槽式太阳能集热器集热管下方呈现一条中央为暗黑条纹的高亮光带，该光带是其主要光学特征。在研究集热器光带形成机理的基础上，经过理论推导得出，该高亮光带的弧长特性与抛物面聚光器的开口宽度、抛物面聚光器的焦距以及集热管的直径相关，这三个参数对光带弧长的影响各不相同。光带中央暗黑条纹的弧长也与以上三个参数相关。优化分析后认为，抛物面焦距与集热管直径的比值应远离12.5。

The highlighted light band with a dark stripe under the collector tubes is the main optical characteristic of parabolic trough solar collectors. Based on research on the formation mechanism of light band, it is derived theoretically that the arc length of light band is related to three parameters, viz. the opening width and the focal length of parabolic trough concentrator and the diameter of collector tube. In addition, the influence of the three parameters on the arc length is different from each other. At the same time, the arc length of the dark stripe in the light band is related to the three parameters as well. After optimization, it is considered that the ratio of the focal length of paraboloid and the diameter of collector tube should be far away from 12.5.