Structural colors with embedded anti-counterfeit features fabricated by laser-based methods

Structural colors can be induced on metals not only to fabricate logos or decorative motives but also to embed anti-counterfeit features for product protection. In this study, stainless steel (EN 1.4301) plates are colorized by growing a thin oxide layer using direct laser writing (DLW) and hidden a...

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Bibliographic Details
Published in:arXiv.org 2024-04
Main Authors: Teutoburg-Weiss, Sascha, Soldera, Marcos, Bouchard, Felix, Kreß, Joshua, Vaynzof, Yana, Andrés Fabián Lasagni
Format: Article
Language:English
Subjects:
Color vision
Counterfeit
Counterfeiting
Diffraction patterns
Direct laser writing
Gratings (spectra)
Laser applications
Lasers
Logos
Microstructure
Microtexture
Patterning
Stainless steels
Visible spectrum
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Summary:Structural colors can be induced on metals not only to fabricate logos or decorative motives but also to embed anti-counterfeit features for product protection. In this study, stainless steel (EN 1.4301) plates are colorized by growing a thin oxide layer using direct laser writing (DLW) and hidden anti-counterfeit measures are included on their surfaces by direct laser interference patterning (DLIP) processing. The periodic microstructures resulting from the DLIP treatment have a spatial period of 1 um and act as relief diffraction gratings, featuring a characteristic diffraction pattern. These microstructures are not visible to the human eye but are easily detectable upon shining a coherent beam on the surface. Furthermore, the reflectance over the visible spectrum of the colorized surfaces with and without the DLIP microtexture is measured, giving low differences in the color perception following the so-called "CIE L*a*b*" color space. Finally, a demonstrator is fabricated, in which colorized fields with and without the security features are shown.
ISSN:2331-8422