Electric field fingerprint sensor apparatus and related methods
US5963679A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 26, 1996 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Jan 26, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/3025
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A fingerprint sensor includes an array of electric field sensing electrodes, a dielectric layer on the sensing electrodes with the dielectric layer for receiving a finger adjacent thereto, and a driver for applying an electric field drive signal to the sensing electrodes and adjacent portions of the finger so that the sensing electrodes produce a fingerprint image output signal. In one embodiment of the invention, the driver provides a coherent drive signal for the array. A respective shield electrode may be associated with each of the electric field sensing electrodes for shielding each electric field sensing electrode from adjacent sensing electrodes. Each shield electrode may be actively driven for further shielding. The fingerprint sensor preferably further includes a synchronous demodulator and contrast enhancer for more accurate output image signals. The fingerprint sensor may be effectively used to control access to a computer workstation. Method aspects are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.