Capacitive distance sensor
US6998855B2 · kind B2 · utility
37Cited by
45References
28Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 20, 2004 |
| Grant date | Feb 14, 2006 |
| Priority date | — |
| Expiry date | Apr 20, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1306
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A distance sensor has a capacitive element in turn having a first plate which is positioned facing a second plate whose distance is to be measured. In the case of fingerprinting, the second plate is defined directly by the skin surface of the finger being printed. The sensor includes an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.