OLED Dam Structure Prevents Edge Smear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In organic light emitting devices, the thick formation of the organic protective layer at the edge of the active area leads to smear and degradation of display quality due to the screen printing process, resulting in a non-flat organic layer.
Innovation Solution
The implementation of a dam structure between the active and pad areas, with a groove positioned separate from the outer portion of the active area, prevents the thick formation of the organic layer at the edge, ensuring flatness and preventing smear by directing the organic material flow during the printing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the organic protective layer is formed by screen printing process, then the protective layer can be formed to cover the OLED, but the organic layer becomes thickly formed at the edge of the active area causing smear
Solution Approach 1:
A planarization layer is formed prior to the organic protective layer to pre-compensate for the edge thickening that will occur during screen printing. This preliminary action ensures that when the organic layer is deposited, the underlying planarization layer maintains the overall flatness, preventing smear while still allowing the protective function.
Solution Approach 2:
The planarization layer is applied specifically to the edge regions of the active area where thickening occurs, providing localized compensation. This allows the organic protective layer to be formed with uniform thickness across the entire active area, eliminating smear at edges while maintaining protection throughout.
2Reliability
If multiple protective layers are formed to protect OLED from moisture, then the protection effectiveness is improved, but the organic layer thickness increases causing edge top formation
Solution Approach 1:
The planarization layer is formed in advance before depositing multiple organic protective layers. This preliminary structure provides a flat foundation that compensates for the cumulative thickness of multiple protective layers, preventing edge top formation while maintaining enhanced moisture protection through the multi-layer structure.
Solution Approach 2:
The thickness of the planarization layer is specifically controlled to match the cumulative thickness of the multiple organic protective layers. By adjusting this parameter, the overall profile remains flat even with multiple protective layers, preventing edge top while maintaining the desired protection level.
Data Source
AI summary
An organic light emitting device includes a base substrate defining an active area and a pad area that surrounds the active area, an organic light emitting layer formed on the active area, a first protective layer formed to cover the active area, where the organic light emitting layer is formed, and the pad area, a second protective layer formed to cover the first protective layer, and a dam formed between the first protective layer and the second protective layer, wherein the dam is located at a boundary between the active area and the pad area and includes a groove that is positioned separate from an outer portion of the active area.