在致冷型红外光学系统中加入温栏会引入杂散辐射。杂散辐射包括温栏自身的辐射及对外部热光的反射。这两种辐射进入探测器后，会降低系统的信噪比和动态范围，影响成像质量。基于辐射及传热理论，提出温栏杂散辐射所引起噪声等效温差的计算模型，并研究了消除温栏杂散辐射的方法。用LIGHT TOOLS进行了光线追迹，对比分析了传统平面环状温栏和球面反射镜型温栏的杂散辐射，验证了理论推导的正确性和消除方法的可行性。结果表明，采用半径为30.3 mm的高反射率球型温栏代替原设计中的粗糙平面型温栏，控制其曲率半径和位置，可使由温栏引入的杂散辐射降低99%以上。

Stray radiation may be introduced after warm shields are mounted in cooled infrared systems. The stray radiation consists of radiation and reflection from the warm shields. Since it degrades the SNR, dynamic range and image quality of the system, it shall be avoided by design. The stray radiation was analyzed based on the theory of radiation and heat transfer, and NETD was calculated. The scheme to avoid stray light effects was proposed and verified by ray tracing. The stray radiation of flat shields and spherical reflective shields was analyzed and compared in LIGHT TOOLS. Stray radiation effects were avoided if spherical reflective warm shields with proper radius are properly positioned. A spherical reflective warm shield with radius 30.3mm was used to replace the original flat one, and the stray radiation dropped by more than 99%.