| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal halide lamp device in which, prior to the occurrence of a rapid decrease in illuminance of a metal halide lamp, the decrease is reliably detected and replacement of the lamp is performed. SOLUTION: A metal halide lamp device, which includes a metal halide lamp in which iron as a light emitting substance and thallium are enclosed in a quartz glass arc tube, includes a light intensity detecting means for detecting luminous intensity of the thallium. The metal halide lamp device includes: a storage means for storing the luminous intensity detected by the light intensity detecting means; a calculating means for comparing the luminous intensity detected by the light intensity detecting means with a set value that is set on the basis of a luminous intensity at an initial stage of lamp lighting stored in the storage means; and preferably a display means for displaying a fact that the luminous intensity has decreased to the set value or less when the luminous intensity detected by the light intensity detecting means has decreased to the set value or less. COPYRIGHT: (C)2010,JPO&INPIT
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