Method and authentication apparatus for authenticating value documents
US8328102B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 2010 |
| Grant date | Dec 11, 2012 |
| Priority date | — |
| Expiry date | Apr 21, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D7/1205
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
Taggants can be incorporated into or onto value documents. The taggants comprise a crystalline taggant doped with two rare earth ions. The substrate or printed matter into which the taggant can be incorporated has a minimal absorption infrared wavelength window and the taggant is excited by incident infrared radiation in this wavelength range. Suitable first rare earth ions function as efficient broad band absorbers of incident infrared radiation and passes energy non-radiatively to a second rare earth ion, which emits infrared radiation at a wavelength greater than the incident infrared radiation. The emitted infrared radiation is also in the minimal absorption transmission window of the printed matter or the substrate into which the taggant is incorporated. Methods of authenticating the value document include detection of the emitted radiation at pre-determined values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.