HIGH-PRESSURE DISCHARGE LAMP, HIGH-PRESSURE DISCHARGE LAMP OPERARING DEVICE, AND HEADLAMP DEVICE FOR AUTOMOBILES

摘要

The present invention relates to a high-pressure discharge lamp, a high-pressure discharge lamp lighting device using the same and an automotive headlamp apparatus using the same, and an object of the invention is to use substantially no mercury and to reduce the discharge flicker. A high-pressure discharge lamp includes: a discharge vessel (1) having a hermetic vessel (1a) having a discharge space (1c) therein and a pair of electrodes (2), (2) hermetically provided at opposite ends of the discharge space (1c) in the hermetic vessel (1a) with facing each other at a distance of 5 mm or less; and a discharge medium substantially containing no Hg, sealed in the hermetic vessel (1a), and containing xenon gas at 3 atmospheres or higher and at least two of halides of light-emitting metals including iodides of Na, Sc and rare earth metals, in which the high-pressure discharge lamp is kept on with a lamp power of 50 W or lower in a stable state, and the temperature T ( DEG C) of the electrode (2) at a point at a distance of 0.3 mm from the tip end to the base end in the stable state and the amount A (mol/cc) of free iodine produced when the lamp is turned off after 100 hours of on-time satisfy the formula (1): T<2>/A > 10<11>. <IMAGE>