Flexible Flat Cable With Air-Containing Insulator

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Solution Overview

Problem

Conventional flexible flat cables face challenges in controlling characteristic impedance and flexibility, leading to issues with signal transmission speed and electromagnetic interference, particularly in high-definition electronic devices, where they are not cost-effective and lack sufficient bending strength.

Innovation Solution

A flexible flat cable design incorporating an air-containing non-woven fabric as an insulating member, with a shield member connected to ground layers at terminal ends, allowing for adjustable dielectric constant and thickness to control characteristic impedance while maintaining flexibility and bending strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flexible printed circuit board type flat cable is used, then good electrical characteristics are achieved, but production cost increases and length is limited to 1,000 mm

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the manufacturing method from etching to lamination, and modifies the insulator material parameters by introducing air-containing foam material with specific dielectric constant range (1.05-1.30), enabling impedance control while reducing production cost and increasing cable length capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure combining foam insulator material with air pockets, base film, and adhesive layers to achieve both flexibility and controlled characteristic impedance, replacing the traditional etched copper on rigid substrate approach

Inventive Principle:

Principle #40Composite materials

2Speed

If signal transmission speed is increased, then device capabilities are enhanced, but characteristic impedance control becomes necessary increasing complexity

Engineering Contradiction:

Improvesignal transmission speedVSAvoidimpedance control requirements

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent controls characteristic impedance by adjusting insulator thickness and dielectric constant parameters, using foam material with air pockets to achieve impedance control without complex multi-layer structures or additional components

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces foam insulator material containing air pockets with controlled porosity to achieve specific dielectric constant values, simplifying impedance control compared to traditional solid dielectric materials requiring precise thickness control

Inventive Principle:

Principle #31Porous materials

3Reliability

If insulator thickness is increased to control characteristic impedance, then electrical characteristics improve, but cable flexibility deteriorates

Engineering Contradiction:

Improvecharacteristic impedance controlVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the dielectric constant parameter by using foam material with air pockets (1.05-1.30) instead of solid materials, enabling impedance control with reduced insulator thickness and improved flexibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses foam insulator material with controlled air pocket distribution to achieve the required dielectric constant with thinner overall insulator structure, maintaining flexibility while controlling characteristic impedance

Inventive Principle:

Principle #31Porous materials

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 the production of a flexible flat cable with good electrical characteristics, high flexibility, and bending strength at a low cost, suitable for high-speed signal transmission in electronic devices, such as notebook computers and flat-screen televisions, without increasing production complexity.

Implementation Method 1

an air-containing layer (14, 15), serving as an insulating member... The air-containing layer (14, 15) includes a non-woven fabric

Methodology Applied

Scientific EffectAir entrapment in foam structure: Foam

Implementation Method 2

a shield member (23, 24) disposed in such a manner as to cover a surface of the air-containing layer (14, 15)... conductively connected to ground layers

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS8138421B2Flat cable

Publication Date: 2012.03.20 DEXERIALS CORP

AI summary

A flexible flat cable capable of having good flexibility and good bending strength while reducing a thickness thereof without damaging a good electrical characteristic of a strip structure and capable of enhancing cost effectiveness is provided. The flexible flat cable includes: an air-containing layer, serving as an insulating member, having a width substantially the same as a transmission path width of a cable body including a plurality of conductors arranged in a prescribed pitch, the air-containing layer being disposed in such a manner as to sandwich the cable body from both sides; and shield members disposed in such a manner as to cover a surface of the air-containing layer and to be conductively connected to a ground layer at terminal portions of both ends of the cable body. The air-containing layer includes non-woven fabrics cut in a width substantially the same as the transmission path width of the cable body.