Foldable Display Hinge FPC Layout for Lower Bending Stress
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Solution Overview
Problem
Foldable electronic devices are prone to damaging the flexible circuit board during the folding process due to increased movable-state bent sections and compact bending angles, leading to reduced controllability and higher stress on the circuit board.
Innovation Solution
The design includes two middle frames, a rotating shaft assembly, and a flexible circuit board with specific mounting members that reduce the number of movable-state bent sections by ensuring a gentle bending form and large space for the circuit board extensions, minimizing stress and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flexible circuit board passes through the rotating shaft assembly with multiple connection points, then the electrical connection is more stable, but the bending stress and damage probability of the circuit board increases
Solution Approach 1:
The patent extracts the middle part of the flexible circuit board from the rotating shaft assembly, allowing only the two ends to pass through. This removes the harmful interaction between the rotating shaft and the circuit board middle section, eliminating the bending stress caused by rotation while maintaining electrical connection stability through the end connection points.
Solution Approach 2:
The patent introduces mounting members as intermediary structures to connect the flexible circuit board to the frame bodies. These mounting members serve as mediators that provide stable electrical connection points without requiring the circuit board to pass through the rotating shaft assembly, thereby reducing bending stress while maintaining connection reliability.
2Device complexity
If the distance between mounting members is small, then the structural compactness is improved, but the bending angle becomes small and bending stress increases
Solution Approach 1:
The patent positions the mounting members in different spatial dimensions and orientations rather than simply increasing the linear distance between them. The first mounting member is oriented perpendicular to the flexible display, while the second mounting member is oriented parallel to it, creating a three-dimensional arrangement that provides adequate bending space without increasing overall device size.
Solution Approach 2:
The patent employs asymmetric orientation of the two mounting members relative to the flexible display. The first mounting member extends perpendicular to the display surface while the second extends parallel to it, creating an asymmetric configuration that optimizes the bending path and reduces stress concentration while maintaining structural compactness.
Data Source
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AI summary
This application provides a foldable electronic device. The foldable electronic device includes two middle frames, a rotating shaft assembly, a flexible circuit board, and a flexible display. The two middle frames are rotatably connected to two sides of the rotating shaft assembly respectively. The flexible display is laid on the two middle frames and the rotating shaft assembly. The rotating shaft assembly includes a principal shaft. The flexible circuit board includes two fastening parts and a first extension section located between the two fastening parts. The first extension section is disposed in the principal shaft in a penetrating manner. Each middle frame is connected to a mounting member. The fastening part is connected to the mounting member. The mounting member includes a first end and a second end. When the foldable electronic device is in an unfolded state, in a thickness direction of the flexible display, a distance between the first end and the flexible display is less than or equal to a distance between the second end and the flexible display. In a direction parallel to the flexible display, a distance between the first end and the principal shaft is greater than a distance between the second end and the principal shaft, or a direction from the first end to the second end is perpendicular to the flexible display. Therefore, the foldable electronic device provided in this application can reduce a damage probability of the flexible circuit board.