Fingerprint sensing devices and systems incorporating such
US5978496A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 17, 1997 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Apr 17, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1306
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fingerprint sensing device comprises an array of sense elements (12) each of which includes a sense electrode (14) which together with an overlying fingerprint portion forms a capacitor (35). The capacitor is charged by operation of a first switching device (16) via a first address conductor (18). A second switching device (17) is then operated to transfer the charge on the sense electrode to a second address conductor (20) where it is sensed (24) and an output indicative of capacitance provided accordingly. Fast, reliable, scanning is achieved. A row and column array of sense elements is conveniently addressed using sets of row and column conductors (18, 20) and the device can readily be implemented using thin film devices, e.g. TFTs, as the switching devices on an insulating support and with integrated drive circuits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.