Flexible Display Inorganic Layer Thickness Reduction

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Solution Overview

Problem

Flexible display devices face stress-related defects and reduced lifespan due to stress applied during bending, particularly in the bending area where the inorganic layer thickness contributes to cracking and wire damage.

Innovation Solution

The display device reduces the thickness of the inorganic layer in the bending area by partially removing the barrier and buffer layers, thereby minimizing stress and preventing defects such as cracks and wire damage, while maintaining display quality and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the inorganic layer thickness is maintained in the bending area, then the structural strength and protection are improved, but stress concentration occurs during bending causing cracks and wire damage

Engineering Contradiction:
Improvestructural strengthVSAvoiddefect prevention
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the inorganic layer thickness across different regions of the display device. The bending area has a reduced inorganic layer thickness compared to the flat area, allowing the structure to adapt to local mechanical requirements. This resolves the contradiction by providing sufficient protection in rigid areas while reducing stress concentration in flexible areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of inorganic layer thickness based on location. By reducing the thickness parameter in the bending area, the patent allows the structure to flex without excessive stress while maintaining adequate protection. This parameter modification resolves the contradiction between maintaining strength and preventing bending-induced defects.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the inorganic layer thickness is reduced in the bending area, then stress is minimized and flexibility is improved, but protection against environmental factors may be compromised

Engineering Contradiction:
ImproveflexibilityVSAvoidenvironmental protection
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by providing differential protection levels in different regions. The flat area maintains full inorganic layer protection against environmental factors, while the bending area uses reduced thickness to achieve flexibility. This resolves the contradiction by matching protection levels to local functional requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the inorganic layer into different thickness zones - a first inorganic layer in the flat area and a second inorganic layer in the bending area with different thickness characteristics. This segmentation allows each zone to perform its specific function optimally, resolving the contradiction between protection and flexibility.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If a complete inorganic layer is maintained across the entire device, then uniform protection is achieved, but stress concentration occurs in the bending area during flexing

Engineering Contradiction:
Improveuniform protectionVSAvoidstress concentration
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The patent implements local quality by creating spatial variation in inorganic layer thickness. The uniform protection requirement is satisfied in the flat area where full thickness is maintained, while the bending area uses reduced thickness to prevent stress concentration. This resolves the contradiction by allowing composition to vary locally based on functional needs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces dimensional variation in the inorganic layer structure by creating multiple layers with different thicknesses at different locations. This dimensional approach allows the structure to provide uniform protection where needed while reducing stress in bending regions, resolving the contradiction through spatial differentiation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3690951B1Display device
Publication Date: 2023.07.12 SAMSUNG DISPLAY CO LTD
  • EP3690951B1 patent drawingFigure 1
  • EP3690951B1 patent drawingFigure 2
  • EP3690951B1 patent drawingFigure 3

AI summary

A display device includes a flat area, and a first bending area at which the display device is bendable, the first bending area including in order in a direction away from the flat area, a first upper bending portion, a first extending portion, and a first lower bending portion, a light-emitting element including an emission layer in the flat area and in the first upper bending portion and with which an image is displayable in both the flat area and the first upper bending portion, and an inorganic layer in the flat area and the in the first bending area. A thickness of the inorganic layer in each of the first upper bending portion, the first extending portion and the first lower bending portion of the first bending area is smaller than a thickness of the inorganic layer in the flat area.