Of course, if the disk is right at the focal length of the objective lens, then the cylindrical lens does not affect the image and it is perfectly circular.
Of course, if the disk is right at the focal length of the objective lens, then the cylindrical lens does not affect the image and it is perfectly circular.
当然，如果正好处于物镜焦距位置，柱面镜就不会影响到光电探测器上的成像，因而会获得一个完美的圆性影像。