OLED Cathode Line Layout for Uniform Display Voltage
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Solution Overview
Problem
In top-emission OLED display apparatus, the equivalent resistance of the cathode line connection is high, leading to significant voltage drops at distances far from the signal source, which affects display uniformity.
Innovation Solution
The cathode line is designed to surround the display area and is electrically connected to the cathode at multiple positions, with sub-lines in the same layer as the anode, and via holes are used to ensure electrical connectivity, reducing the equivalent resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cathode line is designed to surround the display area with multiple connection positions, then the equivalent resistance is reduced and voltage uniformity is improved, but the device complexity increases
Solution Approach 1:
The cathode line is divided into multiple segments (first cathode sub-line and second cathode sub-line) located in different conductive layers. These segments are connected through via holes to form a complete cathode line that surrounds the display area, reducing equivalent resistance while managing structural complexity through layered organization.
Solution Approach 2:
The cathode line structure transitions from a single-layer design to a multi-layer design with the first cathode sub-line in the same layer as the anode and the second cathode sub-line in a different conductive layer. This dimensional change allows the cathode line to surround the display area more effectively, reducing voltage drops through multiple pathways.
2Reliability
If the cathode line is placed in the same layer as the anode, then the contact area with the cathode is increased, but the manufacturing precision requirements increase
Solution Approach 1:
The cathode line is segmented into multiple sub-lines in different layers, with via holes connecting them. This segmentation allows the first cathode sub-line to be in the same layer as the anode for maximum contact area, while the second cathode sub-line is in a different layer to provide additional connection pathways, distributing the manufacturing precision requirements across multiple via holes rather than requiring perfect alignment in a single layer.
Data Source
AI summary
A display substrate is provided. The display substrate includes: a base substrate including a display area and a peripheral area located on at least a first side of the display area; a plurality of pixel units arranged in an array along a first direction and a second direction in the display area of the base substrate, where the pixel units include a pixel driver circuit and a light-emitting device electrically connected to the pixel driver circuit, and the light-emitting device includes a cathode, an anode, and a light-emitting layer disposed between the cathode and the anode; and a cathode line located in the peripheral area and electrically connected to the cathode. The cathode line substantially surrounds the display area and is electrically connected to the cathode line at a plurality of positions. The cathode line includes a first cathode sub-line located in the same layer as the anode.