MERCURY-FREE DISCHARGE BULB

摘要

There is provided a mercury-free discharge bulb for a vehicle. The mercury-free discharge bulb includes an arc tube. The arc tube includes: a light-emitting portion which is formed of a ceramic tube and includes a light-emitting material and a starting xenon gas filled therein, wherein a filling pressure of the starting xenon gas from about 6 atm to about 18 atm; thin tube portions which are formed at respective ends of the light-emitting portion; and electrodes which are fixed inside the thin tube portions and which are provided in the light-emitting portion so as to face each other. The light-emitting material includes at least a sodium halide and a rare-earth metal halide excluding a scandium halide, and a difference between a vapor pressure of the sodium halide and a vapor pressure of the rare-earth metal halide under an environment of about 1000° C. is about 10 kPa or less.