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Proceedings Paper

Infrared lens thermal effect: equivalent focal shift and calculating model
Author(s): Cheng-shuo Zhang; Zelin Shi; Bin Feng; Bao-shu Xu
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Paper Abstract

It's well-know that the focal shift of infrared lens is the major factor in degeneration of imaging quality when temperature change. In order to figure out the connection between temperature change and focal shift, partial differential equations of thermal effect on light path are obtained by raytrace method, to begin with. The approximately solution of the PDEs show that focal shift is proportional to temperature change. And a formula to compute the proportional factor is given. In order to understand infrared lens thermal effect deeply, we use defocus by image plane shift at constant temperature to equivalently represent thermal effect on infrared lens. So equivalent focal shift (EFS) is defined and its calculating model is proposed at last. In order to verify EFS and its calculating model, Physical experimental platform including a motorized linear stage with built-in controller, blackbody, target, collimator, IR detector, computer and other devices is developed. The experimental results indicate that EFS make the image plane shift at constant temperature have the same influence on infrared lens as thermal effect and its calculating model is correct.

Paper Details

Date Published: 20 November 2014
PDF: 8 pages
Proc. SPIE 9300, International Symposium on Optoelectronic Technology and Application 2014: Infrared Technology and Applications, 93001U (20 November 2014); doi: 10.1117/12.2072597
Show Author Affiliations
Cheng-shuo Zhang, Shenyang Institute of Automation (China)
Univ. of Chinese Academy of Sciences (China)
Key Lab. of Opto-Electronic Information Processing (China)
Zelin Shi, Shenyang Institute of Automation (China)
Key Lab. of Opto-Electronic Information Processing (China)
Bin Feng, Shenyang Institute of Automation (China)
Key Lab. of Opto-Electronic Information Processing (China)
Bao-shu Xu, Shenyang Institute of Automation (China)
Key Lab. of Opto-Electronic Information Processing (China)


Published in SPIE Proceedings Vol. 9300:
International Symposium on Optoelectronic Technology and Application 2014: Infrared Technology and Applications
Mircea Guina; Haimei Gong; Zhichuan Niu; Jin Lu, Editor(s)

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