Development of a piezo-driven mechanical stage integrated microdisplacement sensor for calibration of displacements

We fabricated a mechanical stage driven by a piezoelectric actuator and built in a microdisplacement sensor, which is used to decrease the effect of hysteresis and creep in the piezoelectric actuator. The displacement sensor consists of a vertical-cavity surface-emitting laser (VCSEL), eight two-dimensional monolithically integrated photodiodes (PD_s), a frame, and a cover glass. The size of the sensor chip is 3.0 mm by 3.0 mm with a thickness of 0.7 mm. The maximum variation in the position of the mechanical stage caused by hysteresis is 7.5 μm without control when the movement range of the mechanical stage is 84.4 μm. By controlling the applied voltage using our microdisplacement sensor, we reduce the effect of the hysteresis, and the variation in position decreased to 1.9 μm.