Solid Ink Laser Patterning for High‐Resolution Information Labels with Supervised Learning Readout.

Tagging, tracking, or validation of products are often facilitated by inkjet‐printed optical information labels. However, this requires thorough substrate pretreatment, ink optimization, and often lacks in printing precision/resolution. Herein, a printing method based on laser‐driven deposition of solid polymer ink that allows for printing on various substrates without pretreatment is demonstrated. Since the deposition process has a precision of <1 µm, it can introduce the concept of sub‐positions with overlapping spots. This enables high‐resolution fluorescent labels with comparable spot‐to‐spot distance of down to 15 µm (444,444 spots cm−2) and rapid machine learning‐supported readout based on low‐resolution fluorescence imaging. Furthermore, the defined thickness of the printed polymer ink spots can be used to fabricate multi‐channel information labels. Additional information can be stored in different fluorescence channels or in a hidden topography channel of the label that is independent of the fluorescence. [ABSTRACT FROM AUTHOR]