Contents
2023
Volume: 44 Issue 2
8 Article(s)
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Design of Radiation-Proof Long-Wave Infrared Continuous Zoom Optical System
Hai-qing WU, and Da-wei TAN
In order to solve the technical problem of rapid performance degradation caused by radiation when using an infrared thermal imager in a high-radiation environment, based on the mechanical positive group compensation continuous zoom structure, the reflector is introduced into the rear fixed group to form a folding opticIn order to solve the technical problem of rapid performance degradation caused by radiation when using an infrared thermal imager in a high-radiation environment, based on the mechanical positive group compensation continuous zoom structure, the reflector is introduced into the rear fixed group to form a folding optical system, to avoid the back-end detector from the front radiation rays. An uncooled infrared continuous zoom optical system with an operating waveband of 8--12 m, a F-number of 1.2, and a focal length of 25--90 mm is designed. The results show that the system has a reasonable structure and good imaging. The modulation transfer function (MTF) value at the characteristic frequency of 42 1p/mm corresponding to the detector is greater than 0.2, which meets the application requirements. After processing and adjustment, the accuracy of the design is verified by actual imaging test..
- Publication Date: Feb. 01, 2023
- Vol. 44 Issue 2 1 (2023)
Development of Back Thinning Technology for Large-Area Array InSb Detector Chip
Hai-yan LI, Ling-xia CAO, Zi-xian CHEN, Ting HUANG, and Yu CHEN
In order to realize the high quality and high yield back thinning of large size InSb hybrid chips, a single-point diamond turning technology combined with grinding and polishing process is introduced. This process uses single-point diamond turning technology to remove a large amount of thickness of InSb chip, and on thIn order to realize the high quality and high yield back thinning of large size InSb hybrid chips, a single-point diamond turning technology combined with grinding and polishing process is introduced. This process uses single-point diamond turning technology to remove a large amount of thickness of InSb chip, and on this basis, further remove the turning damage through rotary grinding process. Finally the back of 1280×1024 (25 m) large-size InSb hybrid chip is thinned. The half-peak width of the material surface is about 8.20--11.90 arcsec. Compared with the traditional grinding process, this process has strong compatibility with semiconductor chips with large size and poor surface shape, and solves the problems of high crack rate and uneven thinning thickness caused by surface shape problems of large size chips in the traditional grinding process..
- Publication Date: Feb. 01, 2023
- Vol. 44 Issue 2 8 (2023)
Study on Ion Implantation Temperature of Mercury Cadmium Telluride
Bin HE, Huan ZHANG, Gang HAN, Xu-sheng WANG, and Chen LIU
As an important parameter for p-n junction formation, ion implantation temperature has a great influence on lattice defects and material diffusion. During the implantation process of HgCdTe, the implantation temperature greatly affects the size of the implantation region and the morphology of the photolithographic maskAs an important parameter for p-n junction formation, ion implantation temperature has a great influence on lattice defects and material diffusion. During the implantation process of HgCdTe, the implantation temperature greatly affects the size of the implantation region and the morphology of the photolithographic mask. Based on the temperature control of ion implantation process, the beam current, beam energy, roughness of surface and other factors are studied. The influence of implantation temperature on the performance of HgCdTe infrared detectors is investigated by combining the I-V curve of the device. The results show that low beam current, cooling temperature and fine heat conduction surface can ensure that the actual injection temperature is lower than the photoresist temperature, and improve the yield of the process. At the same time, the lower temperature reduces the dark current and diffusion area of the injection region, which contributes to the performance of HgCdTe infrared detectors..
- Publication Date: Feb. 01, 2023
- Vol. 44 Issue 2 13 (2023)
Study on Dislocation Suppression of Si-based CdTe Materials by In-situ Annealing
Zhen LI, Dan WANG, Da GAO, and Wei-rong XING
The epitaxial CdTe buffer layer between silicon and HgCdTe can reduce dislocation density of up to 107 cm-2 generated during epitaxial process. High-temperature thermal annealing is one of the effective methods to suppress dislocations in materials. The traditional out of place annealing technology will lead to processThe epitaxial CdTe buffer layer between silicon and HgCdTe can reduce dislocation density of up to 107 cm-2 generated during epitaxial process. High-temperature thermal annealing is one of the effective methods to suppress dislocations in materials. The traditional out of place annealing technology will lead to process instability and impurity pollution, and in-situ annealing can effectively solve these problems. Dislocation suppress of Si-based CdTe grown by molecular beam epitaxy (MBE) was studied using in-situ annealing technique. The CdTe material with a thickness of about 9 m was subjected to six cycles of thermal cycling annealing at different temperatures. The effect of different annealing temperatures on the dislocation suppression of Si-based CdTe material was explained. Statistical dislocation etch-pits density method was used to compare the dislocation changes of materials before and after annealing. It can be found that the dislocation density can reach 1.2×106 cm-2 when the annealing temperature is 520℃, which is 0.5 orders of magnitude lower than that of the CdTe material without annealing..
