Patent ID: 10780525

Abstract:
The present application relates to a device for the mask projection of femtosecond or picosecond laser beams (2) onto a substrate surface, in which the laser beam (2) consisting of laser beam pulses is, at a location of the optical axis, formed to make laser beam pulses with an expanded laser beam cross section or laser beam pulses with a reduced laser beam cross section and said laser beam (2) has a homogeneous intensity distribution over the laser beam cross section. A stop (6) with a predetermined stop aperture geometry and a mask (7) with a predetermined mask aperture geometry are positioned in succession in the beam (2) path at the location. The device contains a field lens system (8) and an imaging lens (10), which are positioned in such a way that the non-diffracted and diffracted beam components of the laser beam (2) pulses transmitted by the stop (6) and the mask (7) are directed into the imaging lens (10) with a predetermined aperture with the aid of the field lens system (8) in such a way that a reduced image, ac curate in every detail and having a predetermined imaging ratio, of the intensity profile generated by the stop (6) and the mask (7) is generated over the laser beam cross section of the laser beam pulses in the imaging plane. In a beam guiding variant 1, an added lens system (16), the field lens system (8) and the imaging lens (10) are positioned relative to one another in such a way that a focus (19) is generated between the imaging lens (10) and the substrate surface and, in a beam guiding variant 2, the added lens system (16), the field lens system (8) and the imaging lens (10) are positioned relative to one another in such a way that a focus (22) is generated between the field lens system (8) and the imaging lens (10). At least one vacuum cuvette, which surrounds the region of the focus (19) and of the focus (22), is present.