Single sided capacitive force sensor for electronic devices
US7784366B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 2008 |
| Grant date | Aug 31, 2010 |
| Priority date | — |
| Expiry date | Sep 14, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0443
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive force sensor (100) includes a substrate (101) having at least one electrode pair (102,103) defining a capacitance disposed thereon. The substrate (101) is fixed relative to a first plate (106). A drive circuit (104) is configured to apply a voltage relative to a circuit ground (105) to the electrode pair (102,103). The first plate (106) is separated from a second plate (107) that is coupled to circuit ground (105) by a compliance member (108,109). The compliance member (108,109) is configured to oppose a compression force (110) while allowing the first plate (106) to physically move relative to the second plate (107). A capacitive detection circuit (111) is then configured to detect a change the capacitance when the compliance member (108,109) is compressed. The compression force (110) is then determined from the change in capacitance and the spring constant of the compliance member (108,109).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.