Conductive Substrate with Roughened Pattern for Touch Panel

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Solution Overview

Problem

Touch panels with high conductive metal patterns face challenges in maintaining sensitivity as their size increases, leading to higher costs and reduced visibility due to the Moiré phenomenon and diffraction patterns caused by external light.

Innovation Solution

A conducting substrate with a conductive pattern having an arithmetic average roughness height of 0.1-0.3 μm, which reduces diffraction patterns and prevents the Moiré phenomenon by inducing diffuse reflection, is used in a touch panel, allowing for irregular patterns that maintain electrical uniformity and visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If highly conductive metal patterns are used to realize large-sized touch panels, then conductivity is improved, but the Moiré phenomenon and diffraction patterns occur causing visibility degradation

Engineering Contradiction:

ImproveconductivityVSAvoidMoiré phenomenon and diffraction patterns

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating specific surface roughness characteristics (Ra value between 0.05-0.5 μm) only in the regions where metal patterns are formed. This localized surface modification allows the metal patterns to maintain high conductivity while simultaneously reducing the Moiré phenomenon and diffraction patterns through controlled light scattering, thus resolving the contradiction between conductivity improvement and visibility degradation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-treating the surface of the transparent substrate before forming the metal patterns. The surface is prepared with specific roughness characteristics in advance, which then interact with the subsequently deposited metal patterns to prevent the formation of Moiré phenomena and diffraction patterns, thereby maintaining visibility while achieving high conductivity.

Inventive Principle:

Principle #10Preliminary action

2Area of stationary object

If the size of the touch panel is increased, then area is improved, but sensitivity decreases due to high resistance of transparent conductive film

Engineering Contradiction:

Improvetouch panel sizeVSAvoidsensitivity

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent applies parameter changes by transitioning from transparent conductive films with high resistance to metal patterns with significantly lower resistance. This fundamental change in the electrical parameters of the conductive layer allows large-sized touch panels to maintain low overall resistance and high sensitivity, overcoming the limitation that sensitivity decreases as touch panel size increases with traditional transparent conductive films.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If transparent conductive film is used for touch panel, then visibility is improved, but resistance is high causing sensitivity decrease in large panels

Engineering Contradiction:

ImprovevisibilityVSAvoidresistance and sensitivity

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent employs composite materials by combining the transparent substrate material with metal pattern materials. This composite structure leverages the optical transparency of the substrate while utilizing the superior electrical conductivity of metals, thereby achieving both high visibility and low resistance simultaneously, and resolving the contradiction between visibility improvement and resistance reduction.

Inventive Principle:

Principle #40Composite materials

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 the intensity of diffraction patterns and prevents the Moiré phenomenon, ensuring high conductivity and visibility in larger touch panels while maintaining uniformity and cost-effectiveness.

Implementation Method 1

diffuse reflection can be induced by controlling the surface roughness of the conductive pattern, and thus the intensity of light diffraction patterns caused by external light can be reduced

Methodology Applied

Scientific EffectDiffuse reflection: Reflection

Implementation Method 2

employ a transparent conductive film such as an ITO film to recognize a touch by electrical contact or based on a change in capacitance

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a capacitive-type touch panel which utilizes a capacitance coupling in a state in which AC voltage is applied

Methodology Applied

Scientific EffectCapacitance coupling: Capacitance

Data Source

PatentUS9513730B2Conductive substrate and touch panel comprising same

Publication Date: 2016.12.06 LG CHEM LTD

AI summary

The invention relates to a conducting substrate and a touch panel comprising the same. A conducting substrate according to one embodiment of the invention comprises at least one base material and at least one conductive pattern on the base material, wherein the arithmetic average roughness height (Ra) of the surface of the conductive pattern is 0.1-0.3 μm. The conducting substrate and the touch panel comprising the same do not obstruct the view, have excellent conductivity, and can reduce the intensity of a diffraction pattern caused by reflected light.