Patent ID: 7364309

Claim:
An image projection apparatus comprising a light source and projection unit for performing an image display by projection to a projection area on a screen, and a safety mechanism against entry into a passage area of a radiation light from said projection unit toward said projection area, comprising: a detection wave source provided on an opposed plane of an apparatus main body unit to said screen or on said screen; and reflection wave detection means for detecting a reflection wave reflected in a monitoring area, which is located on an outside of said projection area at a distance, after a detection wave is emitted from said detection wave source toward said monitoring area, wherein entry into a monitoring space surrounded by said detection wave, which is arranged so as to wholly surround the radiation light that has been emitted from the projection unit, is detected on a basis of a result of a comparison of a detected level by said reflection wave detection means with a threshold value or a reference region, and wherein said reflection wave detection means comprises: first detection means for detecting said entry into said monitoring space; second detection means for detecting entry into a monitoring space including an area outside of said monitoring space; first alarm means for performing an alarm process if said entry is detected by said first detection means; and second alarm means for performing an alarm process if said entry is detected by said second detection means.