We see Quick Response (QR) codes everywhere on products, and even in cornfields — and by scanning them we get additional information. Scientists got to wondering what would happen if you couldn't see the QR code? They believe an invisible version, only visible under infrared light, could catch counterfeiters.
QR codes are incredibly complex in design, and contain up to 100 times more data than barcodes. This dense detail, useful when visible, can be just as useful when combined with some scientific trickery to make QR codes invisible, which also makes them hard for people to duplicate.
These unseen QR codes are created from nanoparticles combined with blue and green fluorescent ink. The nanoparticles absorb photons at a non-visible wavelength, but can emit them in visible wavelengths such as the infrared light. It's called upconversion.
These codes are invisible to the naked eye and can be applied to any surface — even banknotes. Once a code is created, it is printed onto the surface of choice via aerosol jet printers. Creating the initial code takes about 90 minutes, but mass printing should then take about 15 minutes (depending on the product and amount being treated).
Although any goods that can be counterfeited are great for these codes, the clear intent would be using them on banknotes to stop the costly counterfeit money trade. So to ensure the special codes could withstand the beating that bills take every day, researchers folded paper with the codes on them 50 times and they were still readable.
Researchers at the University of South Dakota and South Dakota School of Mines and Technology developed the technique, and clearly this team means business. While the invisible code can be seen under infrared laser light and can be scanned in the traditional manner or using a code scanner application on a smartphone, already they are thinking about how to add additional security.
Some of the ideas floated more security are controlling the intensity of the infrared lasers used in upconverting or upping the weight of the nanoparticles. Letters or symbols could also be embedded in the code in different upconverting ink requiring a microscope to read that code. All things that are incredibly hard to predict.
So counterfeiters are officially on notice. Visible QR codes are complicated enough — and when this team takes them invisible, with some extra security thrown in, you are in for a tough time.
The research was published in the Journal of Nantechnology.
Via BBC News