US 9,317,158 B2 · Baseline management for input devices

Abstract

Embodiments of the invention generally provide a method and system that is able to minimize or remove the affect of substantially non-random electrical interference on an input device's ability to reliably and accurately sense the position of an object. In one embodiment, the input device is configured to systematically correct for a cyclic variation in the electromagnetic interference (EMI) generated by components within the electronic system, such as interference generated by the process of refreshing or updating an image on a display module that affects the capacitive sensing measurements acquired from a plurality of capacitive sensing elements. However, in some embodiments of the invention, the performance of an input device is improved by reducing the affect that external interference generated outside of the electronic system have on the position sensing data acquired by the input device.

Claims20

Dependent claims

A processing system for an input device, comprising:

a sensor module comprising sensor circuitry, the sensor module coupled with a plurality of sensor electrodes, and configured to:
acquire a plurality of sensing frames comprising a first sensing frame of a first frame type, a second sensing frame of a second frame type different than the first frame type, and a third sensing frame of the second frame type,
form a first differential frame relating the first and second frame types based on a comparison of the first sensing frame with the second sensing frame, and
form a first normalized frame of the first frame type based on a comparison of the first differential frame with the third sensing frame;
and
a determination module configured to compare the first normalized frame with a baseline frame.

3 more elements

An input device, comprising:

a plurality of sensor electrodes configured to sense input objects in a sensing region of the input device;
and
a processing system coupled with the plurality of sensor electrodes, and configured to:
acquire a plurality of sensing frames comprising a first sensing frame of a first frame type, a second sensing frame of a second frame type different than the first type, and a third sensing frame of the second frame type,
form a first differential frame relating the first and second frame types based on a comparison of the first sensing frame with the second sensing frame, and
form a first normalized frame of the first frame type based on a comparison of the third sensing frame with the first differential frame, and
compare the first normalized frame with a baseline frame.

4 more elements

A method of sensing an input object in a sensing region of an input device, comprising:

acquiring a plurality of sensing frames with a plurality of sensor electrodes disposed in a sensing region of an input device, the plurality of sensing frames comprising a first sensing frame of a first frame type, a second sensing frame of a second frame type different than the first frame type, and a third sensing frame of the second frame type;
determining a first differential frame relating the first and second frame types based on a comparison of the first sensing frame with the second sensing frame;
determining a first normalized frame of the first frame type based on a comparison of the first differential frame with the third sensing frame;
and
determining positional information of the input object in the sensing region of the input device based on a comparison of a baseline frame with the normalized sensing frame.

2 more elements

Dependencies are inferred from the claim text.

Baseline management for input devices

Life of this patent

Baseline management for input devices

Life of this patent

Abstract

Claims20