为降低严重的外杂散光对红外探测系统成像性能的影响，对系统的遮光罩、挡光环和镜筒的消光螺纹设计优化。通过 ProE软件和 TracePro软件建立红外镜头的光机模型，采用正向光线追迹法，进行杂散光仿真分析，计算不同的光源离轴角度下的点源透过率值（PST），结合 MATLAB软件绘制不同疏密程度的消光螺纹镜头消杂散光的 PST曲线，并进一步验证三角形消光螺纹的抑制效果。结果表明：设计的挡光环能抑制部分杂散光；添加合理的消光螺纹后能有效抑制红外镜头杂散光；适当增加消光螺纹的密度并采用三角形螺纹，相比无消光螺纹情况下 PST值下降 1～2个数量级。当杂散光入射角大于临界入射角 30.时，杂散光抑制能达到阈值指标，满足杂散光抑制工作需求。

To reduce the influence of severe external stray light on the imaging performance of an infrared detection system, the design of the baffle, vanes, and tube extinction thread are optimized in this study. An optomechanical model of the infrared lens is created using ProE and Trace Pro software. The forward ray tracing method is used to perform stray light simulation analysis, which calculates the point source transmittance (PST) values of different off-axis angles for the light source. PST curves of the astigmatism of a matte threaded lens with different degrees of density are plotted using MATLAB software, and the suppression effect of the triangular matte thread is verified. The results show that the proposed design of the vanes aids in suppressing some stray light. The addition of a reasonable extinction thread was also shown to suppress stray light effectively from the infrared lens. Moreover, as a result of appropriately increasing the density of the extinction thread and adopting a triangular thread, the PST value decreased by approximately 1-2 orders of magnitude compared to when the extinction thread was not used. When the incident angle of stray light was greater than the critical incident angle of 30°, the stray light suppression could reach the threshold index, thus meeting the requirements of stray light suppression.