OLED Metal Pattern for Static Discharge and Step Coverage
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Solution Overview
Problem
Existing organic light emitting displays face issues with static electricity-induced short circuits and compromised step coverage of gate insulating layers due to direct contact between the active layer and the substrate, leading to defects and reliability concerns.
Innovation Solution
A metal pattern is formed on the substrate, excluding the region for the active layer, with an auxiliary layer having a stepped portion to control step coverage and disperse static electricity, and a pixel electrode is formed from the same material as the metal pattern, directly contacting the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the active layer directly contacts the substrate, then the manufacturing process is simplified, but static electricity-induced short circuits occur and reliability deteriorates
Solution Approach 1:
An auxiliary layer is introduced as an intermediary between the substrate and the active layer. This auxiliary layer includes a metal pattern that serves as a static electricity discharge path, allowing static electricity to be safely dissipated without causing short circuits in the active layer, thus resolving the reliability issue while maintaining the direct-contact configuration's manufacturing simplicity
Solution Approach 2:
The metal pattern is extracted and placed specifically in regions where the active layer is not located. This allows the metal pattern to function as a static electricity discharge path without interfering with the active layer's operation, effectively separating the static discharge function from the active layer region
2Productivity
If the gate insulating layer is deposited without stepped portion control, then the manufacturing process is faster, but step coverage is compromised leading to defects
Solution Approach 1:
The auxiliary layer with its stepped portion is formed in advance before depositing the gate insulating layer. This preliminary structuring of the auxiliary layer creates controlled step coverage features that guide the gate insulating layer deposition, ensuring proper coverage without requiring complex real-time process adjustments
Solution Approach 2:
The auxiliary layer is designed with different heights (stepped portions) in different regions, creating local variations in surface topology. This local quality variation in the auxiliary layer's stepped structure enables the gate insulating layer to achieve appropriate step coverage in each specific region during deposition
Data Source
AI summary
An organic light emitting display includes a substrate, a metal pattern on the substrate, the metal pattern directly contacting the substrate, and a thin film transistor including an active layer spaced apart from the metal pattern on the substrate, a gate electrode on the active layer, and a source electrode and a drain electrode on the gate electrode.