| 摘要 |
PROBLEM TO BE SOLVED: To detect a stolen vehicle without delay even in a time window when a parking lot is crowded with people and vehicles in the daytime or even when a special system for theft detection is not loaded on the vehicle. SOLUTION: A vehicle gate 13 of a parking lot 10, a light projector 21 and a photo-detector 22 of a transmission type photoelectric switch which is a vehicle theft detector are arranged. The photo-detector 22 of the vehicle theft detector 20 is provided with a discrimination means 223 for discriminating whether or not a light shield detecting signal outputted based upon shielding of a light axis formed from the light projector 21 and the photo-detector 22 is within a first discrimination time, and when the time shielding the optical axis is shorter than or equal with the prescribed first discrimination time, in accordance with passing of a vehicle in the vehicle gate 13, a vehicle theft signal is outputted. COPYRIGHT: (C)2004,JPO
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