Device for forming longitudinally spaced grooves or slits into a material web with a focused laser beam

A device for forming grooves or slits in a material web while the material web is being moved in a longitudinal direction, the device comprising:

• a laser beam source configured for generating a continuous laser beam;
• a deflection mirror rotatably mounted about an axis of rotation and displaceable parallel to said axis of rotation;
• said deflection mirror having at least one first mirror face, a line of intersection of said mirror face with a sectional plane defined perpendicular with respect to said axis of rotation forming a circular arc about said axis of rotation, with an angular extent of said circular arc varying in dependence on an axial position of said sectional plane, and said first mirror face deflecting the laser beam into a first direction;
• focusing optics disposed along the first direction for focussing the laser beam, after reflection from said first mirror face, onto the material web while the material web is being moved in the longitudinal direction, for forming grooves or slits in the material web spaced apart from one another in the longitudinal direction;
• said deflection mirror having at least one second mirror face inclined with respect to said first mirror face and said axis of rotation, said second mirror face directly adjoining said first mirror face, said first mirror face and second mirror face alternate in a circumferential direction of said axis of rotation, said second mirror face disposed and shaped for deflecting the laser beam in second directions, different from the first direction;
• and
• an absorber disposed along the second directions to receive the laser beam after reflection from said second mirror face.