LCD Display Polarity Control to Reduce Toggle Flicker

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Solution Overview

Problem

Flicker occurs momentarily during polarity toggle operations in liquid crystal display panels, particularly in high-resolution displays like 4K or 8K LCD TVs, due to sudden shifts in common voltage levels, causing luminance changes and afterimages.

Innovation Solution

A method and device that compare the initial common voltage level with the post-toggle level, adjusting the voltage levels of RGB data by applying a gain value to positive levels and an offset value to negative levels to stabilize the common voltage during polarity toggling, thereby reducing flicker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polarity toggle operation is performed to eliminate common voltage shift, then afterimage problem is improved, but flicker occurs momentarily for two frames

Engineering Contradiction:
Improveafterimage eliminationVSAvoidflicker
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by adjusting the voltage levels of RGB data before the polarity toggle operation occurs. The control unit compares the initial common voltage level with the level after polarity toggle, and when change exceeds a threshold, it pre-adjusts the voltage levels of subsequent frames to compensate for the expected flicker, thereby eliminating the harmful effect before it manifests.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by dynamically modifying the voltage levels of RGB data based on the detected common voltage level changes. The control unit inverts the polarity of voltage levels for two frames at a time, and when flicker is detected, it adjusts these voltage parameters to compensate, thereby resolving the contradiction between maintaining polarity toggle benefits and eliminating flicker.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If polarity toggle is applied to prevent common voltage shift, then display stability is improved, but sudden luminance change occurs

Engineering Contradiction:
Improvecommon voltage stabilityVSAvoidluminance
Core Design Contradiction:
Stability of the object's compositionVSIllumination intensity

Solution Approach 1:

The patent implements feedback by continuously monitoring the common voltage level changes and using this information to adjust the voltage levels of RGB data. The control unit compares the initial common voltage level with the level after polarity toggle, and based on this feedback, it dynamically adjusts the voltage parameters to prevent sudden luminance changes while maintaining display stability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses parameter changes to dynamically adjust the voltage levels of RGB data in response to common voltage fluctuations. By inverting and adjusting voltage levels for two frames at a time based on detected changes, the system maintains common voltage stability while preventing abrupt luminance variations that would affect display quality.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4629229A1Display device and operating method thereof
Publication Date: 2025.10.08 LG ELECTRONICS INC
  • EP4629229A1 patent drawingFigure 1
  • EP4629229A1 patent drawingFigure 2
  • EP4629229A1 patent drawingFigure 3

AI summary

A device display device according to an embodiment of the present disclosure, comprises a Liquid Crystal Display (LCD) panel and a control unit configured to compare an initial common voltage level of RGB data applied to the LCD panel with a common voltage level obtained after the initial common voltage level, and when the common voltage level is changed more than a certain ratio compared to the initial common voltage level, adjust a voltage level of the RGB data applied to two frames at a time of a polarity toggle operation to invert the polarity of the voltage level of the RGB data.