Multi-Layer Common Voltage Line for Low-Drop Display Wiring
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Solution Overview
Problem
Light emitting display devices face issues with wiring damage and voltage drop during the transmission of common voltage, primarily due to the structural limitations and material properties of the common voltage lines.
Innovation Solution
A multi-layered common voltage line structure is introduced, featuring a reinforced layer between the second and third layers, which includes inorganic or organic materials like silicon oxide, silicon nitride, or polyimide, and an under-cut structure to prevent damage and ensure efficient voltage transmission by positioning the second electrode in contact with the side of the common voltage line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common voltage line is formed in the display area to connect external common voltage lines, then voltage transmission is enabled, but the wiring may be damaged and voltage drop occurs due to structural limitations
Solution Approach 1:
The common voltage line employs a multi-layer composite structure consisting of a first metal layer, a second metal layer, and a reinforced layer. The reinforced layer contains an inorganic material layer (such as silicon oxide, silicon nitride, or silicon oxynitride) and an organic material layer (such as polyimide or acrylic material), creating a composite structure that enhances mechanical strength and prevents wiring damage while maintaining electrical conductivity.
Solution Approach 2:
The patent introduces a multi-layer vertical structure to solve the wiring damage problem. By stacking multiple layers (first metal layer, second metal layer, reinforced layer with inorganic and organic materials) in the thickness direction, the common voltage line gains enhanced mechanical strength and damage resistance without affecting the planar layout.
2Reliability
If a multi-layered common voltage line structure is introduced with a reinforced layer, then wiring damage is prevented and voltage drop is minimized, but the manufacturing process becomes more complex
Solution Approach 1:
The reinforced layer is formed between the first and second metal layers during the manufacturing process, before the common voltage line is put into service. The inorganic material layer and organic material layer are deposited in advance to provide structural reinforcement, preventing future wiring damage and voltage drop issues.
Solution Approach 2:
The reinforced layer combines inorganic materials (silicon oxide, silicon nitride, silicon oxynitride) with organic materials (polyimide, acrylic material) to create a composite structure that provides both mechanical strength and flexibility, enhancing the overall reliability of the voltage transmission line.
3Ease of operation
If the second layer has an under-cut structure with smaller width than the third layer, then the second electrode can contact the side of the common voltage line, but the manufacturing precision requirements increase
Solution Approach 1:
The second layer is designed with an asymmetric under-cut structure where its width is intentionally made smaller than the first and third layers. This asymmetric configuration allows the second electrode to contact the side of the common voltage line, enabling flexible electrode placement while maintaining electrical connection.
Solution Approach 2:
The under-cut structure creates a local variation in the second layer's width, making it narrower at specific regions to allow side contact with the second electrode. This local quality change enables the electrode contact configuration without affecting the overall structure's integrity.
Data Source
AI summary
A display device according to an embodiment includes a display area and a non-display area, an external common voltage line formed in the non-display area, a common voltage line formed in the display area and connecting a portion and another portion of the external common voltage line, a plurality of pixels positioned in the display area and including a first electrode and an emission layer, and a second electrode positioned on the plurality of pixels. The common voltage line has a multi-layered structure including a first layer, a second layer, a third layer, and a reinforced layer. The reinforced layer is positioned between the second layer and the third layer, the first layer, the second layer, and the third layer include a metal, and the reinforced layer includes an inorganic material or an organic material.