Remotely readable data storage devices and apparatus
US5420569A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 15, 1993 |
| Grant date | May 30, 1995 |
| Priority date | — |
| Expiry date | Jun 15, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C9/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetostrictive element, which may be of rectangular shape, is positioned next to a hard magnetic biasing element field with patterns recorded therein which bias the magnetostrictive element to resonate at selected frequencies, particularly harmonics of the fundamental frequency, in response to an alternating interrogating magnetic field at the same frequencies. Data may thus be encoded by selecting the frequencies at which the element will resonate. In addition to resonance at different harmonics, resonance in different modes, particularly longitudinal, transverse or flexural modes may be produced. The device may be applied to article identity systems, such as security systems but also has many other applications.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.