Organic Light Emitting Display Device With Phosphorescent Green Emission Layer
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Solution Overview
Problem
Organic light emitting display devices face limitations in emission efficiency and lifetime due to the material and structure of the organic light emitting layer, leading to reduced color reproduction rates and shortened lifetimes, particularly when using blue and yellow phosphorescence emission layers.
Innovation Solution
The implementation of a new structure that includes multiple emission layers with different energy band gaps, such as a red, yellow-green, and green emission layers, including phosphorescent materials, to enhance emission efficiency and color reproduction rates while maintaining green lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If white light is emitted by stacking two emission layers having a complementary color relationship, then emission efficiency is improved, but color reproduction rate is lowered due to wavelength range mismatch with color filters
Solution Approach 1:
The invention divides the single white light emission function into multiple separate emission layers, each emitting light of a specific color (blue, green, red). This segmentation allows each layer to be optimized for its specific wavelength range, improving overall color reproduction accuracy while maintaining emission efficiency through targeted material selection for each layer's specific function
Solution Approach 2:
Each emission layer is designed with local quality optimization - the blue emission layer uses materials optimized for blue wavelength emission, the green layer for green wavelengths, and the red layer for red wavelengths. This local optimization ensures that each layer's emission characteristics precisely match the requirements of corresponding color filters, thereby improving color reproduction rate while maintaining overall emission efficiency
2Use of energy by moving object
If blue and yellow phosphorescence emission layers are used, then emission efficiency is improved, but lifetime is shortened due to material limitations
Solution Approach 1:
The invention changes the material parameters of the emission layers by selecting phosphorescence materials with optimized lifetime characteristics for each color. The blue emission layer uses phosphorescence materials with longer lifetime, the green emission layer uses materials with intermediate lifetime, and the red emission layer uses materials with longer lifetime. This parameter optimization allows the device to maintain high emission efficiency while extending overall lifetime by compensating for the shorter lifetime of individual phosphorescence materials through strategic material selection and combination
Solution Approach 2:
The invention employs composite material strategies by combining phosphorescence materials with different lifetime characteristics across multiple emission layers. The blue, green, and red emission layers use different phosphorescence material compositions that complement each other, creating a composite system where the overall device lifetime is extended beyond what any single phosphorescence material could achieve alone, while maintaining high emission efficiency through the synergistic combination of materials
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 configuration improves the color reproduction rate and extends the lifetime of the organic light emitting display device by optimizing the emission efficiency and charge balance between the layers, reducing power consumption and increasing the DCI coverage and area ratio.
Implementation Method 1
an organic light emitting device includes a first emission part including a first emission layer, the first emission part provided between the first and second electrodes, and the first emission layer having at least two emission layers including a blue color emission layer; a second emission part including a second emission layer, the second emission part provided between the first emission part and the second electrode, and the second emission layer having at least two emission layers including an emission layer for emitting light having wavelength longer than that of the blue color emission layer
Implementation Method 2
limitations in emission efficiency and lifetime due to the material and structure of the organic light emitting layer, leading to reduced color reproduction rates and shortened lifetimes, particularly when using blue and yellow phosphorescence emission layers
Data Source
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AI summary
An organic light emitting display device includes a first emission part (210) between an anode (202) and a cathode (204) and a second emission part (220) on the first emission part. At least one of the first emission part and the second emission part includes at least three emission layers emitting lights of different colors (223, 224, 225), and one of the at least three emission layers include a green emission layer including a phosphorescent material. Accordingly, a lifetime and color reproduction rate of the organic light emitting display device having a phosphorescent green emission layer is enhanced.