Organic Light Emitting Display Bank Structure Thickness Control
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Solution Overview
Problem
The solution process for forming organic emission layers in organic light-emitting displays often results in thickness deviations, leading to reduced display quality and lifespan due to pile-up phenomena and irregular layer formation.
Innovation Solution
The use of a substrate with defined areas and banks, where the first bank has hydrophilic properties and the second bank has hydrophobic properties, helps in spreading and confining organic light-emitting materials uniformly, preventing thickness irregularities and improving the uniformity of the organic emission layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a solution process is used to form organic emission layers, then material use ratio is improved (50-80%), but thickness uniformity deteriorates causing pile-up phenomena and dark points
Solution Approach 1:
The patent applies local quality by creating different bank structures in different regions of the substrate. First banks are formed in first areas (central regions) while second banks are formed in second areas (edge regions). This regional differentiation allows the solution process to achieve both high material use ratio and uniform thickness by adapting the bank configuration to local deposition characteristics.
Solution Approach 2:
The substrate is segmented into multiple first areas and second areas, with different bank structures in each region. This segmentation allows independent optimization of the emission layer formation process in different zones, preventing pile-up phenomena in edge regions while maintaining efficient material deposition across the entire large-area substrate.
2Area of stationary object
If large-area substrates are used, then display area is improved, but mask drooping occurs causing deposition failures
Solution Approach 1:
The patent extracts and eliminates the mask component from the deposition system by implementing a maskless solution process. Organic emission layers are deposited directly onto the substrate using a deposition apparatus without masks, thereby avoiding mask drooping issues entirely while enabling large-area deposition with maintained reliability.
Solution Approach 2:
The patent introduces banks as intermediary structures that mediate between the deposition process and the substrate. These banks serve as physical guides and barriers that define emission patterns without requiring masks, enabling precise material deposition on large-area substrates through solution-based processes.
3Temperature
If solution process is used instead of vacuum deposition, then thermal stability is improved, but thickness deviation within subpixels worsens
Solution Approach 1:
The patent implements local quality through region-specific bank structures that address the thickness deviation problem in different areas. First banks in central regions and second banks in edge regions create localized control over solution flow and evaporation, maintaining thermal stability benefits while achieving uniform subpixel thickness across the entire display area.
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 enhances display quality by minimizing thickness deviations and preventing the occurrence of dark points, thereby extending the lifespan of the organic light-emitting display.
Implementation Method 1
the first bank has hydrophilic properties and the second bank has hydrophobic properties, helps in spreading and confining organic light-emitting materials uniformly
Implementation Method 2
the first bank has hydrophilic properties and the second bank has hydrophobic properties, helps in spreading and confining organic light-emitting materials uniformly
Data Source
AI summary
An organic light-emitting display comprises a substrate having a first area and second and third areas neighboring the first area in a column direction and defined in edge parts of both sides in the first area; a plurality of subpixels arranged on the substrate in the column direction and a row direction crossing the column direction; a plurality of first electrodes allocated to each of the plurality of subpixels; and a bank positioned on the first electrodes, wherein the bank comprises a first bank having a first opening exposing the plurality of first electrodes arranged in the row direction; and a second bank having a second opening exposing the plurality of first electrodes arranged in the column direction in the first area and a third opening exposing the one first electrode in at least one of the second area and the third area.