OLED Light-Emitting Layer Thickness Uniformity via Barrier Wall Segmentation

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Solution Overview

Problem

The existing wet film forming process for manufacturing light-emitting layers in electroluminescent devices results in poor thickness uniformity due to non-uniform micro-forces acting on the solution during the drying process, leading to irregular light-emitting structure shapes and affecting the display quality and service life of OLED devices.

Innovation Solution

A method involving the formation of a solution layer on barrier wall structures between pixel regions, ensuring equal micro-forces in both directions during drying, which helps in achieving uniform solute distribution and optimizing the thickness uniformity of the light-emitting layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional wet film forming process is used to manufacture light-emitting layers, then the manufacturing process is simple and fast, but the thickness uniformity of the light-emitting layer is poor due to non-uniform micro-forces during drying

Engineering Contradiction:
Improvethickness uniformityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pixel definition layer is segmented into multiple barrier walls arranged in a specific pattern, creating distinct micro-regions that control solution distribution. This segmentation allows uniform micro-forces to act on the solution in both long-axis and short-axis directions, resolving the thickness uniformity issue while maintaining process simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The barrier walls serve as intermediary structures between the solution and the substrate, mediating the drying process by providing a controlled interface. These barrier walls ensure uniform micro-force distribution during solvent evaporation, enabling uniform solute deposition without complicating the overall manufacturing process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Shape

If the solution is allowed to dry freely on the substrate, then the drying process is simple, but the micro-forces acting on the solution are non-uniform causing irregular light-emitting structure shapes

Engineering Contradiction:
Improvelight-emitting structure shape regularityVSAvoiddrying process simplicity
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The barrier walls segment the drying area into controlled micro-regions, ensuring that micro-forces act uniformly on the solution in both long-axis and short-axis directions. This segmentation produces regular light-emitting structure shapes while keeping the drying process simple and straightforward

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If grooves are added to the pixel definition layer to control solution distribution, then the thickness uniformity is improved, but the device structure becomes more complex

Engineering Contradiction:
Improvethickness uniformityVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of adding grooves to an existing simple pixel definition layer, the invention segments the pixel definition layer itself into multiple barrier walls. This approach achieves uniform thickness control through the inherent structure of the barrier walls, avoiding the need for additional groove features and maintaining structural simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The barrier walls serve multiple functions simultaneously: they define pixel regions, control solution distribution, and ensure uniform micro-force distribution during drying. This multi-functionality achieves thickness uniformity without requiring separate structural elements, thereby avoiding increased device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This approach enhances the uniformity of the light-emitting layer, improving the display effect and extending the service life of electroluminescent devices by ensuring even solvent evaporation and solute distribution in both the long-axis and short-axis directions.

Implementation Method 1

ensuring equal micro-forces in both directions during drying, which helps in achieving uniform solute distribution

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3678181B1Manufacturing method for light-emitting layer, electroluminescent device and display device
Publication Date: 2023.03.29 BOE TECHNOLOGY GROUP CO LTD
  • EP3678181B1 patent drawingFigure 1~2
  • EP3678181B1 patent drawingFigure 3
  • EP3678181B1 patent drawingFigure 4

AI summary

A method for manufacturing a light-emitting layer, an electroluminescent device and a display device are provided, and the method includes: providing a base substrate formed with a pixel definition layer, so that a plurality of barrier wall structures of the pixel definition layer define a plurality of pixel regions on the base substrate, and the plurality of pixel regions include pixel regions arranged along a first direction and pixel regions arranged along a second direction; by a solution-applying process, forming a solution layer on the base substrate formed with the pixel definition layer, so that the solution layer includes a solution formed in the plurality of pixel regions and a solution formed on first barrier wall structures and the solution in the pixel regions does not blend with the solution on the first barrier wall structures; performing a drying process on the solution layer so that the solution in each pixel region forms a light-emitting structure to obtain a light-emitting layer. The present disclosure improves the uniformity of the light-emitting layer.