- Publication Date: Feb. 01, 2023
- Vol. 44 Issue 2 18 (2023)
Review of GaAs-Based VCSEL Dry Etching Technology
Hao-xuan FAN, Wen-bo ZHANG, Mu-ze LI, and Yong-qin HAO
GaAs-based vertical-cavity surface-emitting laser (VCSEL) has been widely used in various fields since its introduction in 1977 with its advantages such as low threshold current, high beam quality, integration into two-dimensional arrays and easy single-mode maser. However, due to its small size, it is difficult to accGaAs-based vertical-cavity surface-emitting laser (VCSEL) has been widely used in various fields since its introduction in 1977 with its advantages such as low threshold current, high beam quality, integration into two-dimensional arrays and easy single-mode maser. However, due to its small size, it is difficult to accurately control the accuracy in manufacturing, and it is easy to cause morphological damage to the mask and side wall during plasma etching, and too many by-products are generated in the etching process, which affects its application scope and improves the manufacturing difficulty. How to maintain high etching rate and reduce etching damage as much as possible has become a hot research topic. The research status and technical difficulties of GaAs-based VCSEL dry etching technology are analyzed, and the future development trend is prospected..
- Publication Date: Feb. 01, 2023
- Vol. 44 Issue 2 24 (2023)
Design of the Light-Weight Hybrid Refractive-Diffractive Medium-Wave Infrared Zoom Optical System
Yang ZHOU, and Jia-li XIE
Aiming at the 640×512 cooled medium-wave infrared focal plane detector, the optical structure of secondary imaging and the compensatory zoom mode of mechanical positive group are adopted, and the silicon diffraction optical element is used in the design, so as to form the refractive-diffractive hybrid zoom opticalAiming at the 640×512 cooled medium-wave infrared focal plane detector, the optical structure of secondary imaging and the compensatory zoom mode of mechanical positive group are adopted, and the silicon diffraction optical element is used in the design, so as to form the refractive-diffractive hybrid zoom optical system. The results show that MTF is close to the diffraction limit at the spatial frequency of 33 lp/mm. 7 lenses are used in the optical system, and 15--300 mm continuous zoom is achieved in the band of 3.7--4.8 m. The total weight of the optical lens is only 86 g and the total length of the optical system is 139 mm. The optical system has the characteristics of large multiplier ratio, high resolution, light weight and small size..
- Publication Date: Feb. 01, 2023
- Vol. 44 Issue 2 35 (2023)
Research on Image Coding Processing Technology Based on Reduced Bit Rate Design
Geng LI, Yi LIU, Li ZHAN, Jia-bin YANG, Xiang ZHANG, and Meng-meng MA
In order to reduce the redundancy of image data caused by additive noise introduced by aging image acquisition equipment, the effect of additive noise on image and video is studied, and the BM3D (block matching 3D) algorithm to process noisy static images is proposed in this paper. It is verified that the image informaIn order to reduce the redundancy of image data caused by additive noise introduced by aging image acquisition equipment, the effect of additive noise on image and video is studied, and the BM3D (block matching 3D) algorithm to process noisy static images is proposed in this paper. It is verified that the image information entropy and data volume can be reduced by reducing noise. Then the noise reduction-coding scheme is proposed. In this scheme, the noisy video is firstly denoised by VBM4D algorithm, and then encoded by H.264. After the scheme processing, the image information entropy is reduced by 16%, the data volume is reduced by 38%, and the encoded code stream is reduced by 59.5% on the premise that the video quality is not significantly reduced. The data show that the encoding compression rate of H.264 can be significantly improved and the transmission of video in small bandwidth communication systems is promoted by this method under the premise of guaranteeing video quality. Compared with H.264 and neural networks, this scheme has low complexity and can process video relatively in real time..
- Publication Date: Feb. 01, 2023
- Vol. 44 Issue 2 41 (2023)
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