METHOD FOR PRODUCING MICROWRITING ON DATA CARRIERS, ESPECIALLY PLASTIC CARDS

摘要

Disclosed is a method for producing a microwriting (MS) on data carriers, especially plastic cards (6) by means of laser radiation. The microwriting (MS) becomes visible in the form of changes of the optical characteristics pertaining to the data carrier material by virtue of irreversible material changes that are caused by the laser beam (2). The laser beam is directed to the data carrier (6) to be inscribed by means of a beam deflecting device (4) comprising two co-ordinates. The microwriting (MS) is carried out by means of the laser beam (2) using vector operation and/or raster technique. The laser beam (2) is provided with an almost Gauss-shaped beam profile and is expanded by means of at least one first optical means (3) in front of the beam deflection device comprising two co-ordinates for subsequently better focussing. The laser beam (2) is focussed on the data carrier by means of at least one second optical means (5) and behind the beam deflection device comprising two co-ordinates. The laser beam (2) is provided with a wave length smaller than 1,064 nm and, before focussing, is expanded to a beam diameter (D2) greater than 5 mm.