Single Via Hole Display Substrate Design
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Solution Overview
Problem
High via hole distribution density in TFT-LCD display devices leads to issues like mura formation and fragile electrode patterns, resulting in circuit breakage and abnormal display due to the need for two via holes to connect metal layers.
Innovation Solution
A display substrate design where a single via hole connects different metal layers, with the second electrode pattern located within the via hole, reducing distribution density and eliminating the need for the electrode pattern to be at steps and corners, thereby minimizing corrosion and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two via holes are used to connect different metal layers, then the connection between metal layers is achieved, but the distribution density of via holes becomes too high, resulting in mura formation and increased probability of disadvantageous phenomena
Solution Approach 1:
The patent merges the functions of two separate via holes into a single via hole structure. The first via hole connects the first electrode pattern to the second metal layer, while the second via hole connects the second electrode pattern to the first metal layer, both passing through the same opening in the insulating layers, thereby reducing via hole distribution density while maintaining connection reliability
Solution Approach 2:
The patent implements a nested structure where the first and second via holes are positioned within the same opening. The first electrode pattern and second electrode pattern are arranged such that they both extend into the via hole region, creating a nested configuration that reduces the number of separate via hole openings needed
2Reliability
If two via holes are used to connect different metal layers, then the connection between metal layers is achieved, but the second electrode pattern span distance becomes large, making it fragile and prone to corrosion and circuit breakage
Solution Approach 1:
By merging the via hole structures, the patent reduces the span distance of the second electrode pattern. The second electrode pattern only needs to extend into the shared via hole opening rather than spanning between two separate via holes, reducing its exposure to corrosive environments at steps and corners
Solution Approach 2:
The patent introduces an intermediary structure where the first electrode pattern acts as a mediator within the via hole. The first electrode pattern connects to the second metal layer and provides a protected pathway for the second electrode pattern to reach the first metal layer, reducing the second electrode pattern's exposure to corrosive environments
Data Source
AI summary
A display substrate comprises a base substrate and a first metal layer, a second metal layer, a first electrode pattern, a second electrode pattern, a first insulating layer and a second insulating layer formed above the base substrate. The first insulating layer is located over the first metal layer, the second insulating layer is located above the first insulating layer, the first electrode pattern and the second metal layer are located between the first insulating layer and the second insulating layer; a via hole is arranged at a position directly above the first metal layer to which the first insulating layer and the second insulating layer correspond, one end of the first electrode pattern is connected with the second metal layer, the other end extends into the via hole, the second electrode pattern is in the via hole and connected with the first electrode pattern and the first metal layer.