Display Device Flicker Prevention via Intermediate Frame Frequency Transition

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Solution Overview

Problem

Liquid crystal display devices experience flicker issues due to response delay caused by dielectric anisotropy when switching from video to still images during intermittent driving, leading to adverse effects on video image visibility.

Innovation Solution

Implementing a display device with a first mode at a higher frame frequency (60 Hz) for at least one frame before switching to a second mode at a lower frame frequency (1 Hz) for intermittent driving, ensuring a transient response is completed within a shorter time frame to prevent flicker recognition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If intermittent driving is implemented to reduce power consumption, then circuit power is reduced, but flicker occurs due to response delay caused by dielectric anisotropy of liquid crystal

Engineering Contradiction:

Improvecircuit powerVSAvoidflicker

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by performing a transition period at an intermediate frame frequency (higher than the target intermittent frequency but lower than normal frequency) before switching to the final intermittent driving mode. This preliminary transition allows the liquid crystal to gradually adapt to the longer frame cycle, completing the transient response before the full intermittent driving begins, thereby preventing flicker while achieving power reduction

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the frame frequency parameter in a stepwise manner rather than making an abrupt change. It transitions from normal frame frequency to an intermediate frame frequency, and then to the target intermittent frame frequency. This gradual parameter change allows the liquid crystal to complete its response at each stage, eliminating flicker while still achieving significant power consumption reduction at the final intermittent mode

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If frame frequency is reduced for intermittent driving, then power consumption is reduced, but video image visibility deteriorates due to blurring

Engineering Contradiction:

Improvepower consumptionVSAvoidvideo image visibility

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the frame frequency adjustable and time-dependent rather than fixed. The system dynamically transitions through different frame frequency stages (normal frequency → intermediate frequency → intermittent frequency) based on the display content type. This dynamic adjustment allows the system to maintain high frame frequency for video images to prevent blurring, while switching to low frame frequency for still images to reduce power consumption

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If frame frequency is reduced simultaneously with switching from video to still image, then power consumption is reduced, but flicker is visually recognized due to incomplete transient response

Engineering Contradiction:

Improvepower consumptionVSAvoidimage stability

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent performs preliminary transitions at intermediate frame frequencies before entering the final intermittent driving mode. When switching from video to still images, it first transitions to an intermediate frame frequency, allows the liquid crystal to complete its transient response, and then transitions to the target intermittent frame frequency. This preliminary action ensures smooth transition without visible flicker while achieving power reduction

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses periodic action by implementing a multi-stage transition process with distinct time periods at different frame frequencies. The transition occurs in periods: normal frequency period → intermediate frequency period → intermittent frequency period. This periodic approach allows the liquid crystal to complete its response at each frequency stage, preventing flicker during mode switching

Inventive Principle:

Principle #19Periodic 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 approach effectively prevents flicker from being visually recognized by completing the transient response within a shorter time frame, enhancing image stability and reducing power consumption.

Implementation Method 1

a flicker occurs due to a response delay caused by dielectric anisotropy of liquid crystal

Methodology Applied

Scientific EffectDielectric anisotropy: Dielectric Permittivity

Data Source

PatentUS9495900B2Display device

Publication Date: 2016.11.15 MAGNOLIA WHITE CORP

AI summary

When normal driving is switched to intermittent driving simultaneously with switching from a video image to a still image, a flicker may occur due to a response delay caused by dielectric anisotropy of liquid crystal. A display device has a first mode (video image driving) in which driving is performed at a first frame frequency and a second mode (still image driving) in which the driving is performed at a second frame frequency lower than the first frame frequency. When the first mode is switched to the second mode, the display device first performs the driving at a frame frequency higher than the second frame frequency for at least one frame and then, the driving is switched to be performed at the second frame frequency.