Flexible Printed Circuit Bending Control via Creases and Elastomers
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Solution Overview
Problem
Flexible printed circuits in electronic devices are prone to damage from abrupt bending and contact with sharp structures, making them unreliable and difficult to manufacture, especially during assembly and disassembly.
Innovation Solution
Incorporating bend promotion features, such as plastic members and creases, and elastic members that can form service loops, along with overbending prevention structures like overmolded elastomeric materials to control bending and protect against sharp edges, ensuring controlled bending and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible printed circuit is bent too abruptly, then routing flexibility is improved, but the signal traces become damaged
Solution Approach 1:
The patent applies preliminary action by forming creases in the polymer substrate before final assembly. These pre-formed creases create predetermined bending zones that guide the flexible circuit to bend in specific locations with controlled radii, preventing abrupt bends that would damage signal traces while still allowing necessary routing flexibility
Solution Approach 2:
The patent implements local quality by creating localized creases at specific positions along the flexible printed circuit. These creases concentrate the bending deformation in predetermined areas with sufficient radius, while other portions of the circuit remain flat and undamaged, thus protecting signal traces while enabling routing adaptability
2Ease of operation
If service loops are included in flexible printed circuits to facilitate assembly and disassembly, then ease of operation is improved, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming creases that define the geometry of service loops before assembly. The creases are created in advance to establish predetermined bending zones, allowing service loops to be formed with controlled radii that facilitate assembly and disassembly operations without adding complex structural elements
Solution Approach 2:
The patent implements segmentation by dividing the flexible printed circuit into distinct functional zones: flat signal transmission areas and creased service loop areas. This segmentation allows the circuit to perform multiple functions (signal transmission and mechanical flexibility) without increasing overall complexity, as each zone is optimized for its specific purpose
3Reliability
If overbending prevention structures are applied to the flexible printed circuit, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements local quality by applying overbending prevention structures only at specific critical locations where bends occur, rather than throughout the entire flexible circuit. The creases create localized zones with controlled bending radii, and the elastomeric material provides targeted protection at these specific points, maintaining reliability while minimizing added complexity
Solution Approach 2:
The patent applies composite materials by combining the flexible polymer substrate with elastomeric material at the creases. This composite construction provides both the flexibility needed for routing and the protective qualities that prevent overbending, achieving reliability enhancement without requiring separate complex protective structures
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 solution enables reliable and efficient routing of flexible printed circuits by promoting controlled bending, forming service loops, and preventing overbending, thereby enhancing the reliability and manufacturability of electronic devices.
Implementation Method 1
Overbending prevention structures such as overmolded elastomeric structures may be applied to the flexible printed circuit at a bend
Implementation Method 2
The elastic member may have ends attached to opposing sides of a bend in the flexible printed circuit. The bend may be formed by contraction of the elastic member
Data Source
AI summary
An electronic device may have a signal cable formed from a flexible printed circuit. A service loop may be formed in the signal cable. The bend may be formed in a desired location on the flexible printed circuit by contraction of an elastic member having ends attached to the flexible printed circuit. The elastic member may be conductive to carry signals and provide shielding. Structures may be attached to the flexible printed circuit to promote bending in a desired location and direction. A crease or other bending promotion feature may be applied to the flexible printed circuit at a desired bend location. Overbending prevention structures such as overmolded elastomeric structures may be applied to the flexible printed circuit at the bend. Integral strain relief features may prevent overbending of the flexible printed circuit upon exiting the elastomeric structures. Overmolded structures may serve as protective bumpers.