Gate Driving Circuit Electrostatic Discharge Protection

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Solution Overview

Problem

In the fabrication process of liquid crystal display panels, electrostatic discharges can damage the gate driving circuit due to the introduction of charges into the switching transistor through the gate line, causing damage to the dense metal pattern areas.

Innovation Solution

The solution involves designing a gate driving circuit where the gate pad and contact portion are spaced apart to prevent direct electrical connection, using a capacitor and connecting electrodes to isolate the electrostatic discharge, and employing a method to manufacture the thin film transistor substrate that includes forming a gate metal pattern with a specific structure to prevent electrostatic discharge introduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the gate pad and contact portion are directly connected to form the gate metal pattern group, then the fabrication process is simple and manufacturing efficiency is high, but electrostatic discharge from the pixel area can be introduced into the gate driving circuit through the gate line, causing damage to the switching transistor and metal pattern

Engineering Contradiction:
Improvefabrication efficiencyVSAvoidelectrostatic discharge damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The gate metal pattern is segmented into separate components: the gate pad and the contact portion are spaced apart rather than directly connected. This segmentation prevents the continuous conductive path that would allow electrostatic discharge to reach the gate driving circuit, while still maintaining electrical connection through alternative means (via the capacitor and connecting electrode structure described in the patent).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A capacitor and connecting electrode structure is introduced as an intermediary between the gate pad and contact portion. This intermediary component isolates the gate driving circuit from direct exposure to electrostatic discharge while still allowing the circuit to function properly. The capacitor acts as a protective barrier that blocks harmful electrostatic charges from reaching sensitive circuit components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the gate pad and contact portion are spaced apart to prevent electrostatic discharge introduction, then circuit reliability is improved, but the fabrication process becomes more complex and manufacturing difficulty increases

Engineering Contradiction:
Improvecircuit integrityVSAvoidfabrication complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The gate metal pattern is divided into separate segments (gate pad and contact portion) that are spaced apart. This segmentation approach, while improving reliability, does increase fabrication complexity as it requires precise positioning and additional processing steps to ensure proper spacing and alignment of the separated components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The introduction of a capacitor and connecting electrode as an intermediary structure between the spaced-apart gate pad and contact portion adds significant fabrication complexity. This intermediary component requires additional deposition, patterning, and alignment steps in the manufacturing process, making fabrication more difficult while achieving the reliability goal of preventing electrostatic discharge damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 damage to the gate driving circuit by isolating electrostatic discharges, ensuring the circuit's integrity and preventing driving failures in liquid crystal displays.

Implementation Method 1

electrostatic discharge generated in the pixel area is introduced into a gate pad formed at one end of the gate line through the gate line

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentEP1942525B1Gate driving circuit, liquid crystal display having the same , and manufacturing method for thin film transistor substrate
Publication Date: 2017.11.15 SAMSUNG DISPLAY CO LTD
  • EP1942525B1 patent drawingFigure 1
  • EP1942525B1 patent drawingFigure 2
  • EP1942525B1 patent drawingFigure 3

AI summary

A gate driving circuit including a plurality of stages dependently connected to one another. Each stage comprises a gate pad formed at one end of a gate line; a pull-up transistor outputting a gate driving signal for driving the gate line; a capacitor formed with a dielectric substance disposed between a first electrode connected to a gate electrode of the pull-up transistor and a second electrode connected to a drain electrode of the pull-up transistor; a first connecting electrode connecting the gate pad to the second electrode; a holding transistor connected to the pull-up transistor to maintain a voltage level of the gate driving signal; a switching transistor connected to the pull-up transistor and the capacitor to control the holding transistor through the gate driving signal; and a second connecting electrode connecting the second electrode to the gate electrode of the switching transistor.