Capacitive fingerprint sensor
US7099497B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 2003 |
| Grant date | Aug 29, 2006 |
| Priority date | — |
| Expiry date | Feb 22, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1306
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A capacitive fingerprint sensor includes a plurality of capacitive sensing members arranged in a 2D array. A charge-sharing principle is utilized to read signals in the capacitive sensing member. Each capacitive sensing member includes an insulating surface layer, a sense electrode, a reference electrode, a reference capacitor, and a signal reading circuit. The sense electrode is below the insulating surface layer. When a finger contacts the insulating surface layer, a sense capacitor is formed therebetween. The reference capacitor is connected between the reference and sense electrodes. The signal reading circuit is connected to the sense and reference electrodes, repeatedly provides control signals to charge the reference capacitor and then enable the reference and sense capacitor to share charges. Finally, the sense voltage of the sense electrode may be read.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.