Dynamics of Thin-film Piezoelectric Microactuators with Large Vertical Stroke Subject to Multi-axis Coupling and Fabrication Asymmetries.
Dynamics of Thin-film Piezoelectric Microactuators with Large Vertical Stroke Subject to Multi-axis Coupling and Fabrication Asymmetries.
复制标题
受多轴耦合和制造不对称影响的大垂直行程薄膜压电微执行器的动力学。
DOI：
10.1088/1361-6439/aa9d3c
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Oldham,Kenn
中科院分区：
文献类型：
--
作者：
Choi,Jongsoo;Wang,Thomas;Oldham,Kenn
基于MEMS的扫描仪的高性能和小尺寸已经允许以小形状因子实现各种光学成像技术。许多这样的设备是共振扫描仪，因此，他们的线性和非线性动态行为已经在过去的研究。相比之下，薄膜压电材料提供足够的能量密度以实现大的静态位移和高频谐振，但是大的变形又会影响动态扫描器行为。本文报道的影响非常大的行程平移的压电垂直致动器的谐振行为，这可能无法完全解释的共振位移的共同原因，如梁的硬化或非线性强迫。为了检查扫描仪运动过程中的结构顺应性的变化，已经开发了一个模型，该模型包括来自残余应力的内力和致动器腿结构之间的由此产生的附加多轴耦合。与之前的一些垂直扫描微致动器一样，这项工作的扫描仪有四条腿，每条腿具有四个串联的薄膜PZT单晶片，使扫描仪在14 V DC下产生大于400 µm的垂直位移。在一个或多个谐振附近使用激励，可以降低输入电压，并且还可以生成互补的多轴旋转，但是需要理解谐振频率随扫描器高度的变化以最大化扫描器性能。所提出的模型很好地预测了实验观察到的扫描器的谐振频率的下降与直流偏置电压的增加。此外，扫描器结构上的残余应力的大小和均匀性的自然频率的影响进行了研究。
The high performance and small size of MEMS based scanners has allowed various optical imaging techniques to be realized in a small form factor. Many such devices are resonant scanners, and thus their linear and nonlinear dynamic behaviors have been studied in the past. Thin-film piezoelectric materials, in contrast, provide sufficient energy density to achieve both large static displacements and high-frequency resonance, but large deformation can in turn influence dynamic scanner behavior. This paper reports on the influence of very large stroke translation of a piezoelectric vertical actuator on its resonant behavior, which may not be otherwise explained fully by common causes of resonance shift such as beam stiffening or nonlinear forcing. To examine the change of structural compliance over the course of scanner motion, a model has been developed that includes internal forces from residual stress and the resultant additional multi-axis coupling among actuator leg structures. Like some preceding vertical scanning micro-actuators, the scanner of this work has four legs, with each leg featuring four serially connected thin-film PZT unimorphs that allow the scanner to generate larger than 400 µm of vertical displacement at 14 V DC. Using an excitation near one or more resonances, the input voltage can be lowered, and complementary multi-axis rotations can be also generated, but change of the resonant frequencies with scanner height needs to be understood to maximize scanner performance. The presented model well predicts the experimental observation of the decrease of the resonant frequencies of the scanner with the increase of a dc bias voltage. Also, the effects of the magnitude and uniformity of residual stress across the scanner structure on the natural frequencies have been studied.