ALEXANDRIA, Va., March 19 -- United States Patent no. 12,252,846, issued on March 18, was assigned to Landqart AG (Landquart, Switzerland).
"Multi-layer printing substrate with hidden information" was invented by Christoph Kocher (Landquart, Switzerland), Muriel Schuler (Chur, Switzerland) and Martin Demierre (Nyon, Switzerland).
According to the abstract* released by the U.S. Patent & Trademark Office: "A security paper, having a first paper ply and a second paper ply, and a plastic ply made of a thermoplastic polymer material arranged between the paper layers (1, 2), wherein a strip-shaped tear-off film is embedded between the paper layers on the inner side of the second paper layer and at least partially embedded into the plastic layer...