OLED Auxiliary Electrode Line via Hole Extraction

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Solution Overview

Problem

Conventional OLED fabrication methods result in pixel shrinkage due to organic emission layer degradation from out-gassing, caused by residual gases and uneven organic layer thickness, and exposure of metal lines to etchants or developing agents during electrode formation.

Innovation Solution

Forming an auxiliary electrode line in contact with the second electrode power supply line to remove the organic layer on the auxiliary electrode line and minimize the organic layer on the pixel region, using a passivation and planarization layer to prevent pixel shrinkage and protect the metal lines from damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the organic layer is formed over the entire substrate including metal line regions, then the organic emission layer provides continuous coverage, but residual gases from the organic layer cause out-gassing that degrades the organic emission layer and leads to pixel shrinkage

Engineering Contradiction:

Improveorganic emission layer integrityVSAvoidpixel dimension stability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent extracts the organic layer from the metal line region by forming a via hole through the organic layer to expose the auxiliary electrode line. This removal eliminates the source of residual gases in the metal line region that would otherwise cause out-gassing and pixel shrinkage, while maintaining organic layer coverage over the pixel region for proper emission function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The substrate is divided into distinct regions: pixel regions where the organic layer is maintained for emission, and metal line regions where the organic layer is removed via via holes to prevent out-gassing. This segmentation allows different areas to serve different functions - emission versus electrical conduction without organic layer interference.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the auxiliary electrode line is exposed during electrode formation, then the metal line can be accessed for electrical connection, but the metal line becomes vulnerable to damage from etchants or developing agents

Engineering Contradiction:

Improveelectrode connection accessibilityVSAvoidmetal line integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The auxiliary electrode line is formed at the same layer as the gate electrode before subsequent processing steps. This preliminary formation allows the auxiliary electrode line to be positioned and protected early in the fabrication process, enabling electrical connection while maintaining protection from later etching and developing operations through the interlayer insulating layer and via hole structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The interlayer insulating layer serves as an intermediary protective barrier between the auxiliary electrode line and the etchants or developing agents used in subsequent processing. The via hole provides a controlled pathway through this intermediary to expose only the necessary portion of the auxiliary electrode line for electrical connection while maintaining overall protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the organic layer thickness varies across the substrate, then the fabrication process is simpler, but uneven thickness leads to degradation of the organic emission layer and pixel shrinkage

Engineering Contradiction:

Improveorganic layer deposition simplicityVSAvoidorganic layer thickness uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent removes the organic layer from the metal line region through via holes, creating a precise boundary between the pixel region (with organic layer) and the metal line region (without organic layer). This extraction ensures uniform organic layer thickness over the pixel region while eliminating the problematic organic layer portions that would cause out-gassing and pixel shrinkage.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS7728510B2Organic light emitting display with auxiliary electrode line and method of fabricating the same

Publication Date: 2010.06.01 SAMSUNG DISPLAY CO LTD

AI summary

Provided are an organic light emitting display (OLED) and a method of fabricating the same capable of improving product reliability by forming an auxiliary electrode line to be in contact with a second electrode power supply line to remove an organic layer on the auxiliary electrode line and minimize the organic layer on a pixel region, thereby preventing pixel shrinkage resulting from degradation of an organic emission layer caused by out-gassing from the organic layer.