| 摘要 |
PURPOSE:To reduce electric power consumption and lengthen a life, by specifying lead wires connected to auxiliary electrodes oasto be connected to starter circuit sides, and by specifying resistance of filaments to be low. CONSTITUTION:Lead wires connected to auxiliary electrodes 2, 2' for current collection are specified to be connected to starter circuit 8 sides so that most of electrons flow into the auxiliary electrodes when the electrodes are at the anode phase. Since the starter circuit 8 is open during the lighting operation of a lamp, the electrons having flowed into the auxiliary electrodes 2, 2' flow from other lead wires to a power supply 10 through filaments 3, 3' so that the filaments are heated at the anode phase which changes to the cathode phase as the temperature of the filaments is high. At the cathode phase, electrons are emitted from emitters held by the filaments 3, 3'. At that time, an intense electric field area called cathode drop area is created in front of the cathode so that the electrons are emitted by ion bombardment. The electric field at the high-temperature portion of the emitter is weak, and the electric power loss at the cathode drop area is small. Since the ion bombardment is reduced, the speed of consumption of the emitter is lowered so that the life is long and the decrease in luminous flux is small.
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