Multi-Cathode Display Panel Structure for Lateral Leakage Blocking
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Solution Overview
Problem
Light emitting display panels experience undesired lighting due to lateral leakage current (LLC) between adjacent pixels, caused by continuous cathode electrodes across adjacent pixels.
Innovation Solution
A light emitting display panel design featuring a first cathode electrode with low and high resistance area electrodes, where the high resistance area electrodes are positioned on banks between adjacent anode electrodes, and a light compensation layer is included to manage electron flow and reduce leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a continuous cathode electrode is used across adjacent pixels, then the manufacturing process is simplified, but lateral leakage current occurs between pixels causing undesired lighting
Solution Approach 1:
The continuous cathode electrode is segmented into multiple discrete cathode electrodes, each corresponding to a specific pixel. This segmentation prevents lateral leakage current between adjacent pixels by electrically isolating the cathode of one pixel from its neighbors, thereby eliminating the harmful effect while maintaining manufacturing feasibility through patterned deposition processes.
Solution Approach 2:
Different regions of the cathode electrode structure are assigned different electrical properties. Specifically, the cathode electrode within each pixel area maintains low resistance for efficient electron transport, while the regions between pixels (on the banks) have high resistance to block lateral leakage. This local differentiation of electrical properties resolves the contradiction between conductivity and leakage prevention.
2Object-generated harmful factors
If high resistance area electrodes are added to the first cathode electrode, then lateral leakage current is reduced, but the device structure becomes more complex
Solution Approach 1:
The low resistance area electrode and high resistance area electrode are merged into a single integrated first cathode electrode structure. This unified structure is formed in one fabrication step through selective deposition or doping, combining the electron transport function (low resistance regions) and the leakage prevention function (high resistance regions) into one component, thereby reducing overall device complexity while achieving both objectives.
Solution Approach 2:
The first cathode electrode is designed to perform multiple functions simultaneously: it serves as the primary electron injection electrode (low resistance function) and as a lateral leakage barrier (high resistance function). This multi-functionality eliminates the need for separate structures for each purpose, reducing device complexity while effectively addressing lateral leakage current.
3Reliability
If the first cathode electrode is patterned with high and low resistance areas, then electron flow control is improved, but manufacturing precision requirements increase
Solution Approach 1:
A light compensation layer is introduced as an intermediary element between the first cathode electrode and the second cathode electrode. This layer facilitates the formation of high resistance area electrodes through selective oxygen permeation during deposition, acting as a mask or template that enables precise patterning without requiring direct complex patterning of the cathode electrode itself, thereby reducing manufacturing precision requirements while maintaining reliable electron flow control.
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 effectively minimizes lateral leakage current, preventing unwanted light emission between pixels and enhancing display quality by controlling electron transfer through the use of high resistance area electrodes and a light compensation layer.
Implementation Method 1
a first cathode electrode on the light emitting layer and including a low resistance area electrode and at least one high resistance area electrode having a higher resistance than the low resistance area electrode
Implementation Method 2
a light compensation layer is included to manage electron flow and reduce leakage
Data Source
AI summary
A disclosed light emitting display panel includes: a substrate; a plurality of pixel driving circuits on the substrate; a planarization layer on the pixel driving circuits; a plurality of anode electrodes on the planarization layer, each of the plurality of anode electrodes being electrically connected with a corresponding one of the pixel driving circuits; a plurality of banks on the planarization layer and including at least one first region bank between two adjacent anode electrodes among the plurality of anode electrodes; a light emitting layer on the plurality of anode electrodes and on the banks; a first cathode electrode on the light emitting layer and including a low resistance area electrode and at least one high resistance area electrode having a higher resistance than the low resistance area electrode; and a second cathode electrode on the first cathode electrode.