Patent ID: 8299396

Claim:
A method of ablation of thin layers on a border region of the surface of a plane substrate coated with a thin film to define a coated surface, whereby the border region runs along the edge or edges of the substrate, and the thin layers on the border region in a region to be ablated are ablated according to the method comprising steps of: preparing a laser beam emitted from an optical unit; pointing the laser beam to establish an ablation region; supporting the substrate such that the coated surface faces away from the optical unit; guiding the region to be ablated through the ablation region so that a vector in the plane of the surface of the substrate is essentially invariant, and has its starting point outside the substrate surface and its end point within the substrate surface during the whole ablation process, while keeping the substrate in an essentially vertical orientation during the ablation process; and moving the substrate such that the ablation region is always on the lower edge of the substrate.