| 摘要 |
PURPOSE:To prevent an irregular movement of the cathode spot and to eliminate an early burn-out or early blackening resulting form the irregular movement of the cathode spot by placing a bypass circuit including an impedance between lead wires or between the wires connected to the lead wires. CONSTITUTION:In a fluorescent lamp unit using a small size fluorescent lamp with a lamp current less than 100mA, a bypass circuit 6 including an impedance is inserted between a pair of lead wires 54 and 55 which are led from an electrode 56, or between wires connected to the lead wires 54 and 55. As a result, the heating at the electrode parts other than the cathode spot is suppressed, the spot position is stabilized, the cathode spot moves from one end to the other end of the filament electrode gradually in order with the passage of the lighting time, and consequently, the electrode never transfers to the unheating electron emission until the majority of the cathode substance is consumed, resulting in a long service life of the fluorescent lamp. |
