TFT Substrate Drain Electrode Plates for Static Protection

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Solution Overview

Problem

Liquid crystal display devices tend to produce ghost images during the display of moving pictures, and increasing the frame frequency to above 60 Hz can lead to vertical line stains or malfunctions due to static electricity, especially when multiple sub-pixels are controlled through multiple gate and data lines, reducing charging rates.

Innovation Solution

A thin film transistor substrate design with alternate driving, where pixel voltages of different polarities are applied to sub-pixel electrodes, and the pixel contact areas of drain electrodes are increased to prevent static electricity malfunctions, featuring a configuration with multiple gate and data lines, thin film transistors, and storage electrode plates that overlap drain electrodes to enhance electrostatic capacity and prevent static discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If multiple sub-pixels are controlled through multiple gate lines and data lines to increase frame frequency above 60 Hz, then the display refresh rate is improved, but the charging rate of each pixel is reduced causing vertical line stains and static electricity malfunctions

Engineering Contradiction:
Improveframe frequencyVSAvoidcharging rate
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The pixel electrode is divided into multiple sub-pixel electrodes (first pixel electrode and second pixel electrode) within each pixel region. Each sub-pixel electrode is independently controlled by separate thin film transistors and connected to different data lines, enabling parallel charging operations that maintain high charging rates while supporting increased frame frequencies

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces alternating polarity driving in the vertical dimension by applying different polarities to adjacent pixel regions. This dimensional approach to signal alternation enables dot inversion that prevents ghost images while maintaining sufficient charging time through the expanded electrode plate structures

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If multiple sub-pixels are controlled through multiple gate lines and data lines, then the frame frequency is increased, but static electricity malfunctions occur due to reduced charging capacity

Engineering Contradiction:
Improveframe frequencyVSAvoidstatic electricity
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent provides beforehand cushioning against static electricity by increasing the contact areas of drain electrodes and introducing drain electrode plates that extend between drain electrodes. This preparatory expansion of conductive structures creates sufficient charging capacity to prevent static electricity accumulation even at high frame frequencies

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the physical parameters of the electrode structures by increasing contact areas and extending drain electrode plates. These parameter modifications enhance the charging capacity and electrical conductivity, providing sufficient charge storage to prevent static electricity malfunctions while operating at elevated frame frequencies

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If dot inversion is implemented through alternate driving with different polarities, then ghost images are prevented, but the device complexity increases

Engineering Contradiction:
Improveghost imagesVSAvoiddriving scheme
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements periodic action through alternate driving schemes where pixel voltages with different polarities are applied to sub-pixel electrodes in neighboring pixel regions. This periodic alternation of polarity prevents ghost images by inverting the display pattern, and the systematic nature of the alternation allows for manageable device complexity through regular, predictable signal sequences

Inventive Principle:
Principle #19Periodic action

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 effectively prevents static electricity damage and enables alternate driving for dot inversion, reducing the likelihood of vertical line stains and ensuring sufficient charging time for pixels even at higher frame frequencies, thereby improving display quality.

Implementation Method 1

a plurality of storage electrode plates each of which partially overlaps the first and second electrode plates in each unit pixel region

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a liquid crystal display device controls the transmittance of light by controlling the orientation of the liquid crystal molecules

Methodology Applied
Scientific EffectOptical anisotropy: Anisotropy

Implementation Method 3

pixel voltages having different polarities are applied to sub-pixel electrodes

Methodology Applied
Scientific EffectElectric field: Electric Field

Data Source

PatentEP1927888B1Thin film transistor substrate and display device therefor
Publication Date: 2015.06.03 SAMSUNG DISPLAY CO LTD
  • EP1927888B1 patent drawingFigure 1
  • EP1927888B1 patent drawingFigure 2
  • EP1927888B1 patent drawingFigure 3

AI summary

The invention relates to a thin film transistor substrate and a display device including the same, and provides a thin film transistor substrate and a display device including the same, which can prevent damage of elements due to static electricity by forming, in each unit pixel region where a pair of first (170a) and second (170b) pixel electrodes, a pair of first (150a) and second (150b) drain electrode plates that are connected to the first and second pixel electrodes and connected to drain terminals of thin film transistors, and can obtain a dot inversion driving effect through line inversion driving by connecting the first drain electrode in one pixel region to the first drain electrode plate, connecting the second drain electrode in the one unit pixel region to the second drain electrode plate, connecting a first drain electrode in another unit pixel region neighboring the one unit pixel region to the second drain electrode plate, and connecting a second drain electrode in another unit pixel region to the first drain electrode plate.