PROBLEM TO BE SOLVED: To achieve increasing sensitivity and widening a band of a pMUT (Piezoelectric Micromachining Ultrasound Transducer) suitable for a dimensional array probe.SOLUTION: An occurring ultrasonic wave is shortened its pulse by separating upper part electrodes into a main electrode and a sub electrode and transmitting a different drive signal to each of them. When receiving the ultrasonic wave, a resonance frequency is shifted along with the lapse of time by changing stress to be imparted to a vibration part by applying voltage to the sub electrode according to the lapse of time from transmission. Thereby, the ultrasonic wave is received in an effective frequency band according to a depth of echo.COPYRIGHT: (C)2013,JPO&INPIT【課題】2次元アレイプローブに適したpMUT(Piezoelectric Micromachining Ultrasound Transducer)素子の高感度化、広帯域化を実現する。【解決手段】上部電極をメイン電極とサブ電極に分け、それぞれに異なる駆動信号を送信することにより、発生する超音波を短パルス化する。また受信時には、サブ電極に送信からの時間の経過に応じた電圧を印加して振動部に与える応力を変化させ、共振周波数を時間の経過とともにシフトさせる。これにより、エコーの深さに合わせた効果的な周波数帯で受信することができる。【選択図】図3
