Capacitive circuit array for fingerprint sensing
US6429666B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 17, 2000 |
| Grant date | Aug 6, 2002 |
| Priority date | — |
| Expiry date | Apr 17, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A compact sensor which maps fingerprints for identification purposes. The sensor consists of an array of pixels with each pixel configured with one or more pickup conductive electrodes surrounded by voltage electrodes of different phases. This configuration performs capacitive differencing to eliminate the large background capacitance without the need for complex sensor circuitry. In addition, the readout lines are electrically shielded from the input voltage lines by an intermediate grounded conductive layer, thereby eliminating the parasitic capacitance and allowing the detection of minute capacitance variation of the finger surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.