Authentication system and method
US5418855A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1993 |
| Grant date | May 23, 1995 |
| Priority date | — |
| Expiry date | Sep 27, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D7/121
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A system for authentication of articles uses a multiplicity of discriminating variables to characterize light detected from the articles after predetermined illumination. Articles are tested which have been marked with substances such as dye or ink that fluoresce in a region of the optical spectrum when illuminated with light in another region of the spectrum, such as the ultraviolet region. The authentication system illuminates the articles with light modulated at a frequency of more than about 50 kHz, and secondary fluorescent light returned from the articles is synchronously detected. A programmable microcomputer digitizes the synchronously detected signal and analyzes it to compare the signal with predetermined standard digital signals. The standard signals incorporate a number of discriminating features, for example the fluorescent light's wavelengths, amplitudes, and time delays relative to the modulated illuminating light. The standard signals may also incorporate spatial distributions such as bar codes as discriminating features. The discriminating features may be re-programmed by the user of the authentication system. Thus the discriminating features define a user-determin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.