METAL HALIDE LAMP

摘要

PROBLEM TO BE SOLVED: To prevent a luminous flux maintenance factor form being reduced early due to blackening on the inner face of an arc tube. SOLUTION: This metal halide lamp comprises a light emitting part 1 and an arc tube 3 having a sealed part 2 disposed on both ends. An electrode 4 is disposed on both ends of the arc tube 3. The electrode 4 is connected to a lead-in body sealed on the sealed part 2. In the portion that the electrode 4 is sealed by the sealed part 2, a metallic body 7 is coated on a sealed electrode L from the border of the light emitting part 1 and the sealed part 2 to an introducing body 5. The weight A (mg) ratio of the metallic body 7 to a weight B (mg) of the sealed electrode part L is defined in the range 0.2<=A/B<=1.6.