Flexible Magnetic Sheet for Wireless Power Modules

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Solution Overview

Problem

Conventional magnetic sheets used in portable electronic devices are brittle and prone to cracking or physical damage, leading to degradation of magnetic properties such as permeability, especially during storage, transfer, and attachment processes, which affects their performance in wireless power transmission and near-field communication.

Innovation Solution

A magnetic sheet with improved mechanical strength and flexibility is achieved by forming a magnetic layer of crushed pieces and applying a thin film coating layer made from ethylene propylene diene monomer (EPDM) rubber, which enhances the sheet's ability to withstand external forces and maintain magnetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the magnetic sheet is made thinner to achieve light weight and compact design, then the portability and compactness are improved, but the magnetic body becomes more prone to cracks and physical damage

Engineering Contradiction:
Improveweight of magnetic sheetVSAvoidresistance to cracks and physical damage
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent uses a composite structure consisting of a magnetic body layer combined with a flexible polymer matrix material. This composite approach allows the magnetic sheet to maintain thin thickness while the polymer matrix provides crack resistance and prevents physical damage to the brittle magnetic body particles.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a flexible polymer matrix that surrounds and protects the magnetic body particles. This flexible matrix acts as a protective shell that prevents cracks from propagating through the magnetic body, enabling the magnetic sheet to be made thin without compromising reliability.

Inventive Principle:
Principle #30Flexible shells and thin films

2Adaptability or versatility

If the magnetic sheet is made thinner to improve flexibility and adaptability to stepped surfaces, then the ability to conform to target surfaces is improved, but cracks and damage easily occur in the magnetic body during disposal and attachment

Engineering Contradiction:
Improveability to conform to stepped surfacesVSAvoidresistance to cracks during handling
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The flexible polymer matrix surrounding the magnetic body particles acts as a protective shell that prevents cracks from forming during handling and attachment. This flexible matrix allows the magnetic sheet to conform to stepped surfaces while maintaining structural integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The composite structure of magnetic body particles embedded in a flexible polymer matrix provides both the flexibility needed to conform to stepped surfaces and the strength to resist cracks during handling and attachment operations.

Inventive Principle:
Principle #40Composite materials

3Area of stationary object

If conventional magnetic sheets are attached to surfaces with stepped portions, then coverage is attempted, but the poor flexibility causes significant inability to bring into close contact and cracks may occur

Engineering Contradiction:
Improvecoverage area on target surfaceVSAvoidability to bring into close contact
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The flexible polymer matrix allows the magnetic sheet to be highly flexible and adaptable to irregular surfaces including stepped portions. This flexibility enables the magnetic sheet to be brought into close contact with the target surface, maximizing coverage area.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If the magnetic body is made brittle to maintain magnetic properties, then magnetic permeability is maintained, but physical damage such as cracks occurs easily during usage

Engineering Contradiction:
Improvemagnetic permeabilityVSAvoidresistance to physical damage during usage
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite structure where magnetic body particles (maintaining magnetic permeability) are embedded in a flexible polymer matrix (providing crack resistance). This composite approach allows the magnetic sheet to maintain desirable magnetic properties while being highly resistant to physical damage during usage including drops and impacts.

Inventive Principle:
Principle #40Composite 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 magnetic sheet exhibits superior tensile and bending properties, preventing physical damage-induced degradation of magnetic permeability and maintaining transmission and reception efficiencies over time, even on surfaces with stepped portions, thus enhancing the performance of wireless power transmission and near-field communication modules.

Implementation Method 1

a thin film coating layer made from ethylene propylene diene monomer (EPDM) rubber, which enhances the sheet's ability to withstand external forces

Methodology Applied
Scientific EffectBuffering: Damping

Implementation Method 2

a magnetic layer formed of a magnetic body in a sheet shape crushed into a plurality of pieces

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP3361487B1Magnetic sheet, module comprising same, and portable device comprising same
Publication Date: 2021.09.22 AMOGREENTECH CO LTD
  • EP3361487B1 patent drawingFigure 1~2a
  • EP3361487B1 patent drawingFigure 2b~3
  • EP3361487B1 patent drawingFigure 4a~4b

AI summary

Provided herein is a magnetic sheet. The magnetic sheet according to one embodiment of the present invention includes a magnetic layer formed of crushed pieces of a magnetic body to improve flexibility of the magnetic sheet, and a thin film coating layer formed on at least one surface of the magnetic layer to maintain the magnetic layer in a sheet shape and buffer an external force applied to the crushed pieces of the magnetic body. According to the present invention, since the magnetic sheet is improved in mechanical strength properties, such as a tensile property, a bending property, and the like, to have significantly superior flexibility, degradation of physical properties, such as magnetic permeability and the like, caused by physical damage such as unintended cracks in the magnetic body provided in the magnetic sheet can be prevented even in the process of storing, transferring, and attaching the magnetic sheet to a target object and during usage of an electronic device provided with the target object to which the magnetic sheet is attached, and the magnetic sheet can be attached to a target surface of the target object with a superior adhering force even when a stepped portion is present at the surface, and at the same time, the magnetic sheet can block the influence of a magnetic field on parts of a portable terminal device or a human body of a user using the portable terminal device, significantly increase transmission and reception efficiencies and distances of a data and/or wireless power signal, and maintain the above-described performance for a long period of time, such that the magnetic sheet can be widely used in various portable devices such as mobile devices, smart appliances, devices for the Internet of Things, and the like.