Metal halide lamp, its lighting device, light projector and projector device

摘要

PROBLEM TO BE SOLVED: To provide a metal halide lamp, its lighting device and flood light device, and a projector device in which no occurrence of temperature difference allowed in an arc tube, and stable luminosity characteristics are obtained. SOLUTION: In a metal halide lamp 1 DC-lighted at 10mm or less of distance between electrodes, when a distance between a pair of electrodes 21 is designated as L(mm), a distance from the center position between the electrodes 21 to the base end portion of an anode 21a, as N, and a distance between the inner end portions of a discharge space in the facing direction of the electrodes, as 2a, following relationship, 0.1=(N-a)/L=2.3 is to be satisfied. A center position between the electrodes 21 is deflected to the cathode 21b side, and the anode 21a is fitted relatively close the cathode 21b. Therefore, the heat of the anode 21a is transferred to the cathode 12b side by radiation and conduction, the temperature difference between the anode 21a side and the cathode 21b side is lessened in a sealed container. Thereby, the evaporation of metal halide is stabilized so that luminous characteristics become excellent.