Common Voltage Compensating Circuit for LCD Panel

Solution Overview

Problem

Large-sized liquid crystal display devices face significant common voltage signal deviations due to RC delay, leading to image quality degradation and horizontal cross-talk, particularly in high-resolution and high-frequency displays with narrow bezels, where the common voltage compensating circuit struggles to maintain uniform voltage levels across the panel.

Innovation Solution

The implementation of a common voltage compensating circuit with multiple supply and feedback lines, where two or more common voltage compensating circuits are used to apply and feedback common voltage signals in different sequences to address signal delays, ensuring stable voltage distribution across the panel by adjusting compensation ratios based on regional differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single common voltage supply line is used in large-sized liquid crystal display devices, then the device complexity is reduced, but common voltage signal deviation increases due to RC delay

Engineering Contradiction:

Improvevoltage supply structureVSAvoidcommon voltage uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the single common voltage supply line into multiple segments (first common voltage supply line and second common voltage supply line) that are distributed across different regions of the liquid crystal panel. This segmentation reduces the RC delay in each individual segment, thereby minimizing common voltage signal deviation and improving voltage uniformity across the large-sized display panel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different common voltage supply configurations to different regions of the liquid crystal panel. The first common voltage supply line serves a first region while the second common voltage supply line serves a second region, allowing each region to receive optimized voltage supply tailored to its specific electrical characteristics and distance requirements.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If multiple common voltage compensating circuits are used to address signal delays, then common voltage uniformity is improved, but device complexity increases

Engineering Contradiction:

Improvecommon voltage uniformityVSAvoidcompensating circuit structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the single common voltage supply line into multiple segments (first common voltage supply line and second common voltage supply line) that are distributed across different regions of the liquid crystal panel. This segmentation reduces the RC delay in each individual segment, thereby minimizing common voltage signal deviation and improving voltage uniformity across the large-sized display panel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different common voltage supply configurations to different regions of the liquid crystal panel. The first common voltage supply line serves a first region while the second common voltage supply line serves a second region, allowing each region to receive optimized voltage supply tailored to its specific electrical characteristics and distance requirements.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If the liquid crystal display device is designed with high resolution and high frequency, then display quality is improved, but common voltage signal deviation increases due to RC delay

Engineering Contradiction:

Improvedisplay resolutionVSAvoidcommon voltage uniformity

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent divides the single common voltage supply line into multiple segments (first common voltage supply line and second common voltage supply line) that are distributed across different regions of the liquid crystal panel. This segmentation reduces the RC delay in each individual segment, thereby minimizing common voltage signal deviation and improving voltage uniformity across the large-sized display panel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different common voltage supply configurations to different regions of the liquid crystal panel. The first common voltage supply line serves a first region while the second common voltage supply line serves a second region, allowing each region to receive optimized voltage supply tailored to its specific electrical characteristics and distance requirements.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP2690616B1Liquid crystal display device including common voltage compensating circuit

Publication Date: 2022.07.06 LG DISPLAY CO LTD

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AI summary

A liquid crystal display device may include: a liquid crystal display panel comprising a first and a second common voltage supply line formed in a first direction at both side ends of the substrate, and at least one feedback line formed in the first direction and connected to the first common voltage supply line and/or the second common voltage supply line; and at least one common voltage compensating circuit, an output terminal of which is connected to the first and the second common voltage supply lines, and an input terminal of which is connected to the feedback line.