DYNAMIC ZOOMING AND FOCUSING IN A LASER PROCESSING DEVICE

Abstract

Laser processing device (10) comprising: a laser input (12) for receiving a laser beam (B) and a laser output (14) for emitting the laser beam (B); an optical system for the laser beam between the laser input (12) and the laser output (14), comprising: an optical beam width control group (20) for adjusting a beam width of the laser beam (B), wherein the optical beam width control group (20) comprises at least two lenses (22, 24), including at least one movable lens (22) for adjusting a beam width of the laser beam (B); and an optical focusing group (30) with adjustable focal length, wherein the optical focusing group (30) is arranged along a beam path of the laser beam (B) between the optical beam width control group (20) and the laser output (14) and comprises at least two lenses (32, 34), including at least one movable lens (32);wherein the optical system is configured to set a focus position of the laser beam and a spot size corresponding to a beam width of the laser beam at the focus position (F); and wherein the optical beam width control group (20) is configured to: - cause a variation of an absolute value of a beam propagation angle of the laser beam (B) of not more than 10°; and - such that a ratio of a distance from the optical beam width control system (20) to the optical focusing system (30) along an optical path of the laser beam (B) over a Rayleigh length of the laser beam (B), measured downstream of the optical beam width control group (20), is not more than 1000.