Organic Light Emitting Display Encapsulation with Plasma-Resistant Monomer
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Solution Overview
Problem
Organic light emitting display devices face issues with moisture and oxygen sensitivity, leading to delamination, degradation of light emission properties, and reliability concerns due to the vulnerability of organic layers to plasma etching and exposure, which affects the encapsulation effectiveness.
Innovation Solution
An organic light emitting display device with a substrate featuring a light emitting area and a non-light emitting area, where a dam is formed on the non-light emitting area to prevent exposure, and an encapsulation layer with alternately stacked inorganic and organic layers, including a photocurable monomer composition without aromatic hydrocarbons, providing high plasma resistance, low water vapor and oxygen permeability, and excellent transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an organic layer is used in the encapsulation layer to protect the organic light emitting element, then the encapsulation function is provided, but the organic layer is etched by plasma which deteriorates the encapsulation function and provides adverse influence on formation of the inorganic layer
Solution Approach 1:
The patent changes the chemical composition parameters of the organic layer by selecting specific materials (cyclic carbonate polymers, cyclic carboxylate polymers, or their copolymers) that inherently possess high plasma resistance. This material parameter change enables the organic layer to withstand plasma etching processes without significant erosion, thereby maintaining the encapsulation function while allowing proper formation of the inorganic layer.
2Device complexity
If the corner of the organic layer is exposed to the corner of an encapsulation layer without protection, then the structure is simplified, but the encapsulation property which protects the organic light emitting element from moisture and/or oxygen is deteriorated
Solution Approach 1:
The patent applies a dam structure as a preliminary protective measure before the encapsulation process. The dam is formed at the corner regions of the substrate, extending from the edge toward the light emitting area, creating a physical barrier that prevents moisture and oxygen from reaching exposed corners of the organic layer. This preliminary action ensures complete encapsulation protection without requiring complex multi-layer structures at the corners.
3Ease of manufacture
If the organic layer is formed by ink jetting, then the manufacturing process is simplified, but the encapsulation composition in a liquid state may spread to a light emitting area or outside of a substrate, thereby thickening the edge of the encapsulation layer
Solution Approach 1:
The patent introduces the dam structure as an intermediary element between the inkjet printing process and the substrate edge. The dam acts as a physical barrier that confines the liquid encapsulation composition within the desired area during the inkjet printing process. This intermediary structure prevents the liquid material from spreading to the light emitting area or outside the substrate, thereby maintaining precise edge thickness control while preserving the simplicity of the inkjet manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the reliability and longevity of the organic light emitting display device by preventing external moisture and oxygen ingress, maintaining light emission properties, and ensuring a thin, flat encapsulation layer with reduced surface roughness and plasma etch rate.
Implementation Method 1
the composition for encapsulating a display device including a photocurable monomer and a photopolymerization initiator
Implementation Method 2
The inorganic layer may be formed by plasma deposition
Data Source
AI summary
Provided is an organic light emitting display comprising: a substrate including a light emitting zone and a non-light emitting zone, which is positioned around the outside of the light emitting zone; at least one organic light emitting diode formed on the light emitting zone; an encapsulation layer for sealing the organic light emitting diode; and a dam formed on the non-light emitting zone, wherein the encapsulation layer includes a structure in which at least one inorganic layer and at least one organic layer are alternatingly stacked, wherein the organic layer is made from a display sealing material composition, and wherein the display sealing material composition comprises a photo-curable monomer and a photopolymerization initiator. The photo-curable monomer comprises: a monomer not having an aromatic hydrocarbon group; and a monomer, represented by chemical formula 1, having at least two substituted or non-substituted phenyl groups, wherein the photo-curable monomer comprises approximately 5 wt. % to 45 wt. % of the monomer having the at least two substituted or non-substituted phenyl groups, and approximately 55 wt. % to 95 wt. % of a monomer not having the aromatic hydrocarbon group.