| 摘要 |
According to the present invention, a lens includes a lens body having a first effective mirror having a first curvature and a second effective mirror having a second curvature; a ring-shaped first groove having a first diameter formed on the top surface of the first effective mirror; and a ring-shaped second groove having a second diameter formed on the bottom surface of the second effective mirror. The first groove, second groove, and the lens main body can be concentrically arranged. |
