Hinge Torque Structure for Foldable Display Devices
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Solution Overview
Problem
The increased restoring torque in foldable electronic devices with larger displays makes it difficult for users to unfold or fold the device with one hand, as the friction torque required becomes substantial.
Innovation Solution
A hinge structure with a torque structure that includes first and second arm shafts, cam structures, and elastic members, providing varying friction torques across different sections to facilitate easy unfolding and folding without significant user effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the display size is increased to provide wider screen functions, then the restoring torque increases, but the friction torque required to fold or unfold the device increases making it difficult to operate with one hand
Solution Approach 1:
The hinge structure divides the folding range into three distinct sections with different friction torque characteristics: a first section (fully folded to free stop) with constant low friction torque for easy one-handed operation, a second section (free stop to flat state) with increasing friction torque for stable maintenance, and a third section with high friction torque for secure locking. This segmentation allows the device to provide easy operability when needed while maintaining stability in folded states.
Solution Approach 2:
The friction torque in the hinge structure is made dynamic rather than constant. The torque structure adjusts the friction torque magnitude based on the folding angle section: low constant torque in the first section for easy unfolding, increasing torque in the second section for stable positioning, and high torque in the third section for secure locking. This dynamic adjustment resolves the contradiction between ease of operation and stability.
2Stability of the object's composition
If the friction torque is increased to stably maintain folded states, then the stability of folded states improves, but the user has to apply greater torque to fold or unfold the device
Solution Approach 1:
The folding operation is divided into three sections with different friction torque levels. In the first section (fully folded to free stop), constant low friction torque enables easy one-handed operation. In the second section (free stop to flat state), increasing friction torque provides stable maintenance. In the third section, high friction torque ensures secure locking. This segmentation allows both easy operation and stable maintenance to be achieved in different operational phases.
Solution Approach 2:
Different sections of the folding range are assigned different friction torque characteristics tailored to their specific functional requirements. The first section has low friction for ease of initiation, the second section has increasing friction for stable positioning, and the third section has high friction for secure locking. This local differentiation resolves the global contradiction between ease of operation and stability.
3Ease of operation
If the friction torque is kept constant and low to enable easy one-handed operation, then the ease of operation improves, but the ability to maintain stable folded states at various angles deteriorates
Solution Approach 1:
The hinge structure segments the folding range into three sections with progressively increasing friction torque. The first section maintains constant low friction torque for easy one-handed operation from fully folded to free stop position. The second section introduces increasing friction torque to provide stable maintenance capability. The third section applies high friction torque for secure locking. This segmentation allows the system to achieve both easy operation and stable maintenance by applying appropriate friction torque in different sections.
Solution Approach 2:
The friction torque is made dynamic, transitioning from constant low torque in the first section to increasing torque in the second section, and finally to high torque in the third section. This dynamic adjustment ensures easy operation during the critical unfolding/folding phase while providing stable maintenance when the device is held in folded positions.
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 torque structure maintains a consistent low friction torque when unfolding from a fully folded state to a free stop section, allowing users to easily fold or unfold the device with reduced rotational force, and supports multiple folded angles.
Implementation Method 1
a first elastic member configured to be compressed or uncompressed by at least one of the first cam structures, second cam structures disposed on the second arm shaft, where at least one of the second cam structures linearly moves in the first axial direction along the second arm shaft, and a second elastic member configured to be compressed or uncompressed by at least one of the second cam structures
Implementation Method 2
The torque structure may be configured to provide a first friction torque in a fully folded state, provide a third friction torque greater than the first friction torque in a free stop section defined between the fully folded state and a flat state, and provide a second friction torque independently of the angle in a first section defined between the fully folded state and the free stop section
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An electronic device is provided. The electronic device includes a housing including a first housing portion and a second housing portion; a flexible display disposed over the first housing portion and the second housing portion; and a hinge structure disposed substantially between the first housing portion and the second housing portion, wherein the hinge structure includes a first shaft configured to rotate about a first axis, a second shaft configured to rotate about a second axis parallel to the first axis; a first cam structure configured to move in a length direction of the first shaft as the first shaft is rotated about the first axis; a second cam structure configured to move in the length direction of the first shaft as the first shaft is rotated about the first axis; a third cam structure configured to move in a length direction of the second shaft as the second shaft is rotated about the second axis; and a fourth cam structure configured to move in the length direction of the second shaft as the second shaft is rotated about the second axis.