| 摘要 |
PROBLEM TO BE SOLVED: To sense a vehicle, preventing a sensing failure, by using fewer light emitting devices and light receiving devices. SOLUTION: Each of a plurality of light emitting devices 1-1 to n arranged in the vertical direction and a plurality of light receiving devices 2-1 to n arranged in the vertical direction is opposed across a vehicle passage. Each light beam 15 emitted from each of the light emitting devices 1-1 to n is received by three light receiving devices in total of the light receiving device having the same height as that of the light emitting device and light receiving devices upper and lower than the light emitting device by one in the vertical direction. A driving part 5 time-dividedly lights and drives the light emitting devices 1-1 to n by a prescribed period so that light beam from two or more than light emitting devices may not simultaneously make incident on each of the light receiving devices 2-1 to n, under the control of a light emitting control part 6. A vehicle sensing processing part 11 outputs a vehicle sensing signal since any light beam is interrupted based on a signal showing each lighting timing for the light emitting devices 1-1 to n and a detection signal from each of the light receiving devices 2-1 to n.
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