Apochromatic lens: Compound lens corrected for chromatic aberration, i.e. the three primary colours , red, green and blue are corrected. Also called Apochromat.

矫正色的：即是红、绿和蓝三原色的色都已矫正。

By chiseling a BOL on a surface of a lens, a apochromatic system is composed, which actualizes the system's apochromatism, as well as revising primary aberration.

并将二元光学面刻画的表面，校正系统初级像的同时，实现了系统的消色。