Polymer Protrusions for Flexible Display Crack Resistance

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Solution Overview

Problem

Flexible touch display devices face challenges in durability, particularly in resisting cracking and damage from bending stresses, due to the stresses imposed on the cover window layer.

Innovation Solution

The implementation of a flexible touch display device design that incorporates a patterned cover window layer with polymer material protrusions, where the light emitting diodes partially overlap these protrusions, helps to distribute bending stresses and enhance resistance to cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional cover window layer is used in flexible touch display devices, then the device structure is simple, but the layer is highly susceptible to bending stresses and cracking

Engineering Contradiction:

Improveresistance to crackingVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cover window layer is segmented into multiple discrete polymer protrusions rather than a continuous layer. Each protrusion is separated from others, allowing independent deformation and stress distribution. This segmentation prevents crack propagation across the entire layer while maintaining protective coverage where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polymer protrusions are strategically positioned to overlap with light emitting diodes, creating localized regions of enhanced stress resistance. The protrusions provide differential protection - areas with protrusions have higher resistance to bending stresses compared to areas without, matching the protective needs with the LED locations.

Inventive Principle:

Principle #3Local quality

2Length of moving object

If the cover window layer is made thinner to reduce device thickness, then portability improves, but the layer becomes more vulnerable to bending damage

Engineering Contradiction:

Improvedevice thicknessVSAvoidbending resistance

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The polymer protrusions have curved, dome-like shapes rather than flat or angular forms. This curvature allows the protrusions to flex and deform more easily under bending stresses, absorbing mechanical energy without fracturing. The rounded geometry distributes stress more evenly compared to sharp edges that would concentrate and initiate cracks.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The cover window layer utilizes thin polymer films forming the protrusions, which inherently possess flexibility. These thin film structures can undergo large deformations without permanent damage, providing both thickness reduction and bending resistance through the material's intrinsic flexibility rather than relying on thick rigid structures.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS12332692B2Electronic device

Publication Date: 2025.06.17 INNOLUX CORP

AI summary

An electronic device includes a substrate, a display layer and a structure layer. The display layer includes a plurality of light emitting diodes on the substrate. The structure layer is disposed on the display layer, wherein the structure layer includes a plurality of polymer material protrusions. At least one of the light emitting diodes partially overlaps at least one of the polymer material protrusions in a normal direction of the substrate.