| abstract |
(57) [Problem] A metal halide lamp has a problem that an arc fluctuates during lighting, that is, an arc and a light emitting portion around the arc fluctuate and cause a flicker of light output. SOLUTION: When a distance between main electrodes of a metal halide lamp is d and a lamp voltage at the time of stable rated lighting is Vla, Vla / d ≦ 24 (where Vla is [V], d Is [mm]. ), The lamp voltage and the distance between the electrodes are specified. The metal halide lamp is The lighting may be performed by a current having a frequency component in which a standing wave is generated in a direction perpendicular to an axis connecting the electrodes. |