双波段共口径共变焦光学系统设计

摘要

In order to identify the both visible and mid?infrared light signals,and achieve the application requirements of synchronous observation and coincident tracking target,a visible/mid?infrared,dual? bandand co?zoom system is designed.The two band information is all received by the same aperture.A method has been used to compensate the focal length and zoom ratio differences between the visible and mid?infrared light.The focal length and zoom ratio of the two bands at any zoom location are similar with the method to meet the requirement of share aperture,common optical path and common?zoom.The design result shows that the zoom ratio is 12×and the focal length range is 7~86 mm.In the normal temperature,the modulation transfer function of visible light band of 0.38~0.76μm and mid?infrared light band of 3 ~5μm is greater than 0.5 and 0.6,at the Nyquist frequency of 80 lp·mm-1 and 20 lp· mm-1 respectively.The volume of the optical system is less than 392 mm×58 mm.The imaging quality meets the requirement.%为了实现可见、红外两个波段同时观测、跟踪及测量的目的，设计了一款可见／中红外双波段连续共变焦光学系统．系统采用共口径方式同时接收可见、红外两个波段的光波．利用直接变倍比差补偿法对两个波段的变倍比差进行补偿，使可见、红外两个波段变倍比相同且在任一变焦位置焦距相等，满足双波段共口径共光路共变焦的要求．设计结果表明：系统变倍比为12×，焦距范围7～86 mm．常温下，可见光工作波段为0．38～0．76μm，其调制传递函数值在空间频率80 lp·mm－1处达到0．5以上；中波红外工作波段为3～5μm，其调制传递函数值在空间频率为20 lp·mm－1处达到0．6以上．总体积小于392 mm×58 mm，成像质量满足设计要求．