在棱镜旋转的情况下，指出了三轴间的位移和角度误差造成的出射光线的轨迹变化就是数学上为人所知的Pascal蚶线。
In the case of rotating prism , resulted from the axis displacement and angle error , the track shift of exit rays , known as limacon of Pascal in mathematics , has been point out .
蚶线