Liquid Crystal Display Common Voltage Compensation

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Solution Overview

Problem

Conventional liquid crystal display compensation structures struggle to accurately compensate for common voltage variations across the panel, leading to signal distortions and picture quality issues like horizontal crosstalk due to line resistance and coupling.

Innovation Solution

The implementation of a common voltage compensator system that divides the display area into sections, receiving feedback common voltages from both sides and outputting compensated voltages to minimize voltage drops and signal distortions by varying the width of common voltage lines based on resistance, using OP amplifiers and resistors to adjust voltages accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional compensation structure with common voltage generator and compensation circuit is used, then common voltage variations are compensated on two sides of the liquid crystal panel, but signal distortions caused by line resistance and coupling occur leading to horizontal crosstalk

Engineering Contradiction:
Improvecommon voltage stabilityVSAvoidsignal distortion and horizontal crosstalk
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The liquid crystal panel is divided into multiple regions (first region and second region) with different common voltage line configurations. The first region uses a first common voltage line while the second region uses a second common voltage line, allowing independent optimization of each region's voltage delivery to minimize signal distortion and crosstalk while maintaining overall voltage stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different common voltage line configurations are applied to different regions of the liquid crystal panel based on their specific electrical characteristics. The first common voltage line is optimized for the first region while the second common voltage line is optimized for the second region, addressing local variations in line resistance and coupling effects to prevent horizontal crosstalk.

Inventive Principle:
Principle #3Local quality

2Reliability

If common voltage lines are made wider to reduce resistance, then voltage drop is minimized, but manufacturing complexity and design difficulty increase

Engineering Contradiction:
Improvevoltage delivery accuracyVSAvoidcommon voltage line configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The common voltage line system is segmented into multiple independent lines (first common voltage line and second common voltage line) serving different regions. This segmentation allows each line to be optimized for its specific region without requiring a single overly complex unified design, simplifying manufacturing while maintaining voltage delivery accuracy.

Inventive Principle:
Principle #1Segmentation

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 approach enables more uniform and accurate compensation of common voltage, minimizing signal distortions and improving picture quality by accounting for position-dependent ripple in the liquid crystal panel.

Implementation Method 1

a first common voltage compensator and a second common voltage compensator, coupled to the first common voltage supply line and the second common voltage supply line, respectively

Methodology Applied
Scientific EffectOperational amplifier amplification:

Implementation Method 2

The liquid crystal display adjusts an arrangement direction of the liquid crystal layer by an electric field generated between the pixel electrodes and common electrodes

Methodology Applied
Scientific EffectElectric field effect on liquid crystal: Electric Field

Implementation Method 3

the common voltage varies with the position of the liquid crystal panel due to the electrical resistance of a wire, capacitor, etc formed on the liquid crystal panel

Methodology Applied
Scientific EffectElectrical resistance effect: Electrical Resistance

Data Source

PatentEP2843653B1Liquid crystal display with common voltage compensation
Publication Date: 2018.03.21 LG DISPLAY CO LTD
  • EP2843653B1 patent drawingFigure 1
  • EP2843653B1 patent drawingFigure 2
  • EP2843653B1 patent drawingFigure 3

AI summary

The present invention has been made in an effort to provide a liquid crystal display comprising: a liquid crystal panel comprising a display area and a non-display area; left and right common voltage lines connected to common voltage lines formed in the display area and located in the non-display area on the left and right sides of the display area; and a common voltage compensator that receives feedback common voltages from the left and right common voltage lines and outputs compensated common voltages based on the feedback common voltages, wherein the common voltage compensator divides the display area into a first display area and a second display area with respect to the center of the liquid crystal panel and supplies different compensated common voltages to the first display area and the second display area.