Position sensing device and method using self-capacitance
US9939932B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 20, 2015 |
| Grant date | Apr 10, 2018 |
| Priority date | — |
| Expiry date | Oct 30, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/955
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive position sensing system has a pickup electrode, a shield electrode partially enclosing the pickup electrode, and an essentially grounded relatively movable target near the pickup electrodes; a capacitance-to-digital converter, and switching means for connecting each electrode in turn to the converter input or to ground. A capacitive position sensing method in the system includes measuring a first capacitance C1 of at least one pickup electrode set with the shield electrode set grounded, measuring a second capacitance C2 of at least one shield electrode set with the pickup electrode set grounded, and measuring a third capacitance C3 of the pickup electrode set and the shield electrode set connected together; and calculating a first result indicating a position of a target using the first capacitance C1, the second capacitance C2 and the third capacitance C3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.