Concave Reflective Electrode for OLED Light Extraction
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Solution Overview
Problem
Organic light emitting display devices (OLEDs) suffer from color mixture and light loss due to light being reflected at great angles to the reflective electrode, causing output to neighboring pixel regions and total internal reflection.
Innovation Solution
A concave reflective electrode is integrated into the OLED structure, with a concave furrow filled by a first filling pattern, allowing the reflective electrode to function as a concave mirror, reducing output angles and preventing light from entering neighboring pixels, and ensuring a flat substrate surface for uniform organic light emitting layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a flat reflective electrode is used, then the device structure is simple, but light is reflected at great angles causing color mixture and light loss
Solution Approach 1:
The reflective electrode is designed with a concave curved surface instead of a flat surface. This curvature causes incident light from the organic light emitting layer to be reflected at smaller angles, concentrating the reflected light within the pixel region and preventing it from entering neighboring pixels, thereby reducing color mixture and light loss
2Loss of energy
If a concave reflective electrode is used, then light loss is reduced, but the substrate surface becomes non-flat
Solution Approach 1:
A filling pattern is introduced in the dimensional space above the concave reflective electrode to fill the凹陷 region. This filling structure restores the flatness of the substrate surface in the upper dimension, allowing subsequent layers to be deposited uniformly while preserving the concave shape of the reflective electrode for optical performance
3Shape
If a filling pattern is added to fill the concave furrow, then substrate flatness is improved, but device complexity increases
Solution Approach 1:
The filling pattern serves multiple functions simultaneously: it fills the concave furrow to restore substrate flatness, provides a foundation for depositing subsequent transparent electrode and organic light emitting layer materials uniformly, and maintains the optical benefits of the concave reflective electrode 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 minimizes color mixture and light loss by concentrating reflected light within the pixel region and reducing lateral light guidance, enhancing brightness uniformity and overall display efficiency.
Implementation Method 1
a reflective electrode in a pixel region on a substrate and including a concave portion defining a concave furrow, a first filling pattern filling the concave furrow
Implementation Method 2
an organic light emitting display device (OLED) known as an organic electroluminescent display device is a display device in which an electron from a cathode and a hole from an anode are injected to an emitting layer between the cathode and the anode to generate an electron-hole pair, and the electron-hole pair disappears to emit a light
Data Source
AI summary
An organic light emitting display device includes a reflective electrode in a pixel region on a substrate and including a concave portion defining a concave furrow, a first filling pattern filling the concave furrow, a first electrode on the first filling pattern and on a portion of the reflective electrode around the first filling pattern, an organic light emitting layer on the first electrode, and a second electrode on the organic light emitting layer.