Rollable Display Length Sensing for Jam-Resistant Extension Control

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Solution Overview

Problem

Existing technologies struggle to accurately determine the extended length of a rollable display in electronic devices, which can lead to mechanical jams and damage to internal components due to unpredictable extension and contraction.

Innovation Solution

The electronic device employs a motor module with an encoder and Hall sensors to measure rotational driving information, allowing precise estimation of the extended display length, and includes a control system to prevent mechanical jams by detecting stalls and adjusting motor operation accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the display is made flexible and rollable to enable various shapes and portability, then the adaptability and portability are improved, but the reliability deteriorates due to unpredictable extension and contraction causing mechanical jams and component damage

Engineering Contradiction:
Improvedisplay flexibilityVSAvoidmechanical stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system uses Hall sensors to detect the position of the magnet attached to the movable housing, providing real-time feedback on the display extension state. This feedback enables the control system to monitor and control the extension and contraction movements, preventing mechanical jams and improving reliability while maintaining flexibility

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces direct mechanical connection and sensing with a magnetic field-based sensing system. Hall sensors detect the magnet's position without mechanical contact, eliminating mechanical wear and improving reliability while allowing smooth flexible movement of the display

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If sensors are added to detect display extension length, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveextended length detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A magnet is introduced as an intermediary carrier that translates the mechanical position of the movable housing into a detectable magnetic field signal. The Hall sensors detect the magnet's position, providing precise measurement of display extension without requiring complex direct mechanical sensing mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the measurement parameter from direct mechanical displacement to magnetic field position detection. By detecting the magnet's position through Hall sensors, the system achieves precise measurement of extension length while simplifying the sensing mechanism

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 solution enables accurate control of the display's extension and contraction, preventing mechanical damage and ensuring smooth operation of the rollable display.

Implementation Method 1

a magnet and a plurality of Hall sensors spaced apart from each other along a direction parallel to the axis on which the magnet is movable

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP4202599B1Electronic device comprising flexible display and driving method
Publication Date: 2026.03.11 SAMSUNG ELECTRONICS CO LTD
  • EP4202599B1 patent drawingFigure 1
  • EP4202599B1 patent drawingFigure 2A
  • EP4202599B1 patent drawingFigure 2B

AI summary

An electronic device is configured to determine a screen length extending in one direction on a display screen viewed on one side, based on motor driving information that is based on rotational driving of a motor and sensed magnetic force information that is generated through magnetic force sensing performed by one or more Hall sensors.