Hearing Aid Magnetostrictive Sensor for Compact Wireless Charging
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Solution Overview
Problem
Hearing aids face challenges with power supply due to the size and maintenance requirements of rechargeable batteries and their charging circuitry, particularly with cordless charging, which often requires a large secondary coil and precise alignment, limiting miniaturization and increasing recharging time.
Innovation Solution
The use of a magnetostrictive electroactive (ME) sensor replaces the secondary coil, allowing for smaller size, increased power transfer efficiency, and flexibility in design by scavenging power from magnetic fields, receiving sound signals, and detecting user commands, thereby reducing the size of the power receiving circuitry and simplifying the mechanical design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cordless charging technology is used to recharge the hearing aid battery, then the hearing aid can be recharged without a cord, but the charging circuitry occupies significant space and requires precise alignment
Solution Approach 1:
The patent replaces the traditional electromagnetic induction charging system with a magnetostrictive electroactive (ME) sensor-based charging system. The ME sensor converts magnetic field energy directly into mechanical strain and electrical energy through magnetostrictive effect, eliminating the need for large secondary coils and complex alignment mechanisms. This substitution of the charging mechanism resolves the contradiction by maintaining cordless charging convenience while dramatically reducing the space required for charging circuitry.
Solution Approach 2:
The patent changes the operating parameters of the charging system by using high-frequency magnetic fields with the ME sensor instead of traditional low-frequency electromagnetic induction. This parameter change enables efficient power transfer with a much smaller sensor size, as the ME sensor can respond to high-frequency magnetic fields and convert them into usable electrical energy for battery charging, thus reducing the volume occupied by charging circuitry while maintaining cordless operation.
2Loss of energy
If a large secondary coil is used for power transfer, then power transfer efficiency increases, but the hearing aid size increases and alignment precision requirements increase
Solution Approach 1:
The patent substitutes the large secondary coil with a compact ME sensor that directly converts magnetic field energy into mechanical and electrical energy. The ME sensor's magnetostrictive properties enable it to respond to magnetic fields by changing its physical dimensions and generating electrical signals, achieving efficient power transfer without requiring the large coil structure. This substitution maintains power transfer efficiency while dramatically reducing the hearing aid size.
Solution Approach 2:
The ME sensor utilizes composite materials with both magnetostrictive and piezoelectric properties, allowing it to efficiently convert magnetic field energy into electrical energy. The composite structure enables high power transfer efficiency in a compact form factor, as the magnetostrictive layer responds to magnetic fields while the piezoelectric layer converts the resulting mechanical strain into electrical energy for battery charging, eliminating the need for large coils.
3Reliability
If traditional battery and charging circuitry are used, then power supply is reliable, but the battery occupies substantial portion of the device and requires frequent replacement
Solution Approach 1:
The ME sensor serves multiple functions simultaneously: it acts as a power receiver for battery charging, a microphone for sound detection, and a control sensor for user commands. This multi-functionality eliminates the need for separate charging circuitry and reduces the number of components required, thereby maintaining power supply reliability while significantly reducing the space occupied by power supply components in the hearing aid.
Solution Approach 2:
The hearing aid system uses the ME sensor to harvest energy from environmental magnetic fields, enabling the device to partially or fully recharge its battery without external charging equipment. This self-service capability reduces the frequency of battery replacements and eliminates the need for bulky charging circuitry, while maintaining reliable power supply through continuous energy harvesting from the environment.
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 solution enables a smaller hearing aid with reduced recharging time, increased power availability, and greater tolerance in alignment, allowing for additional components and broader application in various hearing aid types, while easing mechanical design constraints and user interaction.
Implementation Method 1
A hearing aid includes a magnetostrictive electroactive (ME) sensor that generates an electrical signal in response to a magnetic field or a mechanical pressure
Implementation Method 2
The ME sensor generates a power signal in response to a magnetic field and generates a driving signal in response to another magnetic field or a pressure
Data Source
AI summary
A hearing aid includes a magnetostrictive electroactive (ME) sensor that generates an electrical signal in response to a magnetic field or a mechanical pressure. In various embodiments, the ME sensor is used for cordless charging of a rechargeable battery in the hearing aid by generating an electrical signal in response to a magnetic field generated for power transfer, magnetic sound signal reception, and/or detection of user commands by sensing a magnetic field or a pressure applied to the hearing aid.