The measurement of sky background infrared radiation is one of the important means to obtain background photoelectric characteristics. For general atmospheric measurement software, regional differences are ignored and particular area sky background optical properties can’t be reflected. A measurement method of sky background infrared radiation characteristic based on infrared image inversion is proposed to solve all these problems mentioned above. Firstly, radiation responsiveness is determined by calibrating the infrared measurement equipment. Secondly, using the equipment, sky background image, atmospheric transmittance and atmospheric path radiation data are obtained. Finally, according to the radiation responsiveness of the measuring equipment and atmospheric transmittance data, the sky background infrared radiation is inversed. The experimental result shows that the sky background luminance data of the proposed method and LOWTRAN7 are in good agreement, meeting the needs of practical application.
Infrared sensors, such as indium antimonide (InSb) detectors, are generally required to be cooled to 77 K in operation. High fracture probability under thermal shock, especially in large InSb infrared focal plane arrays (IRFPAs), limits their applicability. It is necessary to establish a realistic three-dimensional (3-D) structural model of large-format InSb IRFPAs. However, few data are available on 3-D high-fidelity structural modeling and simulation of large IRFPAs due to their complicated structure and huge meshing numbers. A simple equivalent modeling method had been used in our early works, which could reduce meshing numbers, but did not consider the complicated structure, and also brought a new problem that the equivalent outer region of the model was not consistent with the actual IRFPAs. To solve the problems, an improved equivalent modeling method is proposed, where a small-format array is first split into two parts and then employed to equivalently replace the real large-format array. A 3-D high-fidelity structural model of large-format hybrid InSb IRFPAs is developed; here, a 32×32 array is adopted to replace the real 128×128 array. The results show that the simulated stress and strain distribution characteristics of InSb chip are well in agreement with the fracture photograph of actual 128×128 InSb IRFPAs in testing, verifying the validity and feasibility of the 3-D structural model of large-format IRFPAs. All these are beneficial to further explore fracture mechanisms and improve the reliability of large-format hybrid InSb IRFPAs.