Foldable Display Hinge Structure for Low-Stress Bending

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Solution Overview

Problem

Existing flexible display devices suffer from significant deformation in the folding area due to repeated folding and unfolding, necessitating a technology to reduce this deformation.

Innovation Solution

A display device design incorporating a folding area with a curvature radius of 1.5 mm to 5.0 mm, flanked by non-folding areas, supported by biaxial rotation shafts and extension parts, with symmetric extension parts forming acute angles, and supported by support plates and cushion layers to mitigate deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the display module is folded repeatedly, then the folding area can be bent to achieve portability, but the folding area undergoes significant deformation reducing reliability

Engineering Contradiction:

ImproveportabilityVSAvoiddeformation of folding area

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The display module is divided into three distinct regions: a first non-folding area, a folding area, and a second non-folding area. This segmentation allows the folding operation to be localized to a specific region while preserving the integrity of the non-folding areas, thereby maintaining portability while reducing overall deformation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the display module are assigned different functional properties: the folding area is designed to be flexible and bendable with a controlled curvature radius (1.5mm to 5.0mm), while the non-folding areas maintain structural rigidity. This local differentiation enables the folding area to accommodate repeated bending without causing deformation to the entire display module

Inventive Principle:

Principle #3Local quality

2Area of moving object

If the folding area is made smaller to improve portability, then the device becomes more compact, but the structural stress during folding increases

Engineering Contradiction:

Improvesize of display moduleVSAvoidstructural stress in folding area

Core Design Contradiction:

Area of moving objectVSStress or pressure

Solution Approach 1:

The folding area is designed with a specific curvature radius range (1.5mm to 5.0mm) when folded, creating a controlled curved geometry. This curvature distribution helps to evenly分散 the structural stress during folding operations, preventing stress concentration that would occur with sharper or more abrupt folds

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Volume of moving object

If the curvature radius of the folding area is reduced to achieve tighter folding, then the device folds more compactly, but the deformation of the folding area increases

Engineering Contradiction:

Improvefolded sizeVSAvoidcurvature radius control

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent specifies an optimal range for the curvature radius (1.5mm to 5.0mm) of the folding area when folded. By controlling this geometric parameter within the specified range, the design achieves a balance between compact folded size and minimized deformation, ensuring that the folding area can withstand repeated folding operations

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3929697B1Display device

Publication Date: 2025.10.01 SAMSUNG DISPLAY CO LTD

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AI summary

A display device includes a display module including a first non-folding area, a second non-folding area, and a folding area disposed between the first and second non-folding areas which are arranged in a first direction, a first support disposed below the first non-folding area, a second support disposed below the second non-folding area, and a hinge including a biaxial rotation shaft disposed between the first support and the second support, the biaxial rotation shaft extending in a second direction intersecting the first direction. The folding area has a curvature radius in a range of about 1.5 mm to about 5.0 mm when the display module is folded by a rotation of the first support and the second support with respect to the biaxial rotation shaft.