定义：

是由阿贝首先提出的一个条件。任何球差矫正透镜，如果要同时消除在透镜光轴附近的彗差，就必须遵守这个条件。数学表达式为：

u´/sin U´ = u/sin U

其中u、u´是从物到像的入射和出射近轴光线的斜率，U、U´是对应的旁轴光线的斜率。

English Expression：

sine condition

Definition:

A condition, first stated by Abbe, that must be met by any spherically corrected lens if it is also to be free from coma in the neighborhood of the lens axis. Mathematically the condition is:

u´/sin U´ = u/sin U

where u, u´ are the slopes of the entering and emerging portions of a paraxial ray from object to image and U, U´ are the corresponding slopes of a marginal ray.

备注：

请参考 阿贝正弦条件。