Gas Barrier Laminate Composition Gradient for Flexible Displays

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Solution Overview

Problem

Existing gas barrier films for flexible displays, such as those using synthetic resin sheets, lack high gas barrier capability and bendability required for organic EL device sealing materials.

Innovation Solution

A gas barrier laminate with a base and a gas barrier unit featuring at least two inorganic layers, including a silicon oxynitride layer with a composition-gradient region, where the oxygen content ratio decreases and nitrogen content ratio increases towards the base, and the composition-gradient region's thickness ratio to the entire silicon oxynitride layer is between 0.15 and 0.4, enhancing both gas barrier performance and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a synthetic resin sheet is used instead of glass substrate, then flexibility is improved, but gas barrier capability deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidgas barrier capability
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite structure consisting of a synthetic resin sheet base and multiple inorganic gas barrier layers (silicon oxide layer and silicon oxynitride layer) stacked thereon. This composite material approach combines the flexibility advantage of synthetic resin with the gas barrier capability of inorganic materials, resolving the contradiction between flexibility and gas barrier performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a multi-layer nested structure where the silicon oxide layer and silicon oxynitride layer are sequentially stacked on the synthetic resin sheet. Each layer is nested within the overall laminate structure, with specific thickness ratios controlled to optimize both flexibility and gas barrier capability. The nested multi-layer configuration allows the flexible base to maintain its properties while the inorganic layers provide the required gas barrier function.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If multiple inorganic layers are stacked on synthetic resin, then gas barrier capability is improved, but surface flatness deteriorates

Engineering Contradiction:
Improvegas barrier capabilityVSAvoidsurface flatness
Core Design Contradiction:
Object-affected harmful factorsVSShape

Solution Approach 1:

The patent controls the thickness parameters of each layer precisely, with the silicon oxide layer having a thickness of 50-200 nm and the silicon oxynitride layer having a thickness of 50-200 nm, where the ratio of the thickness of the silicon oxynitride layer to the total thickness of both inorganic layers is 0.3-0.7. By optimizing these parameter ranges, the patent achieves sufficient gas barrier capability while minimizing surface flatness deterioration.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If conventional gas barrier films are used, then basic gas barrier function is provided, but bendability and flexibility are insufficient

Engineering Contradiction:
Improvegas barrier functionVSAvoidbendability
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent employs thin inorganic film layers (silicon oxide and silicon oxynitride, each 50-200 nm thick) stacked on a flexible synthetic resin sheet base. The thin film configuration, combined with the flexible polymer substrate, enables the gas barrier laminate to maintain excellent bendability and flexibility while providing effective gas barrier function, unlike conventional rigid gas barrier films.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2979860B1Gas barrier laminate, member for electronic device, and electronic device
Publication Date: 2020.03.18 LINTEC CORP
  • EP2979860B1 patent drawingFigure 1~2(b)
  • EP2979860B1 patent drawingFigure 3~4
  • EP2979860B1 patent drawingFigure 5~6

AI summary

The present invention is a gas barrier laminate comprising a base and a gas barrier unit, the gas barrier unit comprising at least two inorganic layers, at least one of the at least two inorganic layers being a silicon oxynitride layer, the silicon oxynitride layer including a composition-gradient region that has a thickness of 25 nm or more, the composition-gradient region being a region in which a content ratio of oxygen decreases and a content ratio of nitrogen increases in a thickness direction toward the base, and a ratio of the thickness of the composition-gradient region to the thickness of the entire silicon oxynitride layer being 0.15 or more. The present invention also relates to: an electronic device member that includes the gas barrier laminate, and an electronic device that includes the electronic device member. The present invention provides: a gas barrier laminate that exhibits a very high gas barrier capability and very high bendability, an electronic device member that includes the gas barrier laminate, and an electronic device that includes the electronic device member.