| 摘要 |
PROBLEM TO BE SOLVED: To form illuminating light having a good color balance in a light source unit prepared with a discharge lamp used as a light source for a projection display unit, etc., and a reflector. SOLUTION: A discharge lamp 10 is provided with an emission part 17 in which metal halide is enclosed, and an electrode sealing part 19 having an approximately rectangular section. the discharge lamp 10 is so mounted to a reflector 21 that long sides of the rectangular section of the electrode sealing part 19 are approximately paralled to a plane approximately perpendicular to a plane 27a which has a tube axis 10a of an emission tube as one side and is level to vent holes 27 the reflector 21. Accordingly, cooling air from the vent holes 27 is flowed around the emission part 17 approximately every. Consequently, the emission part 17 can be cooled approximately evenly, and a temperature distribution within the emission part 17 can be uniformized, also the emission part 17 can be prevented from breaking by thermal stress. |
