| 摘要 |
PURPOSE:To detect a stationary body securely by measuring the distance of a body to be detected by triangulation using plural detection beams, and then detecting the position of said body in a detection area or whether or not it is present in the area. CONSTITUTION:Plural projection beams P are projected on the specific area by a projecting means 3 provided, for example, above a door 7 and a photodetecting means 4 is provided which photodetects reflecting light beams R of each projection beams P individually. When the body to be detected, e.g. human body enters the detection area, the projection beams are reflected by the human body. The reflected light beams R are received by the light receiving means 4 to detect the incidence position, and the distance from the projecting means to the object body is detected by triangulation based upon apparent angles between the projection light beams fro detection and reflecting light beams, thereby detecting the position of the object in the detection area or whether it is present or not. When it is discriminated that the body is present, an operating signal is outputted and the door 7 is open.
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