| 摘要 |
PURPOSE:To obtain a small-sized multi-frequency ultrasonic transmitter and receiver, by providing a drawer terminal inserting between a pair of piezoelectric elements so as to be placed at a specified position against the overall length of a piezoelectric vibrator, and screwing the other to the piezoelectric element as a metallic terminal. CONSTITUTION:Each pair of piezoelectric elements 1, 2 and 3 are provided with electrodes having drawer terminals 4, 5 and 6 between the contact surfaces, respectively. Metallic terminals 7, 8, 9 and 10 are provided on the other surface of the elements 1-3, and are screwed to a metallic bar passing through the piezoelectric element. In this case the elements 1-3 are opposed so that the polarized directions become the same pole each other, and are constituted so that these centers are positioned at 0.125, 0.25 and 0.5 from one end surface, respectively, along the overall length of the vibrator. In this way, nine resonance frequencies can be obtained by one vibrator by changing the mutual connection of the drawer terminals 4, 5 and 6, and setting the driving ends as 4, 5 and 6, 4-5, 4-6 and 5-6 and 4-5-6. |
