OLED Third Electrode Segmentation for Gas Emission
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Solution Overview
Problem
Conventional OLED devices experience pixel shrinkage due to degradation of the organic light emitting layer caused by residual gases in the passivation layer, which is exacerbated by the difficulty in emitting gases from the peripheral region where the pixel electrode layer is mostly formed.
Innovation Solution
The OLED device incorporates a third electrode patterned as an island shape in the peripheral region to facilitate effective out-gassing of residual gases, thereby reducing or preventing pixel shrinkage by separating the electrode patterns and allowing for better gas emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pixel electrode layer is formed in the peripheral region, then the device structure is completed, but residual gases are trapped causing pixel shrinkage
Solution Approach 1:
The electrode layer is segmented into different regions: a first electrode in the display region and a third electrode in the peripheral region. This segmentation allows residual gases to be emitted from the peripheral region through the third electrode, preventing pixel shrinkage while maintaining device functionality.
Solution Approach 2:
The third electrode in the peripheral region acts as an intermediary structure that facilitates gas emission. It provides a dedicated pathway for residual gases to escape from the peripheral region, preventing them from causing damage to the organic light emitting layer.
2Reliability
If the passivation layer is formed to cover the pixel circuit, then the device is protected, but gas emission is hindered
Solution Approach 1:
The passivation layer is segmented to allow specific gas emission regions. By creating openings or thinner regions in the passivation layer at the peripheral electrode positions, residual gases can escape while the rest of the passivation layer continues to provide protective coverage.
3Illumination intensity
If the organic light emitting layer is formed on the electrode, then light emission is enabled, but pixel shrinkage occurs due to gas degradation
Solution Approach 1:
The third electrode is formed in the peripheral region before the organic light emitting layer is deposited. This preliminary structure provides a gas emission pathway that prevents residual gases from degrading the organic layer during and after formation, ensuring long-term reliability while maintaining light emission capability.
Data Source
AI summary
An organic light emitting display (OLED) device is disclosed. The OLED device may include a substrate comprising a display region and a peripheral region, the display region comprising a first transmission portion and at least one light emitting portion, the peripheral region comprising a second transmission portion and at least one electrode placement portion, a first electrode in the display region, an organic light emitting layer on the first electrode, a second electrode in the display region and the peripheral region, the second electrode opposite to the first electrode with respect to the organic light emitting layer, and a third electrode in the peripheral region. The first electrode may be patterned as an island shape to be separated per the light emitting portion. The third electrode may be patterned as an island shape to be separated per the electrode placement portion.