Method of marking and of identifying objects marked by electrically conducting elements
US4350883A · kind A · utility
26Cited by
10References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 24, 1980 |
| Grant date | Sep 21, 1982 |
| Priority date | — |
| Expiry date | Jun 24, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10009
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of marking and of identifying objects (1) which are non-conductors of electricity by inclusion of conducting masses and detection by passage through a high-frequency electromagnetic field and detection of the variation in the corresponding response signal picked up. Metallic wires (2) each selected from a range of specimens of different electric conductivity are used as marking elements. The responses are measured which are each characteristic of one specimen and of a predetermined code value. The invention applies to the recognition of the authenticity of cards or documents thus previously marked.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.