Foldable Display Panel Adhesive Layout for Bending Reliability

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Solution Overview

Problem

Existing flexible display devices face reliability issues due to structural weaknesses that lead to damage and malfunction when folded or bent, particularly in the folding areas.

Innovation Solution

The display device incorporates a flexible display panel with a specialized structure that includes a window layer made of thin-film glass or synthetic resin, an input sensing unit directly on the panel, and a support system with a metal or non-metal plate having a bending part with patterns and a high restoration layer to absorb impact and maintain structural integrity during folding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the plate is folded at the folding area, then the display device becomes flexible and portable, but the adhesive film may tear or detach at the bending portion

Engineering Contradiction:
ImproveflexibilityVSAvoidadhesive film durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The adhesive film is segmented into a first adhesive area and a second non-adhesive area, where the first adhesive area attaches the plate to the display panel and the second non-adhesive area corresponds to the bending portion. This segmentation prevents the adhesive film from tearing or detaching at the folding area while maintaining flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different areas of the adhesive film have different properties: the first adhesive area has adhesive properties to secure the plate, while the second area has non-adhesive properties to allow bending without damage. This local differentiation resolves the contradiction between adhesion and flexibility.

Inventive Principle:
Principle #3Local quality

2Strength

If a complete adhesive film is used to attach the plate to the display panel, then the attachment strength is maximized, but the adhesive film cannot accommodate bending without tearing

Engineering Contradiction:
Improveattachment strengthVSAvoidbending capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The adhesive film is divided into adhesive and non-adhesive areas, allowing the adhesive portions to provide strong attachment while the non-adhesive portion accommodates bending movements without tearing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of making the entire adhesive film adhesive to maximize attachment strength, the invention inverts the approach by making specific portions non-adhesive to enable bending, thus resolving the contradiction between strength and flexibility.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If the adhesive film covers the entire plate including the bending portion, then the plate is securely attached, but the plate cannot be properly folded without damaging the adhesive film

Engineering Contradiction:
Improveattachment reliabilityVSAvoidfolding operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The adhesive film is segmented to exclude the bending portion from adhesive coverage, allowing the plate to be folded without damaging the adhesive film while maintaining reliable attachment in the non-bending areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive film has different local properties: adhesive in areas that require secure attachment and non-adhesive in the bending area to facilitate folding operations without damage.

Inventive Principle:
Principle #3Local quality

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 reliability and durability of the display device by reducing damage and maintaining functionality during folding and unfolding, enhancing the reliability and longevity of the device.

Implementation Method 1

an adhesive film which is between the plate and the display panel and attaches the plate to the display panel, the adhesive film including a non-adhesive area corresponding to the bending portion of the plate

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3936974B1Display device
Publication Date: 2026.04.29 SAMSUNG DISPLAY CO LTD
  • EP3936974B1 patent drawingFigure 1
  • EP3936974B1 patent drawingFigure 2A~2B
  • EP3936974B1 patent drawingFigure 3A~3B

AI summary

A display device includes a display panel which is foldable at a folding area of the display panel, a plate which faces the display panel and is foldable together with the display panel, the plate including a bending portion corresponding to the folding area, a plurality of openings defined in the plate at the bending portion thereof and an adhesive film which is between the plate and the display panel and attaches the plate to the display panel, the adhesive film including a non-adhesive area corresponding to the bending portion of the plate.