YAG LASER, LENS FOR FIBER LASER AND LASER PROCESSING SYSTEM

摘要

A glass lens or a quartz lens is employed for refracting and condensing the beam of a YAG laser or a fiber laser. The lens made of these material often cannot provide an appropriate front and back curved surfaces when the specific function of a single lens is performed. Furthermore, aberration may increase in glass and quartz lenses. In the case of a single fϑ lens, when the beam from a YAG or fiber laser having a circular cross-section is provided to the lens while scanning, the cross-section of a beam refracted to the peripheral portion may be deformed in an elliptical form. As a means for solving the problem, the lens is made of ZnSe. Since ZnSe has a refractive index higher by about 1 than that of glass or quartz, curvature of the curved surface in front and back of the lens can be decreased and thereby aberration can be decreased. In the case of an fϑ lens, elliptical deformation of the cross-section of a beam refracted to the periphery can be reduced.