| 摘要 |
PROBLEM TO BE SOLVED: To improve a light beam buildup characteristic by sealing xenon gas at a specific pressure in a luminescence section sealed with specific quantities of mercury and halogen gas. SOLUTION: This high-pressure mercury lamp 1 has a luminescence section 2 provided with a pair of electrodes 4 in it and sealed with mercury, halogen gas and xenon gas. The sealed quantity of mercury is set to the range of 0.12-0.35 mg/mm3, and at least one kind of chlorine, bromine and iodine is sealed in the range of 10-7-10-2 mol/mm3 as the halogen gas. The xenon gas is sealed in the range of 2.0×105-2.0×106 Pa. The electrodes 4 are mainly made of tungsten and contain potassium oxide 12 ppm or below, the luminescence section 2 is made of quartz glass, and the moisture (OH group) content in the quartz glass is preferably set to 3 ppm or below. Electrode coils made of tungsten having the diameter of 0.25 mm and the potassium oxide content of 5 ppm or below are provided at the tip sections of the electrodes 4.
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