Transparent Conductor with Dual Metal Oxide Layers for Corrosion Resistance

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Solution Overview

Problem

Transparent conductors used in various applications, such as solar cells and touch panels, face challenges in maintaining conductivity and corrosion resistance under high temperature and high humidity environments, as metal layers can corrode due to migration issues.

Innovation Solution

A transparent conductor structure comprising a transparent resin substrate, a first metal oxide layer with zinc oxide, indium oxide, and titanium oxide, and a second metal oxide layer with zinc oxide, indium oxide, and tin oxide, where the tin oxide content is controlled to enhance corrosion resistance and conductivity, preventing metal layer degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal layer is added to improve conductivity, then conductivity is improved, but corrosion resistance deteriorates due to metal layer migration under high temperature and high humidity

Engineering Contradiction:
ImproveconductivityVSAvoidcorrosion resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces metal oxide layers (first and second metal oxide layers) as intermediary protective barriers between the metal layer and the external environment. These oxide layers prevent direct contact between the metal layer and corrosive elements (water vapor, oxygen) under high temperature and high humidity conditions, thereby maintaining corrosion resistance while preserving the conductivity enhancement provided by the metal layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite structure combining metal oxide layers with a metal layer containing silver alloy. This composite transparent conductor leverages the advantages of both materials: the metal oxide layers provide corrosion resistance and transparency, while the metal layer provides enhanced conductivity. The specific composition ratios (SnO2 content: 12-40 mol% in the second layer, ≤40 mol% in the first layer) are optimized to balance conductivity and corrosion resistance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If SnO2 content is increased to improve conductivity, then conductivity is improved, but transparency deteriorates

Engineering Contradiction:
ImproveconductivityVSAvoidtransparency
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies different SnO2 content specifications to different layers: the first metal oxide layer (adjacent to the metal layer) has SnO2 content of 40 mol% or less, while the second metal oxide layer (outer layer) has SnO2 content of 12-40 mol%. This localized quality differentiation allows the inner layer to provide sufficient conductivity support while the outer layer maintains higher transparency for light transmission, resolving the contradiction between conductivity and transparency.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3300084B1Transparent conductor
Publication Date: 2020.01.01 TDK CORP
  • EP3300084B1 patent drawingFigure 1
  • EP3300084B1 patent drawingFigure 2
  • EP3300084B1 patent drawingFigure 3

AI summary

The transparent conductor (100) includes a transparent resin substrate (10), a first metal oxide layer (12), a metal layer (16) containing a silver alloy, and a second metal oxide layer (14) in the order presented. The first metal oxide layer (12) contains zinc oxide, indium oxide, and titanium oxide, and the content of SnO2 in the first metal oxide layer is 40 mol% or less with respect to the total of four components of zinc oxide, indium oxide, titanium oxide, and tin oxide in terms of ZnO, In2O3, TiO2 and SnO2, respectively. The second metal oxide layer (14) contains the four components, and the content of SnO2 in the second metal oxide layer is 12 to 40 mol% with respect to the total of the four components in terms of ZnO, In2O3, TiO2 and SnO2, respectively.