| Summary: | 碩士 === 國立交通大學 === 機械工程系所 === 106 === The study proposed and applied the innovative confocal optical technique with varifocal lens on confocal displacement sensor system. High speed scanning methology of profile measurement for transparent object was developed. Some typical experiments of transparent object configuration measurement are executed and demonstrated. First of all, the thickness measurement of cover glass and slide glass was illustrated and discussed. Varifocal lens driven by current and focal power mode were adopted for comparision. LabVIEW program was developed to detect two peaks from collected confocal signal and transforms it into two groups of displacement data for calculating the thickness of the transparent objects based on the corrected parameters such as optical reflection parameters, etc.. Secondly, the compensating rules in dealing with the offset error of confocal signal was discoveried. The influence of temperature in current mode was detected and studied while observing the relative changes of confocal signals in different temperature ocnditions. In third part, the study proposed the continuously scanning method by using analog triangle mode assisted by DAQ system. Measuring the data of multiple points based on LabVIEW improves the scanning speed while using 20 Hz triangle driving current with this method. The scan speed could reach near 50 ms per scan point, which increases 2.6 times in speed compared with former method. Based on the above methods, the measurement of step-height of stair configuration object with 2D tracjectory was tested as illustrated samples. Finally the surface profile of convex glass lens by continuously multi-point scanning method was studied and discussed. The results of the experiment show that after thecompensation process of regulating tilt of the measuring platform, the center of the lens can be found. The evaluated results demonstrate the improved and practical performance of the confocal displacement sensor system with varifocal lens. The function and precision of the optical measurement system was also available for applying to the transparent object on geometrical configuration measurement applications.
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