| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive gas sensor having a simple constitution, sufficiently downsized, and having a high response speed and high reliability. SOLUTION: In the gas sensor 1, an ultrasonic transmission element 2 and an ultrasonic reception element 3 are provided in counter relationship and the distance (x) between the ultrasonic transmission element 2 and the ultrasonic reception element 3 is set at below 60 mm. The concentration of a mixed gas is detected on the basis of the propagation time difference of an ultrasonic wave in a gap between the ultrasonic transmission element 2 and the ultrasonic reception element 3 when gas other than air gets mixed in the gap, and when the gas does not get mixed in the gap. COPYRIGHT: (C)2010,JPO&INPIT
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