Impedance Tomography for Implantable Device Charging Alignment
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Solution Overview
Problem
Existing medical systems for wireless power transfer to implantable devices lack efficient alignment feedback, leading to suboptimal energy transfer and potential thermal stress on patients.
Innovation Solution
A medical system utilizing impedance tomography with a plurality of metal electrodes arranged on the charging device's housing surface to calculate impedance for each segment, determining the alignment of the primary and secondary coils for optimal energy transfer and providing alignment feedback to the patient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If alignment feedback is not provided to the patient, then the charging process can proceed without additional complexity, but energy transfer efficiency is suboptimal and thermal stress increases
Solution Approach 1:
The patent implements an impedance tomography system that continuously monitors the impedance of multiple electrodes during the charging process. When misalignment is detected (impedance values indicate the implant is not properly positioned under the primary coil), the system provides feedback to the patient via audio or visual signals to guide realignment. This feedback mechanism resolves the contradiction by enabling high energy transfer efficiency only when proper alignment is achieved, while maintaining system simplicity through straightforward impedance measurement and signal guidance.
2Measurement precision
If impedance tomography with multiple electrodes is implemented, then alignment detection precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the charging device housing into multiple segments, each equipped with an electrode. By measuring impedance at each segmented location independently, the system achieves high spatial resolution for detecting implant position and orientation. The segmentation approach allows precise localization of the implant without requiring a single complex sensor, as each electrode provides localized impedance data that collectively maps the implant's position relative to the primary coil.
Solution Approach 2:
The patent uses the patient's body tissue as an intermediary medium between the electrodes and the implant. The impedance measurements are taken through the tissue, which naturally conducts the measurement current from the electrodes to the implant's secondary coil. This intermediary approach simplifies the measurement system by utilizing the body's inherent electrical properties rather than requiring direct contact or additional coupling mechanisms between the charging device and implant.
3Loss of time
If rapid alignment feedback is provided, then charging time is reduced, but the system requires more complex real-time monitoring capabilities
Solution Approach 1:
The patent performs impedance measurements continuously during the charging process, starting from the initial placement of the charging device. By monitoring impedance in real-time from the beginning, the system can detect misalignment early and provide immediate feedback for correction, preventing wasted charging time. The preliminary and continuous measurement approach ensures that alignment issues are addressed before significant energy transfer occurs, reducing overall charging time without requiring post-placement adjustments.
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 system enables rapid and accurate alignment of the charging device over the implantable medical device, ensuring efficient energy transfer, reducing thermal stress, and facilitating faster charging times.
Implementation Method 1
a coil at the charging device excites a coil at the implantable medical device
Implementation Method 2
Impedance measurements consist of an array of electrodes (at least two) to which an alternating current is output and the corresponding voltage is measured. According to Ohm's law, impedance is Z=V/I
Data Source
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AI summary
The present invention relates to a medical system (1) comprising an implantable medical device (2), comprising an energy storage device for supplying electrical energy to the medical device (2), and a secondary coil (20) for transferring electrical energy to the energy storage device, and a charging device (3) which is designed to charge the energy storage device, the charging device (3) having a primary coil (30) via which electrical energy can be transferred to the energy storage device via the secondary coil of the implantable medical device (2). According to the invention, it is provided that the charging device (3) has a plurality of metal electrodes (31) which are arranged in front of the primary coil (30) and are each assigned to a segment (32) of a housing surface (33) of the charging device (3), the charging device (3) being designed to use the metal electrodes (31) to calculate an impedance for each segment (32) and to use the impedances to check whether the primary coil (30) is aligned with the secondary coil (20) for optimum energy transfer.