Design of hyperspectral imager equivalent focal plane assembling module

Abstract

When assembling CCD of hyperspectral imager,20 μm focal depth should be satisfied in longitudinal direction,and alignment in spectral and spacial direction should also be achieved. An equivalent focal plane assembling module is designed to avoid frequent installation of expensive CCD during measurements.The equivalent module is precisely manufactured according to measured dimensions of CCD module. It also provides simulated spectral image that could be observed by microscope. By measuring distance between real and simulated spectral image,spacer's reshape value is calculated,and spectral image is aligned to CCD laterally. Experiment shows that the whole spectral image's defocusing value is in focal depth in the presence of tool microscope measuring error,spacer reparation error and interchangeability error. MTF is higher than 0. 3after 3 iterations in experiment,which shows an improvement on efficiency and safety.