Flexible Display Back Plate Cofferdam Protrusions

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Flexible OLED and QLED display devices face issues with peeling between inorganic layers and the passivation layer during the bending process, leading to poor display performance due to inadequate encapsulation and adhesive forces.

Innovation Solution

A display back plate design featuring a first thin film encapsulation layer with protrusions on a cofferdam, a second cofferdam with additional bonding patterns, and a second thin film encapsulation layer that covers the edges of the first layer, enhancing the contact area and adhesive force to prevent peeling, and incorporating photosensitive resin for manufacturing simplicity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional encapsulation structure is used, then the device structure is simple, but peeling occurs between inorganic layers and passivation layer during bending

Engineering Contradiction:

Improvepeeling resistanceVSAvoidencapsulation structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The encapsulation structure is segmented into multiple functional components: first cofferdam with first bonding pattern, second cofferdam with second bonding pattern, and overlapping thin film encapsulation layers. Each segment performs a specific function (mechanical support, adhesive bonding, edge sealing) to collectively prevent peeling during bending while maintaining overall structural reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Bonding patterns with protrusions are pre-formed on the cofferdams before the bending operation. This preliminary structural preparation ensures that when bending occurs, the adhesive force is already optimized at critical interfaces, preventing peeling between inorganic layers and passivation layer without requiring complex real-time adjustments.

Inventive Principle:

Principle #10Preliminary action

2Strength

If bonding patterns with protrusions are added to cofferdams, then adhesive force increases, but manufacturing complexity increases

Engineering Contradiction:

Improveadhesive forceVSAvoidmanufacturing simplicity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The bonding pattern is created by replacing a purely mechanical cofferdam structure with an integrated structure that includes protrusions formed through gray scale exposure. This substitution allows the protrusions to be formed in a single photolithography step rather than requiring separate mechanical machining or assembly operations, thereby maintaining manufacturing simplicity while achieving enhanced adhesive force through the increased contact area provided by the protrusions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If multiple cofferdams and bonding patterns are implemented, then peeling resistance improves, but device complexity increases

Engineering Contradiction:

Improvepeeling resistanceVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The encapsulation structure employs a nested arrangement where the first thin film encapsulation layer covers protrusions of the first bonding pattern, the second thin film encapsulation layer overlaps the first layer at edges, and multiple cofferdams are positioned at different locations. This nesting creates a hierarchical protective system where each layer reinforces the others, significantly improving peeling resistance while the modular nested design actually simplifies manufacturing by enabling sequential formation of each nested component.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 effectively improves the peeling resistance and adhesive force between layers, preventing peeling issues during bending and ensuring reliable display performance in flexible OLED and QLED devices.

Implementation Method 1

the first bonding pattern includes a plurality of protrusions, and the first thin film encapsulation layer at least partially covers the protrusions... the second bonding pattern includes a plurality of protrusions... enhancing the contact area and adhesive force to prevent peeling

Methodology Applied

Scientific EffectAdhesive force: Adhesive

Implementation Method 2

the material forming the first cofferdam and the second cofferdam is a photosensitive resin, and the first bonding pattern and the second bonding pattern are formed by gray scale exposure

Methodology Applied

Scientific EffectPhotosensitive resin: Photopolymerisation

Data Source

PatentUS11228020B2Display back plate and display device

Publication Date: 2022.01.18 BOE TECHNOLOGY GROUP CO LTD

AI summary

The present disclosure relates to a display back plate and a display device. The display back plate includes a display area and a non-display area surrounding the display area, wherein the non-display area is provided with at least one circle of first cofferdam surrounding the display area, a first thin film encapsulation layer is arranged on the first cofferdam, and the non-display area is provided with a fan-out area, a second cofferdam is arranged on one side of the first cofferdam close to the fan-out area, the second cofferdam is provided with a first bonding pattern including a plurality of protrusions, and the first thin film encapsulation layer at least partially covers the protrusions.