Shielded Flat Cable Ground Wire Segmentation
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Solution Overview
Problem
Shielded flat cables face challenges with noise interference and crosstalk between conductors, particularly when power wires are present, which can disrupt high-speed signal transmission.
Innovation Solution
The design incorporates multiple ground wires and a shield layer with openings that electrically couple to the ground wires, surrounding signal wires to prevent external noise and crosstalk, while allowing for adjustable characteristic impedance and robust bonding through an insulating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield layer is provided outside the FFC to shield signal wires, then external noise is reduced, but crosstalk between conductors increases and bonding strength decreases
Solution Approach 1:
The shield layer is divided into multiple separate shield wires rather than a continuous shield. These segmented shield wires are positioned between signal wires to block crosstalk while reducing overall shielding effectiveness against external noise compared to a continuous shield
Solution Approach 2:
Ground wires are introduced as intermediary elements between signal wires and shield wires, and between shield wires. These ground wires electrically connect to the shield layer through openings in the insulating layer, creating a staged shielding structure that reduces crosstalk while maintaining bonding strength
2Object-affected harmful factors
If a shield layer is provided outside the FFC to shield signal wires, then external noise is reduced, but bonding strength between insulating layer and conductors decreases
Solution Approach 1:
The continuous shield layer is segmented into discrete shield wires positioned at specific locations. This segmentation reduces the total contact area between the shield and insulating layer, thereby preserving bonding strength while maintaining adequate shielding performance
Solution Approach 2:
Ground wires serve as intermediaries that electrically connect the shield layer to the conductor assembly through openings in the insulating layer. This staged connection method reduces direct bonding requirements between the shield and insulating layer, preserving bonding strength while maintaining shielding effectiveness
3Object-generated harmful factors
If multiple ground wires are arrayed parallel to signal wires with openings in insulating layer, then crosstalk is reduced and bonding strength is maintained, but device complexity increases
Solution Approach 1:
Multiple ground wires are merged into a single continuous ground wire that runs parallel to the signal wires. This simplifies the structure by reducing the number of discrete components while maintaining the crosstalk reduction benefits of multiple ground connections
Solution Approach 2:
The ground wire structure serves multiple functions: it reduces crosstalk between signal wires, provides electrical connection to the shield layer through openings, and maintains mechanical bonding strength. This multi-functionality reduces the need for separate components, simplifying the overall device 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 configuration effectively shields signal wires from external noise and crosstalk, ensuring reliable high-speed signal transmission and maintaining bonding strength even in severe environments.
Implementation Method 1
a shield layer provided on an outer surface of the insulating layer. The insulating layer includes multiple openings of which bottoms are respectively an upper surface and a lower surface of each of the one or more ground wires. The one or more ground wires and the shield layer are electrically coupled at the multiple openings, and each of the one or more signal wires is surrounded by the one or more ground wires and the shield layer
Data Source
AI summary
A shielded flat cable 1 includes one or more ground wires G1, the ground wires G1 being arrayed parallel to each other, one or more signal wires S1 and S2 arrayed parallel to the one or more ground wires G1, insulating layers 11 and 12 covering the one or more ground wires G1 and the signal wires S1 and S2, and shield layers 21 and 22 provided on outer surfaces of the insulating layers 11 and 12. In a cross-section of the one or more ground wires, the insulating layers 11 and 12 include openings 13 and 14 of which bottoms are respectively an upper surface and a lower surface of one ground wire G1, and the one ground wire G1 and the shield layers 21 and 22 are electrically coupled at the openings 13 and 14, and the signal wires S1 and S2 are surrounded by the one or more ground wires G1 and the shield layers 21 and 22.