Probe for measuring surface roughness by sensing fringe field capacitance effects
US5270664A · kind A · utility
143Cited by
7References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 19, 1992 |
| Grant date | Dec 14, 1993 |
| Priority date | — |
| Expiry date | May 19, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/34
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitance sensing probe is disclosed for taking measurements of features on a workpiece surface. The probe has two electrodes (E.sub.1, E.sub.2) spaced apart in the direction of movement of the probe with the electrodes being disposed in an attitude normal to the surface. Only the edge of the electrodes are exposed to the surface and an electric circuit (EC) is provided for determining the effect of the surface on the fringe field capacitance between the electrodes. Guard electrodes are used to reduce the stray capacitance being measured. Various embodiments are shown with different numbers and arrangements of electrodes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.