METAL HALIDE LAMP FILLED WITH MINUTE AMOUNT OF TlI FOR IMPROVING LIGHT CONTROL CHARACTERISTICS

PROBLEM TO BE SOLVED : To provide a metal halide lamp which has a higher efficiency and a better color performance under a light dimming state. SOLUTION : The metal halide lamp contains a discharge chamber, in which a pair of electrodes are provided inside, and an ionization substance filled in the discharge chamber, and the ionization substance contains metal halide including at least magnesium halide and sodium halide, rare earth halide, and thallium iodide. The molar amount of thallium iodide is 0.5-5% of the total molar amount of all halide existing in the discharge chamber.