ULTRASONIC VIBRATOR AND MANUFACTURING METHOD THEREFOR

摘要

Provided are an ultrasonic vibrator which enables the adjustment of a resonance frequency and the prevention of output leakage of ultrasonic vibration, and a manufacturing method therefor. In a cylindrical casing (5), at least part of a vibration part (2) configured by integrally forming an acoustic lens (4) and a piezoelectric element (3) is disposed in a peripheral wall part (51). The outer diameter (D2) of the acoustic lens (4) is slightly smaller than the inner diameter (D3) of the peripheral wall part (51). At an end (51B) of the peripheral wall part (51), an enlarged diameter part (55) configured by broadening an inner peripheral surface (51C) outward in a radial direction is formed. An adhesive (6) is provided in the enlarged diameter part (55). The cured adhesive (6) elastically holds the vibration part (2) in the casing (5) while maintaining the vibration part (2) and the casing (5) in a noncontact state. The acoustic impedance of the adhesive (6) is lower than those of the acoustic lens (4) and the casing (5). The ultrasonic vibration of the piezoelectric element (3) does not easily propagate to the casing (5) via the adhesive (6). Further, an ultrasonic vibrator (1) enables the resonance frequency of the acoustic lens (4) by adjusting the amount of the adhesive (6).