Apple Inc.
Compensation techniques for grip and finger coupling to routing traces in a touch sensor panel

Abstract:

Errors in touch signals due to grip and finger coupling to routing traces can be compensated. In some examples, reference traces can be provided to measure a signal contribution from a user's grip to routing traces. In some examples, shielding electrodes can be provided to reduce fringing field coupling between a user's grip and routing traces that are missing a neighboring trace. In some examples, a global correction for finger to trace coupling can be performed based on stored matrices that characterize cross-coupling between touch sensor electrodes in a touch sensor electrode array. In some examples, a determined touch location can be used to apply localized matrix correction to a subset of touch sensor electrodes in the touch sensor electrode array. In some examples, correction for multiple touch locations can be corrected in a specified order to avoid compensating for crosstalk effects of a single touch sensor electrode multiple times.