| 摘要 |
PROBLEM TO BE SOLVED: To enable a passage sensor to detect the passing position of a passing object without arranging sensors on the top side, bottom side, right side, and left side by detecting the passing object by means of two or more light projecting and receiving units and calculating the passing position from the intersection of lines respectively drawn from the positions of the units at detecting angles. SOLUTION: Light projecting and receiving units 11 are vertically arranged at a prescribed interval. A regressive reflecting plate 12 is commonly used for the units 11. When no passing object 13 exists, the light beams projected from the first and second light projecting and receiving units 11 for scanning are reflected by the reflecting plate 10 and the reflected light beams are continuously received by means of the units 11, but, when a passing object 13 exists in the scanning area, the light beam projected from the first unit 11 is intercepted by the object 13 at an angleθ1 and no reflected light beam returns to the first unit 11. Similarly, the light beam projected from the second unit 11 is intercepted by the object 13 at another angleθ2 and no reflected light beam returns to the second unit 11. Therefore, when lines are respectively drawn from the positions of the units 11 at the anglesθ1 andθ2, the position of the object 13 can be calculated as the intersection of the lines.
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