OLED Display Panel Sub-Pixel Segmentation for High Pixel Density
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Solution Overview
Problem
Current OLED display technologies face challenges in achieving high pixel density and preventing color shift due to limitations in fine metal mask (FMM) accuracy and the complexity of top-emission structures, leading to issues with luminous efficiency and image quality.
Innovation Solution
The OLED display panel design includes a pixel unit with three sub-pixels for different colors, where each sub-pixel has a specific organic emission layer configuration and optical thickness ratio, allowing for larger FMM openings and improved pixel density without sacrificing luminous efficiency or causing color shift, by optimizing the energy levels and thicknesses of the emission layers and charge-blocking layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a fine metal mask (FMM) with small openings is used to achieve high pixel density, then the pixel density is improved, but the manufacturing precision and FMM accuracy requirements become excessively stringent
Solution Approach 1:
The pixel unit is divided into multiple sub-pixels (first, second, and third sub-pixels) with different emission colors. Each sub-pixel has its own emission layer (EML) and charge-blocking layer (CBL) configuration. This segmentation allows the FMM to have larger openings while still achieving high pixel density through the combined effect of multiple sub-pixels within each pixel unit.
Solution Approach 2:
The patent introduces a vertical dimension to the pixel structure by stacking multiple EMLs and CBLs in different layers. The first EML covers the first and second sub-pixels, the second EML covers the second sub-pixel, and the third EML covers the third sub-pixel, with CBLs strategically positioned between them. This multi-layer vertical arrangement enables larger FMM openings while maintaining high pixel density through the three-dimensional organization of emission regions.
2Ease of manufacture
If the FMM opening size is increased to improve manufacturing ease, then the ease of manufacture is improved, but the pixel density decreases
Solution Approach 1:
Each pixel unit is segmented into multiple sub-pixels with distinct EML and CBL configurations. The first EML spans across the first and second sub-pixels, the second EML is positioned over the second sub-pixel, and the third EML covers the third sub-pixel. This segmentation allows larger FMM openings to be used while maintaining high pixel density through the combined emission areas of multiple sub-pixels.
Solution Approach 2:
The patent employs a nested structure where multiple EMLs and CBLs are arranged in vertical layers within each pixel unit. The CBLs are positioned between the EMLs to control charge distribution. This nested arrangement allows the FMM to have larger openings while the multi-layer structure ensures that each sub-pixel region receives the appropriate emission layer coverage, thereby maintaining high pixel density.
3Device complexity
If the organic function layer structure is simplified to reduce device complexity, then the device complexity is reduced, but the color accuracy and luminous efficiency deteriorate
Solution Approach 1:
The organic function layer is segmented into multiple EMLs and CBLs with specific configurations for each sub-pixel. The first EML covers the first and second sub-pixels, the second EML covers the second sub-pixel, and the third EML covers the third sub-pixel. The CBLs are positioned to control charge distribution between these EMLs. This segmentation ensures that each sub-pixel emits the correct color with high accuracy while maintaining a relatively simple overall structure that can be manufactured using standard FMM processes.
4Device complexity
If the organic function layer structure is simplified to reduce device complexity, then the device complexity is reduced, but the luminous efficiency deteriorates
Solution Approach 1:
The organic function layer is divided into multiple EMLs and CBLs with optimized configurations. The first EML spans the first and second sub-pixels, the second EML is positioned over the second sub-pixel, and the third EML covers the third sub-pixel. The CBLs are strategically placed to control charge distribution and enhance electron-hole recombination efficiency within each EML. This segmented structure maintains high luminous efficiency by ensuring efficient charge management in each emission region while keeping the overall device structure simple and manufacturable.
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 design enhances pixel density by allowing larger FMM openings while maintaining accurate color representation and luminous efficiency, preventing color shift at various viewing angles and ensuring high image quality.
Implementation Method 1
An OLED display is a display device in which light is emitted by means of the electroluminescence of fluorophor or phosphor organic compounds
Data Source
AI summary
An organic light-emitting diode (OLED) display panel and a display device are provided. A pixel unit of the OLED display panel includes a first sub-pixel, a second sub-pixel and a third sub-pixel and further includes an anode layer, a cathode layer and an organic function layer. The organic function layer includes: a first emission layer (EML1) configured to cover at least two adjacent sub-pixels comprising the first sub-pixel; a carrier blocking layer (CBL) configured to cover the second sub-pixel and the third sub-pixel; a second emission layer (EML2) arranged at an area provided with the first sub-pixel and the second sub-pixel and configured to at least cover the second sub-pixel; and a third emission layer (EML3) configured to cover at least two adjacent sub-pixels comprising the third sub-pixel. The OLED display panel can improve the pixel density.