OBJECT DETECTING APPARATUS INCLUDING PHOTOSENSORS FOR RESTRICTED DETECTION AREA

摘要

An object detecting apparatus of a restricted detection area, which comprises means including many light emitters sequentially actuated for projecting sequential light beams, first means for receiving the light beams directly from the light projecting means, second means for receiving any reflected part of the light beams back from an object in the area, means for receiving an output of the first light receiving means and providing a reference phase for the projected light beams, means for receiving an output of the second light receiving means and providing a detection phase for the reflected part of the light beams, means for continuously actuating only a part of the light emitters which corresponds to the reflected part of the light beams received, and means for restricting the detection area by restraining an output from a phase difference discriminating means to an alarming means when a difference between the reference and detection phases is not within a predetermined range, whereby the detection area can be restricted to a desired range, and the alarm means can be retained non-operative unless the object remains continuously in the area to avoid any malfunction with any transitory object, while the light projecting means actuated in a very short time sequence accelerates the detecting operation with minimized power consumption.