| 摘要 |
PROBLEM TO BE SOLVED: To improve the lamp starting characteristic of a high pressure discharge lamp which uses a large amount of mercury and in which the amounts of mercury adhering to both electrodes are not equal to each other, to reduce the glow discharge generation time period of the lamp, and to keep electrode sputtering of the lamp to the minimum. SOLUTION: An AC rectangular wave voltage output from a full-bridge circuit 2 is applied to a discharge lamp 4 when the lamp starts. Then, an igniter 3 superposes a high voltage pulse synchronized with a polarity of the AC rectangular wave voltage on the AC rectangular wave voltage for the discharge lamp 4 to start AC discharge. Then, each of switching elements Q2 to Q5 in the full-bridge circuit 2 are fixed to ON or OFF, to apply a DC voltage to the lamp. And, after a specified period of time from the transition to the DC operation, the full-bridge circuit 2 generates an AC rectangular wave voltage, and applies the AC rectangular wave voltage to the discharge lamp 4, to shift the lighting to a steady state. COPYRIGHT: (C)2004,JPO |
