OLED Boundary Pattern for Insulation Adhesion
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Solution Overview
Problem
In organic light emitting display (OLED) devices with transparent regions, the adhesion between organic and inorganic insulation layers is low, leading to potential detachment and water/moisture permeation, which can result in dark pixels due to direct contact between the pixel defining layer and the gate insulation layer.
Innovation Solution
The implementation of a boundary pattern that covers the interface between the sub-pixel and transparent regions, using the same materials as the upper electrode, to prevent direct contact between the pixel defining layer and the gate insulation layer, thereby enhancing adhesion and preventing moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the organic insulation layer and inorganic insulation layer are directly contacted to form the OLED device, then the device structure is simplified, but the adhesion between layers is low causing detachment and moisture permeation
Solution Approach 1:
An intermediate layer is introduced between the organic insulation layer and inorganic insulation layer to serve as a bonding bridge. This intermediate layer has adhesion promoters that enhance bonding with both the organic and inorganic layers, preventing detachment while maintaining structural simplicity. The intermediate layer acts as a mediator that resolves the adhesion problem without significantly increasing device complexity.
2Ease of manufacture
If the organic insulation layer and inorganic insulation layer are directly contacted, then manufacturing process is simplified, but water or moisture permeates into the separated space causing dark pixels
Solution Approach 1:
The intermediate layer serves as a moisture barrier between the organic and inorganic insulation layers. It contains hydrophobic materials that prevent water and moisture from permeating into the layer interface, thereby eliminating the cause of dark pixels while maintaining the simplified fabrication process. The intermediate layer provides both mechanical bonding and environmental protection functions.
3Reliability
If a boundary pattern is added to cover the interface between sub-pixel and transparent regions, then adhesion and moisture protection are improved, but device structure becomes more complex
Solution Approach 1:
The intermediate layer with adhesion promoters is applied locally at the critical interface regions between organic and inorganic layers, rather than uniformly across the entire device. This localized application provides enhanced adhesion and moisture protection where most needed, while minimizing the overall structural complexity and material usage. The boundary pattern is formed only at the sub-pixel/transparent region interface where adhesion problems occur.
Data Source
AI summary
An organic light emitting display device includes a substrate, a gate insulation layer, a planarization layer, a boundary pattern, and a sub-pixel structure. The substrate includes a sub-pixel region and a transparent region. The gate insulation layer is disposed on the substrate. The planarization layer is disposed in the sub-pixel region on the gate insulation layer, and exposes the transparent region. The boundary pattern covers a boundary of the sub-pixel region and the transparent region. The sub-pixel structure is disposed on the planarization layer.