Hybrid Touch Sensor Panel Architecture for Precision and Hovering Detection

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Solution Overview

Problem

Existing touch sensor panels face challenges in detecting objects, such as fingers, both touching and hovering over the panel, due to limitations in mutual capacitance and self-capacitance sensing. Mutual capacitance sensing struggles with detecting objects further away, while self-capacitance sensing is prone to noise and jitter, leading to errors in touch outputs. Additionally, matrix architectures for self-capacitance require a large number of electrodes and routing traces, increasing costs and complexity.

Innovation Solution

Combining mutual capacitance and self-capacitance sensing in a single touch sensor panel by integrating touch electrodes that can operate in both modes. This hybrid approach improves touch sensing performance, reduces the number of electrodes and routing traces, and optimizes system integration and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mutual capacitance sensing is used, then touch location precision is improved, but detection capability for hovering objects deteriorates

Engineering Contradiction:

Improvetouch location precisionVSAvoiddetection capability for hovering objects

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent combines mutual capacitance sensing and self-capacitance sensing into a single hybrid touch sensor panel. The touch electrodes are configured to operate in both sensing modes simultaneously, merging the advantages of high precision location detection from mutual capacitance with the superior hovering object detection capability from self-capacitance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The touch electrodes are designed with multi-functionality to serve dual purposes: they can detect both touching objects and hovering objects. By implementing both mutual capacitance and self-capacitance sensing capabilities in the same electrode structure, the system achieves versatile detection across different object states (touching and hovering).

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If self-capacitance sensing is used, then detection capability for hovering objects is improved, but noise and jitter increase leading to errors

Engineering Contradiction:

Improvedetection capability for hovering objectsVSAvoidnoise and jitter resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The hybrid architecture merges self-capacitance sensing (good for hovering detection) with mutual capacitance sensing (more noise-resistant). The combination allows the system to leverage the noise resistance of mutual capacitance while maintaining the hovering detection capability of self-capacitance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mutual capacitance sensing acts as an intermediary that mitigates the noise and jitter issues inherent in pure self-capacitance sensing. By cross-referencing signals from both sensing modes, the system can filter out noise and jitter that would otherwise cause errors in hovering object detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The hybrid touch sensor panel effectively enhances touch sensing precision and accuracy, improves noise resistance, and reduces the complexity and cost associated with the number of electrodes and routing traces, thereby optimizing system performance.

Implementation Method 1

sensing the mutual capacitance of touch electrodes arranged in rows and columns can determine the location of a touch on the touch sensor panel

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

fringing electrical fields used to detect touch can extend beyond the surface of the display, and objects approaching near the surface may be detected near the surface without actually touching the surface

Methodology Applied

Scientific EffectFringing electrical fields: Electric Field

Data Source

PatentUS12204730B2Self-capacitance and mutual capacitance touch sensor panel architecture

Publication Date: 2025.01.21 APPLE INC

AI summary

A touch sensor panel includes a first set of touch electrodes configured to operate as drive lines and that are disposed in a first layer of the touch sensor panel. The touch sensor panel also includes a second set of touch electrodes configured to operate as sense lines and that are disposed in a second layer of the touch sensor panel, different than the first layer of the touch sensor panel, such that one or more mutual capacitance touch nodes are formed by the first set of touch electrodes and the second set of touch electrodes. The touch sensor panel also includes a third set of touch electrodes configured to operate as self-capacitance electrodes and that are disposed in the first layer or the second layer of the touch sensor panel.