Electronic fingerprint sensor with differential noise cancellation
US7460697B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 2005 |
| Grant date | Dec 2, 2008 |
| Priority date | — |
| Expiry date | Mar 5, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1335
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Image sensing apparatus includes an image pickup plate disposed generally orthogonally with respect to an expected direction of movement of an object, such as a finger, multiple image drive plates in spaced relation to the image pickup plate to define sensor gaps between respective image drive plates and the image pickup plate, and a reference plate disposed substantially parallel to the image pickup plate. The reference plate is spaced from the image pickup plate to permit common mode noise and coupling to be cancelled and is spaced from the image drive plates to permit a differential image signal to develop between the image pickup plate and the reference plate. A differential amplifier coupled to the image pickup plate and the reference plate provides noise cancellation. The apparatus may further include a comb plate spaced from the reference plate and coupled to a reference potential, such as ground.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.