| 摘要 |
PURPOSE:To make it possible to detect the amount of the moisture content a medium to be detected by arranging a standing wave emitter and an ultrasonic wave receiver so as to face each other with a detecting space in-between. CONSTITUTION:The comb parts of a comb electrode 9A and a comb electrode 9B of a standing wave emitter 9 are alternately arranged in parallel. The comb parts of a comb electrode 11A and a comb electrode 11B of an ultrasonic wave receiver 11 are alternately arranged in parallel. The standing wave emitter 9 and the ultrasonic wave receiver 11 are arranged so as to face each other with a detecting space in-between. Then, the ultrasonic waves whose phases are aligned are emitted from the comb electrodes 9A and 9B on a piezoelectric substrate 8 of the standing wave emitter 9. The ultrasonic waves become the compressional waves. The waves are propagated in a medium to be detected. Thereafter, the ultrasonic waves are received with the comb electrodes 11A and 11B on a piezoelectric substrate 10 of the ultrasonic wave receiver 11. The propagating speed of the ultrasonic wave which is propagated in the medium to be detected is changed based on the difference in amounts of moisture contents. Therefore, the propagating speed of the ultrasonic wave and the energy of the received wave are detected. Thus, the content of the moisture in the medium can be found. |
