Capacitive measuring device
US5977781A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 5, 1996 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Jun 5, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/2415
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive measuring device has a scale and a transducer, both provided with an array of electrodes. The position of the transducer with respect to the scale is determined in a processing circuit by evaluating the capacitances formed between the two arrays. These capacitances vary periodically as a function of the relative position of the transducer. The scale electrodes are spaced by a pitch (.lambda.). In order to increase the resolution, the transducer electrodes occupy possible initial positions spaced by an elementary interval (P) which is a submultiple of the pitch (.lambda.). The transducer electrodes are thus divided into N groups according to the initial position which they occupy. In order to compensate for manufacturing imprecisions of periodic type, the succession of transducer electrodes is highly non-periodic. To this end, the set intervals (I.sub.j) occupied by the sets of successive electrodes interpenetrate, and the number of unoccupied possible initial position between the bundles of electrodes is variable. A set of electrodes is a set composed of one electrode of each group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.