Transparent Conductive Layer Nanowire Welding

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Solution Overview

Problem

Current transparent conductive layers, such as those using Indium Tin Oxide (ITO), face challenges with flexibility on plastic substrates and limited availability of indium, while silver nanowires require complex patterning processes that can lead to visual defects in display devices.

Innovation Solution

A transparent conductive layer comprising nanowires with a metal core, an oxide or polymeric first shell, and an organic surfactant second shell, where the nanowires are welded together using light irradiation to form conductive regions without a physical patterning process, enhancing flexibility and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If ITO is used to form a transparent conductive layer on a plastic substrate by sputtering, then the transparent conductive layer can be formed, but the flexibility is insufficient and it is not appropriate for flexible substrates

Engineering Contradiction:
ImproveflexibilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent changes the material composition parameters by replacing ITO with metal nanowire networks (silver, copper, or aluminum nanowires), which have different physical and chemical properties that enable flexibility while maintaining conductivity and transparency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structures where metal nanowires are embedded in a transparent matrix or coating layer, combining the high conductivity of metals with the flexibility and transparency requirements of display devices

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If silver nanowires are used to form a transparent conductive layer, then cost is reduced compared to ITO, but a complex patterning process using photolithography is required

Engineering Contradiction:
Improvemanufacturing costVSAvoidpatterning process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the photolithography patterning step from the manufacturing process by using direct nanowire network formation methods that do not require complex photoresist processing and development steps

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the processing parameters from conventional photolithography conditions to alternative approaches such as screen printing, spray coating, or self-assembly methods that form conductive patterns without requiring photoresist materials and complex equipment

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If photolithography is used to pattern the transparent conductive layer, then conductive regions can be formed, but visual defects such as mura and moire are generated

Engineering Contradiction:
Improvepatterning precisionVSAvoidvisual defects
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent removes the photolithography process entirely from the manufacturing sequence, replacing it with direct deposition or self-assembly methods that form nanowire networks without creating the surface unevenness and optical interference patterns that cause mura and moire defects

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent achieves homogeneous and uniform transparent conductive layers by using nanowire networks that self-assemble into even distributions, eliminating the localized thickness variations and surface irregularities that occur with photolithography processing

Inventive Principle:
Principle #33Homogeneity

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 solution simplifies the manufacturing process, improves conductivity, and maintains high transmittance, reducing the need for rare metals and avoiding visual defects, thus enhancing the performance and cost-effectiveness of display devices.

Implementation Method 1

irradiating a light onto the metal nanowire layer to form the transparent conductive pattern

Methodology Applied
Scientific EffectLight irradiation: Laser

Implementation Method 2

the nanowires are welded together using light irradiation to form conductive regions

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2963462B1Transparent conductive layer, method for manufacturing the same and display device including the same
Publication Date: 2022.10.12 LG DISPLAY CO LTD
  • EP2963462B1 patent drawingFigure 1(a)~1(c)
  • EP2963462B1 patent drawingFigure 2
  • EP2963462B1 patent drawingFigure 3(a)~3(c)

AI summary

Disclosed is a display device having a transparent conductive layer that includes a plurality of nanowires, wherein each nanowire may, for example, include a core that includes a metal; a first shell on the core; and a second shell on the first shell, wherein cores of at least two of the plurality of nanowires are in contact with each other through the first shell and the second shell.