Department of Nature-Inspired System and Application, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, 34103, Daejeon, Republic of Korea.
University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea.
Sci Rep. 2022 Jan 27;12(1):1485. doi: 10.1038/s41598-022-05547-7.
The development of a new ultrasonic transducer capable of improved focusing performance has become a necessity to overcome the limitations of conventional ultrasonic transducer technology. In this study, we designed and optimized a metasurface piezoelectric ring device, and using multiphysics finite element analysis, we examined the performance of a planar ultrasonic transducer consisting of this device, a matching layer, a backing layer, and housing in producing a needle-like subwavelength focusing beam in water. For practical experiments, a metasurface piezoelectric ring device was fabricated using a laser ablation process. Subsequently, using a pulse-echo test, we found that the - 6 dB bandwidth of a planar ultrasonic transducer with a center frequency of 1.0 MHz was 37.5%. In addition, the results of an ultrasonic-focusing performance test showed that the full width at half-maximum of the axial subwavelength focusing beam was 0.78λ, and the full lateral width at half-maximum of the subwavelength lateral focusing beam was 7.03λ at a distance of 10.89λ. The needle-like focused ultrasonic beam technology implemented with a piezoelectric ring array based new planar ultrasound transducer is expected to be used in high-resolution imaging devices or medical ultrasound focusing devices in the future.
为了克服传统超声换能器技术的局限性，开发一种具有改进聚焦性能的新型超声换能器已成为当务之急。在本研究中，我们设计并优化了一种超表面压电环器件，并使用多物理场有限元分析，研究了由该器件、匹配层、背衬层和外壳组成的平面超声换能器在水中产生针状亚波长聚焦光束的性能。为了进行实际实验，使用激光烧蚀工艺制造了超表面压电环器件。随后，通过脉冲回波测试，我们发现中心频率为 1.0MHz 的平面超声换能器的-6dB 带宽为 37.5%。此外，超声聚焦性能测试的结果表明，在 10.89λ 的距离处，轴向亚波长聚焦光束的半最大值全宽为 0.78λ，亚波长横向聚焦光束的半最大值全宽为 7.03λ。基于压电环阵列的新型平面超声换能器实现的针状聚焦超声束技术有望在未来用于高分辨率成像设备或医学超声聚焦设备。
