Design Of Zoom Objective With Wide Spectrum And Telecentricity In Imaging Spectrometer

Imaging spectrometer can obtain continuous spectral images while acquiring the twodimensional spatial information of the target.In other words,the imaging spectrometer can simultaneously collect the information of the spectral dimension and the spatial dimension.Since spectral information can be used to identify and classify target attributes,twodimensional image information can also provide the spatial distribution characteristics of target radiation,this combination of image and spectral information makes the imaging spectrometer become one of the most important observation instruments for space-to-ground at present.The special application mode of imaging spectrometer has many corresponding design requirements for its front-end objective lens,such as wide spectrum,telecentric,achromatic,zoom,etc.,which increase the difficulty of objective lens design and have an important impact on the final spectral imaging quality,so it is necessary to focus on the design of objective lens module.This article is aimed at the mask spectrum imaging spectrometer for the broad spectrum of visible and infrared light,and in-depth study of the design of telecentric front objective lens.Focused on design and analysis of the features such as zoom and wide-spectrum achromatism.Among them,the zoom system adopts a mechanical compensation method to achieve 3x zoom of the front objective lens.In the wide spectrum achromatic design,the minimum deflection angle method is used to carry out optical automatic screening for glass combination,which simplifies the process of selecting the initial structure and improves the overall efficiency of the optical system design.The design of a wide-spectrum achromatic zoom objective optical system capable of working in the spectral range of 400nm-1000 nm,the focal length in the range of 49.3mm-148 mm,and the F-number of 4.3 is finally completed.The secondary spectrums at all three focal lengths are less than 0.045 mm.It achieves telecentricity.The modulation transfer function value at 66lp/mm is greater than 0.5,which is close to diffraction limit and has good imaging quality.In addition,the cam curve and tolerance analysis results of the zoom system are also given in this paper,which provides a theoretical reference for actual processing.