LCD Pixel Electrode Neck Portions for Capacitance Balance

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Solution Overview

Problem

Z-type liquid crystal display devices experience dim block issues due to differences in storage capacitance caused by overlay inaccuracies, particularly affecting blue pixels with inverted configurations in zigzag signal driving systems.

Innovation Solution

The design includes a substrate with specific gate and data line configurations, featuring thin film transistors and pixel electrodes with neck portions that ensure consistent overlap with common lines, maintaining balanced storage capacitance across pixels, even with upper/lower or left/right inversions, through extended neck portions that compensate for overlay discrepancies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Z-type driving with inverted pixel configurations is used, then display coverage and driving efficiency are improved, but storage capacitance becomes unbalanced causing dim block

Engineering Contradiction:

Improvedriving efficiencyVSAvoidstorage capacitance balance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies asymmetry by intentionally designing the pixel electrode structure with asymmetric neck portions that extend in specific directions. The first pixel electrode has a first neck portion extending in a first direction, while the second pixel electrode has a second neck portion extending in a second direction, creating asymmetric compensation for overlay errors in inverted pixel configurations

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by adding neck portions specifically at the pixel electrode regions where overlay errors cause capacitance imbalance. The neck portions are located at specific positions (first and second directions from the pixel electrode center) to provide localized compensation only where needed, rather than uniformly modifying all pixel electrodes

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If overlay tolerance is increased to accommodate manufacturing variations, then manufacturing precision requirements are relaxed, but storage capacitance balance deteriorates

Engineering Contradiction:

Improveoverlay precisionVSAvoidstorage capacitance balance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by pre-designing the neck portions to compensate for expected overlay errors before they occur. The neck portions are positioned and dimensioned to create capacitance balance even when overlay errors are present, effectively countering the harmful effect of overlay inaccuracies in advance

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent applies preliminary action by incorporating the compensation structure (neck portions) during the initial pixel electrode formation process. The first and second neck portions are formed as part of the pixel electrode structure before subsequent processing steps, ensuring the compensation capability is built-in from the start

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8189159B2Liquid crystal display device and method for manufacturing the same

Publication Date: 2012.05.29 LG DISPLAY CO LTD

AI summary

The present invention relates to a liquid crystal display, in which dim block caused by overlays is prevented at blue pixels having upside down inverted structures with respect to one another in a Z-type driving in which a signal is applied to data lines in zigzag.