Laser-Induced Carbonization for Anticounterfeiting Tags

The counterfeiting of products is a serious concern for any nation with the increasing activity of counterfeit markets. Anticounterfeiting tags demand low-cost, unclonable, facile, and ultrafast manufacturing processes. In this study, a laser-induced carbonization (LIC) technique is employed to produce discrete sizes of LIC spots distributed randomly in an array fashion, as a tag, preferably on a laser wavelength-sensitive polyimide (PI) film. This technique enables the intrinsic creation of LIC spots in PI without any foreign functional materials, thus avoiding the need for external material. Owing to laser technology, based on the input design and laser processing parameters, the reconfigurable desired output tags can be accomplished in a very short time. Different forms of LIC spots in an optical image are grouped and sorted into three-level bits based on their sizes and brightness for digitalization. The unique LIC-based tags can be applied to the flexible printed circuit board industry to address counterfeiting.