Flexible Electroluminescence Display with Segmented Inorganic Barrier

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Solution Overview

Problem

Flexible electroluminescence display devices face damage and moisture permeation due to bending stress when repeatedly folded or rolled, leading to reduced lifespan.

Innovation Solution

A flexible electroluminescence display device structure featuring a flexible substrate with a bending axis, a first metal layer, an inorganic material layer, recessed portions, a second metal layer, and an organic material layer, where the inorganic material layer is removed to form trenches parallel to the bending axis, and the organic material layer fills these trenches to absorb stress and prevent moisture ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the display device is made flexible and foldable, then the adaptability and portability are improved, but the reliability deteriorates due to cracking and moisture permeation from bending stress

Engineering Contradiction:

ImproveflexibilityVSAvoiddurability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The inorganic material layer is segmented into multiple sections separated by recessed portions, creating a multi-segment structure. This segmentation allows each segment to independently accommodate bending stress without causing cracks to propagate across the entire layer, thereby maintaining reliability while preserving flexibility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The recessed portions are pre-formed in the inorganic material layer before the device is subjected to bending stress. These recessed portions act as pre-prepared stress relief zones that cushion and absorb bending stress during folding operations, preventing damage to the light emitting layer and maintaining device reliability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the inorganic material layer is made continuous to prevent moisture permeation, then the reliability is improved, but the flexibility deteriorates due to cracking from bending stress

Engineering Contradiction:

Improvemoisture barrierVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The inorganic material layer is divided into multiple segments separated by recessed portions. This segmentation creates flexibility by allowing the segments to move independently during bending, while the second metal layer bridges the recessed portions to maintain continuous moisture barrier coverage across the entire surface

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solution moves from a two-dimensional continuous layer to a three-dimensional segmented structure with vertical depth. The recessed portions create depth in the structure, allowing the inorganic material layer to flex vertically while the second metal layer provides horizontal continuity for moisture protection

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the display device is folded repeatedly, then the adaptability is improved, but the lifespan deteriorates due to stress accumulation and damage

Engineering Contradiction:

ImproverepeatabilityVSAvoidlifespan

Core Design Contradiction:

Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

The recessed portions are pre-formed in the inorganic material layer to provide stress relief zones before bending occurs. During repeated folding operations, these pre-prepared zones absorb and distribute bending stress, preventing stress accumulation that would otherwise lead to cracking and device failure, thereby extending lifespan

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The structure changes the physical parameters of the inorganic material layer by introducing recessed portions with specific depth and spacing. This parameter modification allows the layer to accommodate repeated bending cycles by deforming within the recessed zones rather than developing cracks, maintaining device functionality over extended periods

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10886489B2Flexible electroluminescence display

Publication Date: 2021.01.05 LG DISPLAY CO LTD

AI summary

Disclosed is an electroluminescence display device. The electroluminescence display device includes a flexible substrate, a first metal layer, an inorganic material layer, a recessed portion, a second metal layer, and an organic material layer. The flexible substrate has a bending axis. The first metal layer is disposed on the flexible substrate to be parallel with the bending axis. The inorganic material layer is stacked on the first metal layer. The recessed portion is disposed in the inorganic material layer to be parallel to the bending axis and exposes the first metal layer. The second metal layer extends in parallel to the bending axis, covers the recessed portion, and is in contact with the first metal layer. The organic material layer covers the inorganic material layer and the second metal layer.