Capacitive distance sensor
US6362633B1 · kind B1 · utility
116Cited by
44References
31Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 27, 1998 |
| Grant date | Mar 26, 2002 |
| Priority date | — |
| Expiry date | Oct 27, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1306
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The distance sensor has a capacitive element (33, 34) in turn having a first plate (23) which is positioned facing a second plate (18) 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 (13), between the input and output of which the capacitive element (33, 34) 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.