| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lamp lighting device for a cinema projector capable of projecting a video whose brightness is reduced during a period between screenings, and stably maintaining arc discharge. <P>SOLUTION: The lamp lighting device includes a lighting circuit which supplies electric energy to a discharge lamp for horizontal lighting, a control part for constant power control or constant current control with the lighting circuit, and current measurement means and voltage measurement means for the discharge lamp. The control part, at normal illumination, lights the discharge lamp by performing constant power control with the lighting circuit. When the control part receives a light-controlling signal, it lowers a lamp power of the discharge lamp, and shifts to a light control illumination which performs constant power control with a light control lamp power. When a voltage of the discharge lamp comes out of a range that is predetermined with a period after shifting to light control illumination as a reference, during the light control illumination, the lighting circuit is subjected to constant current control to illuminate the discharge lamp. When the voltage of the discharge lamp comes into the range that is predetermined with the period after shifting to light control illumination as a reference, the lighting circuit is subjected to constant power control with the lamp power for illuminating the discharge lamp. <P>COPYRIGHT: (C)2012,JPO&INPIT |
