| 摘要 |
PURPOSE:To reduce aberrations, and to increase the power in laser work and to improve the work precision by installing the 1st and the 2nd meniscus lenses made of zinc selenide so that their convex surfaces face an incident beam, and specifying the radius of curvature of the 2nd positive meniscus lens. CONSTITUTION:The positive meniscus lenses 31 and 32 use ZnSe. The 1st lens 31 uses a convex meniscus lens having the convex lens on the incident beam side, and the 2nd lens 32 has a centripetal and aplanatic surface for the former converged luminous flux and converges the projection luminous flux almost to the spheric center of the projection surface. In this case, the radius R3 of curvature of the 2nd meniscus lens 32 is 1.5F-0.5F, and R4 is 2.0F-0.5F (F: focal length of whole system). Consequently, the values of a spherical aberration and a sine condition are small, and a lateral aberration curve has good symmetry; and power density is increased, and cutting work and perforating work are improved in precision. |
