OLED Bank Layer Moisture Ingress Prevention via Conductive Patterns

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Solution Overview

Problem

The manufacturing process of organic light emitting diode (OLED) display devices faces issues with incomplete removal of the bank layer, leading to poor interface characteristics and potential moisture penetration, which can cause performance degradation and visible blotches due to leftover bank layer material between the ground line and cathode.

Innovation Solution

The formation of first and second conductive patterns prior to the bank layer, made of the same material as the anode, prevents moisture permeation by physically separating them, enhancing conductivity and reducing bezel width without additional mask processes, and ensuring strong bonding with the bank layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the bank layer is deposited and then removed during the manufacturing process, then the ground line area is reduced, but incomplete removal leads to poor interface characteristics and moisture penetration

Engineering Contradiction:
Improveground line areaVSAvoidinterface characteristics
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent forms conductive patterns (anode and ground line patterns) before depositing the bank layer. This preliminary action allows the bank layer to be deposited as a continuous layer without requiring subsequent removal, eliminating the risk of incomplete removal while still achieving the desired ground line area reduction through the pre-formed conductive patterns

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an insulating film as an intermediary layer between the bank layer and the ground line pattern. This insulating film allows the bank layer to be deposited continuously over the ground line area while preventing electrical shorting, thus maintaining reliability without requiring bank layer removal

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the bank layer is completely removed to improve interface characteristics, then adhesion is enhanced, but the manufacturing process complexity increases

Engineering Contradiction:
ImproveadhesionVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The conductive patterns are formed in advance before bank layer deposition, eliminating the need for subsequent bank layer removal steps. This preliminary formation of patterns ensures proper adhesion interfaces are created during the deposition process itself, simplifying the overall manufacturing process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the bank layer removal step from the manufacturing process by forming conductive patterns beforehand. The bank layer is deposited as a continuous layer without needing to be removed, thus eliminating the complex removal and patterning steps while maintaining good interface characteristics

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If additional mask processes are used to form conductive patterns, then precision is improved, but manufacturing time and complexity increase

Engineering Contradiction:
Improvepattern formation precisionVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent merges the formation of the anode pattern and ground line pattern into a single conductive pattern formation step performed before bank layer deposition. This combined approach achieves precise pattern formation without requiring multiple sequential mask processes, reducing manufacturing time while maintaining precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The conductive patterns are formed in advance before bank layer deposition, allowing precise pattern definition to be established early in the process. This preliminary pattern formation eliminates the need for subsequent mask processes to define these patterns, reducing overall manufacturing time while maintaining precision

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2822037B1Organic light emitting diodes display device
Publication Date: 2021.05.19 LG DISPLAY CO LTD
  • EP2822037B1 patent drawingFigure 1
  • EP2822037B1 patent drawingFigure 2~3
  • EP2822037B1 patent drawingFigure 4

AI summary

The present invention provides an organic light emitting diode display device comprising a substrate comprising a display region and a non-display region, a thin film transistor formed in the display region; an organic light emitting layer connected to the thin film transistor, a bank formed to define a light emitting region of the organic light emitting layer, a metal pattern disposed in the non-display region and not covered with the bank; and a conductive pattern connected to the organic light emitting layer while covering the metal pattern and partially physically separated on the metal pattern.