OLED Array Substrate Power Line Relocation for Aperture Ratio
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Solution Overview
Problem
The existing OLED array substrates face issues with reduced aperture ratio due to the power line occupying pixel opening area and capacitor area, leading to voltage drop and fluctuation in light-emitting current, which affects the lifetime and luminance uniformity of OLED devices.
Innovation Solution
The OLED array substrate design includes a power line disposed under and partially overlapping with the pixel structure, connected through a via hole structure in an insulating layer, allowing for reduced resistance and increased aperture ratio by avoiding occupation of the pixel area and using a planar metal mesh power line with a hollow structure to minimize voltage drop and light shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the power line is disposed above the pixel structure, then the connection to driving transistor is simplified, but the aperture ratio is reduced due to occupation of pixel opening area
Solution Approach 1:
The power line is moved from the horizontal plane (above pixel structure) to the vertical dimension (below pixel structure), connecting through via holes in the insulating layer. This dimensional transition allows the power line to occupy non-pixel area while maintaining electrical connection, thus increasing aperture ratio without complicating the connection path.
2Device complexity
If the power line occupies pixel opening area and capacitor area, then the device structure is simplified, but the voltage drop increases and light-emitting current fluctuates
Solution Approach 1:
The power line is extracted from the pixel area and relocated to the peripheral area below the pixel structure. This separation removes the source of voltage drop and current fluctuation from the critical pixel region, improving voltage stability and reliability while the insulating layer with via holes maintains the necessary electrical connection.
3Ease of manufacture
If the power line occupies pixel area, then the manufacturing process is simplified, but the luminance uniformity deteriorates
Solution Approach 1:
The power line is relocated to the vertical dimension below the pixel structure, connected through insulating layers and via holes. This dimensional change allows the power line to be manufactured using the same thin-film deposition processes while preventing its shadow from interfering with light emission, thus maintaining manufacturing simplicity while improving luminance uniformity.
4Area of moving object
If the power line is disposed below the pixel structure with via hole connection, then the aperture ratio is increased, but the manufacturing precision requirement increases
Solution Approach 1:
The insulating layer serves as an intermediary structure that contains the via holes for power line connection. By integrating the via holes into the insulating layer formation process and using the insulating layer as a precise template, the alignment precision requirement is managed through process integration rather than requiring separate high-precision alignment steps.
Data Source
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Figure 5a~5c
AI summary
An organic light-emitting diode (OLED) array substrate and a manufacturing method thereof and a display device are provided. The OLED array substrate includes a base substrate (101), a power line (102) and a pixel structure (105) disposed on the base substrate. The power line (102) is disposed under the pixel structure (105) and is at least partially overlapped with the pixel structure (105); an insulating layer is disposed between the power line and the pixel structure, and a first via hole structure (110) is disposed in the insulating layer; and the power line (102) is connected with a driving transistor (107) in the pixel structure (105) through the first via hole structure (110). The OLED array substrate increases a aperture ratio and decreases the resistance between the pixel and the OVDD line in the display area.