三棱镜对光线的连续两次折射存在一最小偏向角。在已有文献中,关于偏向角的运算以及最小值的证明应用了大量三角函数的知识,过程繁琐冗长,基础较好的参加物理竞赛的学生理解起来都有极高的难度,学习水平一般的学生理解起来就更困难了。笔者试图从中学函数图像的角度提出最小偏向角的全新运算法。一、问题的提出如图1所示,三棱镜对光线的连续两次折射,使 Triangular prism of the light two consecutive refraction there is a minimum deflection angle. In the existing literature, the proof of the deflection angle and the minimum value is applied to the knowledge of a large number of trigonometric functions, the process is tedious and lengthy, and the well-established students participating in the physics competition are extremely difficult to understand. The learning level is generally Students understand it more difficult. The author tries to propose a new algorithm of minimum deviation angle from the perspective of middle school function images. First, the question presented in Figure 1, the prism of the light two consecutive refraction