MUTUAL HOVER PROTECTION FOR TOUCHSCREENS

摘要

Disclosed is a touch sensor and method for detecting a touch in a capacitive touchscreen application, wherein the touch sensor is capable of distinguishing between a finger hovering above the touch sensor and a touch from a stylus having a small contact surface area without having to adjust the sensitivity of the touch sensor. The touch sensor includes a first sensing electrode, a transmit electrode, and a second sensing electrode, wherein the second sensing electrode is positioned substantially around the perimeter of the inner circuitry (i.e., transmit electrode and first sensing electrode). A touch is detected by sensing changes in a first capacitance between the transmit electrode and first sensing electrode and a second capacitance between the transmit electrode and second sensing electrode. The changes in the first and second capacitances are compared to determine whether the changes in the capacitances are due to a finger hover or a touch.

主权项

1. A capacitive sensing structure, comprising:
a first sensing electrode configured to sense a first capacitance and produce a first sense signal indicative of the sensed first capacitance; a transmit electrode positioned substantially around a perimeter of the first sensing electrode; a second sensing electrode positioned substantially around a perimeter of the transmit electrode, the second sensing electrode configured to sense a second capacitance and produce a second sense signal indicative of the sensed second capacitance; and controller circuitry configured to receive the first and second sense signals, to compare a change in the sensed first capacitance to a change in the sensed second capacitance, and to produce an output signal indicative of a user touch based upon the comparison between the change in the sensed first capacitance and the change in the sensed second capacitance.