Shan Yameng, Qian Lei, He Kaixuan, Chen Bo, Wang Kewei, Li Wenchao, Shen Wenjiang
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China.
Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China.
Micromachines (Basel). 2024 Nov 26;15(12):1421. doi: 10.3390/mi15121421.
The MEMS scanning micromirror requires angle sensors to provide real-time angle feedback during operation, ensuring a stable and accurate deflection of the micromirror. This paper proposes a method for integrating piezoresistive sensors on the torsion axis of electrostatic MEMS micromirrors to detect the deflection angle. The design uses a multi-layer bonding process to realize a vertical comb-driven structure. The device structure is designed as a double-layer structure, in which the top layer is the ground layer and integrates with piezoresistive sensor. This approach avoids crosstalk between the applied drive voltage and the piezoresistive sensor. This design also optimizes the sensor's size, improving sensitivity. A MEMS two-dimensional (2D) scanning micromirror with a 1 mm mirror diameter was designed and fabricated. The test results indicated that, in a vacuum environment, the torsional resonance frequencies of the micromirror's fast axis and slow axis were 17.68 kHz and 2.225 kHz, respectively. When driving voltages of 33 V and 40 V were applied to the fast axis and slow axis of the micromirror, the corresponding optical scanning angles were 55° and 45°, respectively. The piezoresistive sensor effectively detects the micromirror's deflection state, and optimizing the sensor's size achieved a sensitivity of 13.87 mV/V/°. The output voltage of the piezoresistive sensor shows a good linear relationship with the micromirror's deflection angle, enabling closed-loop feedback control of the electrostatic MEMS micromirror.
MEMS扫描微镜在运行过程中需要角度传感器来提供实时角度反馈，以确保微镜的稳定和精确偏转。本文提出了一种在静电MEMS微镜的扭转轴上集成压阻式传感器来检测偏转角的方法。该设计采用多层键合工艺实现垂直梳齿驱动结构。器件结构设计为双层结构，其中顶层为接地层并集成了压阻式传感器。这种方法避免了施加的驱动电压与压阻式传感器之间的串扰。该设计还优化了传感器的尺寸，提高了灵敏度。设计并制作了一种镜面直径为1mm的MEMS二维（2D）扫描微镜。测试结果表明，在真空环境下，微镜快轴和慢轴的扭转共振频率分别为17.68kHz和2.225kHz。当向微镜的快轴和慢轴分别施加33V和40V的驱动电压时，相应的光学扫描角度分别为55°和45°。压阻式传感器有效地检测了微镜的偏转状态，通过优化传感器尺寸实现了13.87mV/V/°的灵敏度。压阻式传感器的输出电压与微镜的偏转角呈现出良好的线性关系，可实现静电MEMS微镜的闭环反馈控制。
