Foldable Display Support Sheet for Permanent Deformation Control

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Solution Overview

Problem

Flexible display devices experience permanent deformation due to stress from repeated folding operations, compromising their folding reliability.

Innovation Solution

Incorporating a sheet member with support portions and restoration portions made of materials like invar, stainless steel, or copper alloys, which provide elastic force to offset stress and prevent deformation by applying compressive stress to the display module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible display device is subjected to repeated folding operations, then the device becomes portable and adaptable to various shapes, but stress accumulates causing permanent deformation and reducing folding reliability

Engineering Contradiction:
Improvefolding capabilityVSAvoidfolding reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The restoration portion is pre-formed with a bent shape and elastic properties before the folding device is assembled. This preliminary configuration allows the restoration portion to automatically exert restoring force during folding operations, preventing permanent deformation without requiring active control or additional components during the folding process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful stress accumulation that occurs during folding into a beneficial mechanism by designing the restoration portion to elastically deform and store energy during folding, then release this energy to restore the original shape. The stress that would normally cause damage is instead harnessed to drive the restoration mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If the restoration portion is made more rigid to prevent deformation, then folding reliability improves, but the device loses flexibility and cannot be folded

Engineering Contradiction:
Improvefolding reliabilityVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The sheet member is designed with spatially varying properties: the restoration portion has different mechanical characteristics (elastic modulus, thickness) compared to the support portions. This local differentiation allows the restoration portion to provide the necessary rigidity for stress resistance while the support portions maintain flexibility for folding, resolving the contradiction between rigidity and flexibility at different locations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sheet member can be constructed as a composite structure with multiple layers or materials having different mechanical properties. This allows combining materials that provide elasticity for the restoration portion with materials that provide flexibility for the support portions, achieving both folding capability and stress resistance simultaneously.

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 solution enhances the folding reliability of display devices by preventing stress concentration and reducing the likelihood of permanent deformation, ensuring durability through repeated folding.

Implementation Method 1

the restoration portion may include a first restoration portion connected to the first support portion and bent from the first support portion and a second restoration portion connected to the second support portion and bent from the second support portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3683653B1Display device
Publication Date: 2025.10.01 SAMSUNG DISPLAY CO LTD
  • EP3683653B1 patent drawingFigure 1
  • EP3683653B1 patent drawingFigure 2~3
  • EP3683653B1 patent drawingFigure 4

AI summary

A display device includes a display module on which a first non-folding area, a folding area, and a second non-folding area are sequentially defined in a first direction and which is deformable between a first state that is an unfolded state and a second state that is a folded state and a sheet member including a first support portion overlapping the first non-folding area, a second support portion overlapping the second non-folding area, and a restoration portion overlapping the folding area, which are disposed below the display module. When the display module is in the first state, the restoration portion has an elastic force.