Hydrophilic-Hydrophobic Bank Pattern for OLED Color Purity
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Solution Overview
Problem
High-resolution OLED display devices face color blending issues due to the narrow line width of bank patterns, causing organic emission materials from neighboring sub-pixels to mix and deteriorate picture quality.
Innovation Solution
A thin film transistor array substrate with alternating sub-pixels featuring hydrophilic and hydrophobic bank patterns, where the organic emission layer is formed on non-emission regions with wider widths than emission regions, preventing material mixing by using hydrophilic inorganic and hydrophobic organic insulation materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the line width of bank pattern is narrowed to increase resolution, then the definition of OLED display device becomes higher, but organic emission materials from neighboring sub-pixels mix together causing color blending
Solution Approach 1:
The patent applies local quality by creating different surface energy characteristics in different regions. The bank pattern is formed with a hydrophilic inorganic material layer and a hydrophobic organic material layer, creating regions with different wettability. This allows the organic emission material to be selectively confined to specific sub-pixel regions while preventing diffusion into neighboring sub-pixels, thus maintaining color purity at high resolutions.
Solution Approach 2:
The patent uses composite materials by combining hydrophilic inorganic material (such as silicon oxide or silicon nitride) with hydrophobic organic material (such as organic insulation material) in the bank pattern structure. This composite structure creates a dual-function barrier that both physically separates sub-pixels and chemically prevents organic material diffusion through differential surface energy properties.
2Productivity
If the distance between sub-pixels is reduced to increase resolution, then more sub-pixels can be displayed, but color blending occurs within viewing angle deteriorating picture quality
Solution Approach 1:
The patent implements local quality by creating zones with different surface energies within the bank pattern structure. The hydrophilic inorganic layer and hydrophobic organic layer create distinct regions that control the spread of organic emission materials, allowing high pixel density while maintaining color separation through localized surface energy modulation.
Solution Approach 2:
The bank pattern acts as an intermediary barrier between neighboring sub-pixels. The multi-layer structure with different hydrophilicity levels serves as a mediator that controls the interface between adjacent sub-pixel regions, preventing direct contact and mixing of organic emission materials while allowing close spacing of sub-pixels.
3Ease of manufacture
If a single layer bank pattern is used, then the manufacturing process is simpler, but it cannot effectively prevent mixing of organic emission materials at high resolutions
Solution Approach 1:
The patent employs composite materials by stacking a hydrophilic inorganic material layer and a hydrophobic organic material layer to form the bank pattern. This multi-layer composite structure provides enhanced material separation precision through differential surface energy properties, effectively preventing organic emission material mixing even at high resolutions, while maintaining compatibility with existing manufacturing processes.
Solution Approach 2:
The patent segments the bank pattern into multiple functional layers: a hydrophilic inorganic material layer and a hydrophobic organic material layer. Each layer performs a specific function in controlling organic material distribution, with the inorganic layer providing structural support and hydrophilic regions, while the organic layer provides hydrophobic barriers. This segmentation enables precise control over material separation.
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 effectively prevents color blending between sub-pixels, maintaining picture quality even at high resolutions by ensuring organic emission materials are deposited and formed without mixing, thus enhancing color representation in OLED displays.
Implementation Method 1
forming a first bank pattern with a hydrophilic inorganic insulation material in the first and second non-emission regions
Implementation Method 2
forming a second bank pattern with a hydrophobic organic insulation material on an upper surface of the first bank pattern
Data Source
AI summary
Disclosed is a display device that may include a thin film transistor array substrate that includes a plurality of first sub-pixels and a plurality of second sub-pixels, wherein one of the plurality of first sub-pixels includes a first emission region and a first non-emission region, and one of the plurality of second sub-pixels includes a second emission region and a second non-emission region; a first bank pattern in the first and second non-emission regions, the first bank pattern including a hydrophilic material; and a second bank pattern on an upper surface of the first bank pattern, the second bank pattern includes a hydrophobic material.