Model, Simulation And Design Application Of Microbolometer Infrared Focal Plane Detector

The technology of uncooled infrared focal plane arrays (FPA) is a new developing way for wide commercial applications and military applications, for it owns the advantages of light weight, no need of cryogen, low cost and so on. This project is to do the related research about uncooled infrared FPA.This project is focused on microbolometer FPA. This program includes the development design and simulation tools, material research, fabrication process development, and detector and readout circuitry design, fabrication and characterization. The work done in this paper is described as follows:The theory of microbolometer FPA is expounded. Two important types of uncooled detectors are discussed and compared in detail. Research work is generally described.The main work is focused on the establishment of mathematic model for a microbolometer detector, in order to simulate the structure characteristic and the optical and electrical characteristics. After discussing the simple model, the finite element analysis model is proposed and established, for which a special computer program is programmed. This program can be used to analyze not only static characteristics also transient response ones. A strong base is established for the development of a software tool of microbolometer design and simulation in this paper.Using simple model of a microbolometer biased by pulse, useful practical equations and numerical estimates for the responsivity are derived. Noise, NEDT, NEP, and detectivity of microbolometer arrays are also considered. The work will provide the insight necessary to understand the optimum design and practical operating requirements of microblolmeter arrays. This paper provides a low cost and more practical software tool for predicting and evaluating parameters of the detector.The last effort in this paper is concentrated on the readout circuitry of microbolometer arrays, which is connected to the detector array on chip to forma monolithic chip, and the non-uniformity correction. Besides introducing some different ways of readouting the signal of detector pixel, the principle circuitry of the whole array is also put forward. And a kind of temperature compensated load circuit is put forward to improve the offset correction and the gain correction for non-uniformity.