Touch Sensor Panel Electrode Segmentation for Capacitive Coupling Reduction

Solution Overview

Problem

Capacitive touch sensor panels face performance limitations due to increased capacitive coupling in larger touch electrodes, which hinders touch sensitivity and operating speed.

Innovation Solution

Configurations of touch electrodes and methods that reduce capacitive coupling and resistance, such as making touch electrodes of equal size and using dummy sections and guard layers to minimize unwanted capacitive coupling, while maintaining optical uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If larger-sized touch electrodes are used to improve touch sensitivity coverage, then the touch-sensitive area is increased, but capacitive coupling increases which hinders touch sensitivity and limits operating speed

Engineering Contradiction:

Improvetouch electrode areaVSAvoidoperating speed

Core Design Contradiction:

Area of stationary objectVSSpeed

Solution Approach 1:

The touch electrode is divided into multiple segments with different sizes, where first touch electrodes have a first size and second touch electrodes have a second size. This segmentation allows the panel to maintain adequate touch sensitivity coverage while reducing the overall capacitive coupling that would occur with uniformly large electrodes, thereby improving operating speed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the touch sensor panel are assigned different electrode sizes based on local requirements. Areas requiring higher sensitivity use larger electrodes, while areas where speed is prioritized use smaller electrodes. This local optimization resolves the contradiction by allowing each region to be tuned for its specific performance goal.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If larger-sized touch electrodes are used to improve touch sensitivity coverage, then the touch-sensitive area is increased, but capacitive coupling increases which hinders touch sensitivity

Engineering Contradiction:

Improvetouch electrode areaVSAvoidtouch sensitivity

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The touch electrode is divided into multiple segments with different sizes, where first touch electrodes have a first size and second touch electrodes have a second size. This segmentation allows the panel to maintain adequate touch sensitivity coverage while reducing the overall capacitive coupling that would occur with uniformly large electrodes, thereby improving operating speed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the touch sensor panel are assigned different electrode sizes based on local requirements. Areas requiring higher sensitivity use larger electrodes, while areas where speed is prioritized use smaller electrodes. This local optimization resolves the contradiction by allowing each region to be tuned for its specific performance goal.

Inventive Principle:

Principle #3Local quality

3Speed

If touch electrodes are made of equal size to reduce capacitive coupling, then operating speed improves, but performance uniformity across the panel varies due to different trace lengths

Engineering Contradiction:

Improveoperating speedVSAvoidperformance uniformity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

Different regions of the touch sensor panel are assigned different electrode sizes based on local requirements. Areas requiring higher sensitivity use larger electrodes, while areas where speed is prioritized use smaller electrodes. This local optimization resolves the contradiction by allowing each region to be tuned for its specific performance goal.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent varies the size parameter of touch electrodes across different locations on the panel. By changing the electrode size parameter locally rather than uniformly, the patent optimizes the balance between capacitive coupling (affecting speed) and sensitivity, while compensating for variations in trace lengths to achieve more uniform overall performance.

Inventive Principle:

Principle #35Parameter changes

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

Enhances touch sensitivity and operating speed of touch sensor panels by equalizing touch electrode performance and reducing stray capacitance, thereby improving overall panel responsiveness.

Implementation Method 1

a guard layer configured to capacitively couple to the one or more dummy traces

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS10606430B2Capacitive coupling reduction in touch sensor panels

Publication Date: 2020.03.31 APPLE INC

AI summary

Touch sensor panel configurations and methods for improving touch sensitivity of some or all of the electrodes or portions of the touch sensor panel are disclosed. The touch sensor panel configurations can allow increased speed at which the panel can operate. In some examples, the performance of a given touch electrode can differ from the performance of another touch electrode due to differences in capacitance and/or resistance. The performance of the touch sensor panel can be limited by the touch electrode with the lowest performance relative to the other touch electrodes. The configurations and methods can increase the performance of the touch sensor panel by minimizing the capacitive coupling and/or resistance of touch electrodes. Examples of the disclosure can provide configurations of touch sensor panels and methods for improving optical uniformity of the panel.