Theory and Operation of 2-D Array Piezoelectric Micromachined Ultrasound Transducers
Theory and Operation of 2-D Array Piezoelectric Micromachined Ultrasound Transducers
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DOI：
10.1109/tuffc.956
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发表时间：
2008-11-01
影响因子：
3.6
通讯作者：
von Ramm, Olaf T.
中科院分区：
文献类型：
--
作者：
Dausch, David E.;Castellucci, John B.;von Ramm, Olaf T.
压电微机械超声换能器（pMUT）是一种用于构建二维阵列的新方法，用于前视三维血管内（IVUS）和心内（ICE）成像。二维pMUT测试阵列包含25个元素（5 × 5阵列），在硅基板上进行批量微机械加工。该装置由锆钛酸铅（PZT）薄膜膜形成的硅基板的深反应离子蚀刻。单元宽度从50到200 Inn不等，间距从100到300 Inn不等。声学传输特性进行了测量，在去离子水与校准的水听器放置在20 mm的范围内。测量的pMUT元件的传输频率范围从4到13 MHz，不同的元件尺寸和振动模式。元件电容根据元件尺寸和PZT厚度从30 pF到超过400 pF变化。较小的元件尺寸通常比较大的元件产生更高的声学发射输出以及更高的频率。较厚的PZT层也产生较高的发射输出每单位电场施加。由于在PZT矫顽电压以上的弯曲模式操作，发射输出随着驱动电压的增加而非线性地增加。将pMUT阵列直接连接到杜克大学T5相控阵扫描仪上，以用2-D pMUT阵列产生实时脉冲回波B模式图像。
Piezoelectric micromachined ultrasound transducers (pMUTs) are a new approach for the construction of 2-D arrays for forward-looking 3-D intravascular (IVUS) and intracardiac (ICE) imaging. Two-dimensional pMUT test arrays containing 25 elements (5 x 5 arrays) were bulk micromachined in silicon substrates. The devices consisted of lead zirconate titanate (PZT) thin film membranes formed by deep reactive ion etching of the silicon substrate. Element widths ranged from 50 to 200 Inn with pitch from 100 to 300 Inn. Acoustic transmit properties were measured in de-ionized water with a calibrated hydrophone placed at a range of 20 mm. Measured transmit frequencies for the pMUT elements ranged from 4 to 13 MHz, and mode of vibration differed for the various element sizes. Element capacitance varied from 30 to over 400 pF depending on element size and PZT thickness. Smaller element sizes generally produced higher acoustic transmit output as well as higher frequency than larger elements. Thicker PZT layers also produced higher transmit output per unit electric field applied. Due to flexure mode operation above the PZT coercive voltage, transmit output increased nonlinearly with increased drive voltage. The pMUT arrays were attached directly to the Duke University T5 Phased Array Scanner to produce real-time pulse-echo B-mode images with the 2-D pMUT arrays.