COF Welded Lead Line Corrosion Protection in Display Panels
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Solution Overview
Problem
In TFT-LCD display panels, exposed copper welded lead lines on the COF substrate are prone to corrosion due to electrochemical reactions with ions in the environment, leading to signal transmission issues.
Innovation Solution
The implementation of through holes in the welding region between adjacent terminal wires on the array substrate, exposing a metal layer, which either aluminum or copper, to share the risk of corrosion, thereby delaying the corrosion process of the copper lead lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the COF substrate is welded to connect the PCB and liquid crystal panel, then signal transmission is enabled, but the exposed welded lead lines are prone to corrosion from ions in the environment
Solution Approach 1:
The patent applies the inert atmosphere principle by filling the sealing cavity with inert gas (nitrogen or rare gas) to create a protective environment that prevents ions from reaching and corroding the exposed welded lead lines. The sealing cavity acts as a barrier that isolates the vulnerable copper surfaces from the harmful external environment while maintaining signal transmission functionality.
2Object-affected harmful factors
If tuffy resin is coated on the lateral side of the thin-film transistor, then terminal wires are protected from corrosion, but the back surface of the COF substrate remains unprotected
Solution Approach 1:
The patent transitions from two-dimensional surface coating (tuffy resin on lateral sides) to three-dimensional spatial protection by creating a sealing cavity that encloses the vulnerable areas. This dimensional change allows protection of the back surface and exposed lead lines without adding complex manufacturing steps, as the cavity structure itself provides the protective environment.
3Reliability
If through holes are formed in the welding region to expose the metal layer, then corrosion risk is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by forming the through holes and creating the sealing cavity during the manufacturing process before the product is put into service. This ensures that the protective structure is already in place to prevent corrosion, eliminating the need for later maintenance or repair while maintaining manufacturing efficiency through integrated process design.
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 method effectively reduces the risk of corrosion and breakage of the welded lead lines, extending the product's lifespan and maintaining signal transmission integrity.
Implementation Method 1
When ions are present in air in the environment, an electrochemical reaction occurs, and the welded lead lines will be corroded
Data Source
AI summary
A display panel including an array substrate and a COF substrate is provided. The COF is provided with a plurality of welded lead lines. The array substrate includes a metal layer disposed on a surface of the substrate, a silicon nitride layer disposed on a surface of the metal layer, and a plurality of terminal wires disposed in a spaced arrangement in a welding region on a surface of the second silicon nitride layer. The welding region between the adjacent terminal wires is provided with through holes, which expose the metal layer. The risk of corrosion and breakage of the welded lead lines on the COF substrate is effectively reduced.