Electrostatic discharge protection of a capacitve type fingerprint sensing array
US6483931B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1997 |
| Grant date | Nov 19, 2002 |
| Priority date | — |
| Expiry date | Sep 11, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2203/04107
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A planar fingerprint pattern detecting array includes a large number of individual skin-distance sensing cells that are arranged in a row/column configuration. Each sensing cell includes an amplifier having an ungrounded input node and an ungrounded output node. Output-to-input negative feedback that is sensitive to the fingerprint pattern is provided for each amplifier by way of (1) a first capacitor plate that is placed vertically under the upper surface of a dielectric layer and is connected to the ungrounded amplifier input node, (2) a second capacitor plate that is placed vertically under the upper surface of the dielectric layer in close horizontal spatial relation to the first capacitor plate and is connected to the ungrounded output node, and (3) an ungrounded fingertip whose fingerprint pattern is to be detected, which ungrounded fingertip is placed on the upper surface of the dielectric layer in close vertical spatial relation with the first and second capacitor plates. Electrostatic discharge protection relative to electrostatic potential that may be carried by the ungrounded fingertip is provided by placing a number of grounded metal paths within the dielectric layer to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.