Stmicroelectronics Asia Pacific Pte Limited

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Praveesh Chandran

Ravi Bhatia

Gee-Heng Loh

A capacitive sensing structure includes a first sensing electrode located in a first layer for sensing a first capacitance and producing a first sense signal indicative of the sensed first capacitance. A transmit electrode is located in the first layer and positioned surrounding 90%+ of a perimeter of the first sensing electrode. A second sensing electrode is located in the first layer and positioned surrounding 90%+ of a perimeter of the transmit electrode, the second sensing electrode to sense a second capacitance and produce a second sense signal indicative of the sensed second capacitance. Controller circuitry receives the first and second sense signals, compares a change in the sensed first capacitance to a change in the sensed second capacitance, and produces 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.

Mutual hover protection for touchscreens

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.

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Singapore, Singapore

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