Study And Optimization On The Fast Cooling-down Process Of Miniature Infrared Detector

With the rapid development of detection technologies, the infrared detectors have gained more and more applications. The upgrading military technology also contributes to the study of miniature infrared detectors, while there are few reports about its fast cooling-down analysis currently. The structure design of a miniature infrared detector for fast cooling-down process is established in this paper, and through the numerical simulation and heat transfer calculation, the structure is optimized to satisfy the actual need.In this paper, heat transfer model of the miniature infrared detector is built, and the affecting actors of fast cooling-down are analyzed by the numerical simulation method. The simulating result shows that the thermal contact resistance has significant effect on the detector cooling-down process. The effects of the initial ambient temperature and the diaphragm surface emissivity show few influence on the cooling-down process of the chip, while the temperature of the throttling cool head has a great impact on the cooling-down process. The faster the temperature drops the shorter the startup time of the chip.The performance of the detector is tested by various cool head schemes. The new structure removes the AlN bracket and spectral layers, where is placed the diaphragm directly. Cold diaphragm using copper-nickel alloy integrated structure makes the thermal contact resistance very small. The numerical simulation and experimental test of new structure shows that it can achieve the design requirements completely.Meanwhile, the effect on the surrounding components by heat transfer within 10 min is further analyzed. When considering the heat conduction, the average temperature of the external components is finally maintained at about 281 K, while when the heat convection is concerned, the temperature is kept at about 279 K within 10 min.