Research On Micro-bolometer Optical Thermal And Electrical Parameters Test Technology

Uncooled infrared focal plane array detector has been more and more widely usedin various fields, with rapid development of infrared detector, the performance of theinfrared detector has received lot of attention. It is urgent to establish a completeinfrared detector performance test platform. But as the important part of infrareddetector, microbolometer test has not been enough attention, in order to establish acomplete infrared test system, microbolometer test is essential.In this dissertation, the measurement technology of optical, thermal and electricalparameters of microbolometer is studied. Firstly, principle of microbolometer andvarious parameters for the theoretical analysis had been described. Then, with theresearch of the parameters of microbolometer, different test method for the parametersof microbolometer is proposed, and the microbolometer which developed by ourlaboratory was tested.Microbolometer is heat detector, its performance is influenced by its thermalparameters, and temperature coefficient of resistance (TCR) is proportional to theresponse. The smaller the thermal conductivity, the larger response, but lead to longerresponse time. Reducing the heat capacity means reducing the response time. The noiseof the microbolometer is affected by the temperature coefficient of resistance andthermal conductivity.For microbolometer photoelectric parameters, the phase lock-in amplifyingtechnology and optical chopper technology are used for the response testing. Themethod can respond to weak response signal, improve the ability and the precision ofthe test. For noise test, two stage amplifiers were used, and then the power spectraldensity of the noise signal was analyzed. So that the influence of the surroundingenvironment and the system noise on the test was reduced. Finally, a standard detectorcalibration test is designed for the test of relative spectrum of microbolometer.For microbolometer thermal parameters, for testing the temperature coefficient ofresistance, the microbolometer is in some temperature of the incubator, and then teststhe resistance of the corresponding temperature. The data to the microbolometer resistance and temperature relationship is obtained. Using the I-V test method for thetest of thermal conductivity, the heat generated by the joule effect by current, and theresistance can be used to get the temperature of the microbolometer, and then thethermal conductivity can be calculated. There is one method to calculate response timeand one method to test it directly. But there is no method to test the thermal capacity, sothat it can only be obtained by calculation or simulation.