Flexible Display Stress Distribution via Modulated Encapsulation

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Solution Overview

Problem

Flexible display devices face mechanical reliability issues due to stress accumulation during repeated shape transformations, which can lead to damage, as existing technologies do not effectively distribute stress across folding or bending regions.

Innovation Solution

A flexible display device design featuring a thin film encapsulating layer with alternately stacked inorganic and organic encapsulating films, where the organic encapsulating film has regions with different Young's moduli to distribute stress effectively, and a sensing unit and controller to manage the display's operation based on its shape, ensuring mechanical reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the flexible display device undergoes repeated shape transformations, then the display can be folded or bent, but stress accumulates and damages the device

Engineering Contradiction:
Improveshape transformation capabilityVSAvoidmechanical reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The encapsulating layer is divided into multiple regions with different Young's moduli. The first organic region has a first Young's modulus and the second organic region has a second Young's modulus different from the first. This segmentation allows different parts of the encapsulating layer to handle stress differently during folding, distributing the mechanical load and preventing stress concentration that would damage the device.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the encapsulating layer are given different mechanical properties (different Young's moduli) according to their specific functional requirements. The first organic region and second organic region have locally optimized stiffness characteristics, allowing the structure to be rigid where needed and flexible where required during shape transformations.

Inventive Principle:
Principle #3Local quality

2Device complexity

If a single-material encapsulating layer is used, then the structure is simple, but stress cannot be effectively distributed during folding

Engineering Contradiction:
Improveencapsulating layer structureVSAvoidstress distribution capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The encapsulating layer is constructed as a composite structure with at least a first organic region and a second organic region having different Young's moduli. This composite approach combines materials with different mechanical properties to achieve superior stress distribution during folding, where each material contributes its optimal characteristics to the overall performance.

Inventive Principle:
Principle #40Composite materials

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 design effectively distributes stress across folding regions, enhancing the mechanical reliability of the flexible display device and preventing damage during shape transformations, while allowing for seamless operation across folded and unfolded states.

Implementation Method 1

at least a first organic region (322) including a first organic material and having a first Young's modulus, and at least a second organic region (324) including a second organic material different from the first organic material and having a second Young's modulus different from the first Young's modulus

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3057150B1Flexible display device
Publication Date: 2020.12.02 SAMSUNG DISPLAY CO LTD
  • EP3057150B1 patent drawingFigure 1
  • EP3057150B1 patent drawingFigure 2~3
  • EP3057150B1 patent drawingFigure 4~5

AI summary

A flexible display device includes: a flexible substrate; a display unit on the flexible substrate and including a display area capable of displaying an image; and a thin film encapsulating layer encapsulating the display unit and including at least one inorganic encapsulating film and at least one organic encapsulating film, where the organic encapsulating film includes at least one first organic region including a first organic material and at least one second organic region including a second organic material that is different from the first organic material, and the at least one first organic region extends in a first direction, the at least one first organic region and the at least one second organic region are aligned with each other, and a first Young's modulus of the at least one first organic region is different from a second Young's modulus of the least one second organic region.