摘要
自由曲面具有较高的自由度,在保证光学系统成像质量的同时有效地减少光学元器件的数量。根据三级像差理论设计一套传统卡塞格林望远镜系统。将次镜由双曲面替换为X-Y多项式表征的自由曲面,增大系统视场,通过ZEMAX软件对系统进行优化,并对系统成像质量进行分析。设计结果表明:在未加入任何类型视场校正器前提下,通过优化,该望远镜的对角线视场达到1. 7°。在1. 7°视场范围内,系统点列图的最大RMS半径为13. 15μm。在奈奎斯特频率25 lp/mm处,系统的调制传递函数值均大于0. 4。系统衍射能量的80%集中在直径为30μm的包围圆内,小于两个像素尺寸宽度。该系统结构简单,体积小,重量轻,适用于航空遥感环境。
Freeform surface has high degree of freedom and is capable of reducing the number of optical elements while assuring the imaging quality of an optical system. A conventional Cassegrain telescope system is designed according to the third-aberration theory. The secondary mirror is replaced by the freeform surface represented by the X-Y polynomial. The system is thereby optimized and analyzed by the software ZEMAX when the field of view( FOV) is enlarged. The design results indicate that the diagonal FOV of the optimized system can reach 1. 7° without any field corrector. Within the 1. 7° FOV,the maximum RMS radius of the system's spot diagram is 13. 15 μm. At the Nyquist frequency of 25 lp/mm,all the MTF values are bigger than 0. 4. 80% of the diffraction energy of the system is within a cycle with a diameter of 30 μm which is less than the width of two pixels. The system is simple in structure,small in size,light in weight,and suitable for airborne remote sensing environment.
引文
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