OLED Second Electrode Double-Layer Structure for Low Resistance
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Solution Overview
Problem
Top emission mode OLED display devices face challenges with low transmittance and high resistance due to the second electrode, which limits their application in large-sized displays, and the use of magnesium can cause short circuits and oxidation issues, making repair difficult.
Innovation Solution
A double-layer structure for the second electrode is formed using a magnesium-silver alloy as the first conductive layer and silver as the second conductive layer, with an oxide layer inserted between the electrodes to prevent electrical connection and oxidation, enhancing transmittance and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second electrode is formed thicker to lower resistance in large-sized display devices, then resistance is reduced, but transmittance is lowered
Solution Approach 1:
The second electrode is divided into multiple layers (including an aluminum layer and an aluminum alloy layer) instead of using a single thick layer. This segmentation allows each layer to contribute to conductivity while maintaining overall transmittance by distributing the conductive function across multiple thinner layers.
Solution Approach 2:
The second electrode uses composite material structures combining different aluminum-based materials (aluminum, aluminum alloy) in multiple layers. This composite approach achieves low resistance through material properties while maintaining high transmittance through optimized layer thickness and composition.
2Reliability
If magnesium is used in the second electrode, then conductivity is improved, but short circuits and oxidation occur making repair difficult
Solution Approach 1:
The patent replaces magnesium (which causes oxidation and short circuits) with aluminum-based materials that provide comparable conductivity without the harmful oxidation issues. This substitution eliminates the need for complex repair processes while maintaining electrical performance.
Solution Approach 2:
Instead of using magnesium which oxidizes and creates harmful effects, the patent employs aluminum-based materials that naturally form protective oxide layers without causing short circuits. This converts the potential harm of oxidation into a beneficial protective mechanism.
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 achieves low resistance and high transmittance for large-sized OLED displays, preventing short circuits and oxidation, thereby improving emission efficiency and facilitating repair processes.
Implementation Method 1
a second electrode which includes a first conductive layer formed on the organic emission layer and a second conductive layer formed on the first conductive layer
Implementation Method 2
an oxide layer inserted between the electrodes to prevent electrical connection and oxidation
Data Source
AI summary
An OLED display device is discussed which can include: a first substrate defined into an emission region and a non-emission region; a first electrode formed on the first substrate; a bank pattern configured to expose a part of the first electrode corresponding to the emission region; an organic emission layer formed on the exposed part of the first electrode corresponding to the emission region; a second electrode which includes a first conductive layer formed on the organic emission layer and a second conductive layer formed on the second conductive layer. The first conductive layer is formed from an alloy of magnesium (Mg) and silver (Ag), and the second conductive layer is formed from silver (Ag). Such an OLED display device allows the second electrode to include the first conductive layer and the second conductive layer. As such, a large-sized display device with low resistance and high transmittance can be realized.