| 摘要 |
PROBLEM TO BE SOLVED: To suppress the generation of flickers, and to suppress the degradation of brightness in a projection type picture display device using an AC lighting lamp and a color wheel. SOLUTION: A color wheel (3) has segment angles which are all almost 120°, and a rotation driving circuit (21) controls the rotating speed of the color wheel (3) to be almost twice or more as fast as a vertical synchronizing frequency Fin of a video signal, and the frequency of driving current of a lamp (1) by the lamp power source circuit (21) is set so as to be almost 3/4 times of the rotating speed of the color wheel, and a modulator driving circuit (23) generates at least a long blanking period and a short blanking period alternately when the frequency Fin of the vertical synchronizing signal of the video signal is not less than a prescribed value, and the lamp power source circuit (21) switches the polarity of the driving current in the long blanking period. COPYRIGHT: (C)2003,JPO
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