Conductive Polymer Patterning via Masked Treatment

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Solution Overview

Problem

Current methods for patterning conductive polymers in capacitive touch screens face challenges such as high costs, brittleness, optical mismatch issues, and inefficiencies in vacuum deposition, particularly with indium tin oxide (ITO) coatings, which are brittle and expensive, and existing patterning techniques like laser ablation result in poor visibility and substrate damage.

Innovation Solution

A method involving a conductive polymer layer coated on a support, with a polyvinyl acetal layer pattern-wise transferred to form a mask, allowing treatment to alter conductivity by at least one order of magnitude in uncovered areas, providing a robust and manufacturable solution for high-quality display applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ITO coatings are used for transparent electrodes, then electrical conductivity and transparency are achieved, but the material becomes brittle and prone to cracking especially on flexible substrates

Engineering Contradiction:

ImproveflexibilityVSAvoidbrittleness

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the material parameter from inorganic ITO to organic conductive polymer, fundamentally altering the mechanical properties to achieve flexibility while maintaining conductivity. This material substitution resolves the brittleness issue inherent in ITO coatings.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure by combining conductive polymer with flexible substrate, creating a flexible transparent electrode that overcomes the brittleness of traditional ITO while maintaining electrical functionality.

Inventive Principle:

Principle #40Composite materials

2Reliability

If vacuum sputtering is used to deposit ITO coatings, then transparent conductive layers are formed, but the process becomes slow and expensive

Engineering Contradiction:

Improvecoating qualityVSAvoiddeposition speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical vacuum sputtering process with solution-based coating methods such as spin coating or dip coating, dramatically increasing deposition speed and reducing equipment costs while maintaining coating quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses inexpensive solution-based coating processes instead of expensive vacuum sputtering equipment, making the manufacturing process more accessible and cost-effective for producing transparent conductive coatings.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If ITO coatings are deposited on glass or polymer substrates, then transparent electrodes are formed, but refractive index mismatch leads to unacceptable optical characteristics requiring additional layers

Engineering Contradiction:

Improveoptical characteristicsVSAvoidnumber of layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the refractive index parameter by selecting conductive polymers with refractive indices better matched to common substrates like glass and polymers, eliminating optical mismatch issues and the need for additional refractive index matching layers.

Inventive Principle:

Principle #35Parameter changes

4Manufacturing precision

If laser ablation is used to pattern conductive polymers, then conductive patterns are formed, but the process is slow and causes substrate damage and unwanted line visibility

Engineering Contradiction:

Improvepatterning qualityVSAvoidpatterning speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces laser ablation with photoresist-based photolithography patterning, which achieves high precision patterns without substrate damage, unwanted line visibility, or slow processing speeds.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach enables the creation of optically acceptable patterns with high transparency and flexibility, overcoming the limitations of traditional methods by ensuring robust patterning and effective conductivity changes without substrate damage, suitable for high-quality capacitive touch screens.

Implementation Method 1

subjecting the masked conductive polymer to treatment through the opening that changes the conductivity of the conductive polymer by at least one order of magnitude in areas not covered by the mask

Methodology Applied

Scientific EffectConductivity change through chemical treatment:

Implementation Method 2

pattern-wise transferring a layer containing polyvinyl acetal from a second support onto the conductive polymer to form a mask

Methodology Applied

Scientific EffectPhysical transfer deposition: Deposition (physical)

Data Source

PatentEP2959519B1Patterning of transparent conductive coatings

Publication Date: 2017.05.10 EASTMAN KODAK CO

Figure 1~2
Figure 3A
Figure 3B

AI summary

A method of patterning a conductive polymer includes providing a conductive polymer layer (13) coated over a first support (11) followed by pattern-wise transferring a layer containing polyvinyl acetal (22) from a second support (21) onto the conductive polymer (13) to form a mask (25) with at least one opening. The masked conductive polymer (13) is subjected to treatment through the opening that changes the conductivity of the conductive polymer (13) by at least one order of magnitude in areas not covered by the mask (25).