| 摘要 |
PROBLEM TO BE SOLVED: To cool an arc tube and cool a sealing part of a discharge lamp at the same time by facing at least one outlet opening of cooling air blast holes toward the sealing part and facing at least one outlet opening of other cooling blast holes toward the surface of a concave reflecting mirror. SOLUTION: A light source unit is arranged within a cooling air flow path, and cooling air is passed through the light source unit to efficiently cool the light source unit. Within the light source unit, cooling air flows from a cooling blast hole 40 in the end of a sealing part 12 of a discharge lamp 10 positioned on the opening side of a reflecting mirror 20. The cooling air effectively cools the end of the sealing part 12, impinges on surface of the reflecting mirror 20, flows along the surface, effectively cools luminescent part 11 of the discharge lamp 10, especially the upper part of the luminescent part 11, and is exhausted from a cooling blast hole 50 of a neck part 21. Cooling air from other cooling blast holes 40 is passed toward the inside of the reflecting mirror 20. |
