OLED Pixel Electrode Segmentation for Gas Discharge
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Solution Overview
Problem
Organic light emitting diode (OLED) displays face deterioration in emission characteristics due to gas trapped in the passivation layer, which affects the organic emission layer's performance, especially when the first electrode continuously shields the passivation layer.
Innovation Solution
The design includes a substrate with specific pixel areas and non-emission areas where the first electrode is positioned in the emission areas and not in the non-emission areas, with distances from the pixel area edges to the non-emission areas set to be equal to or less than 50 μm, allowing gas to be discharged through the non-emission areas and preventing continuous shielding of the passivation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first electrode continuously shields the passivation layer, then the OLED structure is compact and manufacturing is simplified, but gas accumulates in the passivation layer causing deterioration of emission characteristics
Solution Approach 1:
The pixel area is divided into an emission area where the first electrode is positioned and a non-emission area where the first electrode is not positioned. This segmentation allows the passivation layer to be exposed in the non-emission area, enabling gas discharge while maintaining electrode shielding in the emission area for compact manufacturing.
Solution Approach 2:
The first electrode is selectively positioned only in the emission area rather than uniformly across the entire pixel area. This local positioning provides different functions in different regions: continuous shielding in the emission area for manufacturing simplicity and gas discharge pathways in the non-emission area for reliability.
2Ease of manufacture
If the first electrode is positioned throughout the entire pixel area, then manufacturing is simplified, but gas discharge from the passivation layer is blocked
Solution Approach 1:
The pixel area is segmented into emission and non-emission regions with distinct electrode positioning strategies. The first electrode is positioned only in the emission area, creating open pathways in the non-emission area for gas to escape from the passivation layer during and after manufacturing.
Solution Approach 2:
The first electrode is extracted from the non-emission area to create gas discharge pathways. This removal allows trapped gas in the passivation layer to escape through the exposed regions, preventing gas accumulation while the electrode remains positioned in the emission area for manufacturing efficiency.
3Area of stationary object
If non-emission areas are positioned far from pixel area edges, then emission area coverage is maximized, but gas discharge efficiency is reduced
Solution Approach 1:
The distance parameter between pixel area edges and non-emission areas is optimized to be equal to or less than 50 μm. This parameter change ensures that gas discharge pathways are sufficiently close to the edges for efficient gas escape, while the non-emission areas are positioned to maximize the emission area coverage.
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 configuration reduces or prevents the deterioration of the organic emission layer's characteristics by ensuring effective discharge of gases from the passivation layer, thereby enhancing the OLED's emission efficiency.
Implementation Method 1
Electrons injected from one electrode and holes injected from the other electrode are combined in the organic emission layer to generate excitons. The generated excitons are changed to a ground state from an exited state, releasing energy to emit light.
Data Source
AI summary
A display device may include a substrate having a first pixel area, a first electrode on the substrate; a passivation layer between the substrate and the first electrode, a second electrode on the first electrode, and an organic emission layer between the first electrode and the second electrode. The first pixel area may include an emission area and a non-emission area surrounded by the emission area.