| 摘要 |
PROBLEM TO BE SOLVED: To reduce the noise of a fan for cooling a liquid crystal panel. SOLUTION: This projection device for projecting color video images by using liquid crystal panels 41-43, while cooling three liquid crystal panels 41-43 by using fans 611-633 for G, R and B panels is provided with a level calculation part 711 for obtaining the luminance level of the R, G and B components of video signals, the level calculation part 721 for obtaining the sound level of sound signals, a fan control part 73 for controlling the rotation speed of the fans 611-633 and a memory 761 for storing the cumulative lighting time of a lamp 21. Then, the rotation speed of the corresponding fan is lowered as the luminance level becomes high, the rotation speed of the fan is raised as the sound level becomes high, and the rotation speed of the fan is lowered as the cumulative lighting time becomes long. Thus, the liquid cryptal panels 41-43 are cooled appropriately, while reducing unwanted noise generated by the fans 611-613.
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