无基底焦平面阵列结构优化设计及性能分析

Structure Optimization and Performance Analysis of A Substrate-free Focal Plane Array

基于光学读出非制冷红外成像技术,本文作者提出并成功设计制作了无基底焦平面阵列结构(Focal Plane Array,FPA),不仅简化了制作工艺,而且大幅提升了成像性能。但由于其为单层膜结构,固有频率值低,可能会引起热机械振动噪声(NETDTM),导致噪声等效温度差(NETD)上升。为解决这一问题,本文提出两种改进的加强梁结构,借助有限元简化模型和激光位移传感器,通过数值模拟和实验验证,证实这两种结构可以大幅度提高FPA固有频率值(分别从74Hz提升至835Hz和404Hz),NETDTM降低约两个数量级,从而实现了对FPA的优化设计。

A substrate-free focal plane array （FPA） was proposed and fabricated successfully by authors of this paper based on optical-readout uncooled infrared imaging technique. It has not only simplified the production process,but also improved the infrared imaging quality. However,it is susceptible to mechanical noise （NETDTM） due to the low inherence frequency of monolayer membrane structure,which could lead to the raise of noise equivalent temperature difference （NETD）. In order to solve the problem,two kinds of improved structure with strengthened beam were proposed. These two structures were proved to have a significantly increase of inherence frequency （from 74Hz to 835Hz and 404Hz respectively） and reduce NETDTM by two orders of magnitude based on finite element analysis and experimental results by using simplified model and laser displacement sensor,which consequently carry out the structural optimization of FPA.