红外光学系统出瞳与冷屏匹配方式及渐晕分析计算

红外光学系统在用于制冷型的探测器时必须考虑出瞳与冷屏的匹配问题,采用二次成像方式进行光瞳匹配导致光学系统结构复杂化使系统透过率降低,采用光学结构简单的不完全匹配方式会存在轴外视场渐晕,但能有效地提高视场中心的透过率,而红外光学系统在用于点目标的跟踪测量时往往用到的是一定范围的中心视场.在本文中,我们分析了几种不同的匹配方式并给出了用冷屏参数表示的估算轴外渐晕的计算公式以便在像差校正之前判断渐晕的大小及采用何种匹配方式以提高光学系统性价比.

The Match Form Between Exit Pupil and Cold Shield and the Vignetting Calculation at a IR Optical System

The matching between the exit pupil with the cold shield must be considered when a cooling detector is used in IR optical system.The secondary imaging form makes the optical configuration complicated and the system transparence is suppressed.The optical configuration is simple if the aperture stop is positioned behind the lens in a certain distance(the incomplete matching form),but the vignette is occurred in this case.Different matching forms result in different system transparency.The transparence at the center of view is improved effectively with the incomplete matching form.It is useful in tracking point target.Several matching forms are discussed.The formulas expressed by cold shield parameter are given to calculate the vignette and amount of vignette is estimated and the matching form can be decided before aberration correcting.