Flexible Printed Circuit With Patterned Voids For Bending And Shielding

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Solution Overview

Problem

Existing flexible printed circuits lack sufficient flexibility and resistance to electromagnetic radiation, making it difficult to conform to desired shapes and reducing product size while maintaining consistent circuit routing.

Innovation Solution

A flexible printed circuit design featuring a first insulating substrate layer with a first electrically conductive layer having a solid portion and a second portion with a pattern of voids, providing varying stiffness and flexibility, and additional conductive layers with voids for enhanced flexibility and electromagnetic shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a solid conductive layer is used for electromagnetic shielding, then electromagnetic radiation resistance is improved, but flexibility and ease of bending deteriorate

Engineering Contradiction:

Improveelectromagnetic radiation resistanceVSAvoidflexibility and ease of bending

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The conductive layer is designed with non-uniform structure: solid portions provide electromagnetic shielding where needed, while void portions provide flexibility where bending is required. This local differentiation resolves the contradiction by making different regions of the same layer serve different functions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The conductive layer incorporates a pattern of voids creating a porous or honeycomb structure. This allows the material to maintain electrical conductivity and electromagnetic shielding properties while significantly improving flexibility and reducing stiffness, enabling the circuit to bend without cracking the conductive layer.

Inventive Principle:

Principle #31Porous materials

2Strength

If the conductive layer is made solid for structural integrity, then strength and reliability are improved, but flexibility and adaptability to shapes deteriorate

Engineering Contradiction:

Improvestructural integrityVSAvoidflexibility and adaptability to shapes

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

Different regions of the conductive layer have different structures: solid portions maintain structural integrity and strength, while void portions provide flexibility. This allows the circuit to maintain overall strength while adapting to desired shapes through selective bending in void regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The conductive layer combines solid and void regions within the same layer, creating a composite structure that integrates both strength-providing and flexibility-providing characteristics, allowing the material to simultaneously achieve structural integrity and shape adaptability.

Inventive Principle:

Principle #40Composite materials

3Ease of operation

If voids are introduced in the conductive layer for flexibility, then ease of bending is improved, but electromagnetic shielding effectiveness may deteriorate

Engineering Contradiction:

Improveease of bendingVSAvoidelectromagnetic shielding effectiveness

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Voids are strategically placed in specific regions where flexibility is needed, while solid portions remain in regions requiring electromagnetic shielding. This localized approach ensures that flexibility is provided only where necessary, maintaining shielding effectiveness in critical areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The void pattern is designed to provide sufficient flexibility for bending while maintaining adequate shielding coverage. The solid portions are distributed throughout the layer to ensure electromagnetic shielding effectiveness is not compromised, even with the presence of voids.

Inventive Principle:

Principle #16Partial or excessive action

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 design allows for easier bending and reduced stiffness in specific portions, enabling more flexible circuit configurations while maintaining effective electromagnetic shielding, thus improving the circuit's ability to conform to shapes and reduce product size.

Implementation Method 1

A second portion having a multiplicity of voids in the first conductive layer in a pattern for providing a lower stiffness in the second portion relative to the first portion, thereby providing more flexibility in the second portion relative to the first portion

Methodology Applied

Scientific EffectStress concentration and distribution:

Implementation Method 2

The first conductive layer may resist electromagnetic radiation from traveling between the traces and an environment external to the flexible printed circuit

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentUS9560748B2Flexible printed circuit

Publication Date: 2017.01.31 BOSE CORP

AI summary

A flexible printed circuit includes a first insulating substrate layer and a first electrically conductive layer located adjacent to a first side of the insulating substrate layer. The first conductive layer has a first portion that is substantially solid and a second portion having a multiplicity of voids in the first conductive layer in a pattern for providing a lower stiffness in the second portion relative to the first portion, thereby providing more flexibility in the second portion relative to the first portion.