Electronic Device with Noise-Cancelling Force Sensor

摘要

An electronic device may have a housing in which components such as a display are mounted. A strain gauge may be mounted on a layer of the display such as a cover layer or may be mounted on a portion of the housing or other support structure. The layer of material on which the strain gauge is mounted may be configured to flex in response to pressure applied by a finger of a user. The strain gauge may serve as a button for the electronic device or may form part of other input circuitry. A differential amplifier and analog-to-digital converter circuit may be used to gather and process strain gauge signals. The strain gauge may be formed form variable resistor structures that make up part of a bridge circuit that is coupled to the differential amplifier. The bridge circuit may be configured to reduce the impact of capacitively coupled noise.

主权项

1. An electronic device, comprising:
a display; a display cover layer, wherein the display cover layer comprises first and second ends; a strain gauge having first and second variable resistors formed on an interior surface of the display cover layer; and a differential amplifier that receives signals from the first and second variable resistors, wherein the first and second variable resistors are located at the second end of the display cover layer, and wherein the first and second variable resistor structures are configured to serve as a button for the electronic device.