Flexible PCB Hinge Layout for Foldable Curvature Stress Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As electronic devices become slimmer, the reduced height of the hinge housing in foldable devices increases stress and curvature variance in the flexible printed circuit board, leading to potential damage, especially in narrow areas.
Innovation Solution
The flexible printed circuit board is designed with varying curvatures in different sections to manage stress, including a first section with consistent curvature and a second section that forms a linear area in the folded state and a curved area in the unfolded state, reducing curvature variance and enhancing durability without additional stiffeners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the hinge housing height is reduced to make the device slimmer, then the device thickness is improved, but the stress and curvature variance in the flexible printed circuit board increases leading to potential damage
Solution Approach 1:
The flexible printed circuit board is designed with different section types (first section with consistent curvature, second section that transitions between linear and curved states) to create local variations in mechanical properties. This allows different parts of the FPCB to handle stress differently, with the second section absorbing curvature variance through its shape-changing capability while the first section maintains structural stability
Solution Approach 2:
The second section of the FPCB is designed to dynamically change its shape between linear and curved states depending on the folding condition. This dynamic adaptation allows the FPCB to manage stress by adjusting its curvature profile, reducing the harmful effects of high variance in curvature that would otherwise occur in a uniformly thin structure
2Length of moving object
If the hinge housing height is reduced, then the device thickness is improved, but the variance in curvature of the flexible printed circuit board increases
Solution Approach 1:
The FPCB is divided into multiple sections (first section and second section) with different geometric configurations. The first section maintains consistent curvature while the second section is designed to form linear areas in folded state and curved areas in unfolded state, thereby segmenting the curvature management function across different parts of the board
Solution Approach 2:
The second section of the FPCB utilizes three-dimensional shape changes by transitioning between linear and curved configurations. This dimensional flexibility allows the FPCB to accommodate the space constraints of a thinner hinge housing while managing curvature variance through out-of-plane deformation
3Device complexity
If narrow areas are present in the flexible printed circuit board, then the device complexity is reduced, but the areas are more easily broken by external force
Solution Approach 1:
The FPCB design incorporates specific section types with different geometric properties to address local weakness. The second section's linear-area-in-folded-state configuration provides enhanced structural support in narrow regions, making them more resistant to breakage without requiring overall structural complexity
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 design effectively prevents damage to the flexible printed circuit board by managing curvature variance, enhancing its durability and reducing the risk of breakage during bending.
Implementation Method 1
a flexible printed circuit board (FPCB), which has a first end connected to a first printed circuit board (PCB) disposed in the first housing, and a second end connected to a second PCB disposed in the second housing
Data Source
AI summary
An electronic device includes: a hinge structure which is a folding area and includes a hinge housing; a first housing connected to the hinge structure; a second housing connected with the first housing through the hinge structure to be rotatable with respect to the first housing; and a flexible printed circuit board (FPCB), which has one end connected to a first printed circuit board (PCB) disposed in the first housing, and the other end connected to a second PCB disposed in the second housing. The FPCB includes a first section and a second section, the second section is extended from one side of the first section, and a variance in a curvature of the second section is greater than a variance in a curvature of the first section when the first housing and the second housing rotate with respect to the hinge structure.