Thin Film Transistor Electrostatic Protection via Segmented Wiring
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Solution Overview
Problem
Conventional liquid crystal display devices face issues with electrostatic breakdown of thin film transistors, particularly in video signal drive and scanning signal drive circuits, which complicates circuit operation testing and reduces manufacturing yield.
Innovation Solution
A manufacturing method involving the formation of a second wiring layer that connects thin film transistors outside the display region, allowing for the generation of drive signals and including through holes in insulating films to cut the second wiring, preventing electrostatic breakdown and enabling circuit operation testing before the cut-off stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitive electrode with wide width is formed parallel to gate bus line to protect thin film transistor against electrostatic breakdown, then thin film transistor reliability is improved, but gate bus line and drain bus line become short-circuited causing loss of information
Solution Approach 1:
The substrate is divided into a display region and a non-display region. The capacitive electrode is formed only in the non-display region, separating the electrostatic protection function from the display function. This segmentation allows circuit operation testing to be performed in the display region without interference from the capacitive electrode in the non-display region.
Solution Approach 2:
The capacitive electrode is extracted from the display region and placed only in the non-display region. This extraction removes the harmful short-circuit effect from the display region while preserving the electrostatic protection function in the non-display region, enabling circuit operation testing.
2Adaptability or versatility
If thin film transistors are formed in video signal drive circuit or scanning signal drive circuit above first substrate, then device functionality is improved, but possibility of electrostatic breakdown increases
Solution Approach 1:
The substrate is segmented into display and non-display regions, with capacitive electrodes formed only in the non-display region. This spatial segmentation protects the drive circuits in the display region from electrostatic breakdown while maintaining their full functionality.
Solution Approach 2:
The capacitive electrode acts as an intermediary protective structure in the non-display region that absorbs or redirects electrostatic charges away from the thin film transistors in the drive circuits, preventing breakdown while allowing the drive circuits to function normally.
3Loss of information
If capacitive portion and panel main body are cut and separated in final step, then circuit operation test can be performed, but manufacturing process complexity increases
Solution Approach 1:
The substrate is segmented into display and non-display regions with the capacitive electrode confined to the non-display region. This segmentation eliminates the need for final-stage cutting and separation, as the capacitive electrode's location naturally prevents short-circuits during testing.
Solution Approach 2:
The capacitive electrode is extracted from the display region and positioned only in the non-display region, removing the need for post-assembly cutting operations. This extraction simplifies the manufacturing process by eliminating the final-step separation requirement.
Data Source
AI summary
A technique that can prevent breakdown of a thin film transistor due to static electricity is provided. A manufacturing method of a display device includes, in forming a plurality of thin film transistors constituting a drive circuit outside a display region as an assembly of pixels, forming a first wiring that is connected to gate electrodes of the thin film transistors to cause the thin film transistors to perform generating operation of a drive signal and a second wiring that connects gate electrodes of the thin film transistors adjacent to one another in the forming region of the drive unit in the same layer as the first wiring, and cutting the second wiring after forming the connected thin film transistors.