OLED Encapsulation Layer Densification Gradient
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Solution Overview
Problem
The inorganic film layer used in existing OLED device encapsulation structures is prone to cracking, leading to poor encapsulation performance and reduced stability and service life of the OLED devices.
Innovation Solution
The encapsulation structure includes an inorganic film layer with at least two sub-film layers, where the densification of the sub-film layer farther away from the structure to be encapsulated is greater than that closer to it, reducing the likelihood of cracks and improving encapsulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low-molecular-weight encapsulating resin is used, then the resin layer can be formed at low temperature and has good step coverage, but the resin has poor heat resistance and dissolves or decomposes at high temperatures causing display defects
Solution Approach 1:
The patent uses a composite resin system combining low-molecular-weight resin (for low-temperature processing and step coverage) with high-molecular-weight resin (for heat resistance). This composite approach allows the encapsulation layer to be formed at low temperatures while maintaining stability at high temperatures during OLED operation.
Solution Approach 2:
The patent modifies the molecular weight parameters of the encapsulating resin by using a mixture of low-molecular-weight and high-molecular-weight resins. This parameter change enables the resin to exhibit both low-temperature formability and high-temperature stability, resolving the contradiction between ease of manufacture and reliability.
2Reliability
If a high-molecular-weight encapsulating resin is used, then the resin has good heat resistance, but the resin cannot be properly formed at low temperatures and shows poor step coverage
Solution Approach 1:
The patent combines high-molecular-weight resin (providing heat resistance) with low-molecular-weight resin (enabling low-temperature processing). This composite material approach allows the encapsulation layer to maintain structural integrity at high temperatures while being formable at low temperatures with good step coverage.
Solution Approach 2:
The patent changes the molecular weight distribution of the encapsulating resin by using a blend of high and low molecular weight components. This parameter modification enables the resin to exhibit dual characteristics: heat resistance from the high-molecular-weight component and low-temperature formability from the low-molecular-weight component.
3Device complexity
If the encapsulation layer is formed by spin coating, then the process is simple, but the resin aggregates during drying causing non-uniform film formation and display defects
Solution Approach 1:
The patent extracts the aggregation problem from the spin-coating process by adding specific additives to the resin solution that prevent aggregation during drying. This allows the simple spin-coating method to produce uniform films without the harmful aggregation effects.
Solution Approach 2:
The patent introduces additives as intermediary substances in the resin solution that mediate between the resin molecules during the drying process. These additives prevent resin aggregation while maintaining the simplicity of the spin-coating process, ensuring uniform film formation.
4Shape
If the encapsulation layer is formed by dip coating, then the process can achieve good step coverage, but the resin aggregates during drying causing non-uniform film formation and display defects
Solution Approach 1:
The patent extracts the aggregation problem from the dip-coating process by incorporating anti-aggregation additives in the resin solution. This allows dip-coating to achieve both good step coverage and uniform film formation without aggregation defects.
Solution Approach 2:
The patent introduces additives as intermediary substances that prevent resin aggregation during the dip-coating drying process. These intermediaries enable the process to achieve excellent step coverage while maintaining film uniformity, resolving the contradiction between shape quality and manufacturing precision.
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
This approach reduces the probability of cracks in the inorganic film layer, thereby enhancing the encapsulation performance and extending the stability and service life of OLED devices.
Implementation Method 1
forming an encapsulation layer with a low-molecular-weight encapsulating resin
Data Source
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AI summary
An encapsulating method that may include forming an inorganic film layer (031) covering a structure (04) to be encapsulated is provided. The inorganic film layer (031) may include at least two sub-film layers (0311, 0312). Among the at least two sub-film layers (0311, 0312), densification of a sub-film layer (0312) farther away from the structure (04) to be encapsulated may be greater than densification of a sub-film layer (0311) closer to the structure (04) to be encapsulated.