本文通过对反射波和入射波振幅的比值关系进行详细解析推导、作图呈现和分析讨论，给出反射光和入射光相位差在折射率-入射角空间的详细分布图，并指明半波损失发生的各种条件，其中包括光由光密介质射向光疏介质时反射光发生半波损失的条件. 研究表明当光束由光密介质射向光疏介质时反射波也可能发生半波损失，而当光束由光疏介质射向光密介质时反射波也不是一定会发生半波损失. 澄清和补充了一些现有教科书中不很明确的结论. 

Through detailed derivation, graph presentation and discussion of the ratio relationship between the amplitude of the reflected wave and that of the incident wave, this article gives the detailed distribution map of phase difference between the reflected light and the incident light in the refractive index-incident angle space. At the same time, various conditions for the occurrence of half-wave loss are specified, including the half-wave loss of the reflected light when the light is emitted from the optically denser medium to the optically thinner medium. Here we show that when the light beam is shot from the optically denser medium to the optically thinner medium, the reflected wave may also occur half-wave loss; when the light beam is shot from the optically thinner medium to the optically denser medium, the reflected wave does not necessarily occur a half-wave loss. Our work clarifies and supplements some unclear conclusions in existing textbooks.