Display Multilayer Common Voltage Line for Stable Electrode Contact
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Solution Overview
Problem
Existing display devices face issues with contact characteristics between electrodes and wiring, leading to voltage drop during voltage transmission.
Innovation Solution
A display device with a common voltage line having a multi-layer structure, including a first layer with planar and non-planar portions, a second layer with a wider center and spaced apart from the first layer, and a third layer, enhancing contact area and stability between the common voltage line and the second electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple single-layer common voltage line structure is used, then the device structure is simple and easy to manufacture, but the contact area between the common voltage line and the second electrode is insufficient, causing voltage drop
Solution Approach 1:
The common voltage line is divided into multiple layers (first layer, second layer, and third layer) with different thicknesses and positions. The first layer has a thickness of 500-1000 Å, the second layer has a thickness of 6000-10000 Å, and the third layer has a thickness of 100-500 Å. This segmentation increases the contact area with the second electrode while maintaining manufacturability through systematic layer construction.
Solution Approach 2:
The common voltage line transitions from a single-layer planar structure to a multi-layer three-dimensional structure. The layers are positioned at different heights and depths, with the first layer at the opening of the dam, the second layer extending downward, and the third layer at the bottom. This dimensional expansion significantly increases the contact area with the second electrode, reducing voltage drop.
2Reliability
If the common voltage line is positioned far from the second electrode, then wiring layout is flexible, but voltage drop increases during transmission
Solution Approach 1:
The multi-layer common voltage line structure is nested within the dam structure. The first layer is positioned at the opening of the dam, the second layer extends downward into the dam, and the third layer is at the bottom. This nesting allows the common voltage line to be positioned close to the second electrode while maintaining wiring layout flexibility through the dam's geometric constraints.
Solution Approach 2:
The dam structure serves as an intermediary that positions and shapes the common voltage line layers. The dam's geometry (with opening, side walls, and bottom) provides a natural framework that places the multi-layer common voltage line in optimal proximity to the second electrode, minimizing voltage drop while allowing flexible wiring layout design.
3Reliability
If the second electrode contacts only the top surface of the common voltage line, then the contact structure is simple, but the contact area is insufficient, leading to high contact resistance
Solution Approach 1:
The contact structure is segmented into multiple contact interfaces: the second electrode contacts the top surface of the first layer, the side surface of the second layer, and the bottom surface of the third layer. This segmentation distributes the contact area across multiple surfaces, significantly increasing the total contact area and reducing contact resistance while maintaining a systematic and manufacturable contact structure.
Data Source
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AI summary
The display device according to an embodiment includes a substrate comprising a display area and a non-display area, an external common voltage line positioned in the non-display area, a common voltage line positioned in the display area and connected to the external common voltage line, a dam positioned between the substrate and the common voltage line and including an opening, multiple pixels positioned in the display area and including a first electrode and a light emitting layer, and a second electrode positioned above the multiple pixels, the common voltage line is a multi-layer structure including a first layer, a second layer, and a third layer, the first layer includes a planar portion positioned at the opening of the dam and a non-planar portion positioned overlapping the dam.