Flexible Display Cavity Region Mitigates Bending Stress

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Flexible display devices often experience failures due to stress concentration when bent, leading to issues like cracking and peeling between the cathode electrode layer and the organic light emitting layer.

Innovation Solution

A flexible display device design featuring a cavity region between the cathode electrode layer and the organic light emitting layer, with protrusions extending from the cathode electrode layer to create a gap, which absorbs and releases bending stress, preventing defects such as cracking and peeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flexible display device is made of a multilayer structure, then the device can achieve basic display functionality, but stress concentration occurs when bent causing layer failure

Engineering Contradiction:

Improvelayer integrityVSAvoidbending stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The cathode electrode layer is divided into multiple segments (first cathode electrode portion and second cathode electrode portion) that are superposed and electrically connected through protrusions. This segmentation allows stress to be distributed across multiple connection points rather than concentrated at a single interface, preventing layer failure during bending.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first cathode electrode portion is disposed on the surface of the organic light emitting layer, and the second cathode electrode portion is superposed above it, with protrusions extending between layers to create electrical connection. This nested arrangement creates a three-dimensional electrode structure that provides mechanical compliance and stress distribution during flexing.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If the cathode electrode layer is directly disposed on the organic light emitting layer, then electrical connection is achieved, but peeling occurs between layers due to stress concentration

Engineering Contradiction:

Improveelectrical connectionVSAvoidadhesion between layers

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The protrusions create a dynamic, flexible connection between the cathode electrode layer and organic light emitting layer. The superposed electrode portions with protrusions can accommodate relative movement and deformation during bending, maintaining electrical connection while preventing peeling through distributed stress management.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The electrode structure transitions from a two-dimensional planar contact to a three-dimensional superposed structure with protrusions extending vertically. This dimensional change creates multiple contact points and pathways for stress distribution, preventing peeling while maintaining electrical connectivity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10833287B2Flexible display device and manufacturing method thereof

Publication Date: 2020.11.10 KUNSHAN NEW FLAT PANEL DISPLAY TECHNOLOGY CENTER CO LTD

AI summary

A flexible display device includes: an organic light emitting layer for emitting light; a cathode electrode layer disposed on the organic light emitting layer; and a cavity region located between a plane where the cathode electrode layer is located and the organic light emitting layer.