Foldable Display Window Panel with Variable Elastic Modulus

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Solution Overview

Problem

Conventional foldable display devices face challenges in achieving both durability and flexibility, particularly in preventing cracking and peeling of the flexible film substrates and maintaining a thin thickness even with multiple functional layers.

Innovation Solution

A foldable display device design featuring a window panel with a flexible area and adjacent rigid areas, where the elastic modulus is lower in the flexible area than in the rigid areas, utilizing a photo-curable transparent adhesive layer and a colour filter on the laminated film, ensuring no cracking or peeling occurs and allowing for a reduced thickness even with multiple layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible substrate is used to enable foldable display, then flexibility is improved, but durability deteriorates due to cracking and peeling

Engineering Contradiction:
ImproveflexibilityVSAvoiddurability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating a window panel with spatially varying elastic modulus - the flexible area has lower elastic modulus than the rigid areas. This gradient structure allows the flexible area to bend without cracking while the rigid areas maintain structural integrity and prevent peeling, resolving the contradiction between flexibility and durability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining multiple layers including flexible film substrates, rigid areas with different elastic moduli, and photo-curable transparent adhesive layers. This composite structure integrates the benefits of both flexible and rigid materials, enabling the display to fold without compromising durability

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If multiple functional layers are provided in the flexible display, then functionality is improved, but thickness increases

Engineering Contradiction:
ImprovefunctionalityVSAvoidthickness
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent employs flexible shells and thin films by using flexible film substrates and thin adhesive layers instead of traditional rigid glass substrates. This allows multiple functional layers to be integrated while maintaining a thin overall thickness, as the flexible film structure can accommodate multiple layers without significant thickness accumulation

Inventive Principle:
Principle #30Flexible shells and thin films

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 enhances the durability and flexibility of the foldable display device, preventing cracking and peeling while maintaining a thin profile, thus improving its reliability and usability in various applications.

Implementation Method 1

Laminated films are bonded to the film substrates with a photo-curable transparent adhesive layer being interposed therebetween

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP2840460B1Foldable display device
Publication Date: 2017.08.23 SAMSUNG DISPLAY CO LTD
  • EP2840460B1 patent drawingFigure 1
  • EP2840460B1 patent drawingFigure 2A~2B
  • EP2840460B1 patent drawingFigure 3

AI summary

A foldable display device is disclosed. In one aspect, the foldable display device includes a display panel and a window panel provided on a front surface of the display panel. The window panel includes a flexible area and a rigid area provided adjacent to at least one side of the flexible area. The elastic modulus of the flexible area of the window panel is lower than that that of the rigid area.