Study On The Mechanical Characteristics Of Micro Cantilever Using Micro Laser Doppler Technology

Micro cantilever has been widely applied in micro field. The mechanicalcharacteristics of micro cantilever are highlighted in the process of study andapplication. Especially in atomic force microscope (AFM), the mechanicalcharacteristics of micro cantilever are important to improve the quality of imaging andthe precision of testing. Moreover, the marked error of mechanical characteristics ofcommercial cantilever is too big to accept. Therefore, measurement of microcantilever mechanical characteristics is a key problem which should be solved.In the dissertation, a cantilever out-of plane motion measuring system based onmicro Laser Doppler technology is set up. The method of indirect measurement ofmicro cantilever mechanical characteristics is analyzed, and experiments about microcantilever dynamic characteristics and mechanical characteristics are done. The majorworks in the dissertation are following:1. The measurement principle of micro Laser Doppler technology is carefullyanalyzed. A cantilever out-of plane motion measuring system is set up, the designof hardware, software and mechanism are accomplished, and experiments ofmicro cantilever are done using this system.2. The relationship of resonance frequency and Young's module is studied. With thesystem, experiments of Young's module of rectangle cantilever and trianglecantilever are done, and the spring constant of the two cantilevers are calculated.Through the experiments, it is proved that this is a quick and efficient way to testmechanical characteristics of micro cantilever.3. System software based on virtual instrumentation technique is designed,including driving output, data acquire and data process, Fast FourierTransformation (FFT), and frequency-scanning. Using this software, theresonance frequency at vary position on cantilever is tested and a consistent resultof resonance frequency is achieved.4. Several experiments of cantilever mechanical characteristics are done, the resultis compared with the data calibrated and the error is analyzed. An improvingmethod is supposed for the test of micro cantilever mechanical characteristics.