Offset External Magnet Assembly for Stable Transcutaneous RF Coupling
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Solution Overview
Problem
Existing auditory prostheses face challenges in maintaining consistent and efficient transcutaneous communication due to variations in skin flap thickness, which affect the coupling coefficient between external and implanted coils, leading to tuning issues and inconsistent RF link strength.
Innovation Solution
A ferromagnet assembly with a ferromagnetic and non-ferromagnetic portion is used to create a variable offset between the external and implanted coils, allowing adjustment based on skin flap thickness without modifying the existing prosthesis design, thereby stabilizing the RF communication link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional electromagnetic pump design is used, then the pump can move fluid through the catheter, but the pump becomes large in size and cannot fit within the catheter lumen
Solution Approach 1:
The pump is divided into discrete modular units, each containing a small magnet and valve assembly. These modular segments can be stacked or arranged to achieve the required pumping capacity while maintaining a compact overall size that fits within the catheter lumen.
Solution Approach 2:
The pump design transitions from a traditional linear electromagnetic pump configuration to a compact arrangement where magnets are positioned offset from the flow path. This dimensional reconfiguration allows the pump to achieve effective pumping action in a reduced volume by utilizing magnetic field interactions in a different spatial arrangement.
2Volume of moving object
If a compact pump design is implemented, then the pump fits within the catheter, but the pump generates significant heat due to high current requirements
Solution Approach 1:
The magnetic field strength is concentrated locally at the offset magnet position rather than requiring uniform high-field coverage throughout the entire pump volume. This localized field concentration allows the use of smaller, more efficient magnets that generate less heat while maintaining effective pumping force at the critical fluid interaction point.
Solution Approach 2:
The offset magnet acts as an intermediary element that transfers magnetic force to the fluid through the valve mechanism rather than requiring direct high-current electromagnetic interaction. This indirect force transmission reduces resistive heating in the electromagnetic components while maintaining pumping effectiveness.
3Volume of moving object
If high current is used to drive the electromagnetic pump, then the pump can operate in a compact size, but the pump consumes excessive power
Solution Approach 1:
The pump utilizes dynamic valve operation synchronized with the alternating magnetic field from the offset magnet. The valves open and close in response to magnetic field cycles, creating a pulsating flow that is more energy-efficient than continuous high-current operation. This dynamic operation allows the pump to achieve compact dimensions with reduced power consumption by leveraging temporal variations in magnetic force rather than sustained high current.
4Productivity
If conventional electromagnetic actuation is used, then the pump can move fluid, but the pump cannot be controlled to deliver precise dosing
Solution Approach 1:
The pump incorporates sensors that detect fluid flow, pressure, or magnetic field characteristics and provide feedback to a control system. This feedback mechanism allows the pump to adjust its operation in real-time, compensating for variations in fluid properties or delivery conditions to maintain precise dosing accuracy while preserving effective fluid pumping capability.
Solution Approach 2:
The pump maintains continuous monitoring and adjustment of its pumping action through the feedback control system, ensuring that dosing precision is maintained throughout the entire pumping cycle rather than relying on discrete control points. This continuous control enables both effective fluid movement and precise dosing delivery.
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 improves the efficiency and consistency of the RF communication link, reduces fitting issues, and extends battery life by maintaining consistent magnetic attraction and reducing sensitivity to skin flap thickness variations.
Implementation Method 1
a small pump including an offset magnet
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An apparatus is provided which includes a cavity and a ferromagnet assembly having a first centroidal axis. The ferromagnet assembly is configured to be contained within the cavity. The ferromagnet assembly includes a first portion including at least one non-ferromagnetic material. The ferromagnet assembly further includes a second portion including at least one ferromagnetic material. The second portion has a second centroidal axis that is offset from the first centroidal axis.