PROJECTION DISPLAY APPARATUS AND METHOD

Not only abnormality of a light output to an exterior but also overturning, vibration, disassembly, deformation, or breakage of a display apparatus including a case and a screen are reliably and promptly detected. A projection display apparatus includes a light source ( 22 ) for generating illumination light, which is provided in a case ( 28 ) having a light-shielding function, a movable aperture ( 23 ) for adjusting the amount of illumination light from the light source ( 22 ), a light valve ( 9 ) for adjusting the amount of light based on an image signal to generate image light for forming an image from the illumination light, a projection optical system ( 10 ) for enlarging the image light from the light valve ( 9 ), and a transmission-type screen ( 29 ) for displaying the image, which is provided to a window of the case ( 28 ). The projection display apparatus further includes first to ninth detectors ( 41 to 49 ) for detecting the abnormality of the light output of the light source ( 22 ) to the exterior and the abnormality of the case ( 28 ) or the transmission-type screen ( 29 ), a warning and alarm unit ( 30 ) for notifying the abnormality by sound or light, and a control unit ( 32 ) for controlling an internal operation when the abnormality is detected.