陆基红外探测系统遮光罩优化设计

Optimizing design of baffle in the ground-based IR optical system

为降低陆基红外探测系统遮光罩自身辐射的大小,提出一种遮光罩优化设计方法。该方法将传统遮光罩的一级消光部分设计为多组相互垂直的反射面,入射到反射面上的杂散辐射光线被反向反射出遮光罩,外部杂散光得到抑制;同时,因为反射面热辐射率低,减小了由于遮光罩自身辐射引起的杂散光。详细介绍了遮光罩的优化设计方法,并结合实例使用TRACEPRO软件进行建模与仿真,计算了优化后遮光罩的PST值和自身热辐射大小。分析结果表明,与传统的遮光罩相比,优化后的遮光罩自身热辐射降低一个数量级,且其PST大小能够满足陆基红外探测系统外部杂散辐射的抑制水平。

A method of optimizing design of baffle was proposed to decrease the inner irradiation of the ground-based infrared optical system. The first order part of the conventional baffle was substituted by several reflective surfaces which were perpendicular to each other. Because the reflective surfaces could retro-reflect the irradiated light, the out-of-field stray light was suppressed. Also the reflective surfaces were of low emissivity, the stray light induced by inner irradiation was decreased. This method of optimizing the baffle was introduced in detail. Taking a ground-based infrared optical system for example, the point source transmittance （PST） and the inner irradiation of the baffle were calculated by the TRACEPRO software. The results show that, compared with the conventional one, the inner irradiation of optimized baffle is reduced about one grade and the level of PST could satisfy the requirement.