Electrical data recording and retrieval based on impedance variation
US5323377A · kind A · utility
Inventors
Key dates
| Filing date | Nov 27, 1992 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Nov 27, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R23/006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Electrical data is recorded and retrieved by producing and detecting impedance change. A layer of high resistivity material on a conductive substrate is used as the recording layer. A conductive probe pressing on it is used for sending writing or reading electrical current flowing in a direction normal to its surface. A large enough electrical voltage pulse is applied on this probe, causing electro-forming in a data spot in the recording layer under the probe, turning the local resistance of this data spot from high to low. This change in resistance or more generally, change in impedance, is utilized to write data. Several kinds of impedance detecting circuits, utilizing the principle of voltage divider circuit or field effect transistors are employed in data reading. A large number of writing/reading units can be integrated compactly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.