Wire Mesh Cathode Conductivity for OLED Panels
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Solution Overview
Problem
Current top-emitting organic light emitting display devices face issues with conductivity due to thin metal cathodes, leading to uneven voltage distribution and poor contact between electrodes, especially in large-sized panels.
Innovation Solution
An organic light emitting display device with a wire mesh structure incorporating silver nanoparticles, where the cathode is in contact with the wire mesh to enhance conductivity, eliminating the need for auxiliary electrodes and improving contact with the organic functional layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the top electrode thickness is reduced to less than 20 nm to achieve high transparency, then the transparency is improved, but the conductivity deteriorates due to greatly limited cross-sectional current
Solution Approach 1:
The patent applies composite materials by combining transparent conductive oxide (TCO) with a wire mesh structure consisting of silver nanoparticles embedded in an ink layer. This composite structure achieves both high transparency and high conductivity, as the TCO provides transparency while the wire mesh provides conductive pathways throughout the cathode structure.
Solution Approach 2:
The patent implements local quality by creating a non-uniform cathode structure where the wire mesh is positioned at specific locations (on the pixel defining layer and extending into the organic functional layer) rather than uniformly distributing material throughout. This localized wire mesh structure provides enhanced conductivity where needed while maintaining overall transparency.
2Reliability
If an auxiliary electrode is added in the panel region to improve conductivity, then the conductivity is improved, but the device complexity increases and contact with vapor-deposited top electrode becomes difficult
Solution Approach 1:
The patent merges the auxiliary electrode function with the cathode structure itself by integrating the wire mesh directly into the cathode. The wire mesh serves dual purposes: it acts as part of the cathode structure and simultaneously provides the auxiliary conductive pathways needed in the panel region, eliminating the need for separate auxiliary electrodes.
Solution Approach 2:
The wire mesh structure performs multiple functions simultaneously: it provides conductivity enhancement in the panel region, serves as part of the cathode structure for top-emission, and facilitates contact with the vapor-deposited top electrode. This multi-functional design eliminates the need for separate auxiliary electrodes.
3Illumination intensity
If a thin metal cathode is used to achieve high transparency, then the transparency is improved, but the voltage distribution becomes uneven across large-sized panels due to internal resistance
Solution Approach 1:
The patent transitions from a two-dimensional thin film cathode to a three-dimensional wire mesh structure. The wire mesh extends vertically from the pixel defining layer into the organic functional layer, creating conductive pathways in the third dimension. This dimensional change allows for better voltage distribution across large panels while maintaining transparency.
Solution Approach 2:
The cathode is segmented into multiple conductive elements (wire mesh strands) distributed throughout the structure rather than relying on a single continuous thin layer. This segmentation creates multiple parallel conductive pathways, reducing overall resistance and improving voltage uniformity across large display panels.
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 significantly increases the conductivity of the cathode, ensuring uniform display performance across large-sized panels by using a wire mesh structure with silver nanoparticles, simplifying the manufacturing process and enhancing the total aperture ratio of display pixels.
Implementation Method 1
The wire mesh structure includes an ink layer and a plurality of silver nanoparticles disposed in the ink layer... the cathode is in contact with the wire mesh structure to improve conductivity of the cathode
Data Source
AI summary
An organic light emitting display device and a method of fabricating the same are provided. The organic light emitting display device includes a substrate, a pixel defining layer, an organic functional layer, a wire mesh structure, a cathode, and a protective layer. The pixel defining layer is disposed on the substrate and includes a plurality of pixel defining units. The organic functional layer is disposed on the anode of the substrate and in a space between any two adjacent pixel defining units. The cathode is disposed on the organic functional layer and in contact with the wire mesh structure.