Holographic Compensation-based Optical Readout Technique for Microcantilever IR Image System

摘要

The progress of MEMS-based uncooled infrared focal plane arrays (IRFPAs) are one of the most successful examples of integrated MEMS devices. We report on the fabrication and performance of a MEMS IRFPA based on bimaterial microcantilever. The IR images of objects obtained by these FPAs are readout by an optical method. However, it is difficult to avoid unwanted shape distortions in fabrication, which can degrade image quality in many ways. In this paper, the actual manufacturing errors of FPA are widely and deeply analyzed. There are basically two kinds of manufacturing error. The limitations of both kind of error are given. It is alse pointed out that the detecting sensitivity has its special complexity if the shape of the FPA is not ideal flat. To overcome the difficulties in readout process caused by manufacturing errors, a novel holographic compensating illumination technology was given. The possibilities of actualizing this technology are analyzed in many aspects. And a model of computer generated holographic compensation is given as a further development to be actualized in future The experiment shows that it is a feasible way to improve system performance, especially when it is too difficult to perfect the techniques of an FPA fabrication.