Acta Photonica Sinica, Volume. 54, Issue 3, 0318003(2025)
Design of Microscopic Objective with Wide-spectrum and Large Field of View for Micro-LED Wafer Defects Detection
Figures & Tables(17)
Fig. 1. Optical path diagram of an automatic optical inspection system for Micro-LED wafer defects
Fig. 2. Schematic diagram of the focal power distribution of the microscope objective
Fig. 6. Dispersion coefficient and dispersion vector of the optical system
Fig. 10. Performance comparison with commercially available microscope objectives
Table 1. The design index of the microscopic objective
View tableView in ArticleTable 1. The design index of the microscopic objective
Parameters Values Focal length 20 mm Spectral range 420~1 064 nm Field of view 3.3 mm Numerical aperture ≥0.3 Working distance ≥5 mm Parfocal length 95 mm Distortion ≤0.5%
Table 2. Parameters of the sensors
View tableView in ArticleTable 2. Parameters of the sensors
Parameters MV-CH650-90YM-M58S-NN MV-CH250-90TN-M58S-NF Resolution 9 433×7 000 5 120×5 120 Pixel size 3.2 μm 2.5 μm Effective detection range 30.2（H）×22.4（V） 12.8（H）×12.8（V） Maximum frame rate 7 1 frame/s 41.5 frame/s Nyquist frequency 156 lp/mm 200 lp/mm
Table 3. The ray tracing parameters of the initial optical system
View tableView in ArticleTable 3. The ray tracing parameters of the initial optical system
Glass φj/mm-1 yj/mm αj η1j η2j 1 H-TF5 -0.057 0 6.800 0 -1.140 7 -0.128 9 0.014 1 2 H-ZF3 0.027 7 8.459 2 0.856 7 -0.084 5 -0.007 9 3 H-K50 0.013 9 10.651 0.682 5 -0.086 7 -0.006 9 4 H-ZBAF5 -0.019 5 11.036 6 -1.026 5 -0.108 2 0.007 3 5 H-FK71 0.034 3 10.050 1.499 7 -0.063 5 -0.007 2 6 H-FK71 0.021 7 9.538 5 0.854 5 -0.063 5 -0.007 2 7 H-LAF6LA -0.028 3 9.114 3 -1.016 8 -0.107 7 0.002 1 8 H-ZPK7 0.041 9 7.648 7 1.060 7 -0.072 4 -0.002 4 9 H-FK61 0.067 6 4.976 6 0.724 3 -0.063 5 -0.007 2 10 H-LAF10LA -0.154 5 3.821 9 -0.976 1 -0.108 1 0.001 8
Table 4. Optimized optical system′s ray tracing parameters
View tableView in ArticleTable 4. Optimized optical system′s ray tracing parameters
Glass φj/mm-1 yj/mm αj η1j η2j 1 H-QF14 -0.044 3 6.800 0 -0.886 1 -0.129 6 0.020 3 2 H-ZF6 0.022 9 8.112 7 0.651 6 -0.182 2 0.060 2 3 H-K10 0.015 1 9.289 5 0.563 0 -0.0876 -0.007 9 4 H-ZK5 0.017 0 9.404 8 0.651 7 -0.092 4 -0.004 5 5 H-LAF50B -0.051 9 8.894 0 -1.777 0 -0.103 7 -0.001 0 6 H-FK71 0.035 0 8.359 6 1.056 9 -0.057 4 -0.006 4 7 H-FK71 0.030 9 8.283 1 0.917 5 -0.057 4 -0.006 4 8 H-ZLAF69A -0.028 3 8.033 5 -0.788 7 -0.110 2 0.004 8 9 H-ZPK7 0.036 8 7.122 6 -0.731 9 -0.072 4 -0.002 4 10 H-FK71 0.064 7 4.950 0 0.807 0 -0.057 4 -0.006 4 11 H-K50 -0.119 9 3.756 8 0.685 9 -0.086 7 -0.006 9
Table 5. Lens data of microscopic objective
View tableView in ArticleTable 5. Lens data of microscopic objective
Surface Radius/mm Thickness/mm Glass Image Infinity Infinity -- 1 -20.95 9.00 H-QF14 2 45.46 9.00 H-ZF6 3 -122.15 2.78 -- 4 65.89 8.55 H-K10 5 -63.60 1.41 -- 6 76.92 8.63 H-ZK5 7 -64.86 8.94 H-LAF50 8 20.21 7.23 H-FK71 9 -30.48 0.30 -- 10 32.53 4.09 H-FK71 11 -27.30 8.13 H-ZLAF69A 12 979.39 3.73 -- 14 19.07 8.95 H-ZPK7 15 -56.17 0.20 -- 16 8.89 4.42 H-FK71 17 -24.46 1.49 H-K50 18 5.14 8.00 -- Object Infinity -- --
Table 6. Tolerance allocation values
View tableView in ArticleTable 6. Tolerance allocation values
Items Value Fringe power 2λ Surface irregularity 0.2λ Thickness ±20 μm Airspace ±20 μm Tilt ±0.01° Decenter ±10 μm Refractive index ±0.001 Abbe-number ±0.5%
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Huimin HONG, Wenjun HE. Design of Microscopic Objective with Wide-spectrum and Large Field of View for Micro-LED Wafer Defects Detection[J]. Acta Photonica Sinica, 2025, 54(3): 0318003
Paper Information
Category: Microscopy
Received: Sep. 9, 2024
Accepted: Nov. 1, 2024
Published Online: Apr. 22, 2025
The Author Email: Wenjun HE (hewenjun@cust.edu.cn)
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