Organic TFT ESD Protection via Integrated Gate Electrode

Solution Overview

Problem

The application of organic thin film transistors (TFTs) to liquid crystal display (LCD) devices is hindered by difficulties in fabrication and their limited use in electrostatic discharge (ESD) protection elements, leading to complex manufacturing processes and increased costs.

Innovation Solution

The integration of three organic TFTs in an ESD protection element configuration, where the drain electrode of the first TFT and the gate electrode of the third TFT are connected, and the source electrode of the second TFT and the gate electrode of the third TFT are connected, with each TFT having a gate electrode, source electrode, and drain electrode, forming a network that includes a common voltage line and data or gate lines, facilitating ESD protection within the LCD.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If organic TFTs are applied to ESD protection elements, then manufacturing cost and process complexity are reduced, but fabrication difficulties prevent favorable results

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidfabrication success rate

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent merges the gate electrode and auxiliary electrode into a single integrated structure. The gate electrode serves dual functions: as the control electrode for the TFT and as the auxiliary electrode for ESD protection. This integration eliminates the need for separate auxiliary electrodes and their corresponding contact holes, simplifying the manufacturing process while ensuring reliable electrical connections for both pixel operation and ESD protection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gate electrode is designed to perform multiple functions simultaneously: it controls the TFT switching operation and provides the auxiliary electrode function for ESD protection. This multi-functionality reduces the total number of components and manufacturing steps while maintaining the reliability of both pixel operation and ESD protection mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate auxiliary electrodes are added to organic TFTs for ESD protection, then ESD protection is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

ImproveESD protection capabilityVSAvoidnumber of electrodes and contact holes

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the gate electrode and auxiliary electrode into a single integrated structure. The gate electrode serves dual functions: as the control electrode for the TFT and as the auxiliary electrode for ESD protection. This integration eliminates the need for separate auxiliary electrodes and their corresponding contact holes, simplifying the manufacturing process while ensuring reliable electrical connections for both pixel operation and ESD protection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gate electrode is designed to perform multiple functions simultaneously: it controls the TFT switching operation and provides the auxiliary electrode function for ESD protection. This multi-functionality reduces the total number of components and manufacturing steps while maintaining the reliability of both pixel operation and ESD protection mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If typical TFTs are used for ESD protection elements while organic TFTs are used for pixel TFTs, then ESD protection is ensured, but manufacturing process becomes complicated and cost increases

Engineering Contradiction:

ImproveESD protection functionVSAvoidmanufacturing process uniformity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent enables organic TFTs to perform both pixel switching and ESD protection functions through the integrated gate electrode structure. This universality allows the same organic TFT fabrication process to be used for both pixel TFTs and ESD protection elements, eliminating the need for separate manufacturing processes and reducing overall manufacturing complexity and cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the gate electrode and auxiliary electrode into a single integrated structure. The gate electrode serves dual functions: as the control electrode for the TFT and as the auxiliary electrode for ESD protection. This integration eliminates the need for separate auxiliary electrodes and their corresponding contact holes, simplifying the manufacturing process while ensuring reliable electrical connections for both pixel operation and ESD protection.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8174635B2Method of manufacturing a liquid crystal display having top gate thin film transistors wherein each gate electrode contacts an auxilliary electrode

Publication Date: 2012.05.08 LG DISPLAY CO LTD

AI summary

An electrostatic discharge protection element, a liquid crystal display device having the same, and a manufacturing method. A first ESD organic TFT, a second ESD organic TFT, a third ESD organic TFT each have a gate electrode, a source electrode and a drain electrode in which the source electrode and drain electrode of the first and second ESD organic TFTs and the gate electrode of the third ESD organic TFT are electrically connected. The gate electrode and the source electrode of the first ESD organic TFT are electrically connected to a first array line and the gate electrode and the drain electrode of the second ESD organic TFT are electrically connected to a second array line. The source electrode of the third ESD organic TFT is electrically connected to a data line or a gate line and the drain of the third ESD organic TFT are electrically connected to a common voltage line.