Stacked Encapsulation Layer for OLED Moisture Barrier
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Solution Overview
Problem
Existing organic light-emitting display systems face challenges in maintaining effective sealing of the thin film encapsulation layer due to stress and peeling issues, which reduces the lifetime of the display, especially when using inorganic films that are prone to increased thickness and subsequent damage.
Innovation Solution
A stacked encapsulation layer structure comprising a first inorganic film, a first organic film, and a second inorganic film, where the second inorganic film contacts the interlayer insulating film outside the active area, and additional layers are formed using silicon nitride and aluminum oxide materials, with a protective layer including a capping layer and a shield layer of lithium fluoride to enhance sealing and prevent moisture and oxygen penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of inorganic film is increased to prevent penetration of moisture or oxygen, then the sealing performance is improved, but stress increases causing the film to peel off
Solution Approach 1:
The encapsulation structure is divided into multiple thin inorganic films (first inorganic film and second inorganic film) separated by an organic film. This segmentation allows each inorganic film layer to maintain lower individual thickness, reducing stress and peeling risk while collectively providing effective moisture and oxygen barrier protection through the stacked configuration.
Solution Approach 2:
The invention uses a composite encapsulation structure combining inorganic films (such as silicon nitride) with organic films. The inorganic films provide excellent barrier properties against moisture and oxygen penetration, while the organic film acts as a stress buffer between inorganic layers, preventing peeling and maintaining overall film adhesion while enhancing sealing performance.
2Object-affected harmful factors
If the thickness of inorganic film is increased to enhance barrier properties, then the prevention of moisture and oxygen penetration is improved, but the film becomes more prone to damage and peeling
Solution Approach 1:
The encapsulation structure is divided into multiple thin inorganic films (first inorganic film and second inorganic film) separated by an organic film. This segmentation allows each inorganic film layer to maintain lower individual thickness, reducing stress and peeling risk while collectively providing effective moisture and oxygen barrier protection through the stacked configuration.
Solution Approach 2:
The organic film is positioned between the first and second inorganic films to act as a stress buffer and cushioning layer. This beforehand cushioning prevents stress concentration and film peeling before damage occurs, maintaining film integrity while allowing each inorganic layer to provide effective barrier protection against moisture and oxygen penetration.
3Weight of moving object
If a thin film encapsulation layer is used to make the display lightweight and flexible, then the weight and flexibility are improved, but the sealing force is reduced
Solution Approach 1:
The invention uses a composite encapsulation structure combining inorganic films (such as silicon nitride) with organic films. The inorganic films provide excellent barrier properties against moisture and oxygen penetration, while the organic film acts as a stress buffer between inorganic layers, preventing peeling and maintaining overall film adhesion while enhancing sealing performance.
Solution Approach 2:
Instead of increasing the thickness of a single encapsulation layer, the invention enhances sealing force by adding multiple layers in the vertical dimension. The stacked structure of first inorganic film, organic film, and second inorganic film provides improved barrier properties and sealing force while maintaining the overall thin profile, keeping the display lightweight and flexible.
Data Source
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AI summary
An organic light-emitting display system and a method of manufacturing the same are disclosed. In one aspect, the organic light-emitting display system includes a substrate (101), a display unit (200) that defines an active area (AA) on the substrate (101) and includes a plurality of thin film transistor (TFTs), and an encapsulation layer (300) that seals the display unit (200) and has a stacked structure in which at least a first inorganic film (301), a first organic film (302), and a second inorganic film (303) are sequentially stacked. The TFTs includes an active layer (202), a gate electrode (204), a source electrode (206), a drain electrode (207), and an interlayer insulating film (205) that is disposed between the gate electrode (204) and the source electrode (206) and between the gate electrode (204) and the drain electrode (207), wherein the second inorganic film (303) directly contacts the interlayer insulating film (205) outside the active area (AA). Accordingly, in various embodiments, since an inorganic layer of a thin film encapsulation layer is prevented from being cracked, penetration of external moisture or oxygen into the active area of the display can be reduced or prevented.