Flexible Display Encapsulation via Segmented Organic-Inorganic Layers

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Solution Overview

Problem

Existing display devices face challenges in maintaining the integrity of their encapsulation layers when the device shape changes, such as in flexible, foldable, or stretchable forms, leading to potential damage and loss of functionality.

Innovation Solution

A display device structure incorporating a thin encapsulation layer with a stacked configuration of organic and inorganic layers, including a hydrophilic organic control layer and multiple inorganic encapsulation layers, which are patterned to efficiently distribute stress and prevent damage during shape changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thick encapsulation layer is used to protect display elements, then reliability is improved, but device flexibility and shape changeability deteriorate

Engineering Contradiction:

Improveencapsulation layer integrityVSAvoidshape changeability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The encapsulation layer is divided into multiple thin layers (first inorganic encapsulation layer, organic encapsulation layer, second inorganic encapsulation layer) instead of using a single thick layer. This segmentation allows each layer to be sufficiently thin to permit shape changes while collectively providing comprehensive protection against moisture and oxygen, resolving the contradiction between reliability and flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The encapsulation structure uses a composite of different materials (inorganic and organic layers) with complementary properties. The inorganic layers provide barrier properties against moisture and oxygen, while the organic layer provides flexibility and stress distribution. This composite structure achieves both protection and shape changeability simultaneously.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If a thin encapsulation layer is used to enable shape changes, then adaptability is improved, but reliability deteriorates due to potential damage

Engineering Contradiction:

Improveshape changeabilityVSAvoidencapsulation layer integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Dividing the encapsulation into multiple thin layers allows each layer to flex independently during shape changes, reducing stress concentration and preventing cracking while maintaining overall protective function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The organic encapsulation layer acts as a flexible intermediate layer that can accommodate shape changes without breaking, while the inorganic layers provide protective barrier functions. This thin-film structure enables both flexibility and reliability.

Inventive Principle:

Principle #30Flexible shells and thin films

3Device complexity

If a single-layer encapsulation structure is used, then device complexity is reduced, but manufacturing precision and stress distribution deteriorate

Engineering Contradiction:

Improveencapsulation structure complexityVSAvoidencapsulation layer uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The multi-layer structure allows each layer to be optimized for specific functions (barrier, flexibility, stress distribution) and manufactured with precise control over thickness and coverage, improving overall manufacturing precision despite increased structural complexity.

Inventive Principle:

Principle #1Segmentation

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 seals the display elements and prevents damage to the encapsulation layers when the device shape changes, ensuring the display device's functionality and longevity.

Implementation Method 1

an organic control layer disposed on the opposite electrode, the organic control layer having hydrophilicity

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

an organic control layer disposed on the opposite electrode, the organic control layer having hydrophilicity

Methodology Applied

Scientific EffectSurface energy: Surface Tension

Data Source

PatentUS10978669B2Display device and method of manufacturing display device

Publication Date: 2021.04.13 SAMSUNG DISPLAY CO LTD

AI summary

A display device is provided. The display device includes: a substrate; a driving thin film transistor disposed over the substrate; a pixel electrode electrically connected to the driving thin film transistor; a pixel-defining layer including an opening overlapping the pixel electrode; an intermediate layer overlapping a portion of the pixel electrode exposed through the opening, the intermediate layer including an emission layer; an opposite electrode disposed on the intermediate layer; an organic control layer disposed on the opposite electrode, the organic control layer having hydrophilicity; an organic encapsulation layer disposed on the organic control layer; and at least one inorganic encapsulation layer overlapping the organic encapsulation layer.