Touch sensing with water rejection
US11157109B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 2020 |
| Grant date | Oct 26, 2021 |
| Priority date | — |
| Expiry date | Feb 10, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2203/04107
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Techniques for rejecting apparent (but false) touches caused by objects such as water droplets located in areas with parasitic capacitive paths to ground are disclosed. To minimize these false touches, one or more guard conductors can be located in proximity to the housing and driven with a stimulation signal to shield objects from being capacitively coupled to ground through the housing. In some examples images of touch can be obtained from a non-bootstrapped or bootstrapped scan and also an extended bootstrapped scan wherein the guard conductor is driven with a stimulation signal that has the same characteristics as the stimulation signal being applied to the sensed touch nodes. In some examples, the results of the extended bootstrapped scan can be subtracted from the non-bootstrapped or bootstrapped scan to identify and reject apparent touches resulting from capacitive coupling to ground.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.