Flexible Printed Circuit Board Stress Distribution in Bendable Displays
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Solution Overview
Problem
Display apparatuses face durability issues due to stress applied to flexible printed circuit boards when bent, which can lead to deformation and reduced reliability.
Innovation Solution
The display apparatus incorporates a curved accommodation member with a greater rigidity than the display panel, where the printed circuit boards are fixed to the rear surface of this member, and flexible printed circuit boards connect the display panel to the printed circuit boards, distributing stress and minimizing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flexible printed circuit boards are used to connect the display panel and printed circuit boards, then ease of operation and adaptability are improved, but stress concentration and deformation occur during bending, reducing reliability
Solution Approach 1:
The circuit board system is segmented into rigid printed circuit boards and flexible printed circuit boards with different functions. The rigid PCBs provide structural support and mounting surfaces, while the flexible PCBs provide electrical connections and accommodate bending. This segmentation allows each part to be optimized for its specific function, resolving the contradiction between flexibility and reliability.
Solution Approach 2:
The flexible printed circuit board acts as an intermediary element between the rigid display panel and the rigid printed circuit boards. It absorbs and distributes the stress generated during bending, preventing direct transmission of stress to the rigid components. This intermediary role allows the system to maintain both flexibility and reliability.
2Device complexity
If printed circuit boards are fixed close to the display panel, then device complexity is reduced, but stress on flexible circuit boards increases during bending
Solution Approach 1:
The printed circuit boards are arranged in a specific spatial configuration relative to the display panel, utilizing the third dimension (depth/distance) to optimize stress distribution. By positioning the PCBs at an optimal distance and angle, the design reduces stress on the flexible connections while maintaining compact overall device structure, effectively managing the trade-off between complexity and stress.
3Adaptability or versatility
If the display module is bent to fit curved surfaces, then adaptability to different display surfaces is improved, but stress concentration occurs on the circuit boards
Solution Approach 1:
The flexible printed circuit boards are designed as thin, flexible films that can conform to curved surfaces without compromising their structural integrity. These flexible PCBs maintain electrical connectivity while adapting to the curvature of the display surface, resolving the contradiction between adaptability and strength.
Solution Approach 2:
The design allows for changes in the geometric parameters of the circuit board assembly, including the bending radius, distance between components, and orientation of PCBs. By optimizing these parameters, the system can adapt to different curvature requirements while maintaining the structural strength and reliability of the circuit board connections.
Data Source
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AI summary
A display apparatus includes a display panel bendable in a bending direction about a bending axis, pad units disposed on one side of the display panel and arranged in the bendable direction, printed circuit boards disposed below the display panel, and flexible printed circuit boards configured to connect the display panel to the printed circuit boards. The printed circuit boards are bendable in the bending direction about the bending axis, are arranged in the bendable direction, and extend in the bendable direction. Each of the flexible printed circuit boards has a first end connected to the display panel and a second end connected to one of the printed circuit boards. A second distance between the second ends of two of the flexible printed circuit boards respectively connected to two adjacent printed circuit boards is greater than a first distance between the first ends of the two flexible printed circuit boards.