| 摘要 |
PROBLEM TO BE SOLVED: To reducing the cost by dispensing with an image pickup means, and to heighten the detecting accuracy. SOLUTION: A driving circuit 23 drives LEDs 1 to 12 according to a lighting control signal from a control part 23. The LEDs 1 to 12 are caused to radiate a plurality of beams in different timing to each of a plurality of separate areas in a designated monitoring region through lenses 31, 32 by the above drive. Reflected light from a retroreflection material 42 provided on a stick 41 is received by a PIN photo diode 13 through a lens 33. A determining part 26 determines whether the retroreflection material 42 exists within the monitoring region or not according to a photo detecting signal from the PIN photo diode 13, and outputs a sensation signal if it exists.
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