Multi-Layer Bank and Sub-Dam Layout for Low-Reflection Displays
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Solution Overview
Problem
Display devices face challenges in reducing external light reflection and minimizing defects due to residual films, while also requiring easy mask alignment during manufacturing.
Innovation Solution
The display device incorporates a substrate with an emission layer, an encapsulation layer comprising inorganic and organic films, and a dam structure with sub-dams and banks, where the encapsulation layer includes a first inorganic encapsulation film, an organic encapsulation film, and a second inorganic encapsulation film, and the dam and bank structures utilize light-blocking materials to manage film overflow and support mask alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-layer bank structure is used, then the device complexity is reduced, but mask alignment precision deteriorates
Solution Approach 1:
The bank structure is divided into multiple layers (first bank layer, second bank layer, third bank layer) with different functions. The first and second bank layers provide structural support, while the third bank layer with light blocking material provides alignment reference, allowing each layer to specialize in a specific function for improved overall performance
Solution Approach 2:
The light blocking layer acts as an intermediary element between the bank structure and the mask alignment process. It provides a visible reference pattern that facilitates precise mask alignment without interfering with the structural integrity or encapsulation functions of the underlying bank layers
2Object-affected harmful factors
If light blocking material is added to the bank structure, then external light reflection is reduced, but device complexity increases
Solution Approach 1:
The third bank layer serves multiple functions: it provides structural continuity as part of the bank structure, and simultaneously acts as a light blocking layer to reduce external light reflection. This multi-functionality reduces the need for separate components and minimizes overall device complexity
Solution Approach 2:
The light blocking function is merged with the bank structure by forming the third bank layer from the same organic material as the other bank layers. This integration eliminates the need for separate light blocking components and simplifies the manufacturing process while still achieving the light reflection reduction goal
3Reliability
If multiple sub-dams are formed, then organic film overflow prevention is improved, but manufacturing complexity increases
Solution Approach 1:
The dam structure is segmented into multiple sub-dams (first sub-dam, second sub-dam, third sub-dam) that are formed at different stages of the manufacturing process. Each sub-dam serves a specific purpose in preventing organic film overflow at different encapsulation stages, providing reliable containment without requiring a single complex high structure
4Reliability
If a multi-layer encapsulation structure is used, then organic light-emitting element sealing is improved, but manufacturing precision requirements increase
Solution Approach 1:
The encapsulation structure is segmented into multiple thin layers (first inorganic encapsulation film, organic encapsulation film, second inorganic encapsulation film) rather than a single thick layer. This segmentation allows each layer to be formed with standard thin-film deposition techniques, reducing the precision requirements compared to forming a single thick encapsulation layer
Solution Approach 2:
The encapsulation structure uses a nested arrangement where inorganic films and organic films are alternately stacked. This nested structure provides enhanced sealing reliability through multiple barriers while allowing each individual layer to be formed with conventional precision, as the cumulative effect of multiple layers provides the overall protection
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 configuration effectively reduces external light reflection, minimizes defects from residual films, and facilitates easier mask alignment during manufacturing, enhancing the display device's performance and manufacturing efficiency.
Implementation Method 1
The pixel defining layer is disposed between the plurality of emission areas and includes a light blocking material
Data Source
AI summary
A display device includes a substrate; an emission layer disposed on the substrate, and including emission areas and a pixel defining layer disposed between the emission areas and including a light blocking material; an encapsulation layer disposed on the emission layer, and including a first inorganic encapsulation film, an organic encapsulation film on the first inorganic encapsulation film, and a second inorganic encapsulation film on the organic encapsulation film; a dam surrounding the organic encapsulation film, including an organic material, and including a plurality of sub-dams; and a bank disposed to surround at least a portion of the dam, and including a first bank layer, a second bank layer on the first bank layer, a third bank layer on the second bank layer, and a fourth bank layer on the third bank layer, wherein the third bank layer includes the light blocking material.