| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that visibility is spoiled, the life of a light source lamp is shortened and power consumption gets high because a projection screen is too bright when screen size is made small in the conventional projector device. SOLUTION: By adjusting the brightness of the light source lamp by a light source lamp output control means linked with the focal distance of a zoom lens detected by a focal distance detecting means, the brightness on the screen is kept nearly the same specified brightness even when the size of the projection screen is changed. Especially, when the projection screen is made small, output from the light source lamp is reduced.
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