METAL HALIDE LAMP AND LIGHTING EQUIPMENT

摘要

This invention provides a metal halide lamp and a lighting equipment that, despite the fact that mercury is not sealed, can provide electrical characteristics comparable with a mercury-sealed metal halide lamp and can provide luminescent characteristics favorably comparable with the mercury-sealed metal halide lamp. A metal halide lamp (MHL) includes a hermetically sealed vessel (1), a pair of electrodes (2), and a discharge medium sealed in the hermetically sealed vessel. The discharge medium contains a first halide, a second halide, and a rare gas. The first halide is composed mainly of a halide of a luminescent metal and contains a halide of thulium (Tm) sealed at the highest sealing ratio in all of metal halides sealed in the hermetically sealed vessel, and the content of an alkali metal halide in the first halide is less than 10% by mass at the highest. The second halide is composed mainly of a metal halide for constituting a lamp voltage, and the content of the second halide is 5 to 20% by mass based on all of the metal halides sealed in the hermetically sealed vessel. The discharge medium is substantially free from mercury.