分析并指出了教科书及光学软件中光学系统照度公式的不恰当地方,推导出了更符合实际的光学系统照度公式。假设透镜系统为无源传输模式,通过对教课书中以及光学设计软件中的照度分布计算公式进行了推导分析,得出轴外视场相对轴上视场照度为cos4ω′关系。当像方视场角减小时,通过模拟得到了与实际相背的无源传输系统能量放大的结论。建立了以入瞳模式为参考的计算模型,对照度公式重新进行推算得到新的与实际相符的照度公式,得出像面照度分布取决的是物方视场角。通过仿真模拟,验证了像面上轴外视场的照度与对应物方视场角的cos4ω成正比。

Some improper points of system illuminance formula in the optics textbook and optical software have been found and analyzed, and more practical formula have been deduced. On the assumption that an optical lens is a passive transfer system, after analysis of the original formula the relationship of the off-axial field of view with the relative illuminance is cos4ω'. When the field angle in image space becomes smaller, the energy will be enlarged, which is impractical in a passive transfer system. Then, by taking entrance pupil as reference, we recalculate the illuminance formula and obtain a reasonable one. Software simulation validates the new function. And the illuminance of image plane off-axial fields is proportional to the cos4ω of the objective field angle.