Organic Thin Film Transistor Gas Barrier Layer Design

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Solution Overview

Problem

Flexible organic thin film transistors face issues with breakage due to low adhesiveness between components when bent and require a sealing structure with high bendability and gas barrier properties to prevent moisture penetration and oxidation, which existing gas barrier films with inorganic layers on resin films do not adequately address.

Innovation Solution

A method of manufacturing organic thin film transistors using a gas barrier layer consisting of a resin layer and an inorganic layer, with a transistor element formed on one side and a sealing layer laminated on the other through an adhesive layer, where the thickness of the resin layers is less than the adhesive layer, enhancing bendability and air stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing structure with high gas barrier properties is introduced to prevent moisture penetration, then air stability is improved, but bendability deteriorates due to the rigid inorganic layers

Engineering Contradiction:
Improveair stabilityVSAvoidbendability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses a flexible polymer film as the base substrate and forms thin inorganic gas barrier layers on it. The polymer film provides the necessary flexibility and bendability, while the thin inorganic layers provide gas barrier properties. This combination resolves the contradiction by making the overall structure flexible through the polymer substrate while maintaining protection through the thin inorganic barrier layers.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure consisting of a polymer film substrate combined with inorganic gas barrier layers. The polymer provides flexibility and mechanical strength, while the inorganic layers provide moisture and oxygen barrier properties. This composite approach allows the structure to simultaneously achieve both bendability and gas barrier performance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the thickness of the inorganic gas barrier layer is increased to improve moisture blocking, then gas barrier properties are improved, but adhesiveness deteriorates and breakage occurs during bending

Engineering Contradiction:
Improvegas barrier propertiesVSAvoidadhesiveness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the thickness parameter of the inorganic gas barrier layers to be sufficiently thin to maintain good adhesiveness and flexibility, while still providing adequate gas barrier properties. By carefully controlling the thickness parameter within an optimal range, the patent achieves both protection and mechanical integrity without excessive thickness that would cause brittleness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different thicknesses or densities of inorganic gas barrier layers at different locations or orientations. The gas barrier layers may be applied selectively on specific surfaces or in specific patterns, providing localized protection where needed while maintaining overall flexibility and adhesiveness of the structure.

Inventive Principle:
Principle #3Local quality

3Reliability

If a laminate structure is used to provide gas barrier properties, then moisture protection is improved, but adhesiveness between components deteriorates leading to breakage

Engineering Contradiction:
Improvemoisture protectionVSAvoidadhesiveness between components
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a flexible polymer film as the fundamental substrate that provides both mechanical strength and flexibility. The inorganic gas barrier layers are applied as thin coatings on this flexible substrate rather than using thick laminate structures, maintaining adhesiveness while providing moisture protection.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure where inorganic gas barrier layers are integrated with a polymer film substrate. This composite approach ensures strong interfacial adhesion between the inorganic and organic components, preventing delamination and breakage during bending while maintaining effective gas barrier properties.

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 approach improves bendability, prevents moisture penetration, and maintains stability in air, resulting in a more durable organic thin film transistor with enhanced durability and performance.

Implementation Method 1

a gas barrier layer consisting of a resin layer and an inorganic layer

Methodology Applied
Scientific EffectGas barrier: Permeation

Implementation Method 2

a sealing layer laminated on the other through an adhesive layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3843128B1Method for manufacturing an organic thin film transistor
Publication Date: 2024.06.19 FUJIFILM CORP
  • EP3843128B1 patent drawingFigure 1~2
  • EP3843128B1 patent drawingFigure 3~4
  • EP3843128B1 patent drawingFigure 5~6

AI summary

Provided are an organic thin film transistor having high bendability and high stability in air and a method of manufacturing the organic thin film transistor. The organic thin film transistor includes: a gas barrier layer consisting of a resin layer and an inorganic layer; a transistor element that is formed on one main surface side of the gas barrier layer and includes a gate electrode, an insulating film, an organic semiconductor layer, a source electrode, and a drain electrode; and a sealing layer that is laminated on a side of the transistor element opposite to the gas barrier layer through an adhesive layer, in which a thickness of the resin layer in the gas barrier layer is less than a thickness ranging from the inorganic layer to the sealing layer in the gas barrier layer.