Touch-Sensitive Display Sense Electrode Segmentation

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Solution Overview

Problem

Existing touch-sensitive displays in portable electronic devices face challenges in minimizing size while maintaining effective touch detection and scanning speed due to the limitations of sensor electrode configurations, which often result in increased resistance and reduced scanning rates.

Innovation Solution

The design incorporates sense electrodes with elongate edges of varying lengths and spacers to increase the space between sense electrodes, reducing cross-coupling and resistance in drive electrodes, thereby enhancing scanning speed and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If sensor electrode configurations are used in compact touch-sensitive displays, then device size is reduced, but resistance in drive electrodes increases and scanning speed decreases

Engineering Contradiction:
Improvedevice sizeVSAvoidscanning speed
Core Design Contradiction:
Volume of moving objectVSSpeed

Solution Approach 1:

The sense electrodes are divided into multiple discrete conductors with varying lengths rather than continuous traces. This segmentation allows optimization of each conductor's length to minimize resistance while maintaining compact device dimensions. The drive electrodes are also segmented into multiple sections that can be independently optimized for scanning performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the sensor electrode structure have different properties: sense electrodes have varying lengths (first elongate edge vs second elongate edge) to optimize local resistance characteristics, spacers are strategically positioned to provide local insulation and maintain spacing, and the configuration varies across different regions of the display to balance compactness with scanning performance.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If sense electrodes are positioned closer together to reduce device size, then portability is improved, but cross-coupling between electrodes increases

Engineering Contradiction:
Improvedevice sizeVSAvoidcross-coupling
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

Spacers are introduced as intermediary elements between sense electrodes and drive electrodes. These spacers maintain appropriate spacing to prevent harmful cross-coupling effects while allowing the overall device to remain compact. The spacers act as physical mediators that enable close positioning without direct harmful interaction between adjacent electrodes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sense electrodes exhibit asymmetric configuration with first and second elongate edges of different lengths. This asymmetric design allows optimization of electrode spacing and positioning to minimize cross-coupling in critical areas while maintaining compact overall dimensions. The varying lengths enable strategic placement to reduce parasitic coupling effects.

Inventive Principle:
Principle #4Asymmetry

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

This configuration reduces the resistance in drive electrodes, allowing for faster scanning speeds and improved touch detection capabilities in compact touch-sensitive displays.

Implementation Method 1

a touch-sensitive display includes a drive electrode and a sense electrode... the sense electrode includes a first conductor and a second conductor... spaced from the drive electrode

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Implementation Method 2

spacers to increase the space between sense electrodes, reducing cross-coupling and resistance in drive electrodes

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP2713248B1Touch-sensitive display
Publication Date: 2017.12.20 BLACKBERRY LTD
  • EP2713248B1 patent drawingFigure 1
  • EP2713248B1 patent drawingFigure 2~3

AI summary

A touch-sensitive display includes a sense electrode comprising a first conductor having a first elongate edge and a second elongate edge that is longer than the first elongate edge, and a second conductor having a third elongate edge and a fourth elongate edge that is longer than the third elongate edge, wherein the first conductor is coupled to the second conductor and spaced from the second conductor such that a first distance from an end of the second elongate edge to an end of the fourth elongate edge is less than a second distance from an end of the first elongate edge to an end of the third elongate edge. The touch-sensitive display also includes a drive electrode spaced from the first conductor and the second conductor and extending between the first conductor and the second conductor.