Foldable Display Panel Encapsulation Layout Against Bending Peeling

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Solution Overview

Problem

Bendable or foldable display panels face issues such as peeling of the encapsulation layer due to bending stress, which affects the touch structure's reliability, and inaccurate etching of touch wires leading to short circuits.

Innovation Solution

The display panel design includes a base substrate with a driving circuit layer, an organic structure, and an encapsulation layer with varying thicknesses in different peripheral regions, featuring a thicker first encapsulation portion in the first peripheral region and a thinner second encapsulation portion in the bending region, along with precise etching of touch wires to avoid short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the encapsulation layer has uniform thickness, then the manufacturing process is simple, but the encapsulation layer peels under bending stress in foldable displays

Engineering Contradiction:
Improveencapsulation layer durabilityVSAvoidencapsulation layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The encapsulation layer is designed with different thicknesses in different regions: a first thickness in the first peripheral region and a second thickness (greater than the first) in the bending region. This local variation in thickness provides enhanced protection where bending stress occurs while maintaining manufacturing feasibility.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If touch wires are etched with standard precision, then the manufacturing process is straightforward, but inaccurate etching leads to short circuits

Engineering Contradiction:
Improvetouch wire etching accuracyVSAvoidetching process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

A first organic structure is formed before etching the touch wires. This pre-formed structure serves as a protective barrier during the etching process, preventing etchant from causing short circuits between adjacent touch wires, thereby enabling accurate etching while maintaining ease of manufacture.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the display panel uses a uniform encapsulation layer, then material usage is minimized, but the touch structure reliability deteriorates under bending stress

Engineering Contradiction:
Improvetouch structure reliabilityVSAvoidencapsulation layer material
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The encapsulation layer thickness is optimized locally: thinner in non-bending regions to minimize material usage, and thicker in the bending region to ensure touch structure reliability under bending stress. This approach balances material efficiency with functional requirements.

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

This design enhances the encapsulation layer's durability against bending stress, preventing peeling and ensures accurate formation of touch wires, thereby maintaining touch functionality and reliability.

Implementation Method 1

a first liquid crystal layer having a vertical orientation in which liquid crystal molecules are oriented in an upright direction

Methodology Applied
Scientific EffectLiquid crystal optical modulation: Liquid Crystals

Implementation Method 2

a second liquid crystal layer having a horizontal orientation in which liquid crystal molecules are oriented in a horizontal direction

Methodology Applied
Scientific EffectLiquid crystal optical modulation: Liquid Crystals

Data Source

PatentEP4006987B1Display panel
Publication Date: 2026.01.28 BOE TECHNOLOGY GROUP CO LTD
  • EP4006987B1 patent drawingFigure 1
  • EP4006987B1 patent drawingFigure 2~4
  • EP4006987B1 patent drawingFigure 5~7

AI summary

A display panel is provided. The display panel has a display region (AA) and a peripheral region (NA) surrounding the display region (AA), the peripheral region (NA) includes a first peripheral region (NA1), a bending region (B), and a second peripheral region (NA2). The display panel includes a base substrate (101), a driving circuit layer, an organic structure, and an encapsulation layer; the organic structure includes a first organic structure (201) and a second organic structure (202) spaced apart in the peripheral region (NA), the first organic structure (201) is in the first peripheral region (NA), and the second organic structure (202) includes a first portion (202A) in the first peripheral region (NA1) and a second portion (202B) in the bending region (B) which are continuous; the encapsulation layer covers the display region (AA) and at least part of the first peripheral region (NA1), the encapsulation layer partially overlaps with the second organic structure (202) in a direction perpendicular to the base substrate (101), a portion of the encapsulation layer which overlaps with the second organic structure (202) includes a first encapsulation portion (301) and a second encapsulation portion (302), and the first encapsulation portion (301) is on a side of the second encapsulation portion (302) close to the display region (AA); and in the direction perpendicular to the base substrate (101), an average thickness of the first encapsulation portion (301) is greater than an average thickness of the second encapsulation portion (302). The display panel has a better reliability.