| 摘要 |
To provide, in a special situation of a mercury-free lamp in which a luminance flicker tends to occur unlike a mercury-containing lamp, a metal halide lamp having an electrode structure modified so as to suppress the luminous flicker that is suitably used as an automotive headlamp, and an automotive headlamp apparatus incorporating the same. A metal halide lamp includes: a hermetic vessel 1 which is fire resistant and translucent; a pair of electrodes 3, 3 sealed in the hermetic vessel 1 with facing each other at a distant of 5 mm or less, the electrodes each having a shaft part 3a having a diameter of 0.25 mm or more and a tip 3b, which originates an arc, having a curved surface having a radius of one-half or less of the diameter of the shaft part; and a discharge medium essentially containing no mercury, sealed in the hermetic vessel 1, and containing halides of metals including a light-emitting metal in an amount of 0.005 mg/mm<3 >of an inner volume of the hermetic vessel or more and a xenon gas at 5 atmospheres or higher at a temperature of 25° C., in which the metal halide lamp is turned on with a lamp power of 60 W or lower in a stable state.
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