PROBLEM TO BE SOLVED: To improve S/N of ultrasonic images by correcting the distortion of ultrasonic transmission/reception sensitivity generated in a vibration element.SOLUTION: The ultrasonic diagnostic apparatus is provided with an ultrasonic probe 10, a transmission circuit 12, a reception circuit 14, an image processing means 16 and a monitor 18. For the ultrasonic probe 10, the plurality of vibration elements 22 for mutually converting ultrasonic waves and electric signals are arrayed, and each vibration element 22 has an insulation film 22c and a gap 22d between opposing electrode 22a and electrode 22b. The ultrasonic transmission/reception sensitivity is changed corresponding to the size of bias impressed between the electrodes, and a bias polarity changing means 26 for inverting the polarity of the bias impressed between the electrodes of the vibration element 22 by a predetermined trigger is provided.COPYRIGHT: (C)2008,JPO&INPIT【課題】振動素子に生じる超音波送受感度の歪みを修正して超音波像のS/Nを向上させる。【解決手段】超音波診断装置は、超音波探触子10と、送信回路12と、受信回路14と、画像処理手段16と、モニタ18とを備え、超音波探触子10は、超音波と電気信号を相互に変換する複数の振動素子22,が配列され、各振動素子22は、対向する電極22aと電極22bの間に絶縁膜22cとギャップ22dを有し、前記電極間に印加されるバイアスの大きさに応じて超音波送受信感度が変化するものとし、振動素子22の電極間に印加されたバイアスの極性を予め定めた契機で反転させるバイアス極性変更手段26を有する。【選択図】図1
