| 摘要 |
PURPOSE:To correct satisfactorily the aberration with two pieces of simple- shaped lenses and to attain the highly accurate beam processing by constituting a collimate lens of flat concave and convex lenses and satisfying the specific conditions. CONSTITUTION:A collimate lens 14 is constituted of a flat concave lens 14a with its surface pointing to the side of a beam splitter 13 and a flat convex lens 14a with its surface pointing to the recessed surface of the lens 14a. Assuming that a focusing distance of the flat convex lens 14b, a curvature radius of the flat concave lens 14a, a distance between these lenses 14b and 14a and a total focusing distance of the lens system are f1, r3, d2 and (f), respectively, the inequalities are safisfied. Thus the aberration can be satisfactorily corrected with use of two pieces of simple-shaped lenses, and the beam processing can be carried out with high accuracy. |
