Counterfeiting of postage stamps remains a problem worldwide, and the US Postal Service has been working on ways to protect them with authentication technologies.
It has just been awarded a US patent – No. 10,535,211 – that covers an approach based on the application of an adhesive incorporating taggants that can emit luminescence in response to a signal, such as a particular light or electromagnetic energy source. It also covers the use of the taggants within the substrate of the stamp, such as paper, or the ink used to print it.
The USPS and US Postal Inspection Service (USPS) don’t publish any data on just how big a problem stamp fraud is in the US – or even provide an obvious way to report it – but the patent suggests it isn’t an insignificant problem.