OLED Display Assistance Electrode Voltage Drop Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In large organic light emitting diode (OLED) displays greater than 10 inches, the high resistance of the cathode in front light emitting type OLEDs leads to significant voltage drops, affecting luminance uniformity and increasing power consumption due to reduced driving voltage margins.
Innovation Solution
An assistance electrode with lower resistance than the second electrode is introduced between the encapsulation substrate and the second electrode in non-light-emitting regions, minimizing the voltage drop across the second electrode and improving luminance uniformity while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the cathode is made of transparent material with small thickness in front light emitting type OLED, then transmittance is improved, but voltage drop increases due to high resistance
Solution Approach 1:
A low-resistance auxiliary electrode is introduced as an intermediary component between the transparent cathode and the encapsulation substrate. This auxiliary electrode serves as a mediator that provides an alternative low-resistance current path, thereby reducing the voltage drop across the transparent cathode while maintaining its high transmittance property.
Solution Approach 2:
The auxiliary electrode is strategically positioned in the non-light-emitting region (peripheral region) of the OLED structure. This local placement allows the low-resistance material to be applied only where it is needed for current collection, without interfering with the light emission quality in the active pixel regions.
2Reliability
If the cathode thickness is increased to reduce resistance, then voltage drop is reduced, but transmittance decreases
Solution Approach 1:
The current collection function is segmented between two components: the thin transparent cathode in the light-emitting region (maintaining transmittance) and the auxiliary low-resistance electrode in the non-light-emitting region (reducing resistance). This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The auxiliary electrode acts as an intermediary that collects current from the transparent cathode in the peripheral region and transports it to the common electrode connection, providing a low-resistance path that compensates for the high resistance of the thin transparent cathode material.
3Area of stationary object
If OLED display size is increased to greater than 10 inches, then display area is improved, but voltage drop in cathode increases due to IR drop
Solution Approach 1:
The auxiliary low-resistance electrode is specifically deployed in the peripheral non-light-emitting regions of large-size OLED displays. This local quality approach addresses the increased voltage drop problem in large displays by providing enhanced current collection paths at the edges, where the current density is highest and the distance to the common electrode connection is longest.
Solution Approach 2:
In large-size OLED displays, the auxiliary electrode serves as a critical intermediary component that bridges the gap between the extensive transparent cathode area and the common electrode connection, providing low-resistance current transport paths that compensate for the increased IR drop inherent in larger display dimensions.
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
The solution effectively reduces the voltage drop across the second electrode, enhancing long-range uniformity of luminance and decreasing power consumption by widening the driving voltage margin of the OLED emitter.
Implementation Method 1
Light is generated by energy created when excitons, that are generated by coupling of electrons and holes within an organic emission layer, drop from an excited state to a ground state
Implementation Method 2
an assistance electrode disposed between the encapsulation substrate and the second electrode, disposed in a non-light-emitting region between the organic light emitter and the second electrode, where the assistance electrode has a lower resistance than the second electrode
Data Source
AI summary
An organic light emitting diode (OLED) display is disclosed. The organic light emitting diode (OLED) display includes an organic light emitter that has a first electrode, an organic emission layer, and a second electrode. The OLED also has an encapsulation substrate covering the organic light emitter and an assistance electrode disposed between the encapsulation substrate and the second electrode. The assistance electrode can be disposed in a non-light-emitting region between the organic light emitter and the second electrode, and can have a lower resistance than a resistance of the second electrode.