Metal Mesh Touch Screen Panel RC Delay Reduction

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Solution Overview

Problem

Capacitive touch screen panels face accuracy issues due to resistance capacitance (RC) delay, which worsens as the size of the panel increases, limiting their effectiveness in medium and large-sized applications.

Innovation Solution

A metal mesh type touch screen panel design featuring first and second touch electrode serials formed by intersecting metal lines, with an insulating layer and bridges connecting separated mesh patterns, using metal materials with lower specific resistance than ITO, reducing overall resistance and improving touch sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ITO is used as the electrode material in capacitive touch screen panels, then the panel can be manufactured with standard transparent conductive materials, but the high specific resistance of ITO causes RC delay that worsens with increasing panel size, limiting touch accuracy in medium and large-sized applications

Engineering Contradiction:
Improvetouch recognition accuracyVSAvoidpanel size
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent changes the material parameter from ITO (high specific resistance) to metal materials (low specific resistance). This parameter change directly reduces the resistance component in the RC delay equation, allowing the panel to maintain high touch recognition accuracy even as the panel size increases. The metal mesh structure formed by intersecting metal lines provides both low resistance and appropriate capacitance distribution.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure combining metal lines with insulating layers to form a metal mesh electrode. This composite material approach allows the metal to provide low resistance while the insulating layer maintains the capacitive sensing function. The combination resolves the contradiction by integrating the beneficial properties of both materials: metal's low resistance and insulator's dielectric properties.

Inventive Principle:
Principle #40Composite materials

2Reliability

If metal materials are used to form mesh patterns instead of ITO, then the specific resistance is reduced and RC delay is minimized, but the manufacturing process becomes more complex requiring precise formation of intersecting metal lines and insulating layers

Engineering Contradiction:
Improvetouch sensitivityVSAvoidelectrode structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the electrode into a mesh structure composed of intersecting metal lines (first and second metal lines) rather than using a continuous transparent conductive layer. This segmentation creates multiple small conductive paths that reduce overall resistance while maintaining capacitive sensing. The segmented metal mesh structure achieves better touch sensitivity by reducing RC delay compared to conventional ITO layers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different materials and structures to different regions: metal lines for low resistance conduction paths, insulating layers for dielectric separation and capacitance formation, and conductive patterns for electrode connections. This local quality differentiation optimizes each region's function - metal where low resistance is needed, insulator where dielectric properties are needed - achieving high reliability while managing complexity through functional specialization.

Inventive Principle:
Principle #3Local quality

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 metal mesh design enhances touch recognition accuracy by reducing RC delay, maintaining high sensitivity even in larger panel sizes, and preventing short circuits while ensuring visibility and conductivity.

Implementation Method 1

an insulating layer configured to insulate the plurality of first touch electrode serials and the plurality of second touch electrode serials

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

using metal materials with lower specific resistance than ITO, reducing overall resistance and improving touch sensitivity

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 3

The capacitive touch screen panel senses a touched position based on changes in capacitance generated in an upper plate or a lower plate when the user touches an equipotential conductive film

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2725463B1Metal mesh type touch screen panel
Publication Date: 2019.11.27 LG DISPLAY CO LTD
  • EP2725463B1 patent drawingFigure 1
  • EP2725463B1 patent drawingFigure 2
  • EP2725463B1 patent drawingFigure 3

AI summary

A touch screen panel includes a plurality of first touch electrode serials arranged in a first direction, a plurality of second touch electrode serials arranged in a second direction crossing the first direction, and an insulating layer insulating the first touch electrode serials and the second touch electrode serials. Each first touch electrode serial includes a plurality of first mesh patterns formed by an intersection of first metal lines. Each second touch electrode serial includes a plurality of second mesh patterns formed by an intersection of second metal lines. The first mesh patterns are connected to one another, and the second mesh patterns are separated from one another. The separated first mesh patterns are connected to one another through a bridge.