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在工业无损评价(NDE)及医学超声成像中,为提高纵向分辨率,希望超声换能器具有窄脉冲宽频带的特性,为此,有人用高阻抗、高衰减材料做为压电晶体的背衬,用作匹配吸收体。也有人采用厚的压电晶体制做换能器,利用其远离共振频率的非谐振状态工作,但上述方法存在一些不足,如换能器径向模的振动,粘接层的影响等。作者提出了一解决问题的方法,即厚片锥状压电换能器,其工作在非共振状态,同时作用面积小。
In NDE and medical ultrasound imaging, it is hoped that ultrasonic transducers will have the characteristics of narrow pulse width and wideband in order to improve the vertical resolution. For this reason, some people use high-impedance and high-attenuation materials as the backs of piezoelectric crystals Lining, used as a matching absorber. Some people use thick piezoelectric crystal transducer to make use of its non-resonant state away from the resonant frequency of work, but there are some shortcomings, such as the vibration of the transducer radial mode, the impact of the adhesive layer. The authors propose a method to solve the problem, namely thick slice conical piezoelectric transducer, its work in non-resonant state, while the role of small area.