基于旋转双光楔的像方扫描大视场成像光学系统设计

Design of Optical System for Wide Field-of-View Imaging with Image Side Scanning Technology Based on Rotary Dual-Wedge

针对无人机传统外挂式光电载荷吊舱窗口尺寸大、无法满足大视场扫描需求的现状,提出了一种基于旋转双光楔的像方扫描红外大视场成像光学系统设计。该系统在传统像方扫描光学镜组基础上引入了双光楔扫描器,以增大系统的扫描视场角,解决了高速无人机目前面临的红外窗口有限且成像视场角小的问题。采用光学设计软件进行了仿真,设计后的光学系统物方视场范围为±21.665°,满足了大视场范围的工作要求。设计结果表明,在工作波段(3.7μm^4.8μm)范围内,该系统的成像质量高,中心视场调制传递函数在33 (lp/mm)空间频率下可达0.45,全视场范围内的调制传递函数>0.42@33 (lp/mm),像点能量集中度较好,接近衍射极限。与传统扫描光学系统相比,采用基于旋转双光楔的新型像方扫描成像光学系统设计,在保证各项设计指标不变的前提下,能够将光学系统的径向尺寸减少20%以上,可满足无人机在未来实现轻量化和小型化的应用需求,拥有良好的应用前景。

In view of the large window size for traditional external photoelectric load pod in the unmanned aerial vehicle(UAV),which can't realize the wide field-of-view scanning,this paper proposes an infrared wide field-of-view imaging design of optical system with image side scanning technology based on rotary dual-wedge.Based on the traditional image side scanning optics,the dual-wedge scanner is introduced to increase the scanning field-of-view in the system,which solves the problem of limited infrared window but small imaging field-of-view faced by high-speed UAV.The optical design software is used to simulate the optical system.The designed object field-of-view is±21.665°,which can meet the requirements of wide field-of-view.The design results show that the imaging quality of the system is high in the laser band of 3.7~4.8μm.The modulation transfer function(MTF)in the central field-of-view can reach 0.45 at the spatial frequency of 33(lp/mm).And the MTF of the whole field-of-view is more than 0.42@33(lp/mm).The energy concentration of image point is good,close to the diffraction limit.Compared with the traditional scanning optical system,this paper adopts a new image side scanning imaging optical system based on rotary dual-wedge,which can reduce the radial size of the optical system by more than 20%under the premise of keeping the design requirements unchanged.The system can also meet the application requirements of lightweight and miniaturization for the UAV in the future,which has a good application prospect.