折衍射混合环形孔径超薄成像光学系统设计

Design of Refractive Diffraction Hybrid Annular Aperture Ultrathin Imaging Optical System

为了突破基底材料的选择局限性,实现成像波段范围内的高质量成像,在环形孔径超薄成像系统引入成像衍射光学元件,设计了以光学塑料聚甲基丙烯酸甲酯(PMMA)为基底材料、焦距为35 mm、有效孔径为29 mm的4次反射结构的折衍射混合环形孔径超薄成像系统.该系统倍率色差小于2.2μm,在空间频率为166 lp/mm时的MTF值大于0.4,实现了高质量成像.对环形孔径成像系统分别进行了公差分析与热分析,结果表明,在空间频率为166 lp/mm时,各视场的子午和弧矢衍射MTF值大于0.2,在温度0℃~40℃时,各视场的子午和弧矢MTF值大于0.28.

In order to break through the selection limitation of substrate materials and achieve high imaging quality in the imaging wave band,the imaging diffractive optical elements is introduced to the ultrathin annular aperture imaging system.A hybrid refractive-diffractive ultrathin annular aperture imaging system is designed with four reflection structure,and the results of image quality evaluation and tolerance analysis are given.The substrate material of the hybrid refractive-diffractive ultrathin annular aperture imaging system is polymethyl methacrylate(PMMA),focal length is 35 mm,and effective aperture is 29 mm.The results show that the lateral color aberration is less than 2.2μm and the Modulation Transfer Function(MTF)is more than 0.4 at the spatial frequency of 166 lp/mm,thus high imaging quality is achieved.The tolerance analysis and thermal analysis of the annular aperture imaging system are given.The MTFs of tangential and sagittal direction are greater than 0.2 for each field of view when the spatial frequency is 166 lp/mm.The MTFs of tangential and sagittal direction are greater than 0.28 for each field of view at 0℃~40℃when the spatial frequency is 166 lp/mm.