非制冷IRFPA像元结构与时空随机噪声的优化理论

Optimal theoretical study of the pixel structure and spatio-temporal random noise of uncooled IRFPA

非制冷红外焦平面探测器(Uncooled IRFPA)像元结构从单层结构向双层结构的发展降低了探测器噪声,提升了性能。介绍了像元的MEMS结构及主要物理参数,指出双层结构与单层结构的主要差异在于像元有效面积和桥臂热导的不同。三维噪声模型是对IRFPA噪声进行分析的有效手段,其中时空随机噪声是非制冷IRFPA最主要的噪声成份。分析了非制冷IRFPA时空随机噪声的产生机理,建立了时空随机噪声模型,得到时空随机噪声与像元有效面积和桥臂热导的关系。将某款单层像元结构探测器改进为双层像元结构并进行噪声测试,实测数据证明了非制冷IRFPA时空随机噪声模型的有效性。

The development of uncooled IRFPA pixel structure from a single-layer structure to a double-layer structure reduces noise and improves performance.The pixel structure and its main physical parameters are introduced.It is noted that the main difference between the double-layer structure and the single-layer structure lies in the difference in the effective area of the pixel and thermal conductivity of the bridge leg.The 3-D noise model is an effective method to analyze IRFPA noise,in which spatio-temporal random noise is the main noise part of uncooled IRFPA.The mechanism of spatio-temporal random noise in uncooled IRFPA is analyzed,and a spatiotemporal random noise model is established.The relationship between spatio-temporal random noise,the effective area of the pixel,the thermal conductivity of the leg is obtained.An uncooled IRFPA with a single-layer pixel structure is improved by changing it into a double-layer pixel structure,and the noise is measured.The measured data proved the effectiveness of the uncooled IRFPA spatio-temporal random noise model.