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2021
Volume: 42 Issue 7
8 Article(s)
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Athermalized Design of Infrared Optical System with Large Field-of-View Based on Chalcogenide Glass
Hai-qing WU
In the infrared optical system with a large field-of-view, the optical passive athermalization system based on ordinary infrared optical materials has the technical problems of a large number of lenses, and it is difficult to achieve lightweight and miniaturization. To solve this problem, a combination of chalcogenide In the infrared optical system with a large field-of-view, the optical passive athermalization system based on ordinary infrared optical materials has the technical problems of a large number of lenses, and it is difficult to achieve lightweight and miniaturization. To solve this problem, a combination of chalcogenide glass and common infrared materials is used to achieve passive optical athermalization, and a miniaturized uncooled infrared imaging optical system with a field-of-view of 40°×32.5° is designed. Its operating waveband is 8～12 m, the F number of the optical system is 1.0, and the operating temperature range is -55℃～+70℃. The design results show that the system has a simple and compact structure and good imaging performance. The modulation transfer function(MTF) value at the spatial frequency of 42 1p/mm is greater than 0.3, which can meet the application requirements of actual projects..
INFRARED
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 7, 1 (2021)
Study of Regional Overheating Dead Pixels in InSb IRFPA Detectors
Yu CHENG, Zhi-hong GONG, Yu XIAO, Ting HUANG, Tao WEN, Zhe KANG, and Ti NING
Regional overheating dead pixels problems of InSb infrared focal plane detectors was studied. Through fault analysis and targeted investigation and comparison tests, factors such as packaging, glue filling and dicing are eliminated, and the fault is located before the passivation process. Through the X-ray photoelectroRegional overheating dead pixels problems of InSb infrared focal plane detectors was studied. Through fault analysis and targeted investigation and comparison tests, factors such as packaging, glue filling and dicing are eliminated, and the fault is located before the passivation process. Through the X-ray photoelectron spectroscopy test on the surface of InSb materials before passivation, it is found that it contains impurity elements such as Al and As, and the surface of the material contains more impurities before passivation. Impurity elements form impurity levels in the depletion region of the PN junction. Impurity elements form impurity levels in the depletion region of the PN junction. After voltage is applied, it is easy to cause high leakage current of the PN junction, degrade the I-V characteristics, and form overheating dead pixels. By reducing the washing liquid replacement period of the cleaning appliance and separating the appliances of multiple production lines, the content of impurities on the surface of the material is reduced, and the problem of regional overheating dead pixels is effectively solved..
INFRARED
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 7, 9 (2021)
Research on Terahertz Dual-passband Filter Based on Frequency Selective Surface
Tian-cheng LI, and He-ming CHEN
The current dual-band frequency selective surface (FSS) structure has limited passband frequency selection performance. In order to improve the performance of the terahertz band passband filter device, a terahertz dual-passband filter based on FSS is designed. The device is mainly composed of three layers of concentricThe current dual-band frequency selective surface (FSS) structure has limited passband frequency selection performance. In order to improve the performance of the terahertz band passband filter device, a terahertz dual-passband filter based on FSS is designed. The device is mainly composed of three layers of concentric metal copper rings in a regular quadrilateral, with a dielectric substrate loaded in the middle. The thickness of the metal layer and the substrate are both 0.04λ, where λ is the wavelength of the low frequency band, and the unit size is 0.15λ. According to the equivalent circuit method (ECM), the reason for the dual-frequency passband of the structure is analyzed, and the structural optimization of the design is further discussed. The geometric parameters of the original structure are equivalently adjusted by changing the parameters of the equivalent circuit components. The simulation results are basically consistent with the theoretical calculations. The optimized device can achieve passband filtering at two center frequencies of 2.74 THz and 8.17 THz. The band range at lower frequencies with insertion loss less than -1 dB is 2.24~3.25 THz, where the maximum insertion loss is only -0.05 dB. At higher frequencies, the band range is 7.63~8.71 THz, where the maximum insertion loss is just -0.12 dB. The steepness of the filter characteristic curve is good, and the relative bandwidth exceeds 10%. The structure has small size, good frequency selectivity, and high angular stability. It can be used for broadband filtering in the terahertz frequency band, and has important application value for future terahertz communications..
