Compound Gear Hinge Structure for Slimmer Foldable Displays

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Solution Overview

Problem

Foldable electronic devices with gear structures face challenges in reducing thickness due to the inherent thickness of the gear structure, and there is a risk of damage to the display from external impacts.

Innovation Solution

A hinge structure with a compound gear design that includes a first and second compound gear with varying radii, providing a space between the display and the gear structure to reduce thickness and minimize display damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a gear structure is implemented in the hinge structure, then the external pressure is shared during folding/unfolding, but the thickness of the foldable electronic device increases

Engineering Contradiction:
Improvepressure sharing capabilityVSAvoiddevice thickness
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The compound gear structure places one gear inside another concentric arrangement, with the first compound gear having a first gear portion and a second gear portion at different radii from the center point. This nesting allows multiple gear functions in a reduced thickness profile, resolving the contradiction between pressure sharing capability and device thickness.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a single-plane gear structure to a multi-radius compound gear structure, utilizing radial dimensionality to achieve pressure distribution. The first and second gear portions operate at different radii, enabling three-dimensional space utilization that reduces overall device thickness while maintaining structural strength.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If a gear structure is implemented in the hinge structure, then the folding mechanism is supported, but the space between the display and gear structure is reduced

Engineering Contradiction:
Improvefolding mechanism supportVSAvoiddisplay damage risk
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The gear structure is segmented into multiple independent gear portions (first gear portion, second gear portion) with different radii, allowing each segment to perform specific functions. This segmentation creates distributed support points that maintain folding mechanism stability while reducing concentrated stress that could harm the display.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compound gear structure acts as an intermediary between the folding mechanism and the display, with its multi-radius design providing buffered support. The first and second gear portions serve as intermediate elements that distribute mechanical stresses, preventing direct transmission of harmful forces to the display while maintaining folding stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4280576B1Foldable electronic device comprising a hinge structure comprising complex gear
Publication Date: 2025.07.16 SAMSUNG ELECTRONICS CO LTD
  • EP4280576B1 patent drawingFigure 1A
  • EP4280576B1 patent drawingFigure 1B
  • EP4280576B1 patent drawingFigure 1C

AI summary

Disclosed is a hinge structure that includes a first shaft, a second shaft, a first arm part, a second arm part, a first rotation part, a second rotation part, a first main gear, a second main gear, and first and second compound gears disposed between the main gears. The first compound gear may include a first gear portion geared with the first main gear, and of which a distance from a center point to a gear tooth end is a first radius, and a second gear portion geared with the second compound gear, and of which a distance from a center point to a gear tooth end is a second radius that is smaller than the first radius. The second compound gear may have a structure corresponding to that of the first compound gear. An electronic device including the hinge structure is also disclosed.