Real-Time Information-Variable Invisible Barcode Comprising Freely Deformable Infrared-Emitting Yarns

Barcodes are utilized for product information management in shops, offices, hospitals, passenger facilities, and factories because they enable substantial amounts of data to be processed quickly and accurately. However, a limited amount of information can be loaded on the currently used monochrome barcodes that are based on thin-film coatings. Therefore, these barcodes require constant replacement with new barcodes to update the information; furthermore, they cannot be applied to textile products. This study demonstrated the performance of wearable invisible infrared (IR)-emitting barcodes by using twisted yarns that comprised five highly elastic/conductive spandex fibers. The barcode information can be actively updated via the selective IR emission from specific yarns of the barcode by controlling the applied voltage to the IR-emitting yarns. Therefore, the IR barcode required a relatively small number of bars to express a higher volume of information compared to the existing monochrome barcodes. Because the emitted IR light from the yarns was invisible to the human eye and was only recognized by an IR camera, the information-variable IR-emitting yarn-based barcode exhibited an aesthetic design and was composed of a sustainable fabric-type material that could be easily applied to clothes, bags, and shoes. It is expected that the fabricated barcode will be widely utilized as wearable invisible barcodes, whose information will remain invisible to humans and can be updated in real time to ensure information fluidity.