Liquid Crystal Display Electrode Arrangement for Uniform Electric Field

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Solution Overview

Problem

In liquid crystal display devices, the random arrangement of projecting patterns on the scattering film leads to variations in electric field intensities, resulting in fluctuated drive voltage and reduced light transmittance and contrast, especially in transreflective FFS or IPS mode displays.

Innovation Solution

The pixel and common electrodes are arranged such that electric field intensities between them are equalized in the reflective display area, with projecting patterns on the reflective film and interlayer insulating film matching the surface topology, ensuring consistent electric field application and orientation control of liquid crystal molecules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If projecting patterns on the scattering film are arranged randomly, then the scattering effect is achieved, but electric field intensities vary and drive voltage fluctuates

Engineering Contradiction:

Improvescattering effectVSAvoidelectric field intensity consistency

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the arrangement of projecting patterns based on location: in the reflective display area, projecting patterns are arranged in an ordered manner (e.g., in rows and columns) to ensure uniform electric field intensity, while in the transmissive display area, projecting patterns can be arranged randomly to optimize scattering effect. This localized differentiation resolves the contradiction between scattering effectiveness and electric field consistency.

Inventive Principle:

Principle #3Local quality

2Device complexity

If no scattering film is provided in the reflective display area, then the structure is simpler, but reflection efficiency is low and viewing angle is narrow

Engineering Contradiction:

Improvestructure simplicityVSAvoidreflection efficiency

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

The patent uses a scattering film with projecting patterns as a thin film structure in the reflective display area. This scattering film enhances reflection efficiency and viewing angle without significantly increasing device complexity, as it integrates into the existing display structure as a thin layer with surface projections.

Inventive Principle:

Principle #30Flexible shells and thin films

3Illumination intensity

If projecting patterns are provided on the scattering film in the reflective display area, then scattering effect is improved, but manufacturing precision is reduced due to random arrangement

Engineering Contradiction:

Improvescattering effectVSAvoidpattern arrangement precision

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

4Device complexity

If electric field intensities are not equalized, then electrode arrangement is simpler, but light transmittance and contrast are reduced

Engineering Contradiction:

Improveelectrode arrangement simplicityVSAvoidlight transmittance and contrast

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

The patent applies equipotentiality by arranging pixel electrodes and common electrodes such that electric field intensities are equalized in the reflective display area. This is achieved by carefully positioning electrodes relative to the projecting patterns, ensuring that the electric field distribution is uniform, which in turn improves light transmittance and contrast performance.

Inventive Principle:

Principle #12Equipotentiality

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 arrangement reduces average drive voltage, enhances light transmittance, and improves contrast by maintaining electric field intensity parallel to the substrate surface, resulting in higher image quality and efficiency.

Implementation Method 1

a scattering film 14′ is provided that is formed of an insulating film and has projecting patterns 14a′ on the front surface side for scattering the light incident from the second substrate 20 side

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 2

pixel electrodes and a common electrode are provided on the same substrate side, in which a lateral electric field almost in parallel to the substrate surface is formed and the lateral electric field drives a liquid crystal device to display images

Methodology Applied

Scientific EffectElectric field: Electric Field

Implementation Method 3

a liquid crystal layer 30 sandwiched between the first substrate 10 and the second substrate 20

Methodology Applied

Scientific EffectLiquid crystal effect: Liquid Crystals

Data Source

PatentUS7755723B2Liquid crystal display device and display apparatus

Publication Date: 2010.07.13 MAGNOLIA WHITE CORP

AI summary

A liquid crystal display device includes: a liquid crystal layer sandwiched between a first substrate and a second substrate; and a reflective display area on the first substrate side, the reflective display area being provided with a common electrode and a pixel electrode having a plurality of slits so as to apply an electric field to the liquid crystal layer, wherein between the first substrate and the pixel electrode, a reflective film and an interlayer insulating film, both films having projecting patterns on a front surface side, are arranged in this order from the first substrate side, and the pixel electrode and the common electrode are arranged so that electric field intensities between the pixel electrode and the common electrode are made equal in the reflective display area.