Design And Study Of A New Laser Scanning Confocal Probe

Recently, non-contact measurement probe has been developed very fast, and it has been one of the important research fields of the development of detecting technology.The design and study of the new laser scanning confocal probe was based on the principle of Laser Scanning Confocal Microscopy. It also used the method of dynamic active adjusting focus and it can satisfy the requirement of non-contact measurement. If the object being measured was on the light axis and in the oscillating scope of the light spot, there would be two times that the light spot was on the micro-sphere being measured in one period. In this case, the detector received the strongest light intense, and the amplitude of the output electrical signal was also the biggest. The thesis mainly introduced the design and study on the structure of the mechanical and optical route. The scheme of time difference measurement, namely the scheme of transforming the measurement of the displacement to the measurement of the time difference, was the distinctive feature of the probe. Finally, a new method of signal processing was proposed.The project is a part of the Study on Semi-Auto ICF Target Semiautomatic Assembly On-line Measuring Technology: The National High tech Development 863 Key Project, No. 2003AA84ts05.All the work on the laser scanning confocal probe was aimed at improving the measurement performance. The main work contents were shown as follows.1. Briefly introduced the principle of dynamic active adjusting focus;2. To improve the output photoelectrical signal, a mathematical modal of the photoelectric signal was proposed;3. Concretely introduced the mechanical and optical structure, simplified the design of the optical path, designed and applied the adjusting device for the pinhole and detector for convenient measurement; illustrated the oscillating units were the crucial part of the mechanical and optical structure of the probe; Chose the drive coil and induction coil; the diameter of the pinhole was decided, the light spot was measured, the pinholes were checked; and then, the intact design of the probe was proposed;4. Explained the hardware and software of the signal processing;5. Tested the frequency stability of the oscillating tuning fork system, the performance of the probe was validated by experiments using gage blocks combining with a micro—motion measuring mount model; basing on the time difference measurement method, the final experimental conclusion was drawn, the feasibility of measuring the target micro-sphere was validated.