压电复合材料用于透镜式聚焦换能器的研究

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。

Properties of a Lens-focused Transducer Based on Piezoelectric Composites

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 increase 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 electro-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.