Chinese Journal of Liquid Crystals and Displays, Volume. 38, Issue 11, 1481(2023)

Tilt sensor based on differential confocal microscope

Ting-yu WANG1,2,3, Zhi-yi WANG1,2,3、*, Yong-qiang YANG1,2, Xiao-tao MI1,2, Jian-li WANG1,2,3、**, Kai-nan YAO1,2,3, and Xue CHENG4,5
Author Affiliations
  • 1Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China
  • 2University of Chinese Academy of Science,Beijing 100049,China
  • 3Jilin Provincial Key Laboratory of Intelligent Wavefront Sensing and Control,Changchun 130033,China
  • 4Suzhou Institude of Biomedical Engineering and Technology,Chinese Academy of Sciences,Suzhou 215163,China
  • 5Jinan Guoke Medical Technology Development Co.,Ltd.,Jinan 250102,China
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    In order to solve the problem that traditional laser differential confocal microscope(LDCM) can not measure the angle of tilt with high precision while measuring the distance, a kind of angle measurement sensor based on LDCM was proposed. When measuring the inclined surface, the sensor first uses the differential response signal obtained by axial scanning to accurately locate the focal position, and then analyzes the pupil field intensity distribution of the microscope and extracts the peak position of the spot image, so as to achieve the accurate measurement of the inclination. First, the field distribution model of the focused beam reflected by the tilted surface to be measured was established, and the field intensity distribution in the pupil plane of the microscope was analyzed at different tilt angles. Then, on the basis of analyzing the characteristics of slanting spot, a method of extracting the peak position of spot using improved Meanshift algorithm is proposed. Finally, the effectiveness of the sensor for tilt angle measurement is verified by experiments. The experimental results show that the average error of the sensor is 0.011° for the tilt degree (0°~8°) and 0.128° for the tilt direction (0°~360°), which can meet the requirements of measuring tilt angle of measuring surface in the process of detecting three-dimensional surface by using LDCM. The sensor provides a new method for high precision contour measurement of free-form surface.

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    Ting-yu WANG, Zhi-yi WANG, Yong-qiang YANG, Xiao-tao MI, Jian-li WANG, Kai-nan YAO, Xue CHENG. Tilt sensor based on differential confocal microscope[J]. Chinese Journal of Liquid Crystals and Displays, 2023, 38(11): 1481

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    Paper Information

    Category: Research Articles

    Received: Feb. 7, 2023

    Accepted: --

    Published Online: Nov. 29, 2023

    The Author Email: Zhi-yi WANG (wangjianli@ciomp.ac.cn), Jian-li WANG (wangzhiyi18@mails.ucas.edu.cn)

    DOI:10.37188/CJLCD.2023-0045

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