Abstract

The gaussian energy distribution common to all laser beams is a serious handicap in most laser beam applications for machining material, such as for drilling, welding and the like. This is especially true in welding extremely thin metal sheets, as in the manufacture and assembly of the transducers of modern magnetic disk files. According to the subject invention, a laser beam is directed to a glass cone or axicon which converts the gaussian energy distribution of the laser beam to one more uniform in cross-section. Depending on the distance of the workpiece from the exit side of the axicon, the energy distribution of the radiation impinging onto the workpiece will be either uniform, saddle shaped or annular cross-section. It has been discovered that saddle shaped or annular energy distributions are optimal for welding very thin metal sheets by a laser beam since the heat dissipation in the center of a welding spot is a minimum and that at the periphery of the laser beam depends on the material, size and shape of the workpiece, which parameters can be matched by adjusting the distance between the axicon and the workpiece.

Other References

• J L. Mauer, et al., IBM Journal of Research and Development, "Electron Optics of an Electron-Beam Lithographic System," vol. 21, pp. 514-521, Nov. 1977
• K. H. Drake, et al., Loten and Schweissen in der Elektronik, "Contacting of Semiconductor Components by Laser Beams with not-Gauss-form Distribution of Intensity", DVS-Berichte 40, 1976, Werner-Verlag GmbH, Dusseldorf