| 摘要 |
PURPOSE:To achieve an ultrasonic wave transducer with high output at a comparatively low voltage, by laminating a plurality of high polymer piezoelectric layers and making different the polarity of piezoelectricity for adjacent layers. CONSTITUTION:Two high polymer piezoelectric substance filters 1a, 1b are opposite for the polarity of piezoelectricity as shown in the arrow, electrodes 2a, 2c are connected to the same pole of an oscillator 3 and an electrode 2b is connected to another pole. When a pulse voltage near the resonance frequency is applied to a transducer 4 from a pulse oscillator 3, two layers of piezoelectric films make thickness oscillation through the incorporation with increased or decreased thickness at the same time. Thus, the resonance frequency is the same as that of one layer construction with the same thickness. On the other hand, the output will be the same with 1/4 voltage when the thickness of the 1a and 1b is equal, because of parallel connection. |
