OLED Thin Film Encapsulation Layer Moisture Infiltration Prevention
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Solution Overview
Problem
The existing thin film encapsulation layers in organic light emitting display apparatuses are ineffective in preventing moisture infiltration, which reduces the lifespan of the devices due to the inability of organic layers to block moisture and the formation of infiltration paths through metal wires with poor step coverage.
Innovation Solution
An improved thin film encapsulation layer structure is implemented, where organic and inorganic layers are alternately stacked, with the organic layers separated from the metal wires to prevent direct contact and moisture infiltration, using materials like polyimide, acryl, and AlOx, SiNx, ensuring the inorganic layers directly contact the display unit and the organic layers are positioned to overlap the metal wires partially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If organic layers are used in the thin film encapsulation layer to provide flexibility and planarization, then the flexibility and planarization of the encapsulation layer are improved, but the moisture infiltration prevention capability deteriorates because organic layers cannot effectively block moisture
Solution Approach 1:
The encapsulation layer is segmented into multiple functional layers: organic layers (for flexibility and planarization) and inorganic layers (for moisture barrier). This segmentation allows each layer to perform its specialized function without compromising the other.
Solution Approach 2:
The encapsulation layer uses a composite structure combining organic and inorganic materials. The organic layers provide mechanical flexibility and planarization, while the inorganic layers provide effective moisture barrier properties, creating a multi-functional composite system.
2Area of stationary object
If organic layers in the thin film encapsulation layer cover the metal wires to provide complete coverage, then the coverage and protection are improved, but moisture infiltration paths are formed because moisture can infiltrate through the organic layers from the metal wires
Solution Approach 1:
An inorganic layer is introduced as an intermediary between the organic layer and the metal wires. This inorganic layer acts as a moisture barrier that prevents moisture from the metal wires from infiltrating through the organic layer into the display unit, while still allowing the organic layer to provide coverage.
Solution Approach 2:
Different regions of the encapsulation structure have different layer configurations. The region over metal wires includes an inorganic layer as a moisture barrier, while other regions may have different configurations optimized for their specific functions.
3Area of stationary object
If the thin film encapsulation layer is formed to completely cover the metal wires with organic layers, then the coverage is improved, but the lifespan of the display apparatus deteriorates due to moisture infiltration through the organic layers
Solution Approach 1:
The inorganic layer serves as a mediator that blocks moisture infiltration paths between the organic layer and metal wires, preventing the degradation that would otherwise occur and extend the apparatus lifespan.
Solution Approach 2:
The combination of organic and inorganic layers creates a composite encapsulation system that provides both complete coverage and effective moisture barrier properties, ensuring long-term reliability and extended lifespan.
Data Source
AI summary
An organic light emitting display apparatus including a thin film encapsulation layer of an improved structure. The organic light emitting display apparatus includes: a display unit formed on a substrate; metal wires formed on an outer portion of the display unit on the substrate; and a thin film encapsulation layer formed by alternately stacking at least one organic layer and at least one inorganic layer on the display unit for sealing the display unit, wherein the at least one organic layer is separated from the metal wires so as not to contact the metal wires. According to the above structure, since the organic layer that is close to the display unit is separated completely from the metal wires formed on an outer portion of the display unit, moisture infiltration to the display unit via the metal wires may be prevented.