Side Mirror-Shaped Dummy Anode for Light Extraction
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Solution Overview
Problem
Light emitting display devices face issues with low light extraction efficiency due to total reflection loss, waveguide loss, and surface plasmon loss, which confine light within the device rather than outputting it effectively.
Innovation Solution
The implementation of a side mirror-shaped dummy anode with an undercut structure at its edge, separated from the main anode, enhances light extraction efficiency by reducing total reflection and waveguide losses, and eliminates the need for a separate patterning process, thereby improving processability and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional light emitting display device structure is used, then the device can be manufactured with standard processes, but light extraction efficiency is degraded due to total reflection loss, waveguide loss, and surface plasmon loss
Solution Approach 1:
The anode is segmented into a main anode and a dummy anode, where the dummy anode is positioned at a specific location to reflect light that would otherwise be lost. This segmentation allows the light extraction function to be separated from the electrical conduction function, enabling improved light extraction efficiency without compromising the overall device structure.
Solution Approach 2:
The dummy anode acts as an intermediary element between the emission layer and the external environment. It intercepts light that would be confined by total reflection or waveguide effects and redirects it toward the external environment, thereby serving as a mediator to improve light extraction efficiency.
2Loss of energy
If the anode is made to improve light extraction efficiency, then light extraction efficiency is improved, but contact resistance and leakage issues may arise
Solution Approach 1:
By segmenting the anode into main and dummy portions, the electrical conduction path is maintained through the main anode while the dummy anode is positioned to perform light reflection. The dummy anode can be electrically isolated or connected in a way that does not compromise electrical reliability, thus avoiding contact resistance and leakage issues while improving light extraction.
Solution Approach 2:
The light reflection function is extracted from the main anode and assigned to a separate dummy anode. This extraction allows the main anode to focus on electrical conduction without the complications of light reflection, while the dummy anode handles the light extraction function, thereby separating the two functions to avoid reliability issues.
3Loss of energy
If a separate patterning process is used to create the dummy anode, then light extraction efficiency is improved, but manufacturing complexity and costs increase
Solution Approach 1:
The formation of the dummy anode is merged with the existing anode formation process. By using the same deposition process and conditions for both the main anode and the dummy anode, no additional patterning steps are required. The dummy anode is formed simultaneously with the main anode, thereby simplifying the manufacturing process while achieving improved light extraction efficiency.
Solution Approach 2:
The deposition process for the anode is made universal to serve both electrical conduction and light reflection functions. By forming both the main anode and dummy anode in the same process step, the manufacturing process achieves multi-functionality, eliminating the need for separate patterning operations and reducing manufacturing complexity.
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 solution improves light extraction efficiency, suppresses contact resistance and leakage issues, and reduces power consumption by effectively redirecting light that would otherwise be lost within the device, while also simplifying the manufacturing process.
Implementation Method 1
a part of the light emitted from the emission layer can be confined in the light emitting display device due to a total reflection loss... the total reflection loss refers to degradation of light extraction efficiency due to light confined in the light emitting display device by a total reflection at the interface between a substrate and air
Implementation Method 2
The waveguide loss refers to degradation of light extraction efficiency due to the light confined in the light emitting display device by the total reflection at the interface between components in the light emitting display device
Data Source
AI summary
A light emitting display device can include a substrate including an emission area and a non-emission area, a thin film transistor on the substrate, a first overcoating layer on the thin film transistor, an organic light emitting diode on the first overcoating layer and connected to the thin film transistor, an encapsulation unit on the organic light emitting diode, and a touch unit on the encapsulation unit. The touch unit can include an open area defined by a plurality of touch electrodes. The organic light emitting diode can include a first electrode, an emission layer and a second electrode. Further, a portion of the first electrode and a portion of a side mirror-shaped dummy first electrode separated from the first electrode can be disposed in the open area defined by the plurality of touch electrodes.