Fringe field capacitive sensor for measuring the size of an opening
US4935700A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1989 |
| Grant date | Jun 19, 1990 |
| Priority date | — |
| Expiry date | Mar 16, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fringe field, capacitive distance sensor for measuring the distance between a probe and the surface of the conductive body. The sensor comprises a conductive plate element mounted by the probe, the thickness of the plate element being substantially less than the height and width of the plate element. The plate element is positioned adjacent to and normal to the body surface, and the fringe field capacitance between the plate element and the body is measured, to thereby determine the distance between the probe and the body surface. The probe may be in contact with and scanned across the body surface, to provide surface profile measurements. A probe including a plurality of plate elements may be positioned inside an opening such as a hole, to measure the geometry of the hole. By maintaining the hole probe adjacent one electrode in contact with the hole wall, both profile and geometry measurements may be made. A noncontacting probe including one or more plate elements may be used to measure surface topography.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.