Laser-stripping of existing thin layer from workpiece along defined track, e.g. to make thin-film solar modules, employs elliptical focal zone having major axis forming angle with direction of travel

摘要

The pulsed laser beam used, has an elliptical focal zone with minor- and major semi-axes (D1, D2). It is directed onto the stripping plane of a coated workpiece and guided along the track (A), forming overlapping focal zones on the plane. The major axis makes an angle (alpha ) with the track direction. In the new process, this angle exceeds 0[deg] and may be up to 90[deg] . The shape of the beam spot is restricted by the size of the minor semi-axis (D1).