Transcutaneous Coil Loop Layout for Stronger Implant Coupling
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Solution Overview
Problem
Conventional wireless transcutaneous links for implantable medical devices, such as hearing aids, suffer from low coupling coefficients due to the parallel coil arrangement, leading to inefficient energy transfer and requiring large, heavy external units with multiple batteries, which are aesthetically unappealing and can cause discomfort and skin irritation.
Innovation Solution
The implementation of a wireless transcutaneous link with a transmitter coil wound around a loop structure that is attached to the body proximal to an implantable receiver coil, using a fixation unit to position the loop structure such that a substantial number of magnetic field lines pass through the receiver coil, enhancing the coupling coefficient and eliminating the need for retention magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a parallel coil arrangement is used for wireless transcutaneous link, then the external unit can be positioned opposite the implantable coil, but the coupling coefficient becomes very low and energy transfer efficiency deteriorates
Solution Approach 1:
The patent transitions from a parallel coil arrangement (both coils on the same side of skin) to a perpendicular arrangement where the external transmitter coil is positioned on the skin surface and the implantable receiver coil is positioned perpendicular to it, extending into the body tissue. This dimensional change optimizes magnetic field coupling and significantly improves the coupling coefficient and energy transfer efficiency.
Solution Approach 2:
The patent employs asymmetric coil positioning where the external transmitter coil and implantable receiver coil are arranged perpendicular to each other rather than in a symmetric parallel arrangement. This asymmetric configuration, combined with the external coil being larger than the implantable coil, optimizes the magnetic field distribution and coupling between the two coils.
2Stability of the object's composition
If retention magnets are used to fix the external unit to the patient's head, then the external unit remains in position, but the external unit weight increases and causes discomfort and skin irritation
Solution Approach 1:
The patent removes the retention magnets from the external unit, eliminating the source of skin irritation and excessive weight. Instead, the external coil is positioned on the skin surface without requiring magnetic fixation, and the implantable coil is secured during surgery without magnets that would require special MRI considerations.
Solution Approach 2:
The patent replaces the mechanical magnetic retention system with a positioning system based on geometric arrangement and fixation units. The external coil is positioned on the skin surface using fixation units rather than magnetic attraction, eliminating the need for heavy retention magnets while maintaining stable positioning.
3Duration of action of moving object
If the external unit includes a huge battery compartment to compensate for low energy transfer efficiency, then the usage period is extended, but the external unit size and weight increase and aesthetic appeal deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the coil arrangement, specifically positioning the external coil on the skin surface perpendicular to the implantable coil, and optimizing the coil sizes and winding configurations. These parameter changes significantly improve energy transfer efficiency, allowing for a more compact external unit with smaller battery compartment while maintaining adequate usage duration.
4Shape
If the external unit is positioned opposite the implantable coil with parallel arrangement, then the coils are aligned, but the magnetic field lines are not effectively coupled and energy transfer efficiency drops
Solution Approach 1:
The patent changes the spatial arrangement from parallel alignment (both coils on the same side of skin) to a perpendicular arrangement where the external coil lies on the skin surface and the implantable coil extends perpendicular to it into the body tissue. This dimensional change optimizes the magnetic field coupling by allowing field lines to pass through the implantable coil more effectively.
Solution Approach 2:
The skin and body tissue act as an intermediary medium between the external transmitter coil and implantable receiver coil. By positioning the external coil on the skin surface and the implantable coil perpendicular to it, the patent optimizes how the magnetic field interacts with this intermediary medium, improving coupling efficiency despite the presence of tissue between the coils.
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 configuration significantly improves the energy transfer efficiency, reduces the size and weight of the external unit, and eliminates skin irritation, providing a more comfortable and aesthetically pleasing solution for implantable medical devices.
Implementation Method 1
an external unit comprising a transmitter coil and an implantable unit comprising a receiver coil... transmit power and/or data signal over a wireless transcutaneous link... coupling between a transmitter coil and an implantable receiver coil
Data Source
AI summary
According to an embodiment, a medical device is disclosed. The medical device includes an external unit and an implantable unit. The external unit includes an electronic unit operationally coupled to a transmitter coil that is configured transmit power and/or data signal over a wireless transcutaneous link, a coil unit comprising a loop structure with the transmitter coil being wound around and along at least a part of length of the loop structure, and a fixation unit configured to attach the loop structure to a user's body i) proximal to an implantable receiver coil that is configured to be implanted within a body part, and ii) around a body part of a user such that a part of the body part is positioned in a hollow section of the loop structure. The implantable unit includes the implantable receiver coil configured to receive the power and/or data signal over the wireless transcutaneous link, a processing unit configured to i) process the received data signal to control functionalities of at least one of the components of the implantable unit, and/or ii) utilize the received power for operation of at least one of the components of the implantable unit. The wireless transcutaneous link includes a coupling between the transmitter coil and the receiver coil, and when the loop structure is attached using the fixation unit, at least a substantial number of magnetic field lines generated in response to excitation of the transmitter coil passes through the implantable receiver coil.