OLED Dam Structure Layout for Visible Scribing Alignment Marks
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Solution Overview
Problem
The second alignment marks in organic light emitting display devices are not easily observable during the scribing process, leading to a less smooth removal of the test area from unit panels, due to the encapsulation layer covering them.
Innovation Solution
A dam structure is disposed in the non-display area of the substrate, with alignment marks positioned outside this structure, preventing them from being covered by the encapsulation material and allowing clear visibility for the scribing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulation layer is formed on the second alignment marks, then the encapsulation is improved, but the alignment marks become not easily observable
Solution Approach 1:
The encapsulation layer is segmented to exclude specific regions. The alignment mark region is divided as a separate zone that is not covered by the encapsulation layer, allowing the alignment marks to remain exposed and observable while other regions receive encapsulation protection.
Solution Approach 2:
The alignment mark region is extracted from the encapsulation coverage area. By specifically excluding the alignment mark region from the encapsulation layer formation, the alignment marks are taken out from under the encapsulation, making them easily observable for the scribing process.
2Reliability
If the alignment marks are covered by the encapsulation layer, then the encapsulation coverage is improved, but the scribing process becomes less smooth
Solution Approach 1:
The encapsulation process is segmented into different regional treatments. The alignment mark region is identified as a special zone that requires different treatment (no encapsulation) compared to other regions, enabling smooth scribing while maintaining encapsulation coverage elsewhere.
Solution Approach 2:
The alignment mark region is predetermined and excluded from encapsulation before the scribing process. By preparing the alignment mark region in advance as an exposed area, the scribing process can proceed smoothly without the interference of encapsulation material covering the alignment marks.
3Difficulty of detecting and measuring
If the alignment mark region is excluded from the encapsulation layer, then the alignment mark observability is improved, but the encapsulation coverage is reduced
Solution Approach 1:
The encapsulation structure exhibits local quality differentiation. The alignment mark region has a different property (no encapsulation) compared to other regions (with encapsulation). This local variation in encapsulation coverage optimizes alignment mark observability in the specific area where it is needed, while maintaining encapsulation protection in other areas.
Data Source
AI summary
An organic light emitting display device including a dam structure disposed in a non-display area of a substrate and an alignment mark disposed outside the dam structure. The alignment mark is not covered by, and does not overlap with, the dam structure, because the alignment mark is disposed outside the dame structure. Thus, a scribing process may be performed smoothly.