LCD Third Common Electrode Line Residual DC Discharge

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Solution Overview

Problem

In IPS-mode LCDs, residual direct current (DC) along the third common electrode line causes image quality deterioration due to afterimages and flickers, as existing static electricity protection patterns block the emission of this residual DC, preventing it from being properly discharged outside.

Innovation Solution

The third static electricity protection pattern is formed on one side of the third common electrode line, and a conductive or metal pattern is integrated on the other side to allow residual DC to be emitted outside when the power is off, replacing the traditional static electricity protection patterns that blocked its emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If static electricity protection patterns are formed on both sides of the third common electrode line, then static electricity protection is improved, but residual DC emission is blocked causing image quality deterioration

Engineering Contradiction:

Improvestatic electricity protectionVSAvoidresidual DC accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different patterns to different locations of the third common electrode line: a static electricity protection pattern (diode structure) on one side and a conductive pattern on the other side. This local differentiation allows the same structure to serve dual functions: protecting against static electricity while enabling residual DC emission, thereby resolving the contradiction between protection and emission requirements

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The third common electrode line is segmented into two functional zones: one side with static electricity protection pattern and the other side with conductive pattern. This segmentation allows independent optimization of each zone's function, enabling simultaneous achievement of static electricity protection and residual DC emission without mutual interference

Inventive Principle:

Principle #1Segmentation

2Reliability

If conventional static electricity protection patterns are used on the third common electrode line, then device protection is improved, but afterimages and flickers occur due to blocked DC emission

Engineering Contradiction:

Improvedevice protectionVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of blocking DC emission on both sides as in conventional designs, the patent inverts the approach by blocking DC on only one side while leaving the other side open for DC emission. This inverted configuration maintains protection functionality while eliminating the harmful effect of trapped residual DC, thereby improving image quality without sacrificing device protection

Inventive Principle:

Principle #13The other way round (Inversion)

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 solution effectively removes residual DC, preventing afterimages and flickers, thereby enhancing image quality by ensuring proper discharge of residual DC from the LCD panel.

Implementation Method 1

the third common electrode line has a static electricity protection pattern formed on one side thereof

Methodology Applied

Scientific EffectDiode function: Diode

Implementation Method 2

a conductive or metal pattern is integrated on the other side to allow residual DC to be emitted outside

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS7525607B2LCD device for removing static electricity having first and second common lines interconnected with a third common line through a protection diode means at the first common line end and a conductive means at the second common line end

Publication Date: 2009.04.28 LG DISPLAY CO LTD

AI summary

An LCD display cable of removing a residual direct current is disclosed. The LCD includes an LC panel for displaying an image, a first and a second common electrode line, a third common electrode line, gate lines, and data lines. The first and second common electrode lines are vertically arranged at left and right of the LC panel. The third common electrode line is connected between the first and second common electrode lines. The gate lines are arranged in parallel with the third common electrode line. The data lines are arranged perpendicularly to the third common electrode line. The third common electrode line has a static electricity protection pattern formed on one side thereof and a predetermined conductive pattern or a predetermined metal pattern formed on the other side thereof. The predetermined conductive pattern or predetermined metal pattern eliminate the residual direct current.