| 摘要 |
PURPOSE:To supply high frequency power to a lamp stably with a high efficiency and make the light-output constant. CONSTITUTION:A lamp lighting device includes a DC power supply part, an inverter part to invert a DC power supplied thereby into a high frequency power, a lamp body 11 in which at least a discharging gas or vapor is encapsulated in a lamp tube, a lighting coil 9 installed in the neighborhood of or within the lamp body and, supplied with a high frequency power from the inverter, and a matching circuit at least composed of a series capacitor for resonance in series connection with the lighting coil and a parallel capacitor 9 for resonance in parallel connection with the lighting coil. The high frequency power is fed to the lamp body through a plasma ring within the lamp body coupled magnetically with the lighting coil, and thereby this discharge lamp of electrodeless type is lighted up. The parallel capacitor 9 is formed by sandwiching a dielectric body 14 having a negative temp. coefficient between two electrode plates 13a, 13a situated opposingly, and it is made possible to reduce the electrostatic capacitance of this capacitor 9 with increase of the temp. |
