Curl-Preventing Pattern in Flexible Display Window Coating

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Solution Overview

Problem

Display devices face issues with curling or delamination due to thermal expansion differences and manufacturing processes, which affect the reliability and durability of flexible displays.

Innovation Solution

A curl-preventing pattern is integrated into the display device's structure, specifically positioned on the second non-light emitting area and covered by the window coating layer, which includes materials with high elastic modulus to prevent delamination and curling, and is designed to overlap the non-light emitting areas to remain hidden from the user.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a flexible display device is manufactured without additional reinforcing structures, then the device maintains flexibility and simplicity, but the device experiences curling and delamination due to thermal expansion differences

Engineering Contradiction:
ImprovestructureVSAvoidcurling prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by placing reinforcing structures (such as reinforcing members or patterns with different elastic moduli) specifically in non-light-emitting areas where they are not visible to users. This allows the flexible substrate to gain structural support and resistance to curling in critical regions without affecting the overall flexibility or visual appearance of the display device.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining the flexible substrate with reinforcing members or patterns that have different elastic moduli. These composite structures are designed to compensate for thermal expansion differences between layers, preventing delamination and curling while maintaining the flexible nature of the display device.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If reinforcing members are added to prevent curling, then the structural stability improves, but the flexibility and thinness of the display device are compromised

Engineering Contradiction:
Improvestructural stabilityVSAvoidflexibility
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The reinforcing structures are strategically placed only in non-light-emitting areas, providing local structural support where needed without adding significant weight or reducing flexibility in the light-emitting areas. This localized approach maintains the overall flexibility and thinness of the display device while improving structural stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses thin film structures and flexible reinforcing members that provide structural support without significantly increasing the overall thickness or weight of the display device. These thin film reinforcements maintain the flexible nature of the device while preventing curling and delamination.

Inventive Principle:
Principle #30Flexible shells and thin films

3Strength

If the window coating layer is made thicker to prevent delamination, then the adhesive strength improves, but the manufacturing complexity and risk of curling increase

Engineering Contradiction:
Improveadhesive strengthVSAvoidmanufacturing process
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Instead of uniformly increasing the thickness of the window coating layer across the entire display, the patent applies reinforcement patterns or members locally in non-light-emitting areas. This provides the necessary adhesive strength and structural support without requiring a thicker coating everywhere, thereby simplifying the manufacturing process and reducing the risk of curling.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces intermediate reinforcing structures (such as patterns with different elastic moduli or reinforcing members) that act as mediators between the window coating layer and the flexible substrate. These intermediaries enhance adhesive strength and prevent delamination without requiring the window coating layer itself to be thicker, thus avoiding manufacturing complexity and curling issues.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 mitigates the curling phenomenon, enhances the resilience of the display device, and simplifies the manufacturing process by preventing delamination and curling issues associated with thermal expansion and adhesive creep.

Implementation Method 1

a first curl-preventing pattern CPA1... which includes a material having a relatively high elastic modulus

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3249713B1Display device
Publication Date: 2024.10.30 SAMSUNG DISPLAY CO LTD
  • EP3249713B1 patent drawingFigure 1
  • EP3249713B1 patent drawingFigure 2A~2B
  • EP3249713B1 patent drawingFigure 2C~2D

AI summary

A display device includes: a display panel layer including a display area and a second non-light emitting area, the display area including a plurality of light emitting areas and a first non-light emitting area, the first non-light emitting area being around each of the light emitting areas, and the second non-light emitting area being outside the display area; a window coating layer directly on a first surface of the display panel layer; and a first curl-preventing pattern overlapping at least one of the first non-light emitting area and the second non-light emitting area when viewed in a plan view and contacting the window coating layer. The first curl-preventing pattern is configured to prevent the window coating layer from curling.