Flexible Display Hinge Length Compensation

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Solution Overview

Problem

Flexible display devices with folding structures face challenges in maintaining uniform deformation, leading to issues with screen flatness and reliability when folded and unfolded.

Innovation Solution

A flexible display device design that incorporates a hinge structure with length compensation through relative sliding between the body and the hinge portion, along with an elastic force providing unit and magnetic forces to maintain display flatness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a flexible display is disposed over two whole bodies across a folding structure, then a large screen can be implemented, but deformation variation occurs during folding and unfolding

Engineering Contradiction:
Improvescreen areaVSAvoiddeformation uniformity
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The hinge portion is divided into multiple hinge segments (first hinge segment, second hinge segment, etc.) that can rotate relative to each other. This segmentation allows each segment to independently adjust and compensate for deformation variations, ensuring more uniform deformation across the entire flexible display while maintaining the large screen area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The distance between one end portions of the hinge segments is varied according to folding and unfolding operations. By dynamically changing the geometric parameters (distances and angles) of the hinge segments, the system compensates for deformation variations and maintains reliable operation of the flexible display across its full range of motion.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the hinge portion length is kept constant, then the structure is simpler, but the flexible display cannot compensate for length variation during folding

Engineering Contradiction:
Improvehinge structure complexityVSAvoidlength compensation capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The hinge portion is designed with dynamic characteristics, allowing the distance between end portions of hinge segments to change during folding and unfolding. This dynamic adjustment enables automatic length compensation without requiring complex additional mechanisms, maintaining both simplicity and reliability.

Inventive Principle:
Principle #15Dynamics

3Strength

If the first body has greater thickness to support the hinge structure, then structural strength is improved, but the overall device size increases

Engineering Contradiction:
Improvestructural strengthVSAvoiddevice volume
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The hinge structure is segmented into multiple segments that distribute mechanical stresses across different locations. This segmentation allows the first body to have adequate local thickness at critical support points while keeping the overall device volume compact, as the load is distributed rather than concentrated in a single thick section.

Inventive Principle:
Principle #1Segmentation

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 enables a compact outer folding type flexible display device with improved reliability by maintaining display flatness and compensating for length variations during folding and unfolding.

Implementation Method 1

an elastic force providing unit configured to provide elastic force to the sliding plate

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a magnetic force providing unit configured to provide magnetic force to maintain flatness of the flexible display when unfolded

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP3886078B1Flexible display device
Publication Date: 2025.04.09 LG ELECTRONICS INC
  • EP3886078B1 patent drawingFigure 1A
  • EP3886078B1 patent drawingFigure 1B
  • EP3886078B1 patent drawingFigure 2

AI summary

Disclosed is a flexible display device comprising: a first body and a second body; a hinge unit for connecting the first body and the second body so as to enable relative rotations thereof; a flexible display unit arranged on one surface of the first body and the second body, and folded and unfolded by the relative rotations; a covering member arranged between the first body and the second body so as to cover a space, formed by the folding of the flexible display unit, between the first body and the second body; and a lever connected to the hinge unit so as to rotate in connection with the folding and the unfolding of the flexible display unit, and formed so as to support at least a part of the covering member.