| 摘要 |
PROBLEM TO BE SOLVED: To prevent a projection image display apparatus that controls focal adjustment from causing a fault which is caused when the focal adjustment is controlled with an insufficient quantity of light from a light source. SOLUTION: The projection image display apparatus includes: a discharge type light source 110; an image forming device 120 which forms an original image and modulates light from the light source; a projection optical system 140 which projects light from the image forming device onto a projection screen; a control means 160 which controls the focal adjustment of the projection optical system; and a luminance detecting means 300 which outputs a signal corresponding to the luminance of light reflected from the projection screen onto which the light is projected by the light source or the projection optical system. After the power source is turned on, the control means limits the control of the focal adjustment until the luminance detected based on the signal from the luminance detecting means reaches a predetermined value. COPYRIGHT: (C)2005,JPO&NCIPI
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