Apparatus and method for marker verification
US4675655A · kind A · utility
3Cited by
4References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 11, 1985 |
| Grant date | Jun 23, 1987 |
| Priority date | — |
| Expiry date | Feb 11, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/067
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A unit and method are provided for the short range scanning of magnetic markers. The scanning unit includes an antenna adapted to provide a narrow interrogation field of short overall range. Control circuitry is provided for establishing the applied magnetic interrogation field and detecting and processing the response signal of the marker. A light emitting diode then provides a signal to the operator indicating whether a response signal is received from the marker being interrogated. The scanning unit is also equipped with a ferromagnetic plate of high magnetic coercivity for producing a dc bias field and activating the marker.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.