Multilayer Protective Structure for Flexible Display Wiring

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Solution Overview

Problem

Flexible display devices face issues with cracks in metal wiring during bending due to the lack of effective protective layers, which can lead to contact with driving circuits or polarizers, degrading display quality.

Innovation Solution

The implementation of a multilayer protective structure using photo-curable resins for the first and second protective layers, with specific thickness and overlap configurations to minimize force on signal wiring and prevent contact with driving circuits or polarizers, thereby enhancing display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective layer is formed in the bending area to prevent breakage of metal wiring, then the reliability of the wiring is improved, but the protective layer contacts driving circuit elements or polarizers causing degradation of display quality

Engineering Contradiction:
Improvewiring reliabilityVSAvoiddisplay quality degradation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protective layer is divided into multiple segments: a first protective layer extending from the bending area toward the display area, and a second protective layer extending from the bending area toward the non-display area. This segmentation allows each layer to be optimized for its specific function and position, preventing the single layer from contacting sensitive components in the display area while still providing comprehensive protection to the bending area wiring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the protective structure are given different properties and extensions. The first protective layer has specific width and thickness parameters (500-800 μm width, 30-70 μm thickness) optimized for protecting wiring near the display area without contacting polarizers, while the second protective layer extends further to protect the non-display area. This local optimization ensures protection where needed while avoiding contact with sensitive components.

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If the protective layer extends further to cover more bending area, then the protection coverage is improved, but the contact with driving circuits or polarizers increases causing display quality degradation

Engineering Contradiction:
Improveprotective coverage areaVSAvoiddisplay quality degradation
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The protective coverage is segmented into two distinct layers with different extension ranges. The first protective layer covers the critical bending area near the display without extending into the display area where polarizers are located. The second protective layer covers the remaining bending area toward the non-display side. This segmentation achieves comprehensive protection while preventing contact with sensitive components through precise spatial separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each protective layer is designed with specific dimensional parameters optimized for its location. The first protective layer has controlled width (500-800 μm) and thickness (30-70 μm) to provide adequate protection in the critical zone near the display area without reaching the polarizer location. The second protective layer extends further to cover the non-display area. This local optimization maximizes coverage while minimizing harmful contacts.

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 solution effectively reduces breakage and moisture permeation in the bending area, maintaining display quality by minimizing contact between protective layers and critical components, thus enabling a narrower bezel design for flexible display devices.

Implementation Method 1

The first protective layer and the second protective layer include a photo-curable resin

Methodology Applied
Scientific EffectPhoto-curable resin: Photopolymerisation

Data Source

PatentEP3300131B1Display device
Publication Date: 2023.03.22 SAMSUNG DISPLAY CO LTD
  • EP3300131B1 patent drawingFigure 1
  • EP3300131B1 patent drawingFigure 2
  • EP3300131B1 patent drawingFigure 3~4

AI summary

A display device includes a substrate having a planar area, a bending area extending from the planar area, and a surrounding area extending from the bending area, a first protective layer at a boundary portion of the bending area, and a second protective layer covering an entire surface of the bending area and covering the first protective layer.