An analysis is made about Descartes rays of transparent round-section fibers-a special internal surface reflection rays of the fiber when parallel rays strike the fibers perpendicularly to fiber axis.

• 摘要分析了透明圆形截面纤维在垂直纤维轴光线照射时纱维内表面反射光的一种特殊现象?笛卡尔线现象。