Liquid Crystal Display Pixel Electrode Slits for Dark Line Suppression

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Solution Overview

Problem

In VA mode liquid crystal display devices with an alignment division structure formed by defining pretilt directions with alignment films, dark lines occur near the edges of pixel electrodes, leading to a decrease in transmittance, viewing angle characteristics, and display quality.

Innovation Solution

The liquid crystal display device incorporates a pixel electrode with slits formed in specific regions corresponding to liquid crystal domains, where the slits extend parallel to the reference alignment directions of the domains, thereby reducing the area of dark lines and improving transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an alignment division structure is formed by defining pretilt directions with alignment films, then viewing angle characteristics are improved, but dark lines occur near pixel electrode edges causing transmittance to decrease

Engineering Contradiction:
Improveviewing angle characteristicsVSAvoidtransmittance
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The pixel electrode is segmented into multiple regions corresponding to different liquid crystal domains, with slits selectively formed in specific regions (first and second regions) but not in others (third and fourth regions). This segmentation allows the patent to address dark line formation in specific areas while preserving transmittance in other areas, resolving the contradiction between viewing angle improvement and transmittance maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel electrode are given different properties: some regions have slits formed to suppress dark lines, while other regions maintain continuous electrode structure for high transmittance. The slits are locally positioned in regions where dark lines would form, creating local quality variations that simultaneously achieve viewing angle improvement and transmittance preservation.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If a light blocking portion is provided to suppress dark lines, then viewing angle characteristics and display quality are improved, but transmittance decreases

Engineering Contradiction:
Improveviewing angle characteristicsVSAvoidtransmittance
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

Instead of using a light blocking portion that would uniformly reduce transmittance, the patent segments the pixel electrode into regions with and without slits. The slits act as localized structures that suppress dark lines only where needed, rather than blocking light across the entire pixel area, thus maintaining overall transmittance while improving viewing angle characteristics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The slits in the pixel electrode serve as an intermediary structure between the alignment division structure and the liquid crystal layer. They mediate the interaction by providing a mechanism to suppress dark line formation through their geometric configuration, rather than using a light blocking portion that would directly interfere with light transmission.

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 configuration effectively suppresses the decrease in transmittance caused by dark lines, enhancing the viewing angle characteristics and display quality of the liquid crystal display device.

Implementation Method 1

pretilt directions of liquid crystal molecules are defined by alignment films

Methodology Applied
Scientific EffectSurface alignment:

Implementation Method 2

when voltage is applied to a liquid crystal layer, four liquid crystal domains are formed in one pixel

Methodology Applied
Scientific EffectTwist alignment:

Data Source

PatentUS12287547B2Liquid crystal display device
Publication Date: 2025.04.29 SHARP DISPLAY TECHNOLOGY CORP
  • US12287547B2 patent drawing
  • US12287547B2 patent drawing
  • US12287547B2 patent drawing

AI summary

Each pixel of the liquid crystal display device includes a first, second, third, and fourth domains arranged in two rows and two columns, and reference alignment directions of the respective domains are first, second, third, and fourth directions. The first direction and the second direction form an angle of approximately 180°, and the first domain and the second domain are adjacent to each other in an oblique direction. The pixel electrode includes a plurality of first slits formed in a region corresponding to the first domain and extending approximately parallel to the first direction, and a plurality of second slits formed in a region corresponding to the second domain and extending approximately parallel to the second direction, and has no slits in a region corresponding to the third domain and no slits in a region corresponding to the fourth domain.