OLED Auxiliary Electrode Reduces Voltage Drop
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Solution Overview
Problem
Conventional OLED displays experience voltage drops due to electrical resistance in the second electrode, leading to non-uniform power supply and potential damage from high current density, which affects the luminance and lifespan of the display.
Innovation Solution
Incorporating a driving power line and an auxiliary electrode with a connection unit between the organic light emitting element and the second substrate, allowing for uniform distribution of the second power voltage across the second electrode, reducing voltage drops and current concentration, and using a thick film connection to minimize defects and moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the second electrode is formed over the entire area of the substrate to minimize luminance deterioration, then the luminance uniformity is improved, but voltage drop occurs due to electrical resistance of the second electrode
Solution Approach 1:
An auxiliary electrode is introduced as an intermediary component between the second electrode and the second substrate. This auxiliary electrode provides an additional electrical conduction path, mediating the power delivery to the second electrode and reducing the voltage drop caused by the electrical resistance of the second electrode itself.
Solution Approach 2:
The electrical conduction path is segmented into multiple routes: one through the second electrode and another through the auxiliary electrode connected via connection units. This segmentation allows the current to be distributed through parallel paths, reducing the current density and voltage drop in the second electrode.
2Illumination intensity
If the second electrode is formed over the entire area of the substrate, then the luminance uniformity is improved, but current density concentration occurs leading to potential damage
Solution Approach 1:
The auxiliary electrode acts as a mediator that shares the current load with the second electrode. By providing an alternative conduction path through the connection units, it reduces the current density concentration in the second electrode, preventing potential damage and extending device lifespan.
Solution Approach 2:
The electrical conduction is extended into a third dimension by adding the auxiliary electrode on the second substrate side. This creates a distributed conduction network that spans across the device thickness, effectively reducing current density in the planar second electrode.
3Device complexity
If a thin film connection is used between the driving power line and the auxiliary electrode, then the device complexity is reduced, but manufacturing defects and moisture ingress increase
Solution Approach 1:
The connection structure parameters are changed from thin film to thick film configuration. This parameter change increases the connection's mechanical robustness and moisture barrier properties, reducing manufacturing defects and moisture ingress while maintaining acceptable device 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 configuration ensures uniform power supply to the second electrode, minimizing voltage drops and current concentration, thereby enhancing the luminance and lifespan of the OLED display while preventing damage from high current density and moisture exposure.
Implementation Method 1
an organic light emitting element including a first electrode disposed on the first substrate, an organic emission layer disposed on the first electrode, and a second electrode disposed on the organic emission layer
Data Source
AI summary
An OLED display is disclosed. The OLED display includes two substrates with organic light emitting elements therebetween. The organic light emitting elements include a second electrode in common among the organic light emitting elements, and one of the substrates includes an auxiliary electrode to connect to the common second electrode to reduce resistance in the electrical path from a power source to the second electrode.