Bidirectional Foldable Display Hinge for Panel Stress Reduction

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Solution Overview

Problem

Existing foldable display devices can only fold in one direction, and there is a challenge in implementing both in-folding and out-folding states without causing damage to the display panel due to repeated folding operations.

Innovation Solution

A bidirectional hinge structure is introduced, comprising a mid bar, flap bars, bending couplers, and gear assemblies that allow the display device to fold in both in-folding and out-folding states, with a rounded edge design to minimize pressure and stress on the display panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single-direction hinge structure is used, then the device structure is simple, but the device cannot achieve bidirectional folding states

Engineering Contradiction:
Improvefolding direction capabilityVSAvoidhinge structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The hinge assembly is divided into multiple independent components: first and second hinge assemblies, each with flap bars, couplers, and gear arms. This segmentation allows each component to perform specific functions while collectively enabling bidirectional folding capability without excessive overall complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hinge assembly components serve multiple functions: the flap bars provide both structural support and folding motion, the couplers transmit force in both directions, and the gear arms enable controlled movement. This multi-functionality achieves bidirectional folding without proportionally increasing complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If repeated folding operations are performed, then the device achieves versatile display configurations, but damage to the display panel occurs due to pressure and stress

Engineering Contradiction:
Improvedisplay configuration flexibilityVSAvoiddisplay panel durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The flap bars are designed with rounded edges instead of sharp corners. This curvature distributes the contact pressure across a larger area of the display panel during folding operations, reducing stress concentration and preventing damage while maintaining folding versatility

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The rounded edge design acts as a preventive measure before damage occurs. By eliminating sharp edges that would concentrate stress, the design proactively protects the display panel from cracking or creasing during repeated folding operations

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If a hinge structure is added to enable bidirectional folding, then folding versatility is improved, but the device complexity increases

Engineering Contradiction:
Improvein-folding and out-folding capabilityVSAvoidhinge assembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The first and second hinge assemblies are symmetrically integrated into the device structure, with corresponding components (flap bars, couplers, gear arms) on each side working together. This merging of symmetric structures achieves bidirectional folding capability while maintaining design efficiency and avoiding excessive complexity

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4394550B1Foldable display device
Publication Date: 2025.10.29 LG DISPLAY CO LTD
  • EP4394550B1 patent drawingFigure 1
  • EP4394550B1 patent drawingFigure 2
  • EP4394550B1 patent drawingFigure 3

AI summary

A foldable display device includes a display panel, a first set housing and a second set housing disposed to face each other in a first direction and respectively supporting two different portions of the display panel, and a hinge assembly disposed between the first set housing and the second set housings and for folding and unfolding the first set housing and the second set housing.