Design Of Nano-scale Precision Position Servo-controller In Fluorescence Microscopy Imaging System

In the fluorescence imaging system, one of the components in protein trajectory research is a position servo-controller with good performance. High-resolution position servo-controller moves microscope objective in nano-scale, and then achieve optical sectioning in submicron and even smaller intervals. With the resulting data, three-dimensional images of specimen can be reconstructed. Requirements of position servo-controller are high-resolution, good linearity and high stability. This thesis designs such a controller.In this thesis, the controller is piezoelectric crystals based. Piezoelectric crystals theoretically have infinite resolution, and large load capacity and they are widely used in high precision mechanical control fields. The controller we design is consisted of microprocessor system which is based on Cypress's EZ-USB FX2, and analog circuits. During the design process, there were series problems encountered and handled, such as power line interference, the encoder's interference, high voltage driver stability with capacitive load, protecting piezoelectric crystals when power-on and power-off.Fluorescent bead experiments were carried out to evaluate the sample controller. It shows that the linearity and stability is good, and the controller basically meets requirements of fluorescence microscopy imaging. Spatial resolution in z-axis has not been measured and the controller has not been used in biological experiments. It's foreseeable that improved micro displacement servo-controller will be ultimately used in three-dimensional imaging experiments and three-dimensional target protein tracking.