| 摘要 |
PURPOSE:To reduce the impedance of a piezoelectric converter with simple structure and excellent workability by separating electrically only an upper electrode of an input/output piezoelectric converter into two and leading out a lead from the two separated upper electrodes. CONSTITUTION:The upper electrode is separated electrically into two parts by using a mask. Leads 6, 7 are bonded respectively to the upper electrodes 4, 5 by using a conductive adhesives such as Silvest. Although the ultrasonic wave irradiated into an ultrasonic wave delay medium from beneath the upper electrode 4 and the ultrasonic wave irradiated into the ultrasonic wave delay medium from beneath the upper electrode 5 are shifted in phase by 180 deg., since the output piezoelectric converter is constituted similarly as the input piezoelectric converter, an output voltage is generated between the leads. Although the ultrasonic waves whose phases are inverted mutually reach one of the split electrodes of the output converter because of the spread of the ultrasonic wave beam and an output voltage is lowered equivalently, the spread in the beam is neglected substantially at high frequencies being several tens of MHz or over. |
