Apple Inc.
Thermal compensation for force-sensitive button

Abstract:

Thermal compensation can be applied to force measurements of a force-sensitive button. A temperature differential between an object and the force-sensitive button can result in changes in the reconstructed force by the force sensor due to thermal effects rather than actual user force, which in turn can result in degraded performance of the force sensor (e.g., false positive or inconsistent activation force). In some examples, a force-sensitive button can include a force sensor configured to measure an amount of force applied to the force-sensitive button, and a temperature sensor configured to measure a temperature associated with the force sensor. The measured temperature can be used to compensate the amount of force measured by the force sensor based on the temperature associated with the force sensor. In some examples, the thermal compensation can be applied when an object is detected contacting the force-sensitive button (i.e., when rapid temperature differentials can occur).