Abstract: A method for welding a copper/aluminum connection includes providing a first workpiece, which consists of a copper-containing material, in particular at least 80% by weight Cu, and a second workpiece, which consists of an aluminum-containing material, in particular at least 80% by weight Al, and welding the first workpiece and the second workpiece to one another in a surface region by means of a laser beam moved in relation to the first and second workpieces along a welding path. The laser beam is directed onto a surface of the first workpiece and the second workpiece is arranged behind the first workpiece with respect to the laser beam, with a greatest spot diameter SD of the laser beam on the surface of the first workpiece, where SD?120 ?m. The welding path is chosen such that the laser beam progressively penetrates into solid workpiece material along the welding path.

Abstract: In a laser machining machine (1) for laser welding of workpieces, in particular for lap welding of DBC structures, comprising a laser beam generator for generating a laser beam and an optical imaging system for imaging the laser beam into a machining plane, according to the invention, the optical imaging system comprises an optical beam-shaping system, which images the laser beam in the machining plane with an imaging depth (?d) of at least ±2 mm, preferably of at least ±5 mm, in such a way that the radial power density distribution (Pr) of the laser beam is bell-shaped along the imaging depth (?d) in each plane at right angles to the beam axis and the maximum values (Pmax) of these bell-shaped power density distributions (Pr) along the imaging depth (?d) vary in relation to one another by less than 10%, preferably by less than 5%.

Abstract: In a laser machining machine (1) for laser welding of workpieces, in particular for lap welding of DBC structures, comprising a laser beam generator for generating a laser beam and an optical imaging system for imaging the laser beam into a machining plane, according to the invention, the optical imaging system comprises an optical beam-shaping system, which images the laser beam in the machining plane with an imaging depth (?d) of at least ±2 mm, preferably of at least ±5 mm, in such a way that the radial power density distribution (Pr) of the laser beam is bell-shaped along the imaging depth (?d) in each plane at right angles to the beam axis and the maximum values (Pmax) of these bell-shaped power density distributions (Pr) along the imaging depth (?d) vary in relation to one another by less than 10%, preferably by less than 5%.