Fringe Field Switching TFT Substrate Multiple-Layer Gate Line
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Solution Overview
Problem
The complex manufacturing process of thin film transistor substrates in liquid crystal display panels, particularly in fringe field switching type, leads to increased manufacturing costs and process complexity due to the requirement of multiple mask processes, including semiconductor processes.
Innovation Solution
A thin film transistor substrate with a multiple-layer structure for the gate line and common electrode, along with a simplified four-mask process fabrication method, which includes forming a first mask pattern group, a gate insulating film, a source/drain metal pattern, a protective film, and a pixel electrode, to reduce the number of mask processes and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple mask processes including semiconductor processes are used to form thin film transistor substrate, then the liquid crystal display panel can be manufactured with required performance, but the fabricating process becomes complex and manufacturing cost increases
Solution Approach 1:
The patent merges the formation of gate line and common electrode into a single mask process by using a multiple-layer conductive structure where both patterns are formed simultaneously. This combines what were previously separate mask processes into one unified operation, reducing overall process complexity while maintaining the required display performance
Solution Approach 2:
The multiple-layer conductive structure serves multiple functions: it forms both the gate line and common electrode patterns in a single mask process, provides proper electrical connectivity, and enables fringe field switching functionality. This multi-functional approach eliminates the need for separate specialized mask processes for each component
2Reliability
If multiple mask processes are used to form thin film transistor substrate, then the liquid crystal display panel can be manufactured with required performance, but manufacturing cost increases
Solution Approach 1:
By merging the formation of gate line and common electrode into a single mask process, the patent reduces the total number of process steps required. This consolidation directly lowers manufacturing costs by reducing mask alignment operations, photo-resist materials, and process time while maintaining display performance requirements
3Reliability
If multiple mask processes are used to form thin film transistor substrate, then the liquid crystal display panel can be manufactured with required performance, but productivity decreases
Solution Approach 1:
The patent combines multiple mask processes into a single operation, thereby reducing the total number of fabrication steps. This consolidation increases productivity by eliminating repeated mask alignment, photo-resist coating, and development cycles, allowing for faster manufacturing while maintaining required display performance
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 simplifies the fabrication process, reduces material and equipment costs, and enhances productivity while maintaining the performance of the fringe field switching type liquid crystal display panel.
Implementation Method 1
The liquid crystal 24 having a dielectric anisotropy is rotated in accordance with an electric field formed by a data signal from the pixel electrode 22 and a common voltage Vcom from the common electrode 8 to control light transmittance
Implementation Method 2
one mask process includes a number of processes such as thin film deposition (coating), cleaning, photolithography (hereinafter, photo process), etching, photo-resist stripping and inspection processes
Implementation Method 3
The thin film transistor 18 applies a data signal from the data line 16 to the pixel electrode 22 in response to a gate signal from the gate line 14
Data Source
AI summary
A thin film transistor substrate of fringe field switching type and a fabricating method thereof for simplifying a process are disclosed. In the thin film transistor substrate of fringe field switching type, a gate line has a multiple-layer structure and includes a transparent conductive layer. A data line crosses the gate line to define a pixel area. A thin film transistor is connected to the gate line and the data line. A common line is provided in a multiple-layer structure and in parallel to the gate line. A common electrode is formed by an extension of a transparent conductive layer of the common line at said pixel area. A pixel electrode is connected to the thin film transistor to form a fringe field with the common electrode in the pixel area.