Organic Light Emitting Display Device with Variable Sub-Pixel Emission Areas
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional organic light emitting display devices face challenges in forming organic emission layers through a solution process due to issues like color mixing and thickness deviation, particularly in large-area or high-resolution displays, where the fine metal mask (FMM) used for sub-pixel fabrication is prone to sagging and shadow effects, leading to fabrication tolerance issues and mechanical strength limitations.
Innovation Solution
The proposed solution involves forming an organic light emitting display device with a bank layer covering the anode edges to define emission and non-emission areas, allowing for uniform distribution of the organic emission layer through a solution process, where the minor axis lengths of emission areas in different sub-pixels are identical, and major axis lengths differ, minimizing ink mixing and thickness deviations, and maximizing the contact area between the cathode and low-potential voltage line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine metal mask (FMM) is used to form organic emission layers in each sub-pixel, then manufacturing precision can be improved, but device complexity increases and mechanical strength deteriorates due to mask sagging and shadow effects
Solution Approach 1:
The patent removes the FMM component entirely from the device structure, replacing it with a solution process using an injector to deposit organic materials directly onto the substrate. This eliminates mask-related complexity and mechanical strength issues while maintaining emission layer formation capability through direct liquid-phase deposition
Solution Approach 2:
The patent replaces the mechanical FMM system with a liquid-phase deposition system using an injector. Instead of using a physical mask to define patterns, the system uses controlled liquid ejection to deposit organic materials only in desired emission areas, substituting mechanical patterning with a solution-based approach
2Measurement precision
If the gap between openings of the FMM is reduced to achieve high resolution, then measurement precision improves, but reliability deteriorates as openings may be clogged by organic material or metals may stick together
Solution Approach 1:
The patent eliminates the FMM openings entirely by using a solution process where organic materials are deposited through an injector. This removes the reliability issue of clogged openings and metal sticking, achieving high resolution through controlled liquid deposition rather than physical mask openings
Solution Approach 2:
The patent uses a liquid-phase deposition system where organic materials are delivered through an injector using fluid dynamics. The solution process allows precise material placement through controlled liquid ejection, avoiding the mechanical constraints of FMM openings while achieving high resolution
3Manufacturing precision
If color mixing of inks is prevented during solution process formation of organic emission layer, then manufacturing precision improves, but device complexity increases requiring precise injector control
Solution Approach 1:
The patent divides the deposition process into separate sequential steps for different sub-pixels. The injector deposits organic materials for each sub-pixel in sequence with precise positioning, ensuring no color mixing occurs between adjacent sub-pixels. This segmented approach achieves high uniformity while managing system complexity through controlled sequential operation
4Manufacturing precision
If thickness deviation of organic emission layer is reduced, then manufacturing precision improves, but productivity decreases due to stricter process control requirements
Solution Approach 1:
The patent controls emission layer thickness by adjusting solution process parameters such as ink concentration, deposition speed, and drying conditions. By optimizing these parameters, the system achieves uniform thickness across the emission layer while maintaining reasonable manufacturing speed through efficient liquid-phase deposition
Data Source
AI summary
Provided is an organic light emitting display device. The organic light emitting display device includes a plurality of sub-pixels, an anode disposed in each of the plurality of sub-pixels, a bank layer covering an edge of the anode and defining emission areas, an organic emission layer disposed on the anode, and a cathode disposed on the organic emission layer. Each of sub-pixels includes a respective one of the emission areas and a respective non-emission area. A minor axis length of the emission area in the first sub-pixel, that of the emission area in the second sub-pixel and that of the emission area in the third sub-pixel are identical to each other. A major axis length of the emission area in the first sub-pixel, that of the emission area in the second sub-pixel and that of the emission area in the third sub-pixel are different from each other.