Segmented Display Substrate Electrode for IR Drop and Arcing
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Solution Overview
Problem
In high-performance displays, the non-uniformity of brightness between pixels due to IR drop caused by voltage differences across the backplane leads to mura (non-uniform display), and adding a large-area metal layer to reduce IR drop can result in arcing discharge during the CVD process, damaging equipment.
Innovation Solution
A display substrate with a power supply electrode comprising a first electrode layer and a mesh-shaped second electrode layer, coupled through via holes, and switch elements to control the first electrode parts, which are spaced apart to prevent charge accumulation and arcing discharge, while ensuring uniform power supply to pixel units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large-area metal layer is added to provide VDD signal, then VDD resistance is reduced and IR drop is reduced, but arcing discharge occurs during CVD process due to charge accumulation on the large-area metal layer, damaging equipment
Solution Approach 1:
The power supply electrode is divided into multiple first electrode parts in the first electrode layer, with each part having an area smaller than the threshold that causes arcing discharge. These segmented electrode parts are arranged in an array and coupled to light-emitting devices, providing distributed power supply that reduces IR drop without causing charge accumulation hazards during CVD processing
2Object-affected harmful factors
If the power supply electrode is segmented into multiple first electrode parts, then charge accumulation is prevented and arcing discharge is avoided, but the number of electrode parts increases and fabrication complexity increases
Solution Approach 1:
Multiple first electrode parts are coupled together through the second electrode layer to form a unified power supply electrode structure. The second electrode layer acts as a common coupling layer that electrically connects all first electrode parts, simplifying the overall structure while maintaining the segmented configuration that prevents charge accumulation
Solution Approach 2:
The second electrode layer serves as an intermediary element that couples the multiple first electrode parts to each other and to the light-emitting devices. This intermediary layer simplifies the connection architecture by providing a common interface, reducing the complexity of direct point-to-point connections
3Reliability
If a mesh-shaped second electrode layer is added to couple first electrode parts, then power supply uniformity is improved and IR drop is reduced, but the device structure and fabrication process become more complex
Solution Approach 1:
The second electrode layer is designed with a mesh-shaped structure that provides different functional qualities in different regions. The mesh pattern allows for optimized electrical connection density where needed while maintaining simplicity in other areas, achieving uniform power distribution without excessive structural complexity
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
The solution effectively reduces IR drop and prevents equipment damage from arcing discharge, maintaining uniform brightness across pixels and enhancing the reliability of the display substrate.
Implementation Method 1
the first electrode layer includes a plurality of first electrode parts spaced apart from each other and each having a block shape; each of the plurality of first electrode parts being electrically coupled to a plurality of light-emitting devices
Implementation Method 2
at least one switch element each coupling any two adjacent first electrode parts to each other; and the switch element is configured to be turned off in a fabricating process of the display substrate and turned on so that the first electrode parts are coupled together in a display stage of the display substrate
Implementation Method 3
the second electrode layer has a mesh-shaped structure and is coupled to the first electrode layer through a via hole
Data Source
AI summary
The present disclosure provides a display substrate, including: a substrate; a plurality of pixel units on the substrate, each of the pixel units having a light-emitting device therein; a power supply electrode configured to supply a power supply voltage to the light-emitting device, wherein the power supply electrode includes a first electrode layer and a second electrode layer, the second electrode layer has a mesh-shaped structure and is coupled to the first electrode layer through a via hole, and the first electrode layer includes a plurality of first electrode parts spaced apart from each other and each having a block shape, each of the first electrode parts being electrically coupled to a plurality of light-emitting devices for supplying the power supply voltage to the plurality of light-emitting devices.