METAL HALIDE LAMP, ITS LIGHTING DEVICE AND CAR HEAD LIGHT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a mercury-free metal halide lamp, its lighting device and a car head light device which are capable of shortening the light-emitting time of a red family at start. SOLUTION: This metal halide lamp 1 comprises a discharge container 2 having a discharge space 2a and seal portions 2b disposed at both edges of the discharge space 2a, and a pair of electrodes 3 having respective protrusions 3c protruded into the discharge space 2a as portions protruded from each seal portion 2b to the discharge space 2a are arranged axially opposed to each other. And also when lighting out after turning on the metal halide lamp 1 for more than 50 hours, free-fluorine 7 adheres to the protrusion 3c in an amount of not less than 0.005 mg and not less than 60% by weight to the whole quantity of existing free-fluorine in the discharge container 2.