LOW-PRESSURE MERCURY VAPOR DISCHARGE LAMP

摘要

PROBLEM TO BE SOLVED: To improve light flux rising characteristics at the initial period of lighting. SOLUTION: This discharge lamp has three U-shaped glass tubes coated with phosphor 1 inside, fluorescent tubes 4 which has bulbs 2 connected by a bridge and an electrodes 3 placed at both the end parts of the bulbs 2,a luminant 5 placed at the center of the space surrounded by the arc tubes 4, and an envelope 6 which has a container 6a covering the arc tubes 4 and the luminant 5 and a case 6b. In the case 6b a high frequency lighting circuit 7 to turn on the arc tubes 4 and a switching circuit 8 to turn on the luminant 5 are housed. The switching circuit 8 turns on the luminant 5 at the same time that the arc tube is turned on, and turns off the luminant 5 when the arc tube 4 gets a specified flux value and the inside of the case 6b reaches a specified temperature.