Auxiliary Electrode for Top-Emitting OLED IR Drop Reduction
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Solution Overview
Problem
Top-emitting OLED display products face issues with large IR drops due to cathodes made of transparent conductive materials, leading to non-uniform voltage distribution and compromised display quality.
Innovation Solution
Incorporating an auxiliary electrode and connecting structure within pixel units, where the auxiliary electrode and anode are made from the same thin film, and applying a voltage difference to establish an electrical connection, thereby reducing the IR drop and ensuring uniform voltage distribution across the display substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the cathode is made of transparent conductive material in top-emitting OLED, then light emission from the cathode side is achieved, but large IR drop occurs causing non-uniform voltage distribution
Solution Approach 1:
The invention divides the single cathode into multiple segmented cathodes within each pixel unit, allowing independent voltage control of each segment. This segmentation enables localized voltage compensation, reducing the overall IR drop effect and improving voltage distribution uniformity across the display panel while maintaining light emission functionality.
Solution Approach 2:
The invention introduces auxiliary electrodes as intermediary elements between the signal line and the cathode. These auxiliary electrodes serve as voltage compensation nodes that can be independently controlled to offset IR drop effects, acting as mediators to achieve more uniform voltage distribution without compromising the transparent conductive cathode's light emission capability.
2Ease of manufacture
If auxiliary electrode and anode are made from the same thin film, then manufacturing complexity is reduced, but electrical connection stability must be maintained
Solution Approach 1:
The invention merges the auxiliary electrode and anode into the same thin film layer, eliminating the need for separate fabrication processes for these two components. This integration simplifies the manufacturing process and reduces the number of deposition steps while maintaining reliable electrical connections through the continuous thin film structure.
Solution Approach 2:
By using the same thin film material for both the auxiliary electrode and anode, the invention achieves material homogeneity, ensuring consistent electrical properties and connection stability. The uniform material composition across both electrodes facilitates reliable electrical connection while streamlining the fabrication process.
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 solution effectively minimizes the voltage difference between the actual voltage on the display electrode and the pixel voltage, enhancing display quality and uniformity by applying an auxiliary voltage through the auxiliary electrode, thus overcoming the limitations of large IR drops in top-emitting OLEDs.
Implementation Method 1
since the top-emitting OLED emits light from a side thereof where a cathode is located, the cathode needs to be made of a transparent conductive material. As such, an IR drop of the cathode is large, thereby affecting uniformity of the panel and the display quality thereof
Data Source
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AI summary
The present disclosure is related to a display substrate. The display substrate may include a plurality of pixel units. Each of theplurality of the pixel units may include a first electrode and a second electrode on a base substrate. At least one of the pixel units further comprises an auxiliary electrode and a connecting structure between the auxiliary electrode and the first electrode. The connecting structure may be configured to electrically connect the auxiliary electrode to the first electrode.