| 摘要 |
PURPOSE:To eliminate unnecessary charge, by using a tubular light source emitting light partially and controlling the part which the tubular light source emits light by varying the voltage or current of the light source. CONSTITUTION:In a tubular electric discharge lamp 21, the distance between an electrode A27 and an electrode B28 is varied in the center part 31 and both end parts 32. When a switch A24 is turned off and a switch B25 is turned on, only both ends 32 of the lamp 21 emit light and control by a current controlling resistance A22 to a necessary current value. When the switch A24 is turned on, current controlling resistances A22 and B23 are made parallel, and the current flowing to the lamp 21 becomes larger, and the voltage between electrodes of the lamp 21 rises, and discharging is started also at the electrode part of the center part where discharging was not performed. |
