紧凑型偏视场多光路耦合同轴四反光学系统设计

Design of high-density coaxial four-mirror optical system with field-bias and multi-light-channel coupled

随着轻小型卫星技术的不断发展,紧凑型光学载荷成为空间光学领域一个新的研究热点。偏视场多光路耦合同轴四反光学系统具有长焦距、大视场和高轻量化水平等优点,可以更好地满足光学载荷高分辨率、多功能性、轻小型和低成本的应用需求,因此在轻小型光学遥感载荷领域有着广泛的应用前景。以高斯光学和三级像差理论为基础,对同轴四反光学系统的初始结构进行了分析。以一种适用于推扫成像的偏视场可见光、中波红外耦合成像光学系统为例,实例中可见光通道焦距4 m,工作谱段0.45~0.85μm,相对孔径1∶10,中波红外通道焦距1.6m,工作谱段3.7~4.8μm,相对孔径1∶4,各通道视场角均为1.4°×0.2°。同时对系统成像质量及公差进行了分析,从分析结果可以看出,各通道成像质量均接近衍射极限,系统光学总长优于f’visible/5.48,具有较高的压缩比,且系统的加工和装配公差较为宽松,易于实现。

With the increasing development of light and small satellite technology,high-density optical payload has become a new hotspot research in space optical field.The field-bias and multi-light-channel coupled coaxial four-mirror optical system has the advantages of long focal length,large field of view and high degree of lightweight,which can satisfy the high-resolution,multi-function and low-cost applications of the optical payloads.Therefore,it has a widely application prospect in the field of light and small optical remote sensing payloads.Based on Gaussian optics and third-order aberration theory,the initial configuration of the coaxial fourmirror optical system was analyzed.An example of field-bias with visible spectrum and MWIR spectrum coupled optical system which was suitable for push-scanning was given.The visible channel has a focal length of 4 m,working spectrum of 0.45-0.85μm,relative aperture of 1∶10,the MWIR channel has a focal length of 1.6 m,working spectrum of 3.7-4.8μm,relative aperture of 1∶4,and the FOV of both channels are 1.4°×0.2°.The imaging quality and tolerance of the system were analyzed,from the results of the analysis,the imaging quality of each channel approaches the diffraction limit,the total length of the optical system is less than f’visible/5.48,the system has higher compression ratio,and has easily implemented quality because of the relatively loose tolerance about processing and assembling.