Flexible Flat Cable Resin Sheet for Low-Loss High-Frequency Bending
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Solution Overview
Problem
Conventional flexible flat cables face challenges in achieving low relative dielectric constant and high flexibility due to the inclusion of flame retardants, which also affect their dielectric loss and stiffness, making it difficult to transmit high-frequency signals effectively.
Innovation Solution
A resin sheet for flexible flat cables is developed with a thermoplastic olefinic elastomer as a primary component, having a relative dielectric constant of 2.3 or less and a dielectric loss tangent of 0.0014 or less, along with a tensile elastic modulus of 40 MPa to 450 MPa, enhancing dielectric characteristics and flexibility while maintaining dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flame retardants are included in the resin sheet to achieve flame retardancy, then safety is improved, but relative dielectric constant increases and dielectric loss worsens
Solution Approach 1:
The patent extracts and removes flame retardant additives from the resin composition. By using a thermoplastic olefinic elastomer without flame retardants, the invention eliminates the source of dielectric loss while maintaining flame retardancy through the inherent properties of the elastomer material itself.
Solution Approach 2:
The patent changes the material parameters by selecting a thermoplastic olefinic elastomer with specific properties (relative dielectric constant of 2.3 or less, dielectric loss tangent of 0.0014 or less). This parameter change enables achieving low dielectric loss without flame retardants while maintaining flame retardancy.
2Reliability
If conventional resin materials are used to achieve flame retardancy, then safety is improved, but flexibility and dielectric characteristics for high-frequency signal transmission deteriorate
Solution Approach 1:
The patent changes the material parameters by selecting a thermoplastic olefinic elastomer with specific tensile elastic modulus (40 MPa to 450 MPa) and dielectric properties. This enables the resin sheet to maintain flexibility for bending operations while achieving flame retardancy and low dielectric loss for high-frequency signal transmission.
3Loss of energy
If low relative dielectric constant layers containing polyolefin are used to improve dielectric characteristics, then dielectric loss is reduced, but flexibility increases (material becomes stiffer)
Solution Approach 1:
The patent optimizes the tensile elastic modulus parameter to a specific range (40 MPa to 450 MPa) for the thermoplastic olefinic elastomer. This parameter change ensures the material maintains sufficient flexibility for bending operations while achieving the required low dielectric loss tangent of 0.0014 or less.
Data Source
AI summary
A resin sheet for a flexible flat cable of the present disclosure comprises one or a plurality of insulating layers and being layered between a plurality of conductors arranged in parallel and a shield layer layered on an outer surface side of parallel arranged surfaces of the plurality of conductors. The resin sheet has a relative dielectric constant of 2.3 or less at 25° C. and 10 GHZ, and a dielectric loss tangent of 0.0014 or less. The resin sheet has a tensile elastic modulus of 40 MPa to 450 MPa. The resin sheet includes a base insulating layer containing a thermoplastic olefinic elastomer as a primary component, and an average thickness of the base insulating layer is 20 μm to 450 μm.