Method for preventing counterfeiting or alteration of a printed or engraved surface
US7684088B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2001 |
| Grant date | Mar 23, 2010 |
| Priority date | — |
| Expiry date | Dec 6, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D7/0056
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The invention describes a process to prevent counterfeiting or alteration of a printed or engraved surface, characterized by the incorporation of a signature of the form of a digital mark into parts or the entire document, and in particular a digital mark technology to hide information in an invisible way through over-printing by using a method called asymmetric amplitude modulation. This method can be applied to any type of printed material such paper, packaging, or any other surface. Visible information can also be printed over the digital mark. As an application example, applied to a paper document the digital mark can be used to guarantee the document authenticity, as it would be destroyed by a copy process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.