A High-Resolution Optical Displacement Detection Method for Piezoelectric Microvibratory Stage

Microdisplacement detection plays a vital role in the position diagnosis and accurate calibration of micro-electro-mechanical systems (MEMS) actuators. An optical microdisplacement detector proposed in this article integrated a vertical cavity surface-emitting laser and nine photodiodes (PDs) to detect the submicrometer translation and subdegree rotation of the piezoelectric microvibratory stage under the limited space. The highly accurate detection was mainly realized by PDs design and quality improvement. Nine PDs layout with high-resolution optical sensors and corresponding calculation guaranteed the detector to precisely acquire out-of-plane displacement and two-axis rotation of the vibratory platform. And the introduction of the light-absorbing layer and the light-shielding layer further improved the sensing quality to reach a higher measurement resolution. The microstage was fabricated by MEMS technology and the experiments of measurement system indicated that the out-of-plane displacement detection accuracy was 150 nm in the range of 500 μm and the angle detection accuracy reached 0.1° in the range of 2°.