Retractable Screen Structure With Rotation-Wheel Friction Reduction

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Solution Overview

Problem

Existing retractable screen structures face challenges in smoothly expanding and retracting flexible displays due to high friction and energy loss, leading to issues like screen bulging and distortion.

Innovation Solution

A retractable screen structure utilizing a rotation shaft assembly with a rotation wheel and slide rail mechanism, where the flexible display screen is wound around the rotation wheel, reducing friction and energy loss by allowing the wheel to act as a pulley during expansion and retraction, and a drive assembly that moves the slide rail mechanism to switch between states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the flexible display screen is directly pulled without a rotation wheel, then the structure is simpler, but friction and energy loss increase causing screen bulging and distortion

Engineering Contradiction:
Improvestructure complexityVSAvoiddisplay smoothness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The rotation wheel acts as an intermediary component between the flexible display screen and the pulling force. It reduces direct friction by allowing the screen to wrap around the wheel, converting sliding friction into rolling motion, thereby preventing screen bulging and distortion while maintaining operational reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical pulling with a pulley-based mechanical system. The rotation wheel functions as a pulley that redirects and smooths the pulling force, substituting a simple linear pull with a controlled rotational mechanism that reduces energy loss and improves display reliability

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

2Reliability

If a rotation wheel is added to reduce friction, then display smoothness improves, but device complexity increases

Engineering Contradiction:
Improvedisplay smoothnessVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rotation wheel serves multiple functions simultaneously: it acts as a pulley to reduce friction, provides structural support for the flexible display screen, and serves as an anchor point for the screen's starting position. This multi-functionality justifies the added complexity by delivering multiple benefits from a single component

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The rotation wheel creates a consistent mechanical advantage throughout the retraction process, maintaining uniform tension distribution across the flexible display screen. This equipotential approach ensures smooth operation without creating stress concentration points that would cause bulging or distortion

Inventive Principle:
Principle #12Equipotentiality

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

The solution enables smooth expansion and retraction of flexible displays with reduced friction and energy loss, maintaining a flat display form and preventing issues like bulging and distortion, enhancing the operational reliability of electronic devices.

Implementation Method 1

reducing friction and energy loss by allowing the wheel to act as a pulley during expansion and retraction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4109211B1Retractable screen structure and electronic device
Publication Date: 2025.07.23 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP4109211B1 patent drawingFigure 1
  • EP4109211B1 patent drawingFigure 2
  • EP4109211B1 patent drawingFigure 3

AI summary

A retractable screen structure and an electronic device are provided. The retractable screen structure includes a holder assembly (10), the holder assembly (10) including a holder (11) and a rotation shaft assembly (12). The rotation shaft assembly (12) includes a rotation shaft support coupled to a side of the holder (11) and having a shaft hole, a rotation shaft (122) passing through the shaft hole, and a rotation wheel fitted over the rotation shaft (122). The retractable screen structure also includes a flexible display screen (90) wound around the rotation wheel. The rotation wheel is driven to rotate when the flexible display screen (90) is expanded or retracted.