Hearing Aid Antenna Interference Reduction via Ferromagnetic Shielding

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Solution Overview

Problem

The limitations in maximum transmission power and reception sensitivity of inductive wireless data transmission in hearing aids due to battery constraints and legal power restrictions, combined with significant interference from electromagnetic emissions from hearing aid components, result in reduced transmission range and quality.

Innovation Solution

A device that reduces interference coupling into the receiving antenna by using a compensation plate or existing metallic/magnetic components to correct field asymmetry and induce symmetrical interference currents, potentially incorporating a variable density coil core to minimize induced interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If inductive wireless transmission is used in hearing aids, then data transmission capability is improved, but transmission range and quality deteriorate due to limited power and interference

Engineering Contradiction:
Improvedata transmission capabilityVSAvoidtransmission quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies ferromagnetic shielding materials to convert the harmful electromagnetic interference fields generated by hearing aid components into beneficial effects. The shielding materials redirect and contain the interference fields, preventing them from coupling into the receiving antenna, thereby improving transmission quality while maintaining data transmission capability

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces ferromagnetic shielding materials as intermediary elements between the interference sources (voltage regulators, semiconductor components, supply lines) and the receiving antenna. These shielding materials act as mediators that intercept and redirect interference fields, protecting the receiving antenna from harmful electromagnetic coupling

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of stationary object

If maximum transmission power is increased to extend range, then transmission range is improved, but battery capacity and power consumption worsen

Engineering Contradiction:
Improvetransmission rangeVSAvoidbattery power consumption
Core Design Contradiction:
Length of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful electromagnetic interference into a beneficial shielding effect. By strategically placing ferromagnetic shielding materials, the interference fields are redirected and contained, effectively reducing interference coupling without requiring increased transmission power, thus extending transmission range while maintaining battery efficiency

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If shielding materials are added to reduce interference, then transmission quality is improved, but device complexity and size worsen

Engineering Contradiction:
Improvetransmission qualityVSAvoiddevice structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the shielding function with existing hearing aid components. The ferromagnetic shielding materials are integrated into the housing structure or positioned adjacent to existing components, combining multiple functions into unified elements and reducing overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shielding materials serve multiple functions simultaneously: they provide electromagnetic shielding, contribute to structural support, and may serve as mounting surfaces for other components. This multi-functionality reduces the need for additional dedicated shielding structures, simplifying device design

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Object-affected harmful factors

If distance between transmitting coil and interference sources is increased, then interference coupling is reduced, but transmission range and compactness worsen

Engineering Contradiction:
Improveinterference couplingVSAvoidtransmission range
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The patent introduces ferromagnetic shielding materials as intermediary elements between the interference sources and the receiving antenna. These shielding materials intercept and redirect interference fields, effectively reducing coupling without requiring increased separation distance, thus maintaining compact device dimensions while reducing interference

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This approach effectively reduces interference coupling, enhancing the reliability and range of inductive wireless data transmission in hearing aids by compensating for asymmetrical field lines and optimizing antenna geometry to minimize induced currents.

Implementation Method 1

A compensation inductance is arranged in a receiver signal line for active shielding of a receiver of the hearing aid device. During operation of the induction coil, the compensation inductance generates a compensation field directed against a magnetic field of the induction coil

Methodology Applied
Scientific EffectMagnetic field compensation: Magnetic Field

Implementation Method 2

the measure to be taken is to shield the source of interference with suitable materials, e.g. with a μ-metal or another suitable electrically conductive material. A so-called μ-metal contains metal alloys of high permeability μ. These shield low-frequency magnetic fields

Methodology Applied
Scientific EffectFerromagnetic shielding: Ferromagnetism

Implementation Method 3

the inductive wireless transmission of data from a hearing aid, a relay station, a programming device or a remote control to a hearing aid equipped with a suitable receiving device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2124481B1Apparatus for reducing interferences in a wireless data transmission in hearing aid applications
Publication Date: 2013.10.30 SIEMENS MEDICAL INSTRUMENTS PTE LTD
  • EP2124481B1 patent drawingFigure 1
  • EP2124481B1 patent drawingFigure 2A~2C
  • EP2124481B1 patent drawingFigure 3

AI summary

The invention discloses a device and a method for reducing interference coupling into a receiving antenna of a wireless data transmission device of a hearing aid caused by asymmetrically formed field lines of at least one hearing aid component. The device comprises at least one first means arranged in the hearing aid, by which the asymmetry of the field lines is reduced and the field distortion is corrected. Additionally, the receiving antenna can also be geometrically adapted to the external interference field of the hearing aid components such that the interference currents induced by field coupling are compensated in the antenna. The advantage of this is that interference coupling into the receiving antenna is thereby reduced.