Coextrusion of periodically modulated structures

A method for manufacturing a foil having a variable strip geometry for employment in a data carrier, having:

• extrusion of at least one first surface and at least one second surface, in such a manner that the surfaces form the foil in a sequence that alternates orthogonally to an extrusion direction, wherein a varying is effected of at least one of the surfaces with respect to its geometry;
• wherein the varying of the geometry's effected by means of a movement of a position-variable distributor rail of an extruder;
• wherein the variable strip geometry comprises an individually adjustable pattern defined as adapting individual strips of the at least one first surface and the at least one second surface with respect to width and in extension along a length of the individual strips;
• wherein the position-variable distributor rail comprises a first position, the first position defining a first height of the position-variable distributor rail in the extrusion direction, and second position, the second position defining a second height of the position-variable distributor rail in the extrusion direction, wherein the first height varies from the second height.