PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of forming an ultrasonic image of high image quality by efficiently performing the sending-out of ultrasonic waves while using an ultrasonic probe having a simple structure.SOLUTION: The organic piezoelectric body 34a of an organic piezoelectric element 34 has thickness D satisfying a λ/4 resonance condition to the wavelength λ of the ultrasonic waves transmitted from an inorganic piezoelectric element 32. The amplifier 52 for the organic piezoelectric element 34 in a receiving circuit 5 is connected to a signal line electrode layer 34b through a transmission cable 54 having electrostatic capacity within a range of 0.1-5 times with respect to the electrostatic capacity of the organic piezoelectric element 34 and a plurality of the organic piezoelectric elements 34 act as the second acoustic matching layer continued to an acoustic matching layer 33 at the time of transmission and utilized as a non-resonance type receiving device at the time of reception. A receiving signal is transmitted to the amplifier 52 for the organic piezoelectric element from a signal line electrode layer 34b through a transmission cable 54 before subjected to A/D conversion by the A/D converter 53 for the organic piezoelectric element.COPYRIGHT: (C)2013,JPO&INPIT【課題】簡単な構造の超音波探触子を用いながらも、効率よく超音波の送出を行って高画質の超音波画像を生成することができる超音波診断装置を提供する。【解決手段】有機圧電素子34の有機圧電体34aは無機圧電素子32から送信される超音波の波長λに対してλ/4共振条件を満たす厚さDを有し、信号線電極層34bに有機圧電素子34の静電容量に対し0.1~5倍の範囲内の静電容量を有する伝送ケーブル54を介して受信回路5内の有機圧電素子用アンプ52が接続され、複数の有機圧電素子34は、送信時に音響整合層33に続く第2の音響整合層として作用し、受信時には、非共振型の受信デバイスとして利用され、受信信号が信号線電極層34bから伝送ケーブル54を介して有機圧電素子用アンプ52に伝送されて増幅された後、有機圧電素子用A/Dコンバータ53でA/D変換される。【選択図】図3
