Capacitive sensor and method for non-contacting gap and dielectric medium measurement
US7256588B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 2004 |
| Grant date | Aug 14, 2007 |
| Priority date | — |
| Expiry date | Oct 2, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for non-contact measurement of a displacement between a surface and a capacitive sensor comprised of at least two superimposed conductive plates electrically insulated one from the other and a sensor circuit coupled to the plates including: positioning the capacitive sensor proximate to the surface such that the displacement is a distance of a gap between the surface and one of the plates; applying a high frequency signal to the plates; applying the high frequency signal and a sensor plate to control a voltage gain of an amplifier in the circuit, where the capacitance on the sensor is indicative of the displacement between the sensor and surface; differentiating an output of the amplifier and the high frequency signal, and determining a value of the displacement based on the difference between the output of the amplifier and the high frequency signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.