METAL HALIDE LAMP

PROBLEM TO BE SOLVED : To provide a metal halide lamp with a high color rendering property obtaining its property by increasing a load of a light-emitting tube as compared with that of conventional high efficiency type lamp, solving such a problem that, sometimes, the arc becomes unstable generating flickers at the time of horizontal lighting in the case of increasing of the lamp voltage up to a 200V class which is almost twice as high as that of a general 100V class. SOLUTION : As for the metal halide lamp at least containing rare earth metal halide like dysprosium iodide as an additive in a light-emitting tube made of quartz having an electrode at each end in which thallium iodide, mercury, and rare gas is enclosed, having a lamp power of not less than 1 KW, and lamp voltage of 200V class, in order to prevent the unstable state of the arc like flickers, it is stipulated that 2.0≤A/d, and B/d≤1.5×10-7, wherein, A[A] is a lamp current at rated lighting, B[mol/cm3] is a total density of rare earth metal halide enclosed in the light-emitting tube, and d[mm2] is a cross section area of an electrode core rod.