Sub-pixel Storage Electrodes for LCD Side Visibility

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Solution Overview

Problem

Liquid crystal display apparatuses with vertical alignment mode suffer from deteriorated side visibility due to brightness differences between high gray voltages, leading to distorted images and defects like vertical specks and flicker, especially in normally black types, caused by non-uniform storage capacitances between sub-pixels.

Innovation Solution

The apparatus includes first and second sub-pixel electrodes with different voltage applications, storage electrodes between pixel and data lines, and conductive members overlapping the second sub-pixel electrodes, ensuring uniform storage capacitance and reduced voltage differences between sub-pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If storage electrodes are provided between data lines and pixel electrodes to improve side visibility, then storage capacitance uniformity improves, but device complexity increases

Engineering Contradiction:

Improveside visibilityVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pixel electrode is divided into first and second sub-pixel electrodes with different storage electrode configurations. The first sub-pixel electrode overlaps with storage electrodes while the second does not, creating segmented storage capacitance regions that compensate for side visibility issues

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel electrode are given different properties: the first sub-pixel electrode region has storage electrodes for enhanced capacitance and side visibility, while the second sub-pixel electrode region lacks storage electrodes to maintain uniform storage capacitance across the display

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If two sub-pixels are divided with different voltages to improve viewing angle, then reference viewing angle improves, but storage capacitance uniformity deteriorates

Engineering Contradiction:

Improveviewing angleVSAvoidstorage capacitance uniformity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The first and second sub-pixel electrodes are designed with asymmetric storage electrode configurations - the first has storage electrodes for wider viewing angle, while the second deliberately lacks them to balance the overall storage capacitance and eliminate flicker

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The asymmetric storage electrode design creates equipotential conditions by balancing the total storage capacitance between the two sub-pixels, ensuring uniform charge distribution and eliminating the flicker effect caused by capacitance imbalance

Inventive Principle:

Principle #12Equipotentiality

3Quantity of substance

If storage electrodes overlap both sub-pixels to increase storage capacitance, then charging ratio improves, but kick-back voltage increases causing defects

Engineering Contradiction:

Improvestorage capacitanceVSAvoidkick-back voltage

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

Storage electrodes are applied partially - only to the first sub-pixel electrode - rather than excessively to both sub-pixels. This partial application provides sufficient storage capacitance for improved charging ratio while avoiding the excessive capacitance that would generate harmful kick-back voltages

Inventive Principle:

Principle #16Partial or excessive action

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 enhances side visibility by maintaining uniform storage capacitance and reducing defects such as flicker and specks, improving the overall image quality and visibility in liquid crystal display apparatuses.

Implementation Method 1

first and second storage electrodes disposed between the pixel electrodes and the data lines disposed at both sides of the pixel electrodes and overlapping the first sub-pixel electrodes

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

applying a voltage to the electric field generating electrodes to generate an electric field in the liquid crystal layer. A magnitude off the electric field determines an alignment of liquid crystal molecules in the liquid crystal layer to control polarization of incident light

Methodology Applied

Scientific EffectElectric field: Electric Field

Data Source

PatentUS8049699B2Liquid crystal display apparatus having storage electrodes overlapping only some sub-pixels

Publication Date: 2011.11.01 SAMSUNG DISPLAY CO LTD

AI summary

A liquid crystal display apparatus includes a plurality of pixel electrodes arrayed in a matrix, each pixel electrode of the plurality of pixel electrodes having first and second sub-pixel electrodes. The apparatus further includes a plurality of first switching devices connected to the first sub-pixel electrodes, a plurality of gate lines connected to the switching devices, a plurality of data lines connected to the first devices and passing between the pixel electrodes to transmit data voltages, and first and second storage electrodes disposed between the pixel electrodes and the data lines disposed at both sides of the pixel electrodes and overlapping the first sub-pixel electrodes.