Encapsulation of Capacitive Micromachined Ultrasonic Transducers Using Viscoelastic Polymer.
Encapsulation of Capacitive Micromachined Ultrasonic Transducers Using Viscoelastic Polymer.
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DOI：
10.1109/jmems.2010.2076786
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发表时间：
2010-12-01
期刊：
影响因子：
--
通讯作者：
Khuri-Yakub BT
中科院分区：
文献类型：
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作者：
Lin DS;Zhuang X;Wong SH;Kupnik M;Khuri-Yakub BT
医学成像或治疗超声换能器的包装应提供保护性绝缘，同时保持高性能。对于电容式微机械超声换能器（CMUT），理想的封装涂层因此将需要静态操作点和动态性能上的有限且可预测的变化，同时将高DC和DC致动电压与环境隔离。为了满足这些要求，粘弹性材料，如聚二甲基硅氧烷（PDMS），被调查的封装材料。此外，玻璃化转变温度低于室温的PDMS提供低杨氏模量，从而保持静态行为;在超声操作的较高频率下，这种材料变得更硬，并且在声学上与水匹配。在本文中，我们演示了粘弹性聚合物作为封装材料的建模和实现。我们介绍了一个有限元模型（FEM），解决粘弹性。这使我们能够正确计算CMUT的静态操作点和动态行为。设计用于医学成像和治疗超声的CMUT被制造和封装。静态和动态测量被用来验证有限元和显示出良好的协议。本文将有助于优化静态和动态行为的粘弹性聚合物涂层CMUT的设计过程。
The packaging of a medical imaging or therapeutic ultrasound transducer should provide protective insulation while maintaining high performance. For a capacitive micromachined ultrasonic transducer (CMUT), an ideal encapsulation coating would therefore require a limited and predictable change on the static operation point and the dynamic performance, while insulating the high dc and dc actuation voltages from the environment. To fulfill these requirements, viscoelastic materials, such as polydimethylsiloxane (PDMS), were investigated for an encapsulation material. In addition, PDMS, with a glass-transition temperature below room temperature, provides a low Young's modulus that preserves the static behavior; at higher frequencies for ultrasonic operation, this material becomes stiffer and acoustically matches to water. In this paper, we demonstrate the modeling and implementation of the viscoelastic polymer as the encapsulation material. We introduce a finite element model (FEM) that addresses viscoelasticity. This enables us to correctly calculate both the static operation point and the dynamic behavior of the CMUT. CMUTs designed for medical imaging and therapeutic ultrasound were fabricated and encapsulated. Static and dynamic measurements were used to verify the FEM and show excellent agreement. This paper will help in the design process for optimizing the static and the dynamic behavior of viscoelastic-polymer-coated CMUTs.