Measuring body capacitance effect in touch sensitive device

摘要

Measuring an effect of body capacitance in a touch sensitive device is disclosed. This effect can be caused by poor grounding of a user or other objects touching the device or of the device itself. The device can operate in a stray capacitance mode to measure a body capacitance effect and in a normal mode to detect a touch on the device. During the stray capacitance mode, the device can obtain a body capacitance measurement from the device. During the normal mode, the device can obtain a touch measurement from the device. The device can calculate a body capacitance factor based on a ratio between the body capacitance measurement and the touch measurement and use the body capacitance factor to compensate for erroneous or distorted touch output values from the device. Various components of the device can be switchably configured according to the particular mode.

主权项

1. A method comprising:
enabling a mode for measuring a body capacitance effect in a touch sensor panel couplable to a sense channel and a drive channel; switching the sense channel from a reference signal input to a stimulation signal input; capturing outputs of the sense channel comprising signals from the touch sensor panel; and determining the body capacitance effect based on the captured outputs wherein determining the body capacitance effect includes determining a body capacitance component of the captured outputs indicative of an amount of body capacitance associated with an object proximate to the panel.