Liquid Crystal Display Flicker Reduction via Flexo Coefficient Control

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Solution Overview

Problem

Liquid crystal display devices, especially those in mobile terminals, face challenges in reducing power consumption while maintaining flicker-free performance, particularly when displaying moving images, as low-frequency or intermittent driving methods lead to visible flicker issues due to luminance fluctuations caused by flexo-electric effects and impedance mismatches.

Innovation Solution

A lateral electric field type liquid crystal display device with a fringe-field switching mode, employing a liquid crystal layer with a flexo coefficient (e11, e33) of 1.6 pC/m or less and intermittent driving at a frame frequency between 10 Hz to 20 Hz, combined with a column-inversion drive scheme to minimize power consumption and reduce flicker by matching the impedances of the liquid crystal and alignment film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If low-frequency driving method is applied to reduce power consumption, then power consumption is reduced, but visible flicker occurs due to luminance fluctuations

Engineering Contradiction:

Improvepower consumptionVSAvoidvisible flicker

Core Design Contradiction:

Use of energy by stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by selecting liquid crystal materials with specific flexo coefficients (e11 and e33 values within defined ranges) and adjusting driving parameters (frame frequency between 10-20 Hz, voltage waveforms) to minimize luminance fluctuations and reduce visible flicker while maintaining low power consumption

Inventive Principle:

Principle #35Parameter changes

2Use of energy by stationary object

If frame frequency is lowered to reduce power consumption, then power consumption is reduced, but flicker becomes more remarkably visible

Engineering Contradiction:

Improvepower consumptionVSAvoidflicker visibility

Core Design Contradiction:

Use of energy by stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes material parameters by specifying liquid crystal materials with flexo coefficients e11 and e33 within particular ranges, and adjusts driving parameters including frame frequency (10-20 Hz) and voltage characteristics to maintain luminance stability and minimize flicker visibility at lower frame frequencies

Inventive Principle:

Principle #35Parameter changes

3Use of energy by stationary object

If intermittent driving method is applied to reduce power consumption, then power consumption is reduced, but luminance fluctuations cause visible flicker

Engineering Contradiction:

Improvepower consumptionVSAvoidluminance stability

Core Design Contradiction:

Use of energy by stationary objectVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by selecting liquid crystal materials with specific flexo coefficient ranges and adjusting driving parameters (frame frequency, voltage waveforms) to minimize luminance fluctuations during intermittent driving periods, thereby reducing visible flicker while maintaining low power consumption

Inventive Principle:

Principle #35Parameter changes

4Speed

If liquid crystal with high flexo coefficient is used, then response speed is improved, but luminance fluctuations increase causing visible flicker at low frame frequencies

Engineering Contradiction:

Improveresponse speedVSAvoidluminance fluctuation

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by specifying liquid crystal materials with flexo coefficients e11 and e33 within defined ranges, and adjusts driving parameters including voltage waveforms and frame frequency to balance response speed with luminance stability, minimizing visible flicker at lower frame frequencies

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces visible flicker and power consumption by controlling luminance fluctuations, ensuring a stable display even at lower frame frequencies, thereby enhancing the viewing experience for mobile devices.

Implementation Method 1

luminance fluctuations caused by flexo-electric effects

Methodology Applied

Scientific EffectFlexo-electric effect: Electro-Optic Effects

Implementation Method 2

an alignment direction of liquid crystal molecules included in a liquid crystal layer held between an upper substrate and a lower substrate is controlled by an electric field generated between a counter-electrode provided in the upper substrate and pixel electrodes provided in the lower substrate

Methodology Applied

Scientific EffectElectric field: Electric Field

Data Source

PatentUS9552784B2Liquid crystal display apparatus

Publication Date: 2017.01.24 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a lateral electric-field type of liquid crystal display device includes a display panel including a plurality of liquid crystal pixels arranged in a matrix, and a controller configured to perform intermittent driving to rewrite an image signal to the liquid crystal pixels, wherein a frame frequency falls within a range of 10 Hz to 20 Hz, and an absolute value of a flexo coefficient (e11, e33) of a liquid crystal applied to the liquid crystal pixels is 1.6 pC/m or less.