Capacitive dimensional measurement chain with linear output
US5065105A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1989 |
| Grant date | Nov 12, 1991 |
| Priority date | — |
| Expiry date | Dec 1, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/023
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive dimensional measurement chain with linear output is essentia comprised of a capacitive sensor formed by a central detection electrode and a guard electrode surrounding the detection electrode that are respectively powered by two a.c. bias voltage sources. The chain also comprises a reference capacitor and a measuring circuit for measuring the distance between the detection electrode and a conductive part placed facing the detection electrode. The bias voltage sources are variable level sources and are level-controlled by a distance measurement signal issued by the measuring circuit. The measuring circuit comprises a level amplifier and a demodulator for amplifying and demodulating an incoming error signal representative of a difference between a load of a sensor capacitance that is defined between the detection electrode and the part separated by the distance to be measured, and a load of the reference capacitor. The distance measurement signal supplied by the measuring circuit linearly represents the distance to be measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.