Infrared and Laser Engineering, Volume. 54, Issue 1, 20240439(2025)
Design and test of the central support structure of the focusing secondary mirror of the large-aperture off-axis three-mirror infrared camera
Figures & Tables(16)
Fig. 3. Finite element model of the secondary mirror and its supporting structure
Fig. 7. Vibration test of the secondary mirror and focus adjustment mechanism, and their coordinate directions
Fig. 8.
Fig. 9.
Fig. 10.
Fig. 11. Surface shape of the secondary mirror after vibration test of the mirror assembly
Table 1. The surface figure accuracy requirements of the secondary mirror under gravitation and 10 ℃ temperature loads
View tableView in ArticleTable 1. The surface figure accuracy requirements of the secondary mirror under gravitation and 10 ℃ temperature loads
Working condition Requirement 1 g gravity Surface figure accuracy RMS≤6 nm 10 ℃ temperature rise Surface figure accuracy RMS≤8 nm Mass ≤3 kg Mechanical test changes ≤0.003λ
Table 2. Comparison of properties between silicon carbide and traditional materials
View tableView in ArticleTable 2. Comparison of properties between silicon carbide and traditional materials
Property SiC Zerodur ULE Be Density/103 kg·m3 3.05 2.53 2.21 1.85 Elastic modulus/GPa 330 90.3 67.6 290 Specific stiffness 13.1 3.64 3.12 16 Thermal conductivity coefficient/W·mK−1 185 1.46 1.31 159 Coefficient of thermal expansion/10−6·K−1 2.5 0.02 0.03 11.4
Table 3. Optimization results of the main parameters of the secondary mirror
View tableView in ArticleTable 3. Optimization results of the main parameters of the secondary mirror
Serial number Parameter Initial value Final value 1 H1 4 3.1 2 H2 4 3.3 3 L 50 60 4 D1 170 167.6 5 D2 184 177.6 6 m 2.9 kg 2.5 kg
Table 4. Optimized secondary mirror deformation under 1
g gravity and 10 ℃ thermal loadView tableView in ArticleTable 4. Optimized secondary mirror deformation under 1
g gravity and 10 ℃ thermal loadWorking condition Surface figure accuracy RMS/nm 1 g gravity 2.9 10 ℃ temperature rise 4.1
Table 5. Vibration test conditions for the secondary mirror and focus adjustment mechanism components
View tableView in ArticleTable 5. Vibration test conditions for the secondary mirror and focus adjustment mechanism components
Direction Frequency/Hz Vibration Scan rate/oct·min−1 X 5-15 1.67 mm （O-P） 4 15-84 2.7 g 85-100 1 g Y 5-15 2.48 mm （O-P） 4 15-84 4 g 85-100 1.5 g Z 5-20 3.29 mm （O-P） 4 20-100 5.3 g
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Chengbin WANG, Tingliang HU, Haijia CONG, Haitao YUAN. Design and test of the central support structure of the focusing secondary mirror of the large-aperture off-axis three-mirror infrared camera[J]. Infrared and Laser Engineering, 2025, 54(1): 20240439
Paper Information
Category: 光学设计
Received: Sep. 21, 2024
Accepted: --
Published Online: Feb. 12, 2025
The Author Email: CONG Haijia (c11s021011@163.com)
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