OLED Common Electrode Resistance Reduction via Merged Voltage Line
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Solution Overview
Problem
The top emission type organic light emitting device faces challenges with increased cathode resistance due to the lack of transparent materials satisfying the work function condition, necessitating an opaque metal cathode and a separate common voltage line, which complicates the manufacturing process.
Innovation Solution
The organic light emitting device incorporates a substrate with intersecting signal lines, switching and driving thin film transistors, an insulating layer, a pixel electrode, an organic light emitting member, and a common electrode, where a member layer, including electron and hole injection/transport layers, electrically connects the common voltage line to the common electrode, reducing resistance and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an opaque metal cathode is used in top emission type OLED, then light can pass through, but cathode resistance increases
Solution Approach 1:
The patent merges the cathode and common voltage line into a single integrated structure. The common voltage line is formed in the same layer as the cathode material, eliminating the need for separate transparent conducting oxide layers. This integration maintains low resistance while enabling top emission functionality.
Solution Approach 2:
The cathode layer serves multiple functions simultaneously: it acts as the electron-injecting electrode, provides the common voltage connection, and enables light emission. By making the cathode material serve both as electrode and voltage transmission path, the patent eliminates the need for additional layers while maintaining performance.
2Reliability
If a separate common voltage line is added to reduce cathode resistance, then resistance decreases, but manufacturing process becomes complicated
Solution Approach 1:
The patent combines the cathode and common voltage line into a single integrated structure formed in the same layer. This merging eliminates the need for separate voltage transmission layers and reduces the number of manufacturing steps while maintaining low resistance performance.
Solution Approach 2:
The cathode material is designed to serve dual purposes: as the electron-injecting electrode and as the common voltage transmission path. This multi-functionality simplifies the device structure and manufacturing process by eliminating redundant layers.
3Reliability
If an additional common voltage line is formed, then electrical connection is improved, but the number of layers and manufacturing steps increases
Solution Approach 1:
The patent merges the cathode and common voltage line into a single integrated structure. The common voltage line is formed concurrently with the cathode layer using the same deposition process, reducing the total number of manufacturing steps while ensuring reliable electrical connection.
Solution Approach 2:
The cathode layer is designed to perform multiple functions: electron injection into the organic light emitting layer and simultaneous transmission of common voltage to the emission layer. This eliminates the need for separate voltage transmission layers and simplifies manufacturing.
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 reduces the resistance of the common electrode and simplifies the manufacturing process by eliminating the need for an additional common voltage line, enhancing the efficiency and reliability of the organic light emitting device.
Implementation Method 1
the member layer is made of a plurality of layers including electrons or holes, and at least one layer of the member layer is disposed between the common voltage line and the common electrode to electrically connect between the common voltage line and the common electrode
Implementation Method 2
an organic light emitting member formed on the pixel electrode and including an emission layer
Data Source
AI summary
An organic light emitting device according to an exemplary embodiment of the present invention includes: a substrate; a first signal line and a second signal line formed on the substrate and intersecting each other; a common voltage line formed on the substrate, and intersecting one of the first signal line and the second signal line; a switching thin film transistor connected to the first signal line and the second signal line; a driving thin film transistor connected to the switching thin film transistor; an insulating layer covering the first signal line, the second signal line, the switching thin film transistor, and the driving thin film transistor; a pixel electrode formed on the insulating layer, and electrically connected to the driving thin film transistor; an organic light emitting member formed on the pixel electrode and including an emission layer and a member layer; and a common electrode formed on the organic light emitting member, wherein the member layer is made of a plurality of layers including electrons or holes, and at least one layer of the member layer is disposed between the common voltage line and the common electrode to electrically connect between the common voltage line and the common electrode.