Shielded Flat Cable Low Dielectric Loss Flame Retardant
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Solution Overview
Problem
Existing shielded flat cables face challenges in improving transmission characteristics due to high dielectric loss tangents and exposure of metal portions, which can lead to signal attenuation and defects during withstand voltage tests.
Innovation Solution
A shielded flat cable configuration featuring parallel flat conductors sandwiched by resin insulating layers with shield layers and adhesive resin films, where the dielectric loss tangent of the resin insulating layers is 0.001 or less at 10 GHz, and the adhesive films are made of flame retardant materials, ensuring proper noise resistance and high-frequency characteristics while preventing exposure of metal portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If resin insulating layers with flame retardant materials are used to ensure flame retardance, then flame safety is improved, but dielectric loss tangent increases leading to degraded transmission characteristics
Solution Approach 1:
The cable structure is segmented into distinct functional layers: signal conductors, resin insulating layers (for flame retardance), and metal shield layers (for EMI shielding). This segmentation allows each layer to optimize its specific function without compromising others, enabling flame retardant materials to be used in insulating layers while maintaining transmission characteristics through the shield layer's interference blocking capability.
Solution Approach 2:
The patent employs composite material structures combining resin insulating layers with metal shield layers. The resin insulating layers provide flame retardance while the metal shield layers provide EMI shielding, creating a composite system where the strengths of different materials complement each other to achieve both flame safety and good transmission characteristics.
2Object-affected harmful factors
If metal shield layers are used to improve EMI shielding, then noise resistance is improved, but metal portions may be exposed leading to defects in withstand voltage tests
Solution Approach 1:
The patent uses resin insulating layers as flexible protective shells that completely cover the metal shield layers. These thin film-like resin layers provide electrical insulation between the metal shield and signal conductors, preventing discharge defects during withstand voltage tests while maintaining the EMI shielding effectiveness of the metal layers.
3Reliability
If resin insulating layers completely cover metal shield layers to prevent exposure, then reliability in withstand voltage tests is improved, but transmission characteristics may be degraded due to additional dielectric material
Solution Approach 1:
The resin insulating layers are strategically positioned to cover only the necessary portions of metal shield layers where electrical insulation is required, rather than uniformly thick coverage. This localized approach provides adequate insulation to prevent discharge defects while minimizing the amount of dielectric material that could degrade transmission characteristics.
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 significantly improves transmission characteristics by reducing signal attenuation and preventing defects during withstand voltage tests, while maintaining flame retardance and reducing production costs by eliminating the need for grounding members.
Implementation Method 1
a dielectric loss tangent of the resin insulating layer, of the pair of resin insulating layers, in contact with the shield layer is 0.001 or less at 10 GHz
Implementation Method 2
the adhesive or the pair of first resin films is made of a flame retardant material
Data Source
AI summary
A shielded flat cable includes a plurality of flat conductors arranged in parallel, a pair of resin insulating layers sandwiching the flat conductors from both sides of a parallel surface of the flat conductors, and covering portions other than end portions of the flat conductors in a length direction, a pair of shield layers in contact with an outer surface of at least one resin insulating layer of the pair of resin insulating layers, and a pair of first resin films with an adhesive covering an outer surface of the pair of resin insulating layers or the shield layer. A dielectric loss tangent of the resin insulating layer, of the pair of resin insulating layers, in contact with the shield layer is 0.001 or less at 10 GHz, and the adhesive or the pair of first resin films is made of a flame retardant material.