分孔径三视场中波红外光学系统

为了克服单一光学通道长焦距与大视场之间的矛盾,设计了一款分孔径大变倍比三视场中波红外光学系统。该光学系统采用分孔径技术,包括小视场光学通道和中视场/大视场光学通道,两个通道之间的转换通过切出切入45°放置的反射镜完成,小视场光学通道采用二次成像,仅采用6片透镜,透过率高;中视场/大视场光学通道采用三次成像;小视场光学通道与中视场/大视场光学通道共用一片反射镜和中继组,实现了共出瞳分入瞳——分孔径;小视场长焦距为1 120mm,大视场短焦距为22.58mm,变倍比达到53×;对小视场光学通道进行了三次立体折叠,对中/大视场光学通道进行了一次折叠,有效地对横向和纵向尺寸进行了控制,外形包络在270mm×217mm×258mm范围内,系统紧凑,实现了兼具长焦距和大视场的三视场中波红外光学系统。设计及实验结果表明该光学系统像质良好,满足热像仪使用要求。

MWIR optical system with dual-optical aperture and three fields of view

A MWIR optical system with three fields of view as well as dual-optical aperture and large zoom ratio was designed in order to overcome the conflict between long focal length and large field of view of single optical channel.The system was equipped with dual-optical aperture,which was composed of optical channels with a narrow field of view and a middle-wide field of view.The switch of the two channels was realized by cutting in and out a reflector inclined at 45° respectively.Using six lenses,the narrow field of view optical system was a re-imaging optical system with high transmission.The middle-wide field of view optical system was a thrice imaging optical system.The two channels share one mirror and a relay group,thus realizing common exit pupil and dual entrance pupils——dual-optical aperture.The long focal length of the narrow field of view is 1 120 mm,the short focal length of the wide field of view is 22.58 mm,and the zoom ratio reaches 53×.The threedimensional dimensions of the optical system is effectively controlled within 270 mm × 217 mm × 258mm by thrice folding the narrow field of view optical system and once folding the middle-wide field of view optical system.The system is compact and realizes MWIR optical system with three fields of view as well as long focal length and large field of view.The design and experiment results indicate that image quality of the optical system is perfect,which meets the requirements of thermal infrared imagers.