Rollable Display Row Driving to Prevent Static Image Afterimages

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Solution Overview

Problem

Existing rollable displays suffer from afterimage issues due to pixel degradation when displaying static images for extended periods, and existing solutions like the orbit algorithm cause screen movement noticeable to the user and increase data rate requirements.

Innovation Solution

A rollable display design that moves the screen in a direction opposite to the physical movement of the display panel, maintaining the apparent position of the exposed display region, thereby distributing stress without visible screen movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the orbit algorithm is applied to rotate the screen to distribute pixel stress, then afterimage prevention is improved, but the user can notice screen movement and the data rate increases

Engineering Contradiction:
Improveafterimage preventionVSAvoiduser perception of screen stability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Instead of rotating the entire screen to distribute pixel stress, this patent inverts the approach by keeping the screen fixed and selectively driving specific pixel rows in reverse sequence. The timing controller applies reverse driving to alternate rows (even rows driven in normal sequence, odd rows driven in reverse sequence), which distributes stress without causing visible screen movement or increasing data rate requirements.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the entire screen is moved to improve orbit effects, then pixel stress distribution is improved, but memory restrictions and visual direction limit the movement capability

Engineering Contradiction:
Improvepixel stress distributionVSAvoidscreen movement flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

This patent segments the pixel driving approach by treating even and odd rows differently. The timing controller divides the pixel array into two groups (even rows and odd rows) and applies opposite driving sequences to each group. This segmentation allows stress distribution across the entire pixel array without requiring physical screen movement, overcoming memory and visual direction limitations.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the screen is rotated in constant direction every minute, then pixel stress is distributed, but the bezel expands and the data rate between host system and timing controller increases

Engineering Contradiction:
Improvepixel stress distributionVSAvoiddata rate increase
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

This patent implements periodic stress distribution through alternating row driving sequences within each frame period. Even rows are driven in normal sequence while odd rows are driven in reverse sequence, creating a periodic pattern that distributes pixel stress without requiring continuous screen rotation. This approach maintains constant data rate requirements while achieving stress distribution effects.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3506247B1Rollable display and driving method thereof
Publication Date: 2025.12.24 LG DISPLAY CO LTD
  • EP3506247B1 patent drawingFigure 1~2
  • EP3506247B1 patent drawingFigure 3A~3B
  • EP3506247B1 patent drawingFigure 4

AI summary

Disclosed is a rollable display and a driving method thereof, and a screen of a flexible display panel is separated into an exposed display region and a non-exposed display region. The present disclosure moves the screen of the flexible display panel using a screen driver, and controls a moving direction of the exposed display region to be opposite to a moving direction of the screen, thereby enabled to distribute stress of pixels, without changing an absolute location of the exposed display region, and defer degradation of the pixels.