INFRARED
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 7, 17 (2021)
Research on the Influence of Optical Lens Arrangement on Aerodynamic Characteristics of Airborne Optical Window
Rui-juan DU, Song-hao LU, Bai-jian YANG, and Jia-liang CHUANG
In order to reduce the impact of aerodynamic load on the airborne optical window and explore the influence of the optical lens arrangement on the aerodynamic characteristics of the optical window, three optical windows with different optical lens arrangements are designed in this paper. Through the dynamic numerical siIn order to reduce the impact of aerodynamic load on the airborne optical window and explore the influence of the optical lens arrangement on the aerodynamic characteristics of the optical window, three optical windows with different optical lens arrangements are designed in this paper. Through the dynamic numerical simulation analysis of these optical window models, the influence of different optical lens arrangements on the aerodynamic characteristics of the optical window is studied, and the model with the least air resistance and the best aerodynamic characteristics is obtained. According to the model′s wind resistance under 0° angle of attack, the simulation analysis of model′s structural mechanics characteristics is carried out. The results show that the optical window model will not be damaged by impact under the wind resistance load, and meets the requirements of rigidity and strength..
INFRARED
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 7, 26 (2021)
Optimal Selection of Medium-Wave Channels in Hyperspectral GIIRS and Its Influence on Cloud Detection
Gen WANG, Li-ying SHAO, Wei-dong DING, Jiao CHEN, Ni LIU, and Fei XIE
The optimal selection of medium-wave channels in the geostationary interferometric infrared sounder (GIIRS) of FY-4A is one of the key technologies for effective variational assimilation of the data, which can reduce the ill-posed assimilation and inversion caused by redundant information. In this paper, the general enThe optimal selection of medium-wave channels in the geostationary interferometric infrared sounder (GIIRS) of FY-4A is one of the key technologies for effective variational assimilation of the data, which can reduce the ill-posed assimilation and inversion caused by redundant information. In this paper, the general entropy reduction method is applied to GIIRS channel optimization. In addition, since the observations of infrared sounders are easily affected by clouds, cloud detection is needed to obtain field points or cloud parameter information in the clear sky during the variational assimilation of GIIRS bright temperature data. In this paper, the minimum residual method is used to conduct cloud detection of GIIRS data. This method can not only determine whether there are clouds, but also obtain the information of effective cloud amount and cloud top pressure at the field-of-view. Since the detection accuracy is affected by the combination of different channels, the influence based on the data of Typhoon "Lekima (2019)" is further discussed in this paper..
INFRARED
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 7, 36 (2021)
Research on the Application Effect of Breast Cancer Examination Based on Infrared Thermal Imager
Yu-ying CHEN
Breast cancer is the cancer with the highest morbidity and mortality among women worldwide. Using infrared thermal imaging can detect early breast cancer and reduce the death rate. The research results at home and abroad are used for reference, and the infrared thermal imaging method under the dual induction of cold enBreast cancer is the cancer with the highest morbidity and mortality among women worldwide. Using infrared thermal imaging can detect early breast cancer and reduce the death rate. The research results at home and abroad are used for reference, and the infrared thermal imaging method under the dual induction of cold environment and thermoelectric excitation is adopted to solve the problem of poor application effect of infrared thermal imaging of small size and deep breast cancerous tissue in the paper. The contrast of infrared thermal imaging is significantly increased, and the temperature contrast in the power-on mode is increased by 26.5%. The results show that the thermal contrast is mainly affected by the size, depth and temperature of the cancerous tissue, as well as the ambient temperature and heat transfer coefficient. In this paper, the thermal contrast ratio is improved by controlling the ambient and the heat source temperature at the same time, and the effect of early detection for breast cancer is expected to be increased by more than 50%..
INFRARED
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 7, 43 (2021)
Application of LiDAR System and VHR Data in Building Detection and Mapping (II)
[in Chinese]
INFRARED
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 7, 50 (2021)
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