| 摘要 |
PURPOSE:To perform an easy start of electric discharge and reduce a time required for a restart when a high pressure electric discharge lamp is restarted, by heating at least one of the parts in electrodes provided in the both ends of a luminous tube and applying voltage across the electrodes in said heated state. CONSTITUTION:Main electrodes 2, 3 are arranged in the both ends of a luminous tube 1, and a filament 5 consisting of tungsten is connected to the main electrode 2, further an auxiliary electrode 4 is provided in the vicinity of the main electrode 3. The auxiliary electrode 4 is connected to a lead wire 8, connected to the main electrode 2, through a starting resistor 6, while the filament 5 is connected to a lead wire 9 through a normally-open thermally operated element 14 and impedance element 15. When an electric discharge lamp, after once turned off, is restarted, an electric current flows in the filament 5 through the thermally operated element 14 in a closed state to heat the main electrode 2, then for the thermally operated element 14 to be in an open state, voltage is applied across the main electrodes 2, 3 to start electric discharge. |
