Dummy Gate Line Inverted Waveform LCD Panel

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Solution Overview

Problem

In liquid crystal display devices with in-cell type touch panels, uneven voltage distribution between driving and receiving electrodes leads to conspicuous striped patterns due to parasitic capacitance and voltage deviations, affecting image quality.

Innovation Solution

A dummy gate line with an inverted waveform is introduced, parallel to the gate lines and perpendicular to touch electrodes, to reduce common voltage variations and pixel voltage fluctuations, thereby eliminating striped patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If receiving electrodes are formed parallel to and overlap with gate lines to enable touch sensing, then touch sensing function is achieved, but parasitic capacitance is generated causing voltage deviation and striped patterns

Engineering Contradiction:
Improvetouch sensing functionVSAvoidparasitic capacitance causing voltage deviation
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

An insulating film is introduced as an intermediary layer between the gate lines and receiving electrodes. This insulating film acts as a mediator that electrically isolates the two conductive elements, preventing parasitic capacitance formation while allowing the receiving electrodes to maintain their overlapping arrangement with gate lines for touch sensing functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful parasitic capacitance effect is extracted and eliminated by separating the gate lines and receiving electrodes through the insulating film. This extraction removes the unwanted electrical coupling between these elements while preserving their spatial arrangement needed for touch sensing.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If driving electrodes are arranged perpendicular to gate lines for optimal touch sensing, then touch sensing accuracy is improved, but vertical striped patterns become more conspicuous

Engineering Contradiction:
Improvetouch sensing accuracyVSAvoidvisible striped patterns
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The insulating film serves as a mediator that prevents electrical coupling between gate lines and driving electrodes arranged perpendicular to them. This eliminates the parasitic capacitance that causes voltage deviation and subsequent vertical striped patterns, while maintaining the perpendicular arrangement optimal for touch sensing accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If common voltage is supplied to both driving and receiving electrodes during image display, then electrode functionality is maintained, but uneven voltage distribution causes brightness patterns and stripes

Engineering Contradiction:
Improveelectrode functionalityVSAvoidvoltage uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The insulating film prevents parasitic capacitance formation that causes uneven voltage distribution. By electrically isolating the gate lines from the touch electrodes, it ensures that common voltage is distributed uniformly to both driving and receiving electrodes during image display, eliminating brightness patterns and stripes while maintaining electrode functionality.

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

The implementation of a dummy gate line with an inverted waveform effectively minimizes voltage variations and luminance differences across pixels, suppressing the appearance of striped patterns along touch electrodes perpendicular to the gate lines, enhancing image quality.

Implementation Method 1

parasitic capacitance may be generated between the gate lines and the driving electrodes TX and also between the gate lines and the receiving electrodes RX

Methodology Applied
Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentEP3029666B1Liquid crystal display panel and liquid crystal display device using the same
Publication Date: 2019.08.21 LG DISPLAY CO LTD
  • EP3029666B1 patent drawingFigure 1
  • EP3029666B1 patent drawingFigure 2~3
  • EP3029666B1 patent drawingFigure 4

AI summary

A liquid crystal display panel (100) and a liquid crystal display device having the liquid crystal display panel (100) are provided in which a dummy gate line (DGL) outputting a dummy gate pulse (DGP) having an inverted waveform of a gate pulse (GP) is formed to be parallel to gate lines (GL) outputting the gate pulses (GP) and to be perpendicular to touch electrodes supplied with a common voltage (Vcom).