Flexible Display Encapsulation Protrusions for Peel Resistance

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Solution Overview

Problem

Flexible display devices face challenges in maintaining stability and preventing peeling phenomena during bending due to inadequate interfacial adhesion between layers, which affects yield rate and service life.

Innovation Solution

A flexible display substrate with a thin film encapsulation layer featuring protrusions that contact the pixel defining layer, increasing the contact area and interfacial adhesion, and a manufacturing method involving the formation of recesses in the capping or pixel defining layers to accommodate these protrusions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional flat encapsulation structure is used, then the device structure is simple, but the interfacial adhesion between layers is insufficient causing peeling during bending

Engineering Contradiction:

Improveinterfacial adhesionVSAvoidencapsulation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The encapsulation layer is designed with localized protrusions at specific positions rather than a uniform structure. These protrusions are formed by filling recesses in the encapsulation layer with additional material, creating localized adhesive contact points that enhance interfacial adhesion specifically where needed without complicating the entire encapsulation structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The protrusions in the encapsulation layer have curved or rounded tops rather than flat surfaces. This curvature increases the contact area and improves adhesion to the underlying layers, particularly at the bending interface where flexible display devices experience stress. The curved geometry allows better conformal contact with the pixel defining layer underneath.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If the encapsulation layer is made thicker to prevent peeling, then adhesion improves, but the flexibility and bendability of the display device deteriorates

Engineering Contradiction:

Improvepeel resistanceVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The encapsulation layer is segmented into multiple functional regions: flat areas that maintain flexibility and bendability, and localized protrusion regions that provide enhanced adhesion. By distributing protrusions at specific intervals rather than making the entire layer thick, the structure achieves peel resistance while preserving the overall flexibility needed for bending applications.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Rather than uniformly increasing the thickness of the entire encapsulation layer, the invention applies additional material locally only where protrusions are needed for adhesion. This localized approach provides peel resistance at critical interfaces while keeping the rest of the encapsulation layer thin enough to maintain device flexibility and bendability.

Inventive Principle:

Principle #3Local quality

3Reliability

If protrusions are added to the encapsulation layer to increase contact area, then interfacial adhesion improves, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveinterfacial adhesionVSAvoidencapsulation layer fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Recesses are formed in the encapsulation layer during the pixel defining layer formation process, before the encapsulation material is deposited. This preliminary preparation allows the encapsulation material to be deposited as a uniform layer that naturally forms protrusions by filling the pre-formed recesses, simplifying the overall manufacturing process compared to attempting to create protrusions through complex molding or post-processing techniques.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The formation of protrusions is merged with the standard encapsulation layer deposition process. By forming recesses beforehand and then depositing encapsulation material that fills these recesses, the protrusion formation becomes an integrated part of the encapsulation process rather than a separate additional step, reducing manufacturing complexity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11264585B2Flexible display device with improved packaging structure and manufacturing method thereof

Publication Date: 2022.03.01 BOE TECHNOLOGY GROUP CO LTD

AI summary

The present disclosure provides a flexible display device and a manufacturing method thereof. The flexible display device includes a base substrate; a pixel defining layer disposed on the base substrate defining a plurality of light emitting regions; and a first electrode layer disposed on a side of the pixel defining layer away from the base substrate and in light-emitting regions. A thin film encapsulation layer covers the first electrode layer and has protrusions protruding toward the pixel defining layer at a plurality of positions.