OLED Double Projection Anode Light Extraction
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Solution Overview
Problem
Organic light emitting display devices (OLEDs) suffer from significant light loss due to total internal reflection, with only 20% of emitted light being extracted outside the device, limiting their efficiency and brightness.
Innovation Solution
The implementation of a double projection structure for the anode layers, comprising first and second anode layers with crystalline projections formed using sputtering and potentially enhanced through etching or laser processes, reduces total reflection and enhances light extraction efficiency by creating diffraction points and improving the injection of holes into the organic emission layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional single-layer anode structure is used, then the device structure is simple, but light extraction efficiency is poor with only 20% of emitted light being extracted
Solution Approach 1:
The anode is divided into two separate layers (first anode layer and second anode layer) with different functions. The first anode layer provides electrical functionality while the second anode layer with projections provides optical functionality for light extraction, thereby resolving the contradiction between structural simplicity and light extraction efficiency
Solution Approach 2:
The second anode layer is transformed from a flat two-dimensional structure to a three-dimensional structure with projections. These projections create multiple interfaces and diffraction points that enhance light extraction efficiency by manipulating light paths in additional spatial dimensions
2Length of moving object
If the OLED is made ultra-thin for modern display requirements, then the device achieves thin profile, but total internal reflection increases causing significant light loss
Solution Approach 1:
The patent introduces three-dimensional projections on the second anode layer that create additional light extraction pathways. These projections enable light to escape through diffraction and scattering mechanisms that bypass the limitations of total internal reflection in ultra-thin structures
Solution Approach 2:
The second anode layer with projections acts as an intermediary structure between the organic emission layer and the external environment. It serves as an optical interface that facilitates light extraction by creating multiple refraction and diffraction points, thereby reducing total internal reflection losses
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 significantly improves light extraction efficiency, enabling higher brightness with lower power consumption and preventing damage to the organic emission layer by reducing the sharpness of projections.
Implementation Method 1
enhances light extraction efficiency by creating multiple diffraction points
Implementation Method 2
suffer from significant light loss due to total internal reflection
Implementation Method 3
comprising first and second anode layers with projections formed using sputtering
Data Source
AI summary
An organic light emitting display device (OLED) includes: a substrate; a first anode layer disposed on the substrate and including a plurality of first projections; a second anode layer formed on the first anode layer and including a plurality of second projections; an organic emission layer formed on the second anode layer; and a cathode layer formed on the organic emission layer. As a result, the anodes are formed to have a double projection structure to enhance light extraction efficiency.