Fingerprint sensor
US9715617B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2014 |
| Grant date | Jul 25, 2017 |
| Priority date | — |
| Expiry date | Oct 2, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/24
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A fingerprint sensor includes a first reference capacitor, a second reference capacitor, a first capacitor and a second capacitor. A first reference voltage is established across the first reference capacitor. The first reference voltage is depended on a touch event, a first reference capacitance of the first reference capacitor and a stray capacitance. The second reference capacitor has a first end and a second end, and is being configured to maintain a voltage difference between the first end and the second end, the voltage difference being a function of the first reference voltage. The first capacitor has a first capacitance and is coupled to the first end. The second capacitor has a second capacitance and is selectively coupled in parallel with the first capacitor. The ratio of the stray capacitance to the first reference capacitance equals the ratio of the second capacitance to the first capacitance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.