Multilayer Common Voltage Line Structure for Stable Display Electrode Contact
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Solution Overview
Problem
Existing display devices face issues with poor contact characteristics between electrodes and wiring, leading to voltage drop during the transmission of common voltage, which affects the overall performance and efficiency of the display.
Innovation Solution
A display device with a common voltage line structure comprising a multi-layered first, second, and third layer, where the second layer has a wider central width and an undercut structure, increasing the contact area with the second electrode, and a spacing area between the first and second layers to stabilize the contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple single-layer common voltage line structure is used, then the device complexity is low, but the contact characteristics between electrodes and wiring are poor leading to voltage drop
Solution Approach 1:
The common voltage line is divided into multiple layers (first, second, and third layers) with different functions. The first layer provides planar contact, the second layer provides undercut contact, and the third layer provides additional planar contact. This segmentation allows each layer to optimize contact characteristics from different angles, resolving the contradiction between simple structure and good contact.
Solution Approach 2:
The patent transitions from a single-layer planar structure to a multi-layer three-dimensional structure. By adding vertical dimension (multiple layers at different heights), the contact area between the common voltage line and second electrode is significantly increased without increasing the horizontal footprint, thus improving contact characteristics while maintaining device compactness.
2Reliability
If the contact area between common voltage line and second electrode is increased, then voltage drop is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The contact interface is segmented into three distinct contact regions across different layers, each with specific geometric characteristics. The first layer provides a first contact region, the second layer provides a second contact region through undercut, and the third layer provides a third contact region. This segmentation allows independent optimization of each contact region's geometry and positioning, reducing the overall manufacturing precision burden compared to a single large contact region.
Solution Approach 2:
Each layer of the common voltage line is designed with specific local characteristics: the first layer has planar contact optimized for flat surfaces, the second layer has undercut contact optimized for angular surfaces, and the third layer has planar contact optimized for flat surfaces. This local quality differentiation allows each contact region to be manufactured with appropriate precision requirements for its specific function, overall reducing the stringency of universal manufacturing precision requirements.
Data Source
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.