| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a metal halide lamp that has a long lifetime by preventing metal halide from infiltrating a sealing part, and further to provide a metal halide lamp turning-on device that can avoid trouble of the sealing part of the metal halide lamp even when a power supply device which turns on the lamp turns on the lamp by switching currents.SOLUTION: There is provided a long arc type metal halide lamp including: iron as a luminescent material in a luminescent tube made of quartz glass; a holding cylinder body which supports a shaft part of an electrode at an end of the luminescent tube; and a molybdenum foil embedded in the sealing part. The holding cylinder body is made of quartz glass with L/I (mm/A) ranging 0.17 to 1.89, where L (mm) is a length of the holding cylinder body, and I (mm) is electric current in the lamp. In addition, metal having higher steam pressure than the iron is charged in the luminescent tube. Further, mercury is charged in the luminescent tube.</p> |
