Capacitive fingerprint sensor and the panel thereof
US7683639B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 2008 |
| Grant date | Mar 23, 2010 |
| Priority date | — |
| Expiry date | Jul 17, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1306
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A capacitive fingerprint sensor comprises a fingerprint capacitor, a reference capacitor, a first transistor and a second transistor. The fingerprint capacitor CF has a capacitance that is either a valley capacitance CFV or a ridge capacitance CFR. The reference capacitor CS has a capacitance CS, and CFV<CS<CFR. The first transistor is configured to precharge the reference capacitor and the fingerprint capacitor during a precharge phase. The second transistor is configured to output the voltage of the reference capacitor during an evaluation phase. The precharge phase is controlled by a first readout select line, the evaluation phase is controlled by a second readout select line, the second readout select line is immediately next to the first readout select line, and the valid time to access the readout line is within an enabling period of the second readout select line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.