一、引言在光辐射测量中,为了限制辐射束通常要使用带光栏孔的挡屏。最常见的是在探测器前准确限定入射辐射通量积分面积的光栏以及扩展型光源(如钨带灯和黑体辐射器等)前面用的所谓“有效光栏”。C.L.Sanders 和 O.C.Jones在用铂点黑体实现光单位——坎德拉的工作中,按 Fraunhofer 衍射理论证明了用他们的光学系统得到的像中心照度要比按几何光学计算所得到的值低0.25%。大 I. INTRODUCTION In optical radiation measurement, a screen with a light bar aperture is usually used to limit the radiation beam. The most common are the light barriers that accurately define the integrated area of ​​the incident flux before the detector and the so-called “effective light barrier” used in front of extended light sources such as tungsten and blackbody radiators. C. L. Sanders and O. C. Jones, working with candelas in the black dot body of platinum dots, have shown, by Fraunhofer diffraction theory, that the centroid illuminance obtained with their optical system is 0.25% lower than that obtained by geometrical optics calculations. Big