Method for the introduction of an integrated predetermined rupture line in a planar expansive body

A method for generating a predetermined breaking line in a one-layer planar extending article having a working side and a decorative side, comprising a material with an inhomogeneous material density distribution, said method comprising the steps of:

• directing a laser beam bundle to the working side for removing material in its beam path and thereby generating holes that are invisible from the decorative side;
• the laser beam bundle and the planar extending article carrying out a relative movement with respect to one another so that the holes are generated in a row along the desired predetermined breaking line;
• switching off the laser beam for a period of time determining the subsequent hole spacing when an amount of radiation generating a detector signal that is greater than a predetermined threshold signal impinges on a detector arranged on the decorative side;
• gradually increasing the output of the laser beam from zero to its maximum nominal value before starting to produce each hole;
• and
• switching off the laser beam immediately when a detector signal that is greater than the predetermined threshold is generated before reaching the maximum nominal value, which is caused by the absence of material or by a small amount of material of the planar extending article in the beam path (pseudo-hole) and prevents removal of the small amount of material and prevents overloading of the detector.

The method for generating a predetermined breaking line in a multiple-layer planar extending article with a working side and a decorative side, in which the layer (final layer) forming the decorative side, said method comprising an inhomogeneous material, comprising the steps of:

• directing a laser beam bundle to the working side for removing material in its beam path and thereby generating holes that are invisible from the decorative side;
• the laser beam bundle and the planar extending article carrying out a relative movement with respect to one another so that the holes are generated in a row along the desired predetermined breaking line;
• switching off the laser beam for a period of time determining the subsequent hole spacing when an amount of radiation generating a detector signal that is greater than a predetermined threshold signal impinges upon a detector arranged on the decorative side;
• reducing the output of the laser beam prior to penetration of the laser beam into the final layer at least until the amount of radiation still being emitted generates a signal smaller than the threshold with full detection;
• activating the detector and subsequently increasing the laser beam again gradually to its maximum nominal value;
• and
• switching off the laser beam immediately when a detector signal that is greater than the predetermined threshold is generated before reaching the maximum nominal value, which is caused by the absence of material or by a small amount of material of the planar extending article in the beam path (pseudo-hole) and prevents removal of the small amount of material and prevents overloading of the detector.