Conductive Polymer Solution for Touch Panel Electrodes

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conductive polymer solutions for touch panels face challenges with low preservation stability and water resistance, particularly in the durability of movable electrode sheets used in touch panels.

Innovation Solution

A conductive polymer solution is developed containing a π-conjugated conductive polymer, a polyanion, an oxetane compound, and a solvent, with specific additives like cation forming compounds and conductive compounds to enhance electrical conductivity and water resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conductive polymer film forming sheet is used as a movable electrode sheet, then flexibility is improved, but durability during repeated deflection deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoiddurability during repeated deflection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses a composite structure consisting of a flexible base sheet combined with a conductive polymer coating layer. This composite material approach allows the movable electrode sheet to maintain flexibility from the base sheet while achieving improved durability through the protective and conductive properties of the polymer coating layer, resolving the contradiction between flexibility and durability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition and physical properties of the conductive polymer coating by controlling parameters such as polymerization conditions, additive composition, and coating thickness. These parameter changes optimize the coating's mechanical strength and flexibility, enabling the movable electrode sheet to withstand repeated deflection while maintaining operational flexibility.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a transparent conductive coating film containing a π-conjugated conductive polymer is used, then flexibility is improved, but preservation stability deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidpreservation stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent employs a composite coating system where the conductive polymer is combined with stabilizing additives and protective layers. This composite structure maintains the flexibility provided by the polymer while the additional components enhance preservation stability by preventing degradation from environmental factors such as oxidation and moisture.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent uses a coating formulation that prioritizes performance during the operational lifetime of the touch panel rather than long-term archival stability. The conductive polymer coating is designed to provide sufficient durability for the expected service life of the device, accepting that the material has limited long-term stability beyond the product's operational lifespan.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If a transparent conductive coating film containing a π-conjugated conductive polymer is used, then flexibility is improved, but water resistance deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidwater resistance
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite coating structure where the conductive polymer layer is combined with water-resistant additives and protective topcoats. This multi-layer composite maintains the flexibility of the polymer while the hydrophobic components and protective layers provide water resistance, preventing water penetration and maintaining electrical properties in humid environments.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces intermediary substances such as coupling agents and barrier layers between the conductive polymer and the environment. These intermediary layers serve as mediators that maintain the flexibility and conductivity of the polymer while providing water resistance by blocking water molecules from interacting with the polymer 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 achieves high preservation stability and forms a highly water-resistant conductive coating film, improving the durability and performance of touch panel electrodes.

Implementation Method 1

a conductive polymer solution which contains a π-conjugated conductive polymer, a polyanion, an oxetane compound and a solvent

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

a transparent conductive coating film containing a π-conjugated conductive polymer

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2338939B1Conductive polymer solution, conductive coating film and input device
Publication Date: 2019.01.16 SHIN ETSU POLYMER CO LTD
  • EP2338939B1 patent drawingFigure 1~2
  • EP2338939B1 patent drawingFigure 3~4

AI summary

The present invention provides a conductive polymer solution capable of forming a conductive coating film having both superior preservation stability and water resistance. The conductive polymer solution of the present invention includes a π-conjugated conductive polymer, a polyanion, a compound having oxetane ring and a solvent; wherein, the amount of the compound having oxetane ring is within the range of 1 to 500 % by mass based on a value of 100% by mass for the total amount of the π-conjugated conductive polymer and the polyanion.