Multiple method micromachining laser platform for fabricating anti counterfeit elements with multiple-scaled features

摘要

Textured metallic parts with multiple-scaled micro-structures have significant advantages for anti-counterfeit applications. For this purpose, the development of an automatized micromachining laser-platform is introduced, which is capable of handling different laser based fabrication methods including direct laser writing (DLW) and direct laser interference patterning (DLIP), using only one laser source (Nd:YAG laser, 1064 nm wavelength, 500 ps pulse duration). Using DLW, line, cross-like and rectangular structures with length scales from 50 to 150 mu m were produced, while DLIP was used to produce line-like patterns structures, with 3.7 and 25 mu m spatial periods. In addition, laser induced periodic surface structures (LIPSS) were also combined and thus obtaining hierarchical patterns with three different length scales in one process. Finally, additional samples were automatically structured to produce examples of definable security features at the touch of a button. The surface topography of the treated samples is analyzed using scanning electron microscopy, optical microscopy and white light interferometry methods.