In order to solve the shortcomings that most of the auto-focus system cannot obtain individual thickness and refractive index of three transparent substrates this thesis proposes a new type of auto-focus system that can simultaneously measure their thickness and refractive index The main structure of this proposed system is based on the basic theorem of optics: the independent propagation law refraction law and reflection law theory and combined with the spot shaping lens The key point of the overall structure is that the binary linear equation relation between the upper and lower planes of the object can be known by the laser spot reflected from the object Using two different incident angles of laser beams the CCDs capture the spot signal for image processing binarization and grouping After the obtained points’ spacing is substituted into the equations the thickness and refractive index of the multi-layer substrates can be calculated According to the relation between thickness and refractive index the system can use the obtained refractive index and thickness to calculate the focusing distance so as to achieve auto-focusing This thesis uses Zemax optical simulation software to analyze system characteristics and tests the image processing effect In the simulation the thicknesses and refractive indices of three transparent substrates can be measured simultaneously From the simulation results the deviation of the simulated thickness and refractive index is about 0 08% Finally the thesis sets up the proposed system with simulation parameters on the optical table for further experiment and analysis From experimental results the deviation of measured thickness is about 2% and the deviation of measured refractive index is about 2 4% In addition the system can achieve fast auto-focusing purpose by using the measured thicknesses and refractive indices
Date of Award | 2020 |
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Original language | Chinese (Traditional) |
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Supervisor | Chien-Sheng Liu (Supervisor) |
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三層透明基板厚度及折射率量測系統與自動對焦顯微鏡之設計
子堯, 翁. (Author). 2020
Student thesis: Master's Thesis