| 摘要 |
PURPOSE: To realize an ultrasonic transmitter-receiver which can transmit and receive an ultrasonic wave of a wide frequency band. CONSTITUTION: Since an ultrasonic resonance member 2 where a piezoelectric element 1 for ultrasonic transmission/reception is arranged, a stress changer 4 which is arranged in this member 2 and changes the stress of this member 2, an ultrasonic resonance chamber provided with a piezoelectric element, and a pressure changer which is provided in this resonance chamber and changes the internal pressure of this resonance chamber are provided, the ultrasonic resonance member 2 has the stress changed to change the natural frequency, and the ultrasonic resonance chamber has the internal pressure changed to change the natural frequency, thereby realizing the device capable of extending the band of the frequency used. |
