OLED Emission Layer Dopant Optimization for Grayscale Color Difference Reduction
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Solution Overview
Problem
Organic light emitting display devices face challenges in reducing grayscale-based color differences due to inefficiencies in emission layers, particularly when using blue and yellow phosphorescence and fluorescence materials, which affect emission efficiency and color reproduction rates.
Innovation Solution
The implementation of an organic light emitting display device with emission layers having different wavelength ranges, where the dopant content in a red emission layer is optimized to be lower than in a yellow-green or green emission layer, ensuring balanced light emission and reduced color differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If blue and yellow phosphorescence and fluorescence materials are used in emission layers, then emission efficiency is improved, but grayscale-based color differences increase
Solution Approach 1:
The patent applies local quality by differentiating dopant content across different emission layers. Specifically, the red emission layer uses a lower dopant content (0.1%-10%) compared to the yellow-green or green emission layers (3%-20%). This localized variation in dopant concentration optimizes each layer's emission characteristics to reduce grayscale-based color differences while maintaining overall emission efficiency.
Solution Approach 2:
The patent implements parameter changes by adjusting the dopant content as a critical variable in the emission layers. By changing the dopant concentration parameter differently across red, yellow-green, and green emission layers, the patent achieves balanced light emission and reduced color differences. The specific parameter ranges (red: 0.1%-10%, yellow-green/green: 3%-20%) demonstrate controlled parameter optimization.
2Illumination intensity
If dopant content in red emission layer is increased to enhance red light emission, then red emission intensity is improved, but color balance deteriorates and grayscale-based color differences increase
Solution Approach 1:
The patent applies local quality by setting distinct dopant content ranges for the red emission layer (0.1%-10%) compared to yellow-green or green emission layers (3%-20%). This localized differentiation ensures that each emission layer contributes appropriately to the overall color balance, preventing excessive red light emission that would disrupt color stability and increase grayscale-based color differences.
Solution Approach 2:
The patent implements parameter changes by optimizing the dopant content parameter in the red emission layer to a lower range (0.1%-10%) compared to other emission layers. This parameter adjustment maintains red light emission intensity while preserving color balance and reducing grayscale-based color differences across different gray levels.
3Manufacturing precision
If multiple emission layers with different wavelength ranges are used, then color reproduction rate is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating distinct emission layers with specific wavelength ranges (red: 600-650nm, yellow-green: 540-560nm, green: 510-540nm) and differentiated dopant content. This localized optimization of each layer's properties achieves improved color reproduction rate while managing complexity through systematic differentiation rather than random complexity.
Solution Approach 2:
The patent implements composite materials by combining multiple emission layers with different wavelength ranges and dopant content into a unified display structure. The red emission layer (0.1%-10% dopant) is combined with yellow-green or green emission layers (3%-20% dopant) to create a composite emission system that achieves high color reproduction rate while maintaining manageable device complexity through structured composition.
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 color reproduction rates and reduces grayscale-based color differences, improving the overall efficiency and image quality of the display device by adjusting the dopant content in the red emission layer to suppress excessive red light emission and maintain yellow-green or green light emission.
Implementation Method 1
An electron and a hole are injected from the two electrodes into the organic emission layer, and an exciton is generated by combining the electron with the hole. The organic light emitting display devices are devices based on the principle that light is emitted when the generated exciton is dropped from an excited state to a ground state.
Implementation Method 2
Organic light emitting display devices face challenges in reducing grayscale-based color differences due to inefficiencies in emission layers, particularly when using blue and yellow phosphorescence and fluorescence materials
Implementation Method 3
Organic light emitting display devices face challenges in reducing grayscale-based color differences due to inefficiencies in emission layers, particularly when using blue and yellow phosphorescence and fluorescence materials
Data Source
AI summary
An organic light emitting display device reduces a grayscale-based color difference of the organic light emitting display device. The organic light emitting display device includes opposite first and second electrodes on a substrate and a plurality of emission parts between the first and second electrodes. At least one among the plurality of emission parts includes a first emission layer and a second emission layer having different wavelength ranges. A dopant content in the first emission layer is lower than a dopant content in the second emission layer.