建立非平行光入射多层膜的模型，给出了在圆形光束锥角入射时的薄膜特性表达式，对三类典型光学薄膜即多腔滤光片、非偏振分光薄膜和非偏振截止滤光薄膜的特性进行了数值实验。研究结果表明：随着光束入射锥角的增加，多腔滤光片的影响是中心波长向短波方向移动，透射率下降和通带形状退化；非偏振分光薄膜的s和p偏振透射率增加，宽带波纹度增加；非偏振截止滤光薄膜的通带透射率出现周期振荡，s偏振的通带波纹度大于p偏振，通带波纹度总体具有增加的趋势，过渡区的陡度具有变大的趋势。

Model of non-parallel light incident multilayer is established. Expressions of film characteristics are given for the case that the incident light beam has a circular cone angle. Numerical experiments are done on the properties of three kinds of typical optical thin films such as multi-cavity filter, non-polarization beam splitter and non-polarization cutoff filter. The results show that as the cone angle of incident light increases, the center wavelength moves to short-wave for the multi-cavity filter, and the transmittance and pass band get worse. The transmittance and waviness increase for both of s and p polarization in non-polarization beam splitter. For non-polarization cutoff filter, the transmittance in pass band shows periodic oscillation, the waviness of s polarization is larger than that of p polarization. There is an increasing trend overall for waviness, in addition the gradient of the transition region is growing.