Flexible Grooved Substrate for Display Bending Area

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Solution Overview

Problem

The challenge in display devices is to protect the bending area of flexible displays from peeling issues of the passivation layer during bending, which leads to stress and potential cracking.

Innovation Solution

A display device design that includes a substrate with a groove in the bending area, where the passivation layer is disposed within the groove, and the groove's side wall forms an angle of 90 degrees or less with the substrate's surface, enhancing adhesion and reducing stress by widening the contact area between the passivation layer and the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passivation layer is provided on the bending part to protect the panel, then protection is improved, but peeling occurs due to bending stress

Engineering Contradiction:

Improveprotection of bending areaVSAvoidadhesion of passivation layer

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The bending area is segmented into a groove structure that separates the passivation layer from the main substrate surface, allowing differential movement and reducing stress concentration at the interface during bending operations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The passivation layer is positioned in a groove that extends into the substrate depth, transitioning from a surface-level 2D interface to a 3D volumetric structure, which distributes bending stress across multiple dimensions and reduces peeling

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the peripheral area is completely separated from the display area, then display quality is improved, but connection of electrical signals and power becomes difficult

Engineering Contradiction:

Improvedisplay qualityVSAvoidconnection of electrical elements

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The peripheral circuit elements are nested within the display panel structure by folding the peripheral area onto the rear surface, creating a compact integrated structure where both display and circuit areas coexist in a space-efficient configuration

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The flexible display panel employs a curved or folded geometry in the peripheral area, allowing the circuit elements to be positioned on the rear surface while maintaining electrical connections through the flexible substrate

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Stress or pressure

If the groove width is increased to reduce stress, then stress distribution is improved, but the contact area between passivation layer and substrate decreases

Engineering Contradiction:

Improvestress distribution in bending areaVSAvoidadhesion strength of passivation layer

Core Design Contradiction:

Stress or pressureVSStrength

Solution Approach 1:

The groove structure extends the passivation layer-substrate contact into the depth dimension, compensating for reduced surface contact area by providing additional bonding interface area along the groove walls and bottom

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12156426B2Display device including flexible grooved substrate

Publication Date: 2024.11.26 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a substrate including a first area, a second area, and a bending area disposed between the first area and the second area; a display area overlapping the first area; and a passivation layer overlapping the bending area, wherein the substrate includes a groove formed in the bending area, and an angle between a side wall of the groove of the substrate and an upper surface of the substrate is about 90 degrees or less.