Flexible Display Substrate Layering for Bending and Delamination

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Solution Overview

Problem

Flexible display devices face challenges in achieving sufficient bending resistance while preventing delamination of the self-luminous element layer, particularly due to stress applied during the removal process from a glass substrate, which affects the organic layer's thickness and structural integrity.

Innovation Solution

A display device with a substrate composed of multiple layers, including a greater number of organic layers in the display element area to prevent delamination and a smaller number in the peripheral, bent area to enhance bending resistance, utilizing inorganic and organic layers to maintain structural integrity and prevent moisture ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the organic layer is increased to prevent delamination of the self-luminous element layer, then the reliability is improved, but the bending resistance is reduced

Engineering Contradiction:

Improveprevention of delaminationVSAvoidbending resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The substrate is divided into multiple organic layers with different thicknesses in different regions. The first organic layer has a first thickness in the display element area, while the second organic layer has a second thickness in the peripheral area, allowing each region to have optimized properties for its specific function

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the substrate are given different organic layer thicknesses according to their specific requirements. The display element area receives a thicker organic layer for delamination prevention, while the peripheral area receives a thinner organic layer for improved bending resistance

Inventive Principle:

Principle #3Local quality

2Strength

If the organic layer is made thinner to improve bending resistance, then the bending resistance is improved, but the stress concentration at the boundary increases causing delamination

Engineering Contradiction:

Improvebending resistanceVSAvoidprevention of delamination

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The organic layer structure is segmented into multiple layers with different thicknesses, allowing the stress distribution to be optimized in each region and preventing stress concentration that would lead to delamination

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thickness parameter of the organic layer is changed according to the spatial position, with the first thickness in the display element area and the second thickness in the peripheral area, optimizing both delamination prevention and bending resistance

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10734462B2Flexible display device including bent flexible substrate and bent circuit layer

Publication Date: 2020.08.04 MAGNOLIA WHITE CORP

AI summary

A display device includes a substrate that is formed of a plurality of layers stacked together and a circuit layer. A circuit layer includes a display element area in which a plurality of pixel electrodes corresponding to a plurality of unit pixels and a self-luminous element layer are provided, and a peripheral area that has a wiring to the display element area and a terminal and is at least partially bent. The substrate includes a first area that overlaps the display element area of the circuit layer and a second area that overlaps the peripheral area and is at least partially bent. The layers include at least one inorganic layer and a plurality of organic layers. The number of the organic layers in the first area is greater than the number of the organic layers in the second area.