Flexible Display Adhesive Patterning for Low-Stress Bending
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Solution Overview
Problem
Flexible displays face mechanical stress issues when bent or rolled, which can lead to deterioration and destruction, particularly with smaller bending radii enhancing stress and reducing portability.
Innovation Solution
A patterned adhesive layer is applied to the display module with elements separated in the in-plane direction, and a refractive index matching agent is used between adhesive layers to reduce mechanical stress and prevent light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the adhesive layer is made continuous to ensure strong bonding, then bonding strength is improved, but mechanical stress increases when the display is bent
Solution Approach 1:
The adhesive layer is divided into multiple separate adhesive regions rather than being continuous. Each adhesive region is positioned over specific pixel regions, creating discrete bonding zones that allow the display to flex more easily between adhesive regions, thereby reducing mechanical stress during bending while maintaining adequate bonding strength.
2Ease of operation
If the adhesive layer is made discontinuous to reduce mechanical stress, then portability is improved, but light reflection increases at adhesive interfaces
Solution Approach 1:
A refractive index matching layer is introduced between the adhesive regions and the surrounding medium. This intermediary layer has a refractive index that matches both the adhesive and the surrounding environment, eliminating optical interfaces that would otherwise cause light reflection and glare, while allowing the adhesive regions to remain discontinuous for flexibility.
3Stability of the object's composition
If the adhesive layer covers the entire display surface to ensure uniform bonding, then bonding uniformity is improved, but mechanical stress distribution becomes less favorable
Solution Approach 1:
The adhesive layer is applied selectively to specific local regions corresponding to pixel areas rather than uniformly across the entire display surface. This localized adhesive application provides sufficient bonding uniformity within each adhesive region while creating stress-relief zones between regions, optimizing the balance between bonding and flexibility.
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 reduces mechanical stress, allowing for smaller winding radii and improved portability while maintaining image quality by distributing stress and minimizing light reflection.
Implementation Method 1
a refractive index matching agent is filled between the adhesive layers... reflection of light at the interface between air and the adhesive layer is prevented
Data Source
AI summary
A flexible display includes a display layer having a plurality of light emitting elements for displaying an image; a first layer disposed on a first surface of the display layer; a second layer disposed on a second surface of the display layer; and an adhesive layer disposed between the display layer and the first layer and/or between the display layer and the second layer. The adhesive layer comprises elements separated in the in-plane direction.