Flexible OLED Substrate Blocking Layer Moisture Protection

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Solution Overview

Problem

Flexible OLED devices using polyimide substrates face thermal degradation due to moisture absorption, leading to reliability issues and reduced lifespan of thin film transistors and light emitting diodes.

Innovation Solution

A flexible substrate with a first and second thin film and an intermediate blocking layer between them, where the blocking layer is positioned in the display area to prevent moisture and oxygen penetration and thermal degradation, while allowing direct contact in specific regions to prevent peeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an intermediate blocking layer is added between the first and second thin films to prevent moisture and oxygen penetration, then the reliability and lifespan of the flexible OLED device is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvereliability of flexible OLED deviceVSAvoidcomplexity of flexible substrate structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flexible substrate is segmented into three distinct layers: a first thin film, an intermediate blocking layer, and a second thin film. This segmentation allows each layer to perform its specific function - the first and second thin films provide flexibility and structural support, while the intermediate blocking layer specifically prevents moisture and oxygen penetration, thereby resolving the contradiction between reliability improvement and structural complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The intermediate blocking layer is positioned specifically in regions where moisture and oxygen penetration is most critical, rather than uniformly across the entire substrate. This local quality approach ensures that the blocking function is applied where needed most, improving reliability without unnecessarily increasing complexity across the entire device structure.

Inventive Principle:

Principle #3Local quality

2Reliability

If the intermediate blocking layer is positioned in the display area to block moisture and oxygen, then thermal degradation is prevented, but the risk of peeling between thin films increases

Engineering Contradiction:

Improveresistance to thermal degradationVSAvoidadhesion between thin films

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The intermediate blocking layer is strategically positioned in the display area where thermal degradation from moisture and oxygen penetration is most critical. By localizing the blocking layer to this specific region, the patent achieves effective protection against thermal degradation while minimizing the overall impact on adhesion strength between the thin films.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The intermediate blocking layer serves as a mediator between the first and second thin films, providing both moisture blocking functionality and adhesion promotion. The layer is designed to chemically or physically bond with both adjacent thin films, acting as an intermediary that prevents peeling while maintaining its moisture-blocking function in the display area.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If the first and second thin films directly contact in the second region to prevent peeling, then adhesion strength is improved, but moisture and oxygen penetration may occur

Engineering Contradiction:

Improveadhesion between thin filmsVSAvoidmoisture and oxygen penetration

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The flexible substrate is divided into two functional regions: a first region (display area) where the intermediate blocking layer is present to prevent moisture and oxygen penetration, and a second region where the first and second thin films directly contact to provide strong adhesion. This spatial segmentation allows both requirements - moisture blocking and adhesion strength - to be satisfied simultaneously in different areas of the substrate.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different structural configurations are applied to different regions of the flexible substrate. The display area (first region) has the triple-layer structure with the intermediate blocking layer for moisture protection, while the peripheral area (second region) has a dual-layer structure with direct film contact for maximum adhesion. This local quality approach optimizes each region for its specific functional requirement.

Inventive Principle:

Principle #3Local quality

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 effectively prevents thermal degradation and reliability issues by blocking moisture and oxygen, enhancing the lifespan of thin film transistors and light emitting diodes, and improving the overall reliability of the flexible OLED device.

Implementation Method 1

an intermediate blocking layer between the first and second thin films and in the first region

Methodology Applied

Scientific EffectPermeation blocking: Permeation

Data Source

PatentUS11211585B2Flexible substrate and flexible organic light emitting diode device

Publication Date: 2021.12.28 LG DISPLAY CO LTD

AI summary

A flexible substrate includes a first flexible thin film including a first region and a second region surrounding the first region; a second flexible thin film on the first thin film and in the first and second regions; and an intermediate blocking layer between the first and second thin films and in the first region.