Performance Analysis And Bionic Research Of The Substrate-free Focal Plane Array

In recent years, with the development of infrared radiation detection technology and the decrease of its production cost, its application has been developed from military field to industry, medical, meteorological and civil field which includes night vision and safety monitoring. The new optical readout infrared imaging technology has become a hot research field in recent years because of its low cost and high resolution of theoretical limit temperature. Research group designed and fabricated the substrate-free bi-material micro-cantilever infrared focal plane array with multi-fold interval metallized leg, and successfully achieved the infrared image of the human body under atmosphere. This paper based on the previous work of the research group, improved the original theoretical analysis model which was based on temperature-constant substrate, and bionic reaearch of pit vibers has been done. And the dissertation mainly includes the following aspects:(1) Equivalent circuit model of the substrate-free focal plane array based on the optical readout uncooled infrared imaging system. Finite element analysis(FEA) shows that, the substrate-free FPA has a temperature variable support frame structure, the heat of infrared radiation absorbed by one pixel unit influence its neighboring pixel units in the way of point spread function, the original themal analysis model based on the assumption of temperature-constant substrate is no longer efficient any more. Therefore, an equivalent circuit model is presented to analyze the thermal response characteristics of substrate-free FPA with electrics and holistic approach. According to this model, the thermal characteristics of substrate-free FPA under non-vacuum environment were analyzed, result shows that, the substrate-free FPA has excellent infrared imaging performances under standard atmospheric pressure, while its NETD (noise equivalent temperature difference) is just increased several times than in the vacuum environment.(2) Bionics reaearch of pit vibers on infrared imaging of substrate-free FPA. There are three parts of pit viber:the inner cavity, the external cavity and the membrane, which is separated from the biological substrate by an air gap with the thickness of 1 millimeter. In this paper, FEA model of pit viper with substrate-free structure is eatablished and whose thermal response characteristics has been analyzed after, so does another pit viper with the assumption of substrate not free. The infrared imaging performances of these two kinds of membrane were analyzed by the method of the centric thermal loading and the periodic thermal loading. Then, the FEA models of the substrate-free FPA fabricated by reaearch group and the traditional FPA are eatablished. The infrared imaging performances of these two kinds of FPA are analyzed by the method of the centric thermal loading and the periodic thermal loading. The equivalent total thermal and thermal response time of the substrate-free FPA and traditional FPA under non vacuum conditions are further analyzed. The results show that the substrate structure is very difficult to achieve the infrared imaging of the atmospheric pressure. Finally, the infrared imaging of the human body under atmospheric pressure is realized by the substrate-free FPA.(3) Detection of thermoforming defects of ballonet materials based on phase-locked infrared technology. Aerostat ballonet material usually consists of composite fiber materials thermoformed together, and bubbles, impurities and virtual thermoforming defects will appear in the thermofoming process. The author presented an approach to detect these defects with phase-locked infrared technology, and developed the equipment after. In this paper, the detection principle and design scheme of the system are introduced. Then, the standard phase database is established according to the material and parameters of the ballonet. Meanwhile the best detection sensitivity is achieved by the determining of the optimum detection frequency; finally, two ballonet which were prefabricated different defect types are detected by the developed equipment, test results show that, the device can identify different defect locations, sizes and types according to the phase differences comparing with the phase dataphase, the successful implementation of the ballonet thermoforming defects detection shows high reliability and strong anti-interference ability of the developed equipment.In addition, author also engaged in other reaearch areas during the graduat studies, mainly include:(1) Three Dimensional Shape Accuracy Measurement Based On Digital Image Correlation. Study on measurement accuracy of 3D DIC method has been a topic of common concern to domestic and foreign scholars, author set up a dual camera 3D DIC system, one RMB coin is selected as the test object,3D surface topography is reconstructed after the calculation of the captured speckle pattern images, local features of the topography are choosen to compared with the results got by step profiler. The results show that the measurement accuracy of 3D DIC method can reach 3μm when the visual field is 30mm30mm, which means the measurement accuracy of the 3D DIC method reaches 1/10000 of visual field.(2) Development of teaching equipment for three dimensional digital image correlation. With the increase of applications of 3D DIC, college has the demand of teaching students how to using 3D DIC equipments. Author develops a set of equipments includes 2D DIC and 3D DIC analysis software, loading device, species for teaching work and standard teaching experiments. According to which, students learn the theory of DIC, understand the sources of precision and master the operational approach.(3) Research and development of micro-cantilever array biochemical sensor based on acoustic optical modulation technology. In this paper, a micro-cantilever array sensor based on acoustic optical modulation is designed, and the effectiveness of the device is verified by the experimental results of the system temperature sensitivity experiment and the detection of the concentration of clenbuterol.