OLED Display Panel Reflective Electrode Segmentation
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Solution Overview
Problem
The challenge in OLED display panels is achieving high resolution while maintaining accurate coating alignment of small emissive structures, which leads to unwanted color mixing due to shifts in emissive structures during the manufacturing process.
Innovation Solution
The OLED display panel design incorporates reflective structures with multiple regions having different reflective ratios, where the first region has a higher reflective ratio than the second region, reducing unwanted color mixing by minimizing the impact of emissive structure shifts during alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resolution of the OLED display panel is increased, then the pixel density is improved, but the size of each emissive structure becomes smaller making accurate coating alignment more difficult
Solution Approach 1:
The reflective electrode is segmented into multiple reflective structures (first reflective structure, second reflective structure, third reflective structure) with different reflective ratios. This segmentation allows each structure to serve a specific function: the first reflective structure provides high reflectivity for pixels with shifted emissive structures to maintain brightness, the second reflective structure provides moderate reflectivity for normally aligned pixels, and the third reflective structure provides low reflectivity to minimize color mixing effects. This resolves the contradiction by making the system adaptable to alignment variations without sacrificing resolution.
Solution Approach 2:
Different regions of the reflective electrode are assigned different reflective ratios based on their functional requirements. The first reflective structure has a higher reflective ratio than the second reflective structure, which in turn has a higher reflective ratio than the third reflective structure. This local differentiation allows the display panel to maintain high resolution while compensating for alignment errors in specific regions without affecting the overall image quality.
2Measurement precision
If the size of emissive structures is reduced for higher resolution, then pixel density is improved, but the impact of alignment shifts increases causing unwanted color mixing
Solution Approach 1:
The reflective ratio parameter is changed across different reflective structures to compensate for alignment shifts. By having reflective structures with varying reflective ratios (first > second > third), the system can maintain color accuracy even when emissive structures are small and prone to alignment shifts. The parameter change in reflectivity counteracts the increased sensitivity to alignment errors caused by smaller emissive structure sizes.
Solution Approach 2:
The invention converts the harmful effect of alignment shifts and emissive structure size reduction into a benefit by using multiple reflective structures with different reflective ratios. Instead of treating alignment variations as purely detrimental, the system uses them to activate appropriate reflective structures that compensate for the shifts, thereby maintaining color accuracy and even improving robustness against manufacturing variations.
3Reliability
If multiple reflective structures with different reflective ratios are used, then color mixing is reduced and color accuracy is improved, but the device complexity increases
Solution Approach 1:
The reflective electrode is divided into distinct segmented regions (first, second, and third reflective structures) that can be independently controlled. This segmentation enables color accuracy improvement through differential reflectivity while maintaining a relatively simple overall structure that follows the basic OLED layer architecture, thus balancing complexity with performance.
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 the resolution of OLED display panels to above 600 pixels per inch, reducing grainy patterns and improving color accuracy by ensuring precise alignment and minimizing color mixing issues.
Implementation Method 1
a reflective electrode layer disposed on the substrate and having a plurality of reflective structures, wherein each of the reflective structures has a first region and a second region
Implementation Method 2
a plurality of organic emissive structures correspondingly formed in the openings and covering the reflective structures, forming a plurality of pixels
Data Source
AI summary
An organic light emitting diode (OLED) display panel includes a substrate, a reflective electrode disposed on the substrate, and a pixel define layer (PDL) formed on the substrate and the reflective electrode layer. The reflective electrode layer has multiple reflective structures, and each reflective structure has a first region and a second region. The PDL is provided with multiple openings corresponding to the reflective structures, such that the first region and the second region of each of the reflective structures are exposed in a corresponding one of the openings. Multiple organic emissive structures are correspondingly formed in the openings and covering the reflective structures, forming a plurality of pixels. For each respective pixel of the pixels, a first reflective ratio of the respective pixel corresponding to the first region is greater than a second reflective ratio of the respective pixel corresponding to the second region.