Flexible Display Adhesive Modulus Zoning for Bend Durability

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Solution Overview

Problem

Flexible displays in electronic devices face challenges with stress-induced plastic deformation, reduced lifespan, and damage due to uneven adhesive layer properties across areas with varying deformation frequencies.

Innovation Solution

A multilayer adhesive layer with low and high modulus areas is used in flexible displays, where the low modulus area corresponds to deformable areas and the high modulus area to non-deformable areas, ensuring predetermined flexibility and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a uniform adhesive layer is used across the entire flexible display, then manufacturing is simplified, but the adhesive cannot effectively respond to varying deformation characteristics in different areas

Engineering Contradiction:
Improveadhesive layer manufacturing simplicityVSAvoidadhesive performance matching deformation characteristics
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The adhesive layer is divided into multiple regions with different modulus values: a first adhesive layer with first modulus in a first area, and a second adhesive layer with second modulus in a second area. This local differentiation allows each region to be optimized for its specific deformation characteristics, resolving the contradiction between manufacturing simplicity and performance matching.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The adhesive layer is segmented into distinct portions with different mechanical properties. The first adhesive layer and second adhesive layer are separated into different spatial areas, allowing independent optimization of each segment's modulus to match local deformation requirements while maintaining overall structural integrity.

Inventive Principle:
Principle #1Segmentation

2Strength

If the adhesive layer has high modulus for durability, then structural stability is improved, but flexibility in deformable areas is reduced

Engineering Contradiction:
Improveadhesive layer durabilityVSAvoidflexibility in deformable areas
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

Different regions of the adhesive layer are assigned different modulus values based on local functional requirements. Areas requiring flexibility are assigned lower modulus adhesive, while areas requiring structural stability are assigned higher modulus adhesive, thus simultaneously achieving both flexibility and durability in their respective locations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The modulus parameter of the adhesive layer is varied spatially across different areas. By changing the modulus parameter from first modulus in the first area to second modulus in the second area, the adhesive layer can provide appropriate mechanical response to local deformation characteristics while maintaining overall structural integrity.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the adhesive layer has low modulus for flexibility, then deformability is improved, but structural stability in non-deformable areas is reduced

Engineering Contradiction:
Improveflexibility in deformable areasVSAvoidstructural stability in non-deformable areas
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The adhesive layer composition is locally optimized by assigning different modulus values to different areas. Low modulus adhesive is placed in deformable areas to enable flexibility, while high modulus adhesive is placed in non-deformable areas to maintain structural stability, thus resolving the contradiction between flexibility and structural integrity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4714648A1Electronic device comprising flexible display
Publication Date: 2026.03.25 SAMSUNG ELECTRONICS CO LTD
  • EP4714648A1 patent drawingFigure 1
  • EP4714648A1 patent drawingFigure 2A
  • EP4714648A1 patent drawingFigure 2B

AI summary

The present disclosure relates to an adhesive layer having different rigidities in correspondence to a deformed area and a non-deformed area of a flexible display included in an electronic device. To this end, the electronic device may comprise a flexible display, which uses an adhesive layer so as to have a multilayer structure. The adhesive layer can include a low modulus area corresponding to a variable area of the flexible display and a high modulus area corresponding to a non-variable area of the flexible display. Other various embodiments are possible.