Imaging Arrays With Improved Transmit Power Capability
Imaging Arrays With Improved Transmit Power Capability
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DOI：
10.1109/tuffc.2010.1655
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发表时间：
2010-09-01
影响因子：
3.6
通讯作者：
Nightingale, Kathryn R.
中科院分区：
文献类型：
--
作者：
Zipparo, Michael J.;Bing, Kristin F.;Nightingale, Kathryn R.
结合低损耗压电陶瓷的多层陶瓷和复合材料已被应用于超声成像阵列，以提高声发射功率水平并减少内部加热。来自多个供应商的市售硬PZT的特征在于微观结构、加工能力和电声特性。与通常用于成像阵列的较软的PZT 5-H相比，使用最好材料的多层膜展示了权衡。三层PZT 4复合材料表现出的有效介电常数是单层PZT 5 H的三倍，机械Q值高50%，声阻抗低30%，耦合系数仅低10%。应用低损耗多层线性相控和大型曲面阵列的结果等效或更好的元件性能。一个3层的PZT 4复合阵列实现了相同的发射强度，在40%的发射电压和35%的表面温度比PZT-5控制降低增加。虽然B模式图像显示类似的质量，声辐射力脉冲（ARFI）图像显示增加的位移为一个给定的驱动电压。延长操作后多层膜的失效率增加表明，有必要进一步开发粘合工艺。总之，粘结多层陶瓷和复合材料允许额外的设计自由度，以优化阵列和提高整体性能
Bonded multilayer ceramics and composites incorporating low-loss piezoceramics have been applied to arrays for ultrasound imaging to improve acoustic transmit power levels and to reduce internal heating. Commercially available hard PZT from multiple vendors has been characterized for microstructure, ability to be processed, and electroacoustic properties. Multilayers using the best materials demonstrate the tradeoffs compared with the softer PZT5-H typically used for imaging arrays. Three-layer PZT4 composites exhibit an effective dielectric constant that is three times that of single layer PZT5H, a 50% higher mechanical Q, a 30% lower acoustic impedance, and only a 10% lower coupling coefficient. Application of low-loss multilayers to linear phased and large curved arrays results in equivalent or better element performance. A 3-layer PZT4 composite array achieved the same transmit intensity at 40% lower transmit voltage and with a 35% lower face temperature increase than the PZT-5 control. Although B-mode images show similar quality, acoustic radiation force impulse (ARFI) images show increased displacement for a given drive voltage. An increased failure rate for the multilayers following extended operation indicates that further development of the bond process will be necessary. In conclusion, bonded multilayer ceramics and composites allow additional design freedom to optimize arrays and improve the overall performance