Common Voltage Mesh Layout for Narrow-Bezel Display Panels
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Solution Overview
Problem
Display devices face issues with common voltage drops and bezel thickness, particularly in emissive display devices aiming for whole-surface display technology without bezels.
Innovation Solution
The display device incorporates an external common voltage line in the non-display area connected to common voltage lines in the display area, forming a mesh structure with transverse and longitudinal components, and includes separate driving and initialization voltage lines with multi-layered structures to prevent voltage drops and minimize bezels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common voltage line is extended to the edges of the display area to prevent voltage drops, then the voltage stability is improved, but the bezel thickness increases
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement where common voltage lines must extend to the edges, to a three-dimensional multi-layered structure. By routing common voltage lines through multiple layers (including connecting non-adjacent layers via connection holes), the patent achieves voltage stability without increasing the horizontal bezel thickness, as the additional routing space is utilized in the vertical dimension rather than expanding the horizontal boundary.
2Manufacturing precision
If separate driving and common voltage lines are used for each pixel, then the voltage control precision is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple common voltage lines that would otherwise need to extend independently to each pixel into shared common voltage lines that serve multiple pixels. By having pixels share common voltage lines and using multi-layered routing, the patent reduces the total number of voltage lines while maintaining precise voltage control through selective connection points and layer-specific routing.
Solution Approach 2:
The patent makes common voltage lines multi-functional by having them serve multiple pixels simultaneously. A single common voltage line can provide reference voltage to multiple pixels across different layers, reducing the overall complexity of the voltage line network while maintaining the precision needed for each individual pixel's operation.
3Length of stationary object
If the common voltage line is routed through the display area to minimize bezel, then the bezel thickness is reduced, but the long-range uniformity deteriorates due to voltage drops
Solution Approach 1:
The patent resolves the conflict between minimizing bezel and maintaining uniformity by utilizing the vertical dimension through multi-layered routing. Common voltage lines are distributed across multiple layers and connected via connection holes, allowing the lines to reach pixels at the edges of the display area without extending the horizontal bezel thickness, thereby maintaining long-range uniformity while minimizing the visible bezel.
Solution Approach 2:
The patent introduces connection holes as intermediary elements that enable vertical communication between layers. These connection holes act as mediators that allow common voltage lines to transition between layers, facilitating the routing of voltage lines to edge pixels without requiring horizontal extension into the bezel area, thus maintaining both uniformity and minimal bezel thickness.
Data Source
AI summary
A display device includes: a substrate including a display area and a non-display area; an external common voltage line disposed in the non-display area; a plurality of pixels and a common voltage line disposed in the display area; and a driving voltage line connected to each of the plurality of pixels, wherein a subset of the plurality of pixels overlaps the common voltage line in the display area in a plan view, and the external common voltage line and the common voltage line are connected to each other.