Research On Key Techniques Of Uncooled Infrared Focal Plane Detector System

The thermal imaging technology, or infrared (IR) imaging technology, is one of the most important night vision technologies. By converting the information in infrared band into the naked eye recognizable one, or visible signal, it can realize observing and tracking in the dark conditions. The core device in the thermal imaging technology is the IR detectors. Among them, the uncooled infrared detector has got broad application in the civil, industrial and military areas due to its advantages in price, volume and weight.In the light of the night or outdoors application, this dissertation proposed an uncooled infrared focal plane detector system and its power management system. In this system, the following parts have been researched and discussed as the key techniques including the signal processing circuit of uncooled infrared focal plane detector, the non-uniformity correction method of infrared focal plane, the maximum power point tracking (MPPT) control system of photovoltaic cells, the battery charger control system of photovoltaic cells, and the single inductor multiple (dual) outputs (SIDO) Buck converter controller with self-adapted pseudo continuous conduction modes (PCCM). After comprehensive investigation and thorough analysis, the detector system's structure has been proposed, and the control scheme has been decided. Circuit chips have been designed, processed, and tested, and the test results agree with the expects.The main works and innovation achievements are shown as follows.(1) Based on the research of infrared detect resistor, pyroelectric bolometer, ferroelectric bolometer, and temperature differential electric detector, the scheme of using infrared sensitivity resistor has been proposed, and the correspondent floorplan process and specification of detector have also been proposed. Then the 320X240 pixels array signal processing circuit has been designed and simulated, the circuit of which including digital control part and active pixel signal process circuit, blind pixel signal process circuit, integrator circuit, sampling circuit and etc. The noise issue has been discussed deeply. The simulation results agree with what has been expected for. The chip has been processed in HHNEC 0.5um process, the test result has been analyzed.(2) Based on the summary of the two points temperature correction method, the constant statistic average method, the high pass filter correction method, the artificial neural network method, the algebra algorithm based on scene, and the self-adapted algorithm based on the interference cancelled principle, a new self-adapted correction algorithm of non-uniformity has been proposed. This method can adjust the gain factor and offset factor of the non-uniformity correction according with the variation of temperature. The test results have been verified by simulation results in Matlab.(3) In the light of mobile application of this system, the power management system of infrared focal plane detector has been proposed which can utilize the photovoltaic energy. The power management system includes three parts:energy acquisition part, charging control part and energy assignment part. The maximum power point tracking of photovoltaic cells and charging control of batteries have been solved as important issues. Based on the analysis of three MPPT control policy, which are constant voltage method, interference observation method, and the conductance increment method, a new MPPT control policy which integrates the two methods of constant voltage method and interference observation method, has been proposed. This chip has been processed and tested, the function has been achieved. In the light of the working condition of infrared focal plane detector and the battery charge control, a new battery charge control circuit has been brought up, which utilizes four phases charge method. The chip has also been processed and tested, the test results verifies the design idea. Besides, in the light of multiple power supplies of the infrared focal plane detector, a new Buck converter controller with single inductor multiple (dual) outputs (SIDO) structure has been proposed. To prevent the crosstalk and realize large drive ability, the pseudo continuous conduction mode scheme has been proposed. And the load current level can be adjusted according with the load conditions, therefore the self-adapted control has been realized.This dissertation has given a deep research and analysis of the important technology of the uncooled infrared focal plane detector system and its power management. The research work includes system constituted, circuit designed, control scheme with algorithm and back-end realization. The good results have been achieved. The accumulated experience will give positive impetus to the research and realization of uncooled infrared focal plane detector system.