Reader/writer having coil arrangements to restrain electromagnetic field intensity at a distance
US6176433A · kind A · utility
222Cited by
4References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 15, 1998 |
| Grant date | Jan 23, 2001 |
| Priority date | — |
| Expiry date | May 15, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0715
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention provides a reader and/or writer for performing both the supply of operating power to an IC card and transmission of a communication signal to the IC card or transmission and reception thereof to and from the IC card, wherein a main coil or a spiral antenna for generating an electromagnetic field for the two or at least power supply, and auxiliary coils or spiral antennas for generating magnetic fields opposite in phase to the electromagnetic field generated by the main coil or spiral antenna to thereby restrain the intensity of the electromagnetic field in the distance are provided side by side.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.