Although PZT driving stage is a practical and widely used component in optical scanning measurement, its creep, hysteresis, poor long-term stability and the vibration of stage hindered the promotion in driving and positioning accuracy. Based on feedback control, the stage can have nanometer level driving accuracy. For attaching the displacement feedback sensor, a special structure that is called expanded hinge is designed. For getting higher sensitivity, a shallow groove is cut in it. In order to confirm the effect of the additional structure on the performance of the stage, the finite element software is employed, the analysis had been completed, and the simulated results are presented. With the vibration model of the 2D flexible hinge stage, the mathematic model of the vibration control can be achieved, and the PID control system is set up. After the sensors are carefully attached to the corresponding spot and the processing circuit is completed, the simulation and test of the overall performance of the stage can be executed.
Geometric measurements based on optical methods have been studied, and the capacitance sensor is applied
to detect the focusing displacement. In order to improve the edge effect of the flat capacitance sensor, an
equipotential ring is used. According to the Abbe principle, a double equipotential rings flat capacitance sensor
with a central hole is developed. The axis of the optical system perforates through the hole of the sensor, thus
avoiding the Abbe error. In order to get narrow gap between the equipotential ring and the electrode as well as
thin electrodes, MEMS technique is applied to machine the capacitance electrodes, then the gap between the
ring and the electrode can be no more than 10μm, meanwhile the measurement accuracy can be promoted
greatly. This paper emphasizes on the design of structure flat capacitance sensor and the manufacture of
double rings capacitor with MEMS technique. After completing the circuit and finishing the experiment for
testing the sensor, it can make further qualitative analysis on the result of the linearity and the sensitivity.