Huang Chih-Hsien, Yao Junjie, Wang Lihong V, Zou Jun
Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA.
Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
Microsyst Technol. 2013;19(4):577-582. doi: 10.1007/s00542-012-1660-4. Epub 2012 Sep 13.
Fast scanning is highly desired for both ultrasound and photoacoustic microscopic imaging, whereas the liquid environment required for acoustic propagation limits the usage of traditional microelectromechanical systems (MEMS) scanning mirrors. Here, a new water-immersible scanning mirror microsystem has been designed, fabricated and tested. To achieve reliable underwater scanning, flexible polymer torsion hinges fabricated by laser micromachining were used to support the reflective silicon mirror plate. Two efficient electromagnetic microactuators consisting of compact RF choke inductors and high-strength neodymium magnet disc were constructed to drive the silicon mirror plate around a fast axis and a slow axis. The performance of this water-immersible scanning mirror microsystem in both air and water were tested using the laser tracing method. For the fast axis, the resonance frequency reached 224 Hz in air and 164 Hz in water, respectively. The scanning angles in both air and water under ±16 V DC driving were ±12°. The scanning angles in air and water under ±10 V AC driving (at the resonance frequencies) were ±13.6° and ±10°. For the slow axis, the resonance frequency reached 55 Hz in air and 38 Hz in water, respectively. The scanning angles in both air and water under ±10 V DC driving were ±6.5°. The scanning angles in air and water under ±10 V AC driving (at the resonance frequencies) were ±8.5° and ±6°. The feasibility of using such a water-immersible scanning mirror microsystem for scanning ultrasound microscopic imaging has been demonstrated with a 25-MHz ultrasound pulse/echo system and a target consisting of three optical fibers.
超声和光声显微成像都非常需要快速扫描，然而，声学传播所需的液体环境限制了传统微机电系统（MEMS）扫描镜的使用。在此，设计、制造并测试了一种新型的水浸式扫描镜微系统。为了实现可靠的水下扫描，采用激光微加工制造的柔性聚合物扭转铰链来支撑反射硅镜板。构建了两个由紧凑型射频扼流圈电感器和高强度钕磁碟组成的高效电磁微致动器，以驱动硅镜板绕快轴和慢轴转动。利用激光跟踪法测试了这种水浸式扫描镜微系统在空气和水中的性能。对于快轴，在空气中的共振频率分别达到224 Hz，在水中为164 Hz。在±直流16 V驱动下，在空气和水中的扫描角度均为±12°。在±交流10 V驱动（在共振频率下）时，在空气和水中的扫描角度分别为±13.6°和±10°。对于慢轴，在空气中的共振频率分别达到55 Hz，在水中为38 Hz。在±直流10 V驱动下，在空气和水中的扫描角度均为±6.5°。在±交流10 V驱动（在共振频率下）时，在空气和水中的扫描角度分别为±8.5°和±6°。使用这种水浸式扫描镜微系统进行超声显微成像的可行性已通过一个M25 - Hz超声脉冲/回波系统和一个由三根光纤组成的目标得到了证明。
