TFT Substrate Corrosion Prevention via ITO-Mo Composite Terminals
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Solution Overview
Problem
Conventional thin film transistor substrates for liquid crystal displays are prone to metal corrosion, particularly in the gate and data terminals, which can spread and affect the display quality after the test circuit is cut off, due to the vulnerability of metals like molybdenum and aluminum to air corrosion.
Innovation Solution
The implementation of a thin film transistor substrate design featuring two independent terminal portions connected by an anticorrosive material, such as indium tin oxide (ITO), and curved or S-shaped leads to reduce exposure and delay corrosion, thereby preventing its spread to the display region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal materials like molybdenum and aluminum are used for gate leads and data leads, then electrical conductivity and ease of manufacture are improved, but susceptibility to air corrosion increases, leading to quality deterioration after test circuit cutoff
Solution Approach 1:
The patent applies composite materials by combining ITO (indium tin oxide) layer and Mo (molybdenum) layer to form a composite lead structure. The ITO layer provides corrosion resistance while the Mo layer provides electrical conductivity. This composite structure resolves the contradiction between corrosion resistance and ease of manufacture, as the multi-layer composite can be deposited using standard sputtering processes while achieving both electrical performance and corrosion resistance.
Solution Approach 2:
The patent applies local quality by using different materials for different parts of the lead structure. The ITO layer is applied specifically at the exposed terminal portions that are most susceptible to corrosion, while the Mo layer provides the conductive path. This localized application of corrosion-resistant material resolves the contradiction by protecting only the critical areas without requiring complete redesign of the entire lead structure.
2Reliability
If straight leads are used, then ease of manufacture is improved, but exposure area to air is maximized, accelerating corrosion
Solution Approach 1:
The patent applies curvature by designing the gate leads and data leads with bent or curved configurations instead of straight lines. This curvature reduces the exposed surface area of the leads to air, thereby slowing down the corrosion process. The curved leads maintain electrical connectivity while presenting a smaller attack surface to corrosive environmental factors, resolving the contradiction between corrosion delay and manufacturing complexity.
3Productivity
If test circuit is cut off after testing, then productivity is improved by enabling subsequent processes, but exposed lead sections become vulnerable to corrosion that can spread to display region
Solution Approach 1:
The patent applies preliminary action by pre-coating the gate leads and data leads with an ITO layer before the leads are cut off from the test circuit. This preliminary protective coating is applied in advance during the manufacturing process, ensuring that when the leads are later exposed after cutoff, they already have corrosion protection. This resolves the contradiction by preparing the protection beforehand, allowing both high productivity and reliability.
Solution Approach 2:
The patent applies the concept of inert environment by using ITO (indium tin oxide), which is chemically inert and resistant to oxidation and corrosion. The ITO layer creates a protective barrier that isolates the reactive Mo metal from the corrosive air environment. This inert protective layer allows the leads to be cut and exposed without immediate corrosion, maintaining both production efficiency and long-term reliability.
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 design effectively prevents metal corrosion from spreading to the display area, ensuring the quality of the liquid crystal display device by using anticorrosive materials and lead configurations that reduce exposure and delay corrosion, thus maintaining normal signal transfer and panel reliability.
Implementation Method 1
the metal molybdenum used for forming the gate leads 21 is a metal which is easy to be corroded... the first signal terminal portion and the second signal terminal portion are connected electrically by a signal end electrode made of anticorrosive material
Data Source
AI summary
The invention provides a thin film transistor (TFT) substrate comprises a plurality of gate lines, a plurality of data lines, gate terminals, data terminals and thin film transistors as well as a liquid crystal display (LCD) device having the TFT substrate. The gate terminal and/or data terminal contain a first portion and a second portion, and the first potion and the second portion are connected electrically with an end electrode made of a material which is anticorrosive in the air. The thin film transistor substrate of the invention prevents the spreading of the metal corrosion occurred at the gate leads to the display region of the LCD, and therefore the quality of the LCD device can be ensured.