把入射光作为从不同方向入射的空间光,应用傅里叶光学的方法分析了通过机械准直器中一组不同间距的栅格挡光片的物理过程。建立了准直光束的理论计算公式, 给出了采用数值方法精确计算准直光束的主要步骤和计算中应注意的问题,计算了空间频率分布。对于从各方向入射的光辐射,证明了机械准直器的准直性能,对于平行光入射,计算了通过机械准直器的光辐射衍射,衍射超出了准直器的几何阴影区,得到了准直光束空间频率的二维分布图形。与国外一维的方法相比,该方法更准确、快捷,计算结果与实验数据比较,更接近实验结果。

Assuming that the incident light is from different directions, the process of the incident light passing a series of grids with different intervals has been described and analyzed by applying two-dimensional Fourier optical method. A formula for the distribution of the collimated beam's spatial frequency is established and the spatial frequency distribution of the incident light is obtained. The main procedures and key points in the calculation are listed. When the incident light is from every direction, the calculation demonstrates the collimation performance, when the incident radiation strikes on the collimator paralle, the calculated result shows the diffraction of the collimated beam. The diffraction reaches out of the geometrical shade. The two-dimensional distribution of the collimated beam's spatial frequencies is obtained. The data agree better with the published experimental result than the one-dimensional calculation of foreign peers. This method is a quick and accurate way to calculate the performance of the collimator.