| 摘要 |
PURPOSE:To improve and stabilize transmission efficiency by using a filler with a little variation in acoustic characteristics with water pressure by making flank and bottom-surface directions, viewed from a vibrator, equivalent to those with no load. CONSTITUTION:When the wavelength of an ultrasonic wave, generated by vibrator 1, in filler 6 is denoted by (lambda), perforation sizes of vibrator 1 and metal case 5 are fixed so that L1 is (mlambda) and L2 is (nlambda) [(n) and (m) are natural integers]. Namely, L1 is twice the distance between the bottom of vibrator 1 and the deepest point of reflecting surface R1, and L2 is twice that between the flank of vibrator 1 and the deepest point of reflecting surface R2. Here, an ultrasonic wave emitted from the bottom of vibrator 1 propagates in filler 6 vertically and returns to the bottom of vibrator 1 after being reflected twice by reflecting surface R1. Then, the run distance of the ultrasonic wave is L1. Similarly, an ultrasonic wave from the flank of vibrator 1 advances in filler 6 horizontally and then returns to the flank of vibrator 1 after being reflected twice by reflecting surface R2. Then the run distance of the ultrasonic wave is L2. Either returning wave is in phase with the emitted wave and a load viewed from vibrator 1 can be considered to be zero. |
