Top-Emission OLED Auxiliary Electrode Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Top-emission organic light emitting display devices face challenges in reducing thickness and manufacturing costs due to the need for additional layers and high reflectivity metals like silver, which are prone to corrosion, leading to contact defects and increased resistance in the second electrode.
Innovation Solution
The device incorporates a light-shielding layer, auxiliary electrodes, and a pad protection layer to reduce thickness and manufacturing costs, with a three-layer structure for the auxiliary electrodes and pad parts to decrease resistance and prevent corrosion, while eliminating the need for a connection electrode and additional planarization films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a connection electrode and auxiliary electrode are added to reduce resistance, then the resistance of the second electrode is reduced, but the thickness of the device increases
Solution Approach 1:
The connection electrode and auxiliary electrode are merged into a single integrated electrode structure. This single electrode serves both functions: connecting the first electrode to the thin film transistor and reducing the resistance of the second electrode, thereby eliminating the need for separate layers and reducing overall device thickness.
Solution Approach 2:
The single electrode is designed to perform multiple functions simultaneously: it acts as both a connection electrode (electrical connection between components) and an auxiliary electrode (resistance reduction for the second electrode), maximizing structural efficiency and minimizing layer count.
2Reliability
If additional layers and masks are used to form connection electrode, then the resistance is reduced, but manufacturing costs increase
Solution Approach 1:
The formation of connection electrode and auxiliary electrode is merged into a single manufacturing process step. By patternning the single multi-functional electrode once, the number of photolithography masks and processing steps is reduced, directly lowering manufacturing costs while achieving the same electrical performance.
Solution Approach 2:
The unnecessary connection electrode layer is extracted/removed from the structure. Only the essential auxiliary electrode function is retained and integrated into the connection electrode, eliminating redundant manufacturing steps and associated costs.
3Illumination intensity
If silver is used for pad part, then reflectivity is improved, but corrosion resistance deteriorates
Solution Approach 1:
The pad part is constructed as a composite material structure with multiple layers. A highly reflective metal layer (such as silver) is combined with protective metal layers (such as titanium nitride or aluminum oxide) that provide corrosion resistance. This composite structure achieves both high reflectivity and excellent corrosion resistance simultaneously.
Solution Approach 2:
Different regions of the pad part structure have different material properties optimized for their specific functions: the inner layer provides high reflectivity for light emission, while the outer protective layers provide corrosion resistance for environmental stability, with each layer having locally optimized material composition.
Data Source
AI summary
An organic light emitting display device secures an auxiliary electrode with a sufficient area without forming a passivation layer, an additional planarization film, an additional connection electrode and an auxiliary electrode. Accordingly, manufacturing of a top-emission organic light emitting display device may use three to four fewer masks, thus advantageously simplifying the process and reducing manufacturing costs, the thickness of the organic light emitting display device and the resistance of the second electrode.