OLED Array Substrate Vertical Overlap for Aperture Ratio
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Solution Overview
Problem
The 3T1C external compensation technology in OLED display devices results in a small pixel aperture ratio, necessitating increased luminous intensity, which affects the device's lifetime.
Innovation Solution
An OLED array substrate design where a conductive layer is overlapped with wires, driving transistors, and storage capacitors in a direction perpendicular to the substrate, reducing the effective display area occupied by common power supply lines and increasing the pixel aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 3T1C external compensation technology is applied to solve threshold voltage drift and luminance nonuniformity, then display quality is improved, but pixel aperture ratio decreases
Solution Approach 1:
The patent transitions the common power supply line from a planar configuration to a three-dimensional stacked configuration. The conductive layer is positioned above the insulation layer, which covers the wire, creating vertical overlap instead of horizontal adjacency. This dimensional change allows the power supply line to occupy space in the Z-direction rather than consuming additional display area in the X-Y plane, thereby resolving the contradiction between maintaining display quality and preserving pixel aperture ratio.
Solution Approach 2:
The patent implements a nested structure where the conductive layer containing the common power supply line is positioned above and overlaps with the insulation layer that covers the wire. This nesting arrangement allows the power supply line to be embedded within the vertical space already occupied by other components, effectively hiding the power supply infrastructure within the existing structure and preventing it from reducing the pixel aperture ratio.
2Area of moving object
If pixel aperture ratio is increased to improve display quality, then luminous efficiency is improved, but common power supply line layout becomes more difficult
Solution Approach 1:
By moving the common power supply line to a higher vertical level (above the insulation layer), the patent enables increased pixel aperture ratio in the display area without compromising power supply connectivity. The vertical stacking approach separates the power supply routing from the planar layout constraints, making it easier to achieve higher aperture ratios while maintaining manufacturability through standard layered fabrication processes.
Solution Approach 2:
The patent divides the substrate structure into distinct functional layers: the wire layer, the insulation layer covering the wire, and the conductive layer above the insulation layer. This segmentation allows each layer to be optimized independently - the wire layer for signal routing, the insulation layer for electrical isolation, and the conductive layer for power distribution - thereby simplifying the overall manufacturing process despite the three-dimensional arrangement.
3Reliability
If common power supply lines occupy more display area to ensure voltage distribution, then power supply stability is improved, but pixel aperture ratio decreases
Solution Approach 1:
The patent resolves this contradiction by relocating the common power supply line to a vertical position above the insulation layer, allowing it to overlap with existing structures in the X-Y plane without expanding the total area occupied. This maintains adequate voltage distribution capability while preserving maximum pixel aperture ratio, as the power supply line effectively uses the Z-dimension for its presence rather than consuming additional display area.
Data Source
AI summary
An OLED array substrate and a manufacturing method thereof, an array substrate and a display device are provided. The OLED array substrate includes a wire; a plurality of pixel units, each of which includes an OLED light-emitting unit, a driving transistor and a storage capacitor; an insulation layer which covers the driving transistor, the storage capacitor and the wire; and a conductive layer, which is on the insulation layer and is configured to provide a common voltage to the plurality of the pixel units. At least one of the wire, the driving transistor and the storage capacitor is overlapped with the conductive layer in a direction perpendicular to the OLED array substrate.