OLED Display Substrate Cathode Mesh for Uniform Pixel Current
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Solution Overview
Problem
In OLED display devices, the interconnected cathodes lead to voltage drops and uneven driving currents across pixels due to varying distances from the driving signal terminal, resulting in increased power consumption and uneven display brightness.
Innovation Solution
A display substrate with a base substrate, light-emitting units, and an auxiliary conductive layer that couples with the second electrode through a via hole, forming a mesh or chain structure, which reduces resistance and ensures consistent current supply to each pixel by matching the material with the first and second electrodes of the driving transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the cathodes of light-emitting units are interconnected to form an integral cathode layer, then the structural simplicity is improved, but the voltage drop increases and power consumption increases
Solution Approach 1:
The patent divides the cathode layer into multiple independent cathodes, each connected to the driving signal terminal through separate pathways. This segmentation reduces the current density in each cathode, thereby reducing voltage drops and power consumption while maintaining structural simplicity through systematic arrangement.
Solution Approach 2:
The patent implements local quality by creating different cathode configurations for different regions of the display. Cathodes in different pixel regions have optimized connection paths and dimensions tailored to their specific current requirements, reducing overall power consumption while maintaining local performance.
2Ease of manufacture
If the cathodes are interconnected to form an integral cathode layer, then the manufacturing process is simplified, but the display brightness uniformity deteriorates
Solution Approach 1:
By segmenting the cathode layer into multiple independent cathodes with separate connection paths, the patent enables more precise control over current distribution to different pixel regions, thereby improving display brightness uniformity while maintaining manufacturing simplicity through standardized fabrication processes.
Solution Approach 2:
The patent applies local quality by optimizing cathode connection paths and dimensions for specific pixel regions, ensuring uniform current distribution and brightness across the display while using consistent manufacturing techniques throughout.
3Ease of operation
If the driving signal terminal is positioned around the display area, then the ease of operation is improved, but the distance variation to different light-emitting units increases
Solution Approach 1:
The patent segments the cathode connections so that multiple independent pathways radiate from the driving signal terminal to different pixel regions. This segmentation compensates for distance variations by providing dedicated low-resistance paths to each region, maintaining ease of operation while reducing the impact of varying distances.
Solution Approach 2:
The patent optimizes cathode connection paths for specific distance requirements of different pixel regions, creating locally adapted current pathways that compensate for distance variations from the driving signal terminal, thereby maintaining uniform brightness while preserving ease of operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces voltage drops and power consumption while maintaining consistent driving currents across pixels, leading to uniform brightness and improved display performance.
Implementation Method 1
a certain voltage drop occurs in the cathode layer due to the large resistance thereof
Implementation Method 2
each second electrode has a portion extending out of the pixel region and coupling to the auxiliary conductive layer through a via hole
Data Source
AI summary
A display substrate includes: a base substrate; a light-emitting unit in each pixel region and including a first electrode, an organic light-emitting layer, and a second electrode sequentially disposed in a direction away from the base substrate; an auxiliary conductive layer between the light-emitting unit and the base substrate; a pixel circuit in each pixel region and including a driving transistor. The auxiliary conductive layer is on a side of the pixel circuit away from the base substrate, the second electrode has a portion extending out of the pixel region and coupling to the auxiliary conductive layer through a via hole not overlapping the pixel region, the auxiliary conductive layer is insulated and spaced apart from the first electrode and has a mesh or chain shape, and a material of the auxiliary conductive layer is the same as a material of the first and second electrodes of the driving transistor.