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With the advances in precision manufacturing, optical metrology has played a vital role in inspecting for processing quality. Chromatic confocal displacement sensor (CCDS) is broadly used in optical detection field, which can achieve submicrometer- level resolution and precision. Although CCDS has many advantages, its measurement uncertainty is easily influenced by various factors when detecting distance. Measurement uncertainty is associated with measurement results, which characterizes the dispersion of the values that could reasonably be attributed to the measurand [1]. The uncertainty is low when the measurement result is stable and of high quality. This paper provides a systematic analysis on the measurement uncertainty evaluation of CCDS. Firstly, we briefly introduce CCDS’s principle and the algorithm of uncertainty calculation. Then, main sources of uncertainty when measuring distance are analyzed utilizing a commercial CCDS. Three sets of experiments are conducted: different colors, different angles ranging from -20°to 20°, and different roughness. And they were all carried out with different measuring distances ranging from 0.500mm to 11.500mm. Individual standard uncertainty is evaluated for each source based on GUM method [2]. For different colors’ surfaces, the trends of values’ distributions are similar. And the maximum is about 0.013μm, appearing at about 3.600mm. For different measuring angles, the distributions are almost symmetrical, but the symmetry is weakening as the distance increases from 0.500mm to 9.000mm. The values are low for different roughness’s surfaces, ranging from 0.003μm to 0.006μm. Finally, the implications of measurement uncertainty caused by these factors are discussed, providing guidance for future experiments and applications.
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