IPS LCD Pixel Electrode Overlap with Counter Electrode for Brightness

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Solution Overview

Problem

The numerical aperture and display brightness of IPS-type liquid crystal display devices are limited due to the non-contributory areas around the contact hole and thin film transistor, which also pose a risk of short-circuiting and defective liquid crystal orientation.

Innovation Solution

The solution involves using the contact hole and thin film transistor areas as reflective display regions, with a counter electrode positioned to avoid the contact hole and employing a leveled insulation film surface to ensure accurate liquid crystal orientation, thereby enhancing numerical aperture and preventing short-circuiting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the contact hole and thin film transistor areas are used as display regions, then the numerical aperture and display brightness are improved, but the risk of short-circuiting increases

Engineering Contradiction:

Improvedisplay brightnessVSAvoidshort-circuiting risk

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The contact hole area is extracted from the non-display region and converted into a display region. The counter electrode is positioned to avoid the contact hole, allowing the contact hole area to contribute to light modulation and display brightness without causing short-circuits between electrodes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

An insulation film is introduced as an intermediary layer between the pixel electrode and counter electrode in the contact hole area. This insulation film prevents direct contact between the electrodes, eliminating the short-circuiting risk while allowing both areas to function as display regions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the counter electrode is positioned to avoid the contact hole, then short-circuiting is prevented, but the display area is reduced

Engineering Contradiction:

Improveshort-circuiting preventionVSAvoiddisplay area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The problem is solved by transitioning to a different dimensional approach - instead of positioning the counter electrode to avoid the contact hole in the planar dimension, an insulation film is added in the vertical dimension. This allows the counter electrode to be positioned directly over the contact hole area without causing short-circuits, thereby maximizing the display area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the pixel electrode is positioned to avoid the contact hole, then manufacturing is simplified, but the numerical aperture is reduced

Engineering Contradiction:

Improveelectrode positioningVSAvoidnumerical aperture

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

The contact hole area is extracted from the non-display region and converted into a display region by positioning the counter electrode to avoid it. This allows the pixel electrode to extend over the contact hole area, increasing the numerical aperture while maintaining manufacturing simplicity through the straightforward electrode layout.

Inventive Principle:

Principle #2Taking out (Extraction)

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 configuration increases display brightness and numerical aperture by utilizing previously non-display areas and ensures reliable operation by preventing short-circuiting and improving liquid crystal orientation, leading to a more effective and defect-free display.

Implementation Method 1

a liquid crystal layer between the first substrate and the second substrate

Methodology Applied

Scientific EffectLiquid crystal orientation control: Liquid Crystals

Implementation Method 2

lateral-electric-field-type liquid crystal display device

Methodology Applied

Scientific EffectElectric field effect: Electric Field

Data Source

PatentUS11036098B2Liquid crystal display device having rectangular-shaped pixel electrodes overlapping with comb-shaped counter electrodes in plan view

Publication Date: 2021.06.15 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

The present invention realizes a bright image display by enhancing a numerical aperture of pixels. At least a portion of a pixel electrode is overlapped to a thin film transistor by way of a first insulation film, the pixel electrode is connected to an output electrode of the thin film transistor via a contact hole which is formed in the first insulation film, the counter electrode is arranged above the pixel electrode by way of a second insulation film in a state that the counter electrode is overlapped to the pixel electrode, the counter electrode is formed at a position avoiding the contact hole formed in the first insulation film as viewed in a plan view, and at least a portion of the counter electrode is overlapped to the thin film transistor.