压电复合材料用于透镜式聚焦换能器的研究

摘要

为了增加聚焦换能器的带宽,抑制其多模振动耦合现象,提高电声转换效率,实验采用1-3型压电复合材料代替压电陶瓷作为超声发射材料,设计并制作了一种新型的1-3型压电复合材料透镜式聚焦换能器。通过频率特性的对比研究,证明了1-3型压电复合材料透镜式聚焦换能器不仅能增加换能器的带宽,达到PZT压电陶瓷透镜式聚焦换能器带宽的3.13倍,而且能明显抑制径向振动,得到单一纯净的厚度振动模态。另外,1-3型压电复合材料透镜式聚焦换能器的电声转换效率达到PZT压电陶瓷透镜式聚焦换能器的1.88倍,为高效率聚焦超声换能器的实现提供了理论及实验基础。%To broaden the bandwidth of focused transducer with suppressing the multimode coupling phenomenon, and improving the electro-acoustic conversion efficiency, 1-3 piezoelectric composites as the ultrasonic emission material was used to replace Pb-based lanthanum doped zirconate titanates ceramic. A new type of lens-focused transducer was designed and produced based on 1-3 piezoelectric composites. Through the comparative study of frequency characteristic, it is proved that the 1-3 piezoelectric composites lens-focused transducer can not only in-crease the bandwidth of the transducer which is 3.13 times of the one based on Pb-based lanthanum doped zirconate titanates, but also suppress the radial vibration obviously to obtain a single pure vibration modes. Besides, the elec-tro-acoustic conversion efficiency of the former lens-focused transducer is 1.88 times of the latter one. These results provide a theoretical and experimental foundation for the realization of ultrasonic transducer of high efficiency on reliability and stability.