OLED Thin Film Encapsulation Edge Barrier
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Solution Overview
Problem
Organic light emitting diode (OLED) displays are prone to deterioration due to external moisture and oxygen intrusion, leading to display failures and reduced lifespan, especially when the thin film encapsulation layer contacts organic layers at the edge of the display area.
Innovation Solution
A nonorganic layer is formed under the thin film encapsulation layer along the edge, using materials like Al, Cu, Mo, Ti, silicon oxide, or silicon nitride, to prevent external moisture and oxygen from entering the encapsulation layer, thereby protecting the OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thin film encapsulation layer contacts the organic layer at the edge of the display area, then the device structure is simplified and manufacturing is easier, but external moisture and oxygen intrude along the edge causing OLED deterioration
Solution Approach 1:
A nonorganic layer is introduced as an intermediary barrier between the thin film encapsulation layer and the organic layer at the edge region. This nonorganic layer (comprising inorganic materials such as silicon oxide, silicon nitride, or aluminum oxide) prevents direct contact and blocks the intrusion path for moisture and oxygen, thereby protecting the OLEDs at the edge while maintaining the simplified TFE structure
Solution Approach 2:
The protective structure applies different material properties to different regions: the display area uses the standard thin film encapsulation layer, while the edge region incorporates an additional nonorganic layer with superior moisture and oxygen barrier properties. This localized enhancement addresses the specific vulnerability at the edge without complicating the overall device structure
2Reliability
If the thin film encapsulation layer covers the entire display area including edges, then OLED protection is improved, but moisture and oxygen intrude along the organic layer interface causing edge OLED deterioration
Solution Approach 1:
The nonorganic layer serves as a mediator that blocks the harmful interaction between environmental contaminants (moisture and oxygen) and the OLEDs at the edge. By positioning this layer between the encapsulation structure and the organic layer, it creates a effective barrier that prevents the harmful intrusion path while maintaining the encapsulation coverage
Solution Approach 2:
The edge protection structure uses a composite of multiple materials: the thin film encapsulation layer (alternating organic and inorganic layers) combined with an additional nonorganic layer (pure inorganic material). This composite structure provides enhanced barrier properties against moisture and oxygen compared to the single encapsulation layer alone
Data Source
AI summary
An organic light emitting diode display includes a substrate having organic light emitting diodes thereon. A thin film encapsulation layer is formed on the substrate such that the thin film encapsulation layer covers the organic light emitting diodes. A nonorganic layer is formed under the thin film encapsulation layer along the edge of the thin film encapsulation layer.