NFC Timepiece Magnetic Screen for Signal Reliability

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Solution Overview

Problem

Timepieces equipped with near-field communication devices often suffer from reliability issues due to electromagnetic disturbances caused by metallic components, leading to malfunctions in signal connection and maintenance challenges.

Innovation Solution

Incorporating a magnetic screen with high magnetic permeability and low magnetic losses between the communication device and metallic components to isolate the magnetic field, thereby reducing signal attenuation and improving communication efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the communication device is integrated into metallic components of the timepiece, then the device can be compactly arranged, but electromagnetic disturbances occur leading to reduced reliability

Engineering Contradiction:
Improveintegration compactnessVSAvoidcommunication reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

A magnetic screen made of ferrite material is introduced as an intermediary element between the communication device and metallic components. This magnetic screen absorbs and redirects magnetic field lines, preventing direct interaction between the NFC antenna and metallic parts that would cause electromagnetic disturbances. The magnetic screen thus mediates the spatial relationship, allowing compact integration while maintaining communication reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The magnetic screen changes the magnetic field distribution parameters in the vicinity of the communication device. By introducing a material with high magnetic permeability (ferrite), the magnetic field lines are redirected and concentrated within the magnetic screen rather than interacting with metallic components. This parameter change in magnetic field distribution eliminates the harmful electromagnetic effects while preserving device compactness.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a large antenna is used to overcome electromagnetic disturbances, then communication reliability improves, but the integration becomes complex and maintenance difficult

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidintegration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Rather than enlarging the antenna, the patent introduces a magnetic screen as an intermediary protective element. This approach maintains the original antenna size and integration simplicity while effectively blocking electromagnetic disturbances. The magnetic screen provides the necessary protection without adding integration complexity or maintenance burden.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the communication device is placed close to metallic components, then space is saved, but signal attenuation increases due to electromagnetic interference

Engineering Contradiction:
Improvedevice spaceVSAvoidsignal attenuation
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The magnetic screen serves as a protective intermediary that allows the communication device to remain in close proximity to metallic components without suffering signal attenuation. The ferrite material absorbs and redirects magnetic field lines, preventing energy loss through electromagnetic interference while maintaining compact device spacing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The magnetic screen modifies the magnetic field parameters in the space between the communication device and metallic components. By introducing high permeability ferrite material, the magnetic field is redirected and concentrated, reducing signal attenuation and energy loss while preserving compact device arrangement.

Inventive Principle:
Principle #35Parameter changes

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 screen enhances the reliability and sensitivity of radio signal transmission and reception by isolating the communication device from metallic components, reducing electromagnetic interference and facilitating easier maintenance.

Implementation Method 1

The magnetic screen 8 also called magnetic shielding element has a magnetic permeability adapted to the frequency bands of the magnetic field generated by the communication device 4

Methodology Applied
Scientific EffectMagnetic permeability: Magnetic Field

Implementation Method 2

the magnetic screen 8 is able to separate the timepiece 35 into two zones, a first zone comprising the magnetic fields generated by the communication device 4 and a second zone which is not exposed to these magnetic fields

Methodology Applied
Scientific EffectMagnetic shielding: Magnetism

Implementation Method 3

low magnetic losses μ′′ with μ′′ < 0.5 and an electrical resistivity greater than 1000 KΩ/m

Methodology Applied
Scientific EffectMagnetic losses: Magnetic Hysteresis

Data Source

PatentEP3112958B1Timepiece comprising a near field communication device
Publication Date: 2022.03.16 BULGARI HORLOGERIE SA
  • EP3112958B1 patent drawingFigure 1~6
  • EP3112958B1 patent drawingFigure 7~8
  • EP3112958B1 patent drawingFigure 9~10

AI summary

The invention relates to a timepiece provided with a dial and/or a bezel comprising a near field communication device capable of receiving/transmitting a signal, said communication device being arranged at the level of the dial or the bezel of said timepiece and being associated with a magnetic screen in particular made of ferrite.