DIRECT CURRENT LIGHTING METAL HALIDE DISCHARGE LAMP, DIRECT CURRENT LIGHTING METAL HALIDE DISCHARGE LAMP LIGHTING DEVICE, AND LIGHTING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide electrical characteristics and light emitting characteristic which are nearly equal to those of a mercury sealed type metal halide discharge lamp, without substantially using mercury having a large environmental load and the magnitude of an anode can be restrained. SOLUTION: This direct current lighting metal halide discharge lamp is provided with a positive electrode 11 and a negative electrode 12 sealed in an airtight container, a discharge medium sealed in the airtight container while including a first halogenide, a second halogenide and the rate gas, as the first halogenide compound, one or plural kinds of halogenide selected among a group of sodium, scandium and a rear earth group metal is used. As the second halogenide, one kind or plural kinds of halogenide of a metal having a relatively large steam pressure and hard to emit the light in a visible area in comparison with the meal of the first halogenide is used; and a base 8 electrically connected to the positive electrode and the negative electrode and fitted to the end of a metal halide lamp and arranged in the positive electrode 11 side relatively sealed in the airtight container. This lamp is lighted by the direct current without practically sealing mercury.