Study On DSP-based High-Speed Scanning In X-Y Direction And Image Construction Technology

As a series of microscopes with nano or sub-nanometer, SPM(scanning probe microscope) symbolized by STM(scanning tunneling microscope) and AFM(atomic force microscope)play a great role in the development and renovation of Chemistry, Physics, Life and Material Science. Traditionally, saw-tooth voltage of which the output voltage is the direct ratio of the time in one periodic time is used as the fast scan driving signal of PZT scanner of the STM or AFM etc. But if the sine wave signal is used as the driving voltage of the of PZT scanner, the mechanical hysteresis induced by the sudden change of voltage will be decreased obviously. And it is a good way of improving the scanning and imaging speed of the SPM. It also presents a new idea that some driving signals are more suitable to the scanner can be found. Based on the study of the quartering electric tube, a controllable driving system that can generate both the saw-tooth and sine waves is used to drive the scanner. By comparison of the two different results, we will find the advantages of the new idea are found. And at last, a technique of image construction is presented too.It is obvious that the improvement SPM X-Y scanning speed is a great help to the related fields. This paper gives a new kind of method to improve the performance and in this new design, instead of the triangular signal or the saw-tooth wave, the sinusoidal signal is used as the driving signal in the fast scan axis of SPM. The design of the driving circuit which bases on the DSP TMS320C5402 is developed. The rationality of the new design is proved by the comparing results.The main content of the thesis is as following:1. According to the achievement of high-speed scanning, The paper gives an conclusion Analysis of the main factors that influence the imaging speed of SPM;2. The main technique and the theory of the generation of the sine wave;3. The design of driving system of piezo scanner of AFM, including the two parts: the design of the generator of the fast-scanning axis driving circuit (it contains both the sine and saw-tooth wave generators), slow-scanning axis circuit;,4. The design of auxiliary parts of the system: they are the displacement driving signals of the x- and y- and a special part that can exchange the fast and low axis;5. The high voltage amplify circuit and the power supply;6. The study of the image construction; 7. Experiments of the system and analysis of the results.