Foldable Display Hinge Torque Structure for Stable Folding Angles

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Solution Overview

Problem

Foldable electronic devices with flexible displays face issues in maintaining a stable folded state due to restoring torque, which is strongest in a fully folded state, compromising portability and requiring additional members like magnets for support.

Innovation Solution

A hinge structure with a torque structure that includes cam structures and elastic members to provide a frictional torque greater than the restoring torque, allowing stable folding and unfolding angles, eliminating the need for additional support members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a hinge structure is used to enable folding, then the display can be deformed to a curved surface improving portability, but a restoring torque is applied to the folded state making it unstable

Engineering Contradiction:
Improvedisplay deformation capabilityVSAvoidfolded state stability
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The elastic member is pre-compressed to generate a frictional torque that acts in advance to counterbalance the restoring torque generated by display deformation. This preliminary counteracting force prevents the display from automatically unfolding, achieving stable folded state without additional support members.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The restoring torque generated by display deformation, which normally causes instability, is converted into a beneficial effect. By using the elastic member to generate frictional torque that counterbalances this restoring torque, the harmful restoring force becomes a controllable parameter that enables stable folding at various angles.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Stability of the object's composition

If additional support members like magnets are used to maintain folded state, then stability is improved, but device complexity increases

Engineering Contradiction:
Improvefolded state stabilityVSAvoidhinge structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The elastic member serves multiple functions: it generates frictional torque to counterbalance restoring torque, enables stable folding at various angles, and eliminates the need for separate support members like magnets. This multi-functionality reduces device complexity while maintaining stability.

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

Solution Approach 2:

The support function previously requiring separate magnetic components is merged into the hinge structure itself through the elastic member. The elastic member integrates the stabilizing function directly into the folding mechanism, eliminating additional components and simplifying the overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

3Area of stationary object

If the display is made larger to provide wider screen, then display area is improved, but portability deteriorates

Engineering Contradiction:
Improvedisplay areaVSAvoidportability
Core Design Contradiction:
Area of stationary objectVSWeight of moving object

Solution Approach 1:

The display transitions from a static flat state to a dynamic curved state during folding. This dynamic deformation capability allows a large display area to be collapsed into a compact portable form, resolving the contradiction between large screen size and portability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flexible display is nested within itself through folding, with the curved folded state allowing the large display area to be contained within a compact volume. This nesting capability enables large screens to maintain portability when not in full display mode.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 hinge structure maintains stable folding states and provides detent functions, ensuring secure folding and unfolding without additional components, enhancing portability and usability.

Implementation Method 1

a first elastic member disposed between the first cam member and a first side wall of the first fixed structure and that is compressed or prolonged in correspondence to linear movement of the first cam member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

provides a frictional torque such that an arbitrary folded state is stably maintained in correspondence to a restoring torque of a display

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4224277B1Electronic device having torque structure
Publication Date: 2026.01.21 SAMSUNG ELECTRONICS CO LTD
  • EP4224277B1 patent drawingFigure 1
  • EP4224277B1 patent drawingFigure 2A
  • EP4224277B1 patent drawingFigure 2B

AI summary

Disclosed is an electronic device having a hinge structure. The hinge structure may comprise: a first fixed structure on which a first arc-shaped guide rail is formed; a second fixed structure on which a second arc-shaped guide rail is formed; a first rotating structure including a first coupling portion rotatably coupled to the first guide rail; a second rotating structure including a second coupling portion rotatably coupled to the second guide rail; and a torque structure configured to provide torque to the first rotating structure and the second rotating structure, wherein the torque structure may comprise: a cam structure formed on the first rotating structure and the second rotating structure; a cam member including a moving cam engaged with the cam structure; and an elastic member configured to be compressed or tensioned in response to linear movement of the cam member. Various other embodiments understood through the specification are also possible.