为了满足紫外告警相机的特殊应用需求, 分析了超广角光学系统的结构形式、像差平衡以及像面照度的一致性。设计了工作于0.254~0.272 m波段的大视场、大相对孔径紫外光学系统, 其视场角为120°, 相对孔径为1/2。该系统采用反远距, 准像方远心光路设计, 减小了轴外视场和轴上视场的像面不均匀性; 通过优选光学材料并合理分配光焦度优化了系统特性。实验显示, 该系统在满足成像质量要求的前提下, 具有成像畸变小、像面照度均匀等特点。光学系统全视场最大弥散斑半径小于63.5 m, 轴上、轴外视场像面照度均匀性小于10%, 0.71视场的相对畸变小于20%。整个光学系统结构紧凑, 满足设计指标要求, 适合紫外告警相机的使用。

For the special use demands of ultraviolet warning cameras, the structures, distortion balances and the consistency of image plane illumination of ultra wide-angle optical systems were analyzed. An ultraviolet optical system with a large field of view of 120° and a large relative aperture of 1/2 was designed. The system is a double imaging configuration with the spectral range from 0.254 m to 0.272 m. By using inverse telephoto structure, its back working length is 7.48 mm. A quasi-telecentric optical system was selected to improve the illumination uniformity for off-axis and on-axis view fields. Then, by choosing optical materials and distributing the focal powers reasonably, the optical system was optimized. The experiments demonstrate that the system is characterized by smaller imaging distortion and uniform image plane illumination, the dispersion spot diameter is smaller than 63.5 m, and the relative distortion at 0.71 field of view, the relative illumination uniformity for off-axis and on-axis view fields are less than 20% and 10%,respectively. The structure of the whole system is compact and feasible, and is suitable for ultraviolet warning cameras.