| 摘要 |
PROBLEM TO BE SOLVED: To easily identify a baggage and a person by arranging an ultrasonic receiver in the generation region of stationary waves, and detecting the presence of an occupant based on the change of the output of the ultrasonic receiver when the occupant seated on a seat moves. SOLUTION: Ultrasonic waves 13 are generated between the position X1 of a ultrasonic generator 10 and the position X2 of the body of an occupant 14 in the state B. When the body of the occupant 14 is bent forward into the state C, stationary waves are formed between the position X1 of the ultrasonic generator 10 and the position X3 of the body of the occupant 14 in the state C. The signal for the decrement of the stationary waves is received by a ultrasonic receiver 12 arranged in the generation region of the stationary waves, and the signal is outputted to the ultrasonic receiver 12 while the occupant 14 is changed from the state B to the state C. Whether an object is put on an assistant's seat or whether a person is seated there can be easily detected. |
