| 摘要 |
PROBLEM TO BE SOLVED: To restrain the deterioration in life characteristic of a high-pressure discharge lamp in a projection type system to the minimum while applying negative pulses to the lamp current of the high-pressure discharge lamp for a long time. SOLUTION: The projection type system is equipped with: the high-pressure discharge lamp 1; a rotary type color filter 3 divided into a plurality of color segments to separate luminous fluxΦ1 radiated from the high-pressure discharge lamp into a plurality of colors; a reflection type optical element 4 performing grading and modulation according to a video signal to luminous fluxΦ2 passing through the color filter; a projection lens system 6 projecting luminous fluxΦ3 reflected by the optical device to a screen; and a lighting means 5 driving the high-pressure discharge lamp by changing the power level of the high-pressure discharge lamp according to the revolving speed of the color filter and the color switched by the color filter synchronizing with the optical device. The negative pulses shorter than the conventional ones are superposed on the lamp current of the high-pressure discharge lamp to be applied synchronizing with at least one color segment. COPYRIGHT: (C)2007,JPO&INPIT
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