Patent ID: 9662680
Date: 2017-05-30
CPC Classifications: B06B,G10K,H01L

Claim:
1. An ultrasonic transducer comprising: a case having a plurality of ultrasonic wave emission holes; an ultrasonic wave generator including a piezoelectric vibrator and being disposed in the case such that a plurality of acoustic paths extend from the piezoelectric vibrator to the plurality of ultrasonic wave emission holes, respectively, wherein the piezoelectric vibrator is configured to generate an ultrasonic wave that creates air resonance in the acoustic path, wherein all of the acoustic paths extend from a center region of a surface of the piezoelectric vibrator at which displacement is greatest during excitation to the plurality of ultrasonic wave emission holes and are equal in distance to each other, and wherein the piezoelectric vibrator is configured to be driven at a driving frequency at which a temperature-sound pressure characteristic for the air resonance and a temperature-amplitude characteristic at the driving frequency have opposite tendencies.