| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an ultrasonic sensor that can easily specify the location of occurrence of disconnection. <P>SOLUTION: The sensor includes a piezoelectric element 11 and a resonance circuit 122 connected in parallel to the piezoelectric element 11. The piezoelectric element 11 is driven by a driving signal input, via the resonance circuit 122, from a transmission circuit 21 controlled by a control section 24. First, the frequency of the driving signal is set to be a predetermined first driving frequency, and a first determination operation is performed in which whether or not disconnection has occurred is determined based on the input from the resonance circuit 122. When the first determination operation determines that disconnection has occurred, the frequency of the driving signal is set to be a second driving frequency, which is closer to a resonance frequency of the resonance circuit 122 alone than the first driving frequency. Further, based on the input from the resonance circuit 122, a second determination operation is performed to determine which of the front side and the back side of the resonance circuit 122 the disconnection has occurred at. The second determination operation enables one to easily specify the location of occurrence of disconnection, thereby making repairing relatively easy. <P>COPYRIGHT: (C)2013,JPO&INPIT |
