TFT Substrate Wiring Configuration for LCD Static Electricity Shielding
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Solution Overview
Problem
In liquid crystal display devices, the rubbing step during alignment film formation generates charges in the conductive region, leading to dielectric breakdown in peripheral circuits due to static electricity, particularly affecting thin film transistors directly supplied with signals from adjacent terminals.
Innovation Solution
The liquid crystal display device design includes a TFT substrate with a pixel circuit and peripheral circuits, where the counter substrate has a transparent conductive film covering the pixel circuit area, and wiring connections are made to distribute the ground potential and signals to peripheral circuits in a way that extends the wiring length, reducing the risk of dielectric breakdown by increasing resistance and attenuating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a transparent conductive film is provided on the counter substrate to shield static electricity, then the shielding effect is improved, but charges generated during rubbing extend the conductive region and cause dielectric breakdown in peripheral circuits
Solution Approach 1:
The conductive region is segmented into multiple separate conductive regions rather than a single continuous region. This segmentation limits the spread of generated charges, preventing them from extending too far and causing dielectric breakdown in peripheral circuits while maintaining the shielding effect over the display area.
Solution Approach 2:
An insulating film is introduced as an intermediary layer between the conductive region and the peripheral circuits. This insulating film acts as a mediator that prevents direct contact and charge transfer from the conductive region to the peripheral circuits, thereby protecting against dielectric breakdown while allowing the conductive film to maintain its shielding function.
2Object-affected harmful factors
If the conductive region is extended to cover more area for better shielding, then the shielding effectiveness is improved, but more charges are generated during rubbing and increase the risk of dielectric breakdown
Solution Approach 1:
The conductive region is divided into multiple separate regions that are distributed across the counter substrate. This segmentation allows the shielding to cover the necessary display area while limiting the continuous path for charge generation during rubbing, thereby reducing the total charge accumulation that could lead to dielectric breakdown.
Solution Approach 2:
The conductive film is provided with different characteristics in different regions. The conductive regions are strategically positioned to provide shielding where needed while leaving other areas with different properties (such as insulating film) that reduce charge generation during rubbing operations.
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 reduces the occurrence of dielectric breakdown in peripheral circuits during the rubbing step by distributing static electricity and reducing the risk of electrostatic damage to thin film transistors, particularly those directly supplied with signals.
Implementation Method 1
a transparent conductive film is provided on an outer surface (surface on a side opposite to the liquid crystal layer) of the counter substrate for shielding from the static electricity or the like. The transparent conductive film is connected to a terminal for conduction provided on the TFT substrate through a conductive member
Implementation Method 2
in a rubbing step of forming an alignment film of the liquid crystal layer, generation of charges in the conductive region due to fibers for rubbing
Implementation Method 3
The transparent conductive film is connected to a terminal for conduction (hereinafter referred to as conductive region) provided on the TFT substrate through a conductive member
Data Source
AI summary
The TFT substrate includes a conductive region electrically conducted to the transparent conductive film and a terminal region, on a first side not covered with the counter substrate. The terminal region includes a ground terminal connected to the conductive region and an adjacent terminal which is adjacent to the ground terminal and supplies signals or power source to the peripheral circuit. The adjacent terminal is connected to the peripheral circuit through a first wiring installed along a third side of the TFT substrate toward a second side facing the first side. The first wiring is extended to a middle point of the third side and then connected to the peripheral circuit.