Patent ID: 7382101
Filing Date: 2008-06-03
Classification: H05B,Y02B

Abstract:
1. A lighting system including: a metal halide lamp having an arc tube housed within an outer tube; and a lamp lighting device for operating the metal halide lamp, the lamp lighting device comprising: a power supply unit operable to supply an electric power to the metal halide lamp; a detecting unit operable to detect an electrical property of the metal halide lamp; a judging unit operable to judge, based on the detected electrical property, whether a currently occurring discharge is in either of (i) an outer-tube discharge state in which a discharge occurs inside the outer tube but outside the arc tube and (ii) a state preceding the outer-tube discharge state; and an instructing unit operable to instruct the power supply unit to suspend or reduce the electric power supply to the metal halide lamp upon a judgment by the judging unit that the currently occurring discharge is in either of the outer-tube discharge state and the preceding state.