OLED Display Structure With Wavelength Conversion for Uniform Color Output
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Solution Overview
Problem
Current organic light emitting display devices face challenges in achieving full color display with efficient light emission and high color reproducibility due to variations in light conversion efficiency across different color regions.
Innovation Solution
The display device incorporates a layered structure with specific organic light emitting layers, charge generating layers, and wavelength conversion patterns to optimize light emission, including a first base portion with defined light emitting regions, pixel electrodes, and a common electrode, along with a thin film encapsulation layer and color filters to manage light emission and conversion efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple light emitting layers with different colors are stacked in the organic layer, then full color display capability is improved, but light emission efficiency varies across different color regions
Solution Approach 1:
The patent applies local quality by introducing a charge generating layer between light emitting layers with different colors. This layer has specific local properties (charge generation capability) that address the efficiency variation problem in specific regions where color transitions occur, while maintaining the multi-color capability of the overall structure.
Solution Approach 2:
The charge generating layer acts as an intermediary between different light emitting layers. It mediates the charge transfer process between layers emitting different colors, ensuring efficient charge supply to each layer and reducing energy loss at the interfaces between different color regions.
2Manufacturing precision
If a wavelength conversion pattern is added to convert light from one color to another, then color reproducibility is improved, but device structure becomes more complex
Solution Approach 1:
The patent merges the wavelength conversion function directly into the organic layer structure by stacking light emitting layers that emit different colors, including converted colors. This integration eliminates the need for separate wavelength conversion patterns, reducing device complexity while maintaining color reproducibility.
3Productivity
If multiple charge generating layers are introduced between light emitting layers, then light emission efficiency is improved, but manufacturing process becomes more difficult
Solution Approach 1:
The patent uses parameter changes by carefully controlling the properties of charge generating layers (such as hole transport capability and thickness) to optimize charge transfer efficiency. By adjusting these parameters, the manufacturing process remains manageable while achieving high light emission efficiency across all color regions.
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 enhances light emission efficiency and color reproducibility by ensuring consistent light output across different color regions, improving the overall display quality and luminance of the organic light emitting display device.
Implementation Method 1
a first wavelength conversion pattern disposed on the common electrode, overlapping the first organic layer, and wavelength-converting light of a first color into light of a second color different from the first color
Implementation Method 2
Electrons and holes provided from the two electrodes are recombined in the organic light emitting layer to generate excitons, and the generated excitons are shifted from the excited state to the ground state to emit light
Data Source
AI summary
A display device includes first and second light emitting regions; first and second pixel electrodes in the first and second light emitting regions, respectively; a first organic layer in the first light emitting region, including first and second light emitting layers; a second organic layer in the second light emitting region, including a third light emitting layer; a common electrode on the first and second organic layers; a wavelength conversion pattern on the common electrode, overlapping the first organic layer, and wavelength-converting light of a first color into light of a second color, different from the first color; and a light transmitting pattern on the common electrode, overlapping the second organic layer. The third light emitting layer and one of the first and second light emitting layers emit light of the first color, and another one of the first and second light emitting layers emits light of the second color.