高变焦比中波红外连续变焦光学系统

MWIR zoom optical system with large zoom range

摘要: 针对高变焦比连续变焦光学系统，提出了一种双双组联动型变焦系统的设计方案，完成了变焦方程的推导。采用非球面技术，运用所推导出的变焦方程，完成了变焦比为40 倍、F 数为4、工作波段为3.7~4.8 m 的中波红外连续变焦光学系统的设计。光学系统由八片透镜组成，引入了四个非球面，可以实现10~400 mm 连续变焦，满足冷光阑效率为100%，变焦曲线平滑无拐点。在不同的变焦位置，光学系统的奈奎斯特频率处（16 lp/mm）MTF 值均大于0.3，RMS 点斑半径均小于22 m。系统具有成像质量高、镜片数量少和结构紧凑等特点。

Abstract: For the continuous zoom system with large zoom range, a design method named double twogroup zoom system was introduced and the correspondent formulas were derived in this paper. Then a MWIR continuous zoom system with zoom range of 40 was designed. The system consisted of 8 elements with 4 aspheric surfaces, and worked in the wave band of 3.7-4.8 m. It performed with 100% cold shield efficiency in the continuous zoom range of 10-400 mm. The F/number was 4 and the zoom paths were smooth. The MTF value in Nyquist limit (16 lp/mm) was more than 0.3 and the RMS radius of the spot diagram was less than 22 m over the full zoom range. The system is of high image quality and compact in structure.