TFT-LCD Protection Circuit for Data Line Charge Discharge

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Solution Overview

Problem

Thin Film Transistor liquid crystal display (TFT-LCD) panels experience shutdown flicker and electrostatic discharge damage due to charge accumulation on data lines during power failure, as electric charges are not released in time.

Innovation Solution

A protective circuit comprising a control sub-circuit and a discharge sub-circuit, where TFTs are connected to data lines and output signal lines to release charges via a common voltage signal, preventing charge accumulation and electrostatic discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If no protective circuit is added, then device complexity is low, but charge accumulation causes shutdown flicker and electrostatic discharge damage

Engineering Contradiction:
Improveprotection against charge accumulation and electrostatic dischargeVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a protective circuit as an intermediary component between the data lines and the pixel units. This circuit includes discharge paths and control circuits that actively manage charge accumulation, preventing electrostatic discharge damage while maintaining the existing display panel structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective circuit performs preliminary discharge of electric charges from data lines before power failure occurs. By continuously monitoring and discharging accumulated charges through controlled paths, the system prevents the harmful effects of charge accumulation and electrostatic discharge before they can damage the display panel.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If protective circuit is added, then protection against charge accumulation is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveprotection against charge accumulationVSAvoidcircuit integration
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The protective circuit is merged with the existing data line structure by integrating discharge paths into the same conductive layers. The control circuits are combined with the gate driver circuits, allowing the protective function to be added without requiring completely separate manufacturing processes or additional layered structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protective circuit components serve multiple functions: they provide discharge paths for charge accumulation protection, act as control circuits for managing pixel operations, and integrate with existing gate driver functionality. This multi-functionality reduces the need for separate dedicated components, simplifying manufacturing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 protective circuit effectively prevents flickering and electrostatic discharge damage by ensuring timely release of electric charges on data lines during power-off, enhancing the reliability of TFT-LCD display panels.

Implementation Method 1

a first capacitor, configured to have a first endpoint connected to the first transistor's gate and a second endpoint connected to a voltage source

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

a second capacitor, configured to have a first endpoint connected to the second transistor's gate and a second endpoint connected to a voltage source

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 3

a touch electrode and an emission electrode, which are configured to overlap with each other

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3633665B1Protection circuit, array substrate and display panel
Publication Date: 2024.05.01 BOE TECHNOLOGY GROUP CO LTD
  • EP3633665B1 patent drawingFigure 1~2
  • EP3633665B1 patent drawingFigure 3~4
  • EP3633665B1 patent drawingFigure 5~6

AI summary

There is provided a protective circuit, an array substrate and a display panel. The protective circuit includes: a control sub-circuit (101), having a first end electrically connected to a voltage input terminal (10) and a second end configured to output a common voltage signal supplied by the voltage input terminal (10); and a discharge sub-circuit (102), having a first end electrically connected to the second end of the control sub-circuit (101) and a second end electrically connected to at least one data line (DL1-DLN). The discharge sub-circuit (102) releases electric charges on the at least one data line (DL1-DLN) under the control of the common voltage signal supplied from the control sub-circuit (101).