红外技术, 2018, 40 (2): 119, 网络出版: 2018-03-21
紧凑型中波红外成像系统无热化设计
Athermalization Design of Compact Medium-wave Infrared Imaging System
中波红外成像 卡塞格林系统 光学设计 紧凑型 消热差 MW infrared imaging infrared Casey Grain system optical design compact athermalization
摘要
红外成像光学系统应用日益广泛,并且对小型化有了更高要求,因此提出一种紧凑型中波红外成像系统的无热化光学设计。首先针对需求对光学参数进行了分析与计算,根据参数要求采用卡塞格林系统缩短系统纵向尺寸,然后用中继透镜组校正像差,考虑到透镜易于加工、成本低,中继透镜组采用全球面面型,最终实现了卡塞格林系统的次镜到红外探测器之间的尺寸小于47 mm,使系统足够紧凑。通过合理选择材料以及光焦度的分配,推导光学被动消热差方程,计算出系统的初始结构,利用Zemax 光学设计软件进行优化,最终实现波段为3.7~4.8 μm,视场为3°×3°,温度范围-40℃~+50℃消热差结果,在空间频率17 lp·mm-1 处,各视场光学调制函数(MTF)值均大于0.5。
Abstract
As the infrared imaging optical system is used more and more widely with higher requirement to miniaturization, an athermal optical design for a compact medium wave infrared imaging system has been proposed. At the beginning, the optical parameters were analyzed and calculated based on the requirements, the vertical size of system was shortened by utilizing Casey Green system in accordance with the parameter requirement, and then the relay lens set was used to correct the aberration. Considering the lower processing cost of the lens, a full global surface type was adopted for the relay lens set, which finally shortened the size between the secondary lens of Casey Green system and the infrared detector by 47 mm, making the system sufficiently compact. Through the rational selection of material and distribution of focal power, the optical passive differential equation of heat elimination was derived and the primary structure of the system was calculated consequently. By means of optimization of Zemax optical design software, the heat dissipation results, such as 3.7-4.8 μm of wave, field of view of 3°×3° and the temperature range of -40℃-+50℃, were eventually realized. Moreover, in a place with space frequency of 17 lp·mm-1, the optical modulation transfer function (MTF) values of each field of view were all greater than 0.5.
李瑞瑶, 付跃刚, 刘智颖. 紧凑型中波红外成像系统无热化设计[J]. 红外技术, 2018, 40(2): 119. LI Ruiyao, FU Yuegang, LIU Zhiying. Athermalization Design of Compact Medium-wave Infrared Imaging System[J]. Infrared Technology, 2018, 40(2): 119.