| 摘要 |
PROBLEM TO BE SOLVED: To avoid non-lighting and to improve safety and convenience by annunciating a remaining life of a discharge lamp at an early stage to promptly urge the replacement of the discharge lamp. SOLUTION: In this discharge lamp lighting device 3, a D.C. voltage application part 31 first brings a switch 311 into an on-state to apply a D.C. voltage between electrode filaments 20 and 21 of a discharge lamp 2 immediately after turning on a D.C. power source 1 and before starting an inverter part 30. A preheating part 32 brings a switch 322 into an on-state to heat the electrode filament 21 by supplying a preheating current I2. Next, an emission time detection part 332 measures a voltage V1 between both ends of a resistor 331 and detects an emission time at a point of time the voltage V1 between both the ends and a voltage VL between both ends of the discharge lamp 2 rapidly drop. A life estimation part 34 estimates the remaining life of the discharge lamp 2 by finding a cumulative lighting time from the emission time detected by the emission time detection part 332. Finally, an annunciation part 35 annunciates warning with sound when the discharge lamp 2 approaches the end of its life. COPYRIGHT: (C)2007,JPO&INPIT |
