Bilayer Light-Shielding Elements for OLED Viewing Angle
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Solution Overview
Problem
Organic light-emitting display devices face challenges in achieving an optimal balance between viewing angle and luminance, particularly in flexible and foldable display applications where traditional polarizers are unsuitable and reduce light efficiency.
Innovation Solution
The use of light-shielding elements with a bilayer structure, comprising metal and organic materials, where the second light-shielding layers are wider and thicker than the first, and strategically positioned to enhance the viewing angle while maintaining low reflectivity, thereby improving the ratio of viewing angle to luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional polarizers are used in organic light-emitting display devices, then viewing angle can be improved, but light efficiency is reduced
Solution Approach 1:
The patent changes the material parameters of the light-shielding layers, using a bilayer structure with metal material (first layer) and organic material (second layer) to achieve optimal optical properties. By adjusting material composition and thickness parameters, the device achieves improved viewing angle without the light efficiency loss associated with traditional polarizers
Solution Approach 2:
The patent employs composite materials in the light-shielding elements, combining metal material and organic material in a bilayer structure. This composite approach allows the device to achieve both improved viewing angle and maintained light efficiency, resolving the contradiction between these two parameters that plagues traditional polarizer-based solutions
2Object-affected harmful factors
If light-shielding layers are made thicker to reduce reflectivity, then viewing angle improves, but device complexity increases
Solution Approach 1:
The patent uses composite materials (metal and organic layers) to achieve effective light shielding and reflectivity control with a manageable bilayer structure. The combination of materials with different optical properties allows for reduced reflectivity without requiring excessive thickness or complex multi-layer configurations
Solution Approach 2:
The patent applies different material properties to different layers of the light-shielding element. The metal material layer provides one set of optical properties while the organic material layer provides complementary properties, allowing each layer to be optimized for its specific function rather than requiring a single complex uniform structure
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 the viewing angle and luminance ratio while reducing reflectivity, making it suitable for flexible display devices without the drawbacks of traditional polarizers, such as reduced light efficiency.
Implementation Method 1
holes injected from the hole injection electrodes and electrons injected from the electron injection electrode are combined at the organic emission layers, and excitons generated by this combination fall from an excited state to a ground state and emit light
Implementation Method 2
light-shielding elements on the upper layers... first light-shielding layers including first materials, and second light-shielding layers including second materials different from the first materials
Data Source
AI summary
An organic light-emitting display device includes a pixel electrode, an emission layer on the pixel electrode, an opposing electrode covering the emission layer, a plurality of upper layers on the opposing electrode, light-shielding elements on the upper layers, and a color filter layer on the upper layers. The light-shielding elements include first light-shielding layers and second light-shielding layers. The first light-shielding layers include first materials, and the second light-shielding layers include second materials different from the first materials. The second light-shielding layers overlay the first light-shielding layers.