameter. SOLUTION: This lamp is covered with a reflective film 5 capable of defining an aperture 16 by an electrodeless lamp bulb 14. A loop 17 for inductive connection is driven by a solid state RF supply source 18 to supply the lamp power. A directional coupler supplies a signal representing the forward power and the reflected power to an RF control circuit. The RF supply source 18 is constituted so us to adjust a predetermined operating frequency on the basis of a low voltage DC signal. Whereby the RF control circuit provides the coherent lighting of the lamp, the quick operation of the lamp for full power, and the stable lamp operation over a life period of the lamp. |
