Metal-Mesh Touch Screen Floating Electrode Dielectric Breakdown

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Solution Overview

Problem

Conventional touch screen panels using indium-tin-oxide (ITO) for touch sensing electrodes face issues with flexibility, high sheet resistance, increased manufacturing costs due to ITO's rarity, and potential dielectric breakdown at metal-mesh intersections, leading to short circuits and reliability concerns, especially in flexible and large-size display devices.

Innovation Solution

A metal-mesh type touch screen panel is developed with a floating electrode between mesh patterns to reduce potential differences and induced charges, thereby suppressing dielectric breakdown and improving reliability by minimizing current flow at overlapping points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal-mesh type electrodes are used to replace ITO, then flexibility and sheet resistance are improved, but dielectric breakdown occurs at intersection points due to high voltage potential difference

Engineering Contradiction:

Improveflexibility and sheet resistanceVSAvoiddielectric breakdown at intersections

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A floating electrode is introduced as an intermediary element between the first and second mesh pattern electrodes at their intersection points. This floating electrode acts as a mediator that reduces the voltage potential difference between the crossing metal-mesh electrodes, preventing dielectric breakdown while maintaining the flexibility and low sheet resistance benefits of the metal-mesh structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The floating electrode is designed to create equipotential regions at the intersection points of the metal-mesh electrodes. By establishing equal potential zones, the voltage difference between crossing electrodes is minimized, eliminating the high electric field conditions that cause dielectric breakdown while preserving the electrical performance of the touch sensor.

Inventive Principle:

Principle #12Equipotentiality

2Illumination intensity

If ITO is used for touch sensing electrode, then transparency is maintained, but manufacturing cost increases due to ITO rarity

Engineering Contradiction:

ImprovetransparencyVSAvoidmanufacturing cost

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from ITO (transparent conductive oxide) to metal materials (such as aluminum, silver, or copper) for the mesh pattern electrodes. This parameter change replaces the expensive and rare ITO with more abundant and cost-effective metals, significantly reducing manufacturing costs while maintaining the necessary electrical conductivity through optimized mesh design.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures combining metal mesh patterns with insulating layers and floating electrodes. This composite approach allows the use of inexpensive metals while managing the electrical and mechanical properties through multi-layer construction, achieving both cost reduction and functional performance.

Inventive Principle:

Principle #40Composite materials

3Speed

If metal-mesh electrodes are used, then response speed is improved, but induced charges between meshes cause potential differences

Engineering Contradiction:

Improveresponse speedVSAvoidpotential difference between meshes

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The floating electrode serves as a mediator that equalizes the potential distribution between the first and second mesh pattern electrodes. By introducing this intermediate conductive element at intersection points, the patent reduces induced charges and minimizes potential differences, ensuring reliable operation while preserving the fast response characteristics of the metal-mesh structure.

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 solution effectively reduces induced charges and potential differences between mesh electrodes, enhancing the reliability of the touch screen panel by preventing dielectric breakdown and improving response speed, while maintaining image quality and reducing manufacturing costs.

Implementation Method 1

Methodology Applied

Scientific EffectElectrostatics: Electrostatics

Data Source

PatentEP3495931B1Touch screen panel and display device including the same

Publication Date: 2021.11.03 LG DISPLAY CO LTD

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AI summary

A touch screen panel (113) includes a plurality of touch sensors (TS1 to TS9). A touch sensor includes a first touch electrode unit (TX) that includes a plurality of first mesh pattern electrodes (TX_M) disposed to be spaced apart from each other in a sensing area (TA5) where the first touch electrode unit (TX_M) and a second touch electrode unit (RX) intersect. The touch sensor also includes the second touch electrode unit (RX) that includes a plurality of second mesh pattern electrodes (RX_M) disposed between the plurality of first mesh pattern electrodes (TX_M) in the sensing area (TA5) to be spaced apart from each other. The touch sensor also includes at least one floating electrode (Ft) disposed between the plurality of first mesh pattern electrodes (TX_M) and the plurality of second mesh pattern electrodes (RX_M). The dielectric breakdown of the first touch electrode unit (TX) and the second touch electrode unit (RX) is suppressed to improve reliability of the touch screen panel.