| 摘要 |
PROBLEM TO BE SOLVED: To avoid tone widely known problem by not only omitting mercury from the viewpoint of environmental protection but completely avoiding or sharply reducing the use of sodium. SOLUTION: This lamp has a rare gas as a buffer gas, a first group of metal halides, and a second group of metal halides. The first group metal halides have a boiling point of 1,000 deg.C or higher, and have at least Dy and Ca as metals. The mol ratio of the two groups of metal halides is 0.1 to 10. The second group metal halides have a boiling point lower than 1,000 deg.C, and have at least one element as metal among In, Zn, Hf, and Zr. The total filling amount of the first group metal halides is 5 to 100μmol/cm3, while the total filling amount of the second group metal halides is 1 to 50μmol/cm3. |
