Flexible Display Buffer Layer Step Coverage
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Solution Overview
Problem
Existing thin film encapsulation layers in flexible display devices are prone to damage due to process complexities and impurity introduction during manufacturing, leading to compromised performance and reliability.
Innovation Solution
A display device with a thin film encapsulation layer featuring a buffer layer and a barrier layer, where the buffer layer has a multi-layered structure with varying silicon, oxygen, and carbon compositions to reduce step differences and prevent damage, and the barrier layer is manufactured using the same process as the buffer layer to enhance manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic layers and organic layers are alternately stacked to form a thin film encapsulation layer, then moisture and oxygen blocking performance is improved, but manufacturing process complexity increases and impurities may be introduced during chamber transfer
Solution Approach 1:
The patent combines the buffer layer and barrier layer into a single integrated thin film encapsulation layer structure that can be manufactured in one chamber using one atomic layer deposition (ALD) process. This merging eliminates the need for alternating deposition of separate inorganic and organic layers in different chambers, thereby reducing manufacturing process complexity while maintaining the moisture and oxygen blocking performance through the coordinated structure of the buffer and barrier layers.
Solution Approach 2:
The thin film encapsulation layer is designed to perform multiple functions simultaneously: the buffer layer provides step coverage and reduces step differences, while the barrier layer provides moisture and oxygen blocking. Both functions are achieved within a single integrated structure manufactured by one ALD process, eliminating the need for separate manufacturing processes for different functional layers.
2Reliability
If inorganic layers and organic layers are manufactured via different processes in different chambers, then each layer can be optimized for its specific function, but impurities may be introduced during transfer between chambers causing damage to the thin film encapsulation layer
Solution Approach 1:
The patent merges the manufacturing of the buffer layer and barrier layer into a single continuous ALD process within one chamber. This eliminates the physical transfer between chambers that introduces impurities and causes damage, while still allowing functional optimization through the distinct structural design of the buffer and barrier layers with different thicknesses and material compositions.
Solution Approach 2:
By conducting the entire thin film encapsulation layer manufacturing process in a single ALD chamber, the patent maintains a controlled inert environment throughout the process. This prevents exposure to ambient air and potential contaminants that would be introduced during chamber transfer, thereby protecting the thin film encapsulation layer from damage and impurity introduction.
3Reliability
If a buffer layer is added to reduce step differences, then barrier layer damage is prevented, but device structure becomes more complex
Solution Approach 1:
The patent segments the thin film encapsulation layer into two distinct functional sub-layers: a buffer layer with greater thickness designed to reduce step differences and provide step coverage, and a barrier layer with lesser thickness designed to provide moisture and oxygen blocking. This segmentation allows each layer to be optimized for its specific function while maintaining an integrated structure that can be manufactured in one ALD process, avoiding the complexity of multiple separate manufacturing processes.
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 effectively prevents damage to the barrier layer from step differences and improves the encapsulation layer's characteristics, such as moisture and oxygen blocking, while simplifying the manufacturing process, resulting in improved display device performance and reliability.
Implementation Method 1
a buffer layer configured to reduce a height difference due to the at least one step portion
Implementation Method 2
A display device having a slim profile and a flexible characteristic may include a thin film encapsulation layer in order to block penetration of moisture, oxygen, and/or the like from outside
Data Source
AI summary
A display device includes a display substrate including at least one step portion, and a thin film encapsulation layer above the display substrate, the thin film encapsulation layer including a buffer layer configured to reduce a height difference due to the at least one step portion and a barrier layer above the buffer layer, the buffer layer including a plurality of sub-layers and interfaces between the plurality of sub-layers, and the interfaces including a curved surface changing from a concave shape to a convex shape toward a portion overlapping the step portion from an outer portion of the step portion.