| 摘要 |
PROBLEM TO BE SOLVED: To provide a lamp for vehicle having excellent light emitting efficiency at a low power by sealing the ScI3-NaI-based metal, and setting the electrode diameter in a specified range in the rated power set in a specified range. SOLUTION: An electrode is structured so that flow-out of the heat from the electrode can be prevented so as to sufficiently raise the temperature of a light emitting tube by setting a diameterΦn of a pair of first electrode and second electrode 20 to be inserted into an arc chamber electrically connected to a molybdenum foil 21 so as to beΦn<=0.25 mm. In the case where the first electrode and the second electrode 20 are respectively formed of an electrode part 22 and an electrode tip part 23, assuming diameter of the electrode part 22ΦS mm, and diameter of the electrode tip part 23 formed into a spherical shapeΦP mm, and by settingΦS<=ΦP, since the tip of the electrode is formed into a shape having a cross sectional area to be increased and the heat hardly to flows out, lowering of the light emitting efficiency due to the reduction of the input power can be prevented.
|
