OLED Array Substrate VDD Grid Switching for Voltage Drop Reduction
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Solution Overview
Problem
In AMOLED display systems, the illumination luminance is sensitive to variations in the driving voltage signal, leading to non-uniform display quality due to voltage drops along the driving voltage signal lines.
Innovation Solution
An OLED array substrate with a VDD grid arranged in a crisscross pattern and connected to driving voltage signal lines via switches, which are activated during the light-emitting stage to reduce the total resistance and voltage drop, ensuring uniform luminance across the display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single VDD line is used for driving voltage signal, then the device complexity is reduced, but the voltage drop increases causing non-uniform display quality
Solution Approach 1:
The single VDD line is segmented into multiple parallel VDD lines (first VDD line, second VDD line, etc.) to distribute the current load. Each scanning control line has its own dedicated VDD line, reducing the current density and voltage drop in each individual line, thereby improving display quality uniformity across the panel.
Solution Approach 2:
The patent introduces a grid-like structure by arranging VDD lines in parallel alongside scanning control lines, creating a two-dimensional voltage distribution network. This dimensional expansion allows voltage to be supplied from multiple directions (through the VDD grid), reducing the effective path length and resistance for current delivery to OLEDs across the display area.
2Manufacturing precision
If multiple parallel VDD lines are provided for each scanning control line, then the voltage drop is reduced improving display uniformity, but the device complexity increases
Solution Approach 1:
Multiple parallel VDD lines are merged into a unified VDD grid structure that spans across the display area. The grid combines horizontal and vertical conductive lines forming a network, where multiple lines work together as an integrated system rather than separate independent structures, reducing overall complexity while maintaining the benefits of multiple current paths.
Solution Approach 2:
The VDD grid structure serves multiple functions simultaneously: it provides voltage supply to multiple scanning control lines, acts as a current distribution network, and functions as a reference plane for signal timing. This multi-functionality reduces the need for separate dedicated structures for each function, thereby managing complexity.
3Area of stationary object
If the VDD line extends in the scanning direction, then the coverage area is improved, but the voltage drop increases causing variation in driving voltage signal
Solution Approach 1:
The long VDD line is segmented into multiple shorter parallel segments (first VDD line, second VDD line, etc.), each serving a specific scanning control line. This segmentation reduces the length of each individual voltage supply path, thereby reducing the cumulative resistance and voltage drop while still covering the entire display area through the combined network.
Solution Approach 2:
The voltage supply is transitioned from a one-dimensional linear extension to a two-dimensional grid network. By adding the vertical dimension with multiple parallel lines arranged in a grid pattern, the patent creates multiple shorter transmission paths simultaneously, reducing the maximum path length any current must travel while maintaining full area coverage.
Data Source
AI summary
The present disclosure provides an OLED array substrate, and a display panel and a display device including the OLED array substrate. A VDD grid is provided in an existing AMOLED array substrate with a compensation function, VDD lines are connected with the VDD grid via switches, which are applied with corresponding voltages to be switched on during a light emitting stage, such that the VDD lines are electrically connected in parallel to the VDD grid, thus a total resistance of the VDD lines and the VDD grid connected in parallel is decreased relative to the own resistance of the VDD line, so as to reduce the voltage drop on the VDD line in a direction in which the scanning control lines extend, and in turn to decrease a variation in a OLED driving voltage signal effectively, ensuring uniformity of luminance across the display area.