Touch Array Substrate Connection Wiring Design
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Solution Overview
Problem
In In-Cell Touch display panels, the dummy wiring can short-circuit with the bottom transparent electrode due to its floating state, leading to poor touch control, especially when the critical dimension of metal wiring is large or overlay marks are offset, causing direct short-circuiting between the top and bottom transparent electrodes.
Innovation Solution
A touch array substrate design with a metal wiring layer including a touch signal line, dummy wiring, and connection wiring, where the connection wiring is smaller in critical dimension than the touch signal line and dummy wiring, and is positioned to avoid the via connecting the top and bottom transparent electrodes, with a portion of the connection wiring bent away from the via to increase distance and prevent short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the critical dimension of metal wiring is increased, then the manufacturing precision is improved, but the risk of short-circuiting between connection wiring and via increases
Solution Approach 1:
The patent divides the metal wiring layer into three distinct types of wirings (first wiring, second wiring, third wiring) with different critical dimensions. The first wiring has a larger critical dimension for manufacturing precision, while the second and third wirings have smaller critical dimensions to avoid short-circuiting with the via, thus resolving the contradiction between manufacturing precision and short-circuit risk.
Solution Approach 2:
Different regions of the metal wiring layer are assigned different critical dimensions based on their functional requirements. The first wiring near the via has a smaller critical dimension to prevent short-circuiting, while other wirings can have larger critical dimensions for better manufacturing precision. This local differentiation resolves the contradiction by optimizing each region's dimensions according to its specific needs.
2Device complexity
If the connection wiring is positioned close to the via, then the device complexity is reduced, but the risk of direct short-circuiting between top and bottom transparent electrodes increases
Solution Approach 1:
The patent segments the wiring functions by creating separate first, second, and third wirings with different roles. The second wiring is specifically designed to connect to the via while maintaining a safe distance, separating the connection function from the signal transmission function. This segmentation allows the connection wiring to be positioned close to the via for simplicity while preventing short-circuiting through dedicated spacing design.
Solution Approach 2:
The patent introduces an insulating layer as an intermediary between the metal wiring layer and the bottom transparent electrode. This insulating layer acts as a mediator that allows the connection wiring to be positioned close to the via while preventing direct electrical contact, thus reducing device complexity without increasing short-circuit risk.
3Reliability
If the dummy wiring is in contact with the bottom transparent electrode, then the static electricity accumulation is prevented, but the manufacturing precision requirement increases due to alignment sensitivity
Solution Approach 1:
The insulating layer serves as an intermediary that enables the dummy wiring to contact the bottom transparent electrode through a controlled via structure. This intermediary layer provides alignment tolerance and reduces the sensitivity to overlay errors, allowing the dummy wiring to prevent static electricity accumulation while reducing the manufacturing precision requirements.
Data Source
AI summary
A touch array substrate and a touch display panel are provided, including a base substrate, a TFT layer, a flat layer, a metal wiring layer, an insulating layer, a bottom transparent electrode, a passivation layer and a top transparent electrode. The metal wiring layer includes a touch signal line, a dummy wiring and a connection wiring connecting the touch signal line and the dummy wiring. The critical dimension of the connection wiring is smaller than the critical dimensions of the touch signal line and the dummy wiring, or a portion of the connection wiring close to the first via is bent away from the first via, to enlarge the distance between the connection wiring and the first via. The connection wiring is prevented from falling into the first via and contacting the TFT layer, and the top transparent electrode and the bottom transparent electrode are prevented from being directly short-circuited.