Active Medical Device Bushing With Integrated Filtering
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Solution Overview
Problem
The existing manufacturing technology for active implantable medical devices faces mechanical fragility and limited functionality due to the passive nature of electrical feedthroughs, which are prone to micro-defects and require complex and costly filtering solutions, and do not easily integrate additional components like RF antennas or sensors.
Innovation Solution
The proposed solution involves a metal casing with a conductive outer layer deposited over the insulating oxide layer, providing mechanical reinforcement and enabling the integration of capacitive filtering and additional functional elements like RF antennas and sensors, without additional components, by extending the conductive layer beyond the feedthrough region to form a capacitor or antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin oxide layer is used to electrically isolate the island from the wall, then electrical insulation is achieved, but mechanical strength and hermeticity are reduced
Solution Approach 1:
The patent applies composite materials by combining multiple layers with different properties: an insulating oxide layer (12) provides electrical insulation, while an additional conductive metal layer (28) deposited on top provides mechanical reinforcement. This composite structure maintains hermeticity through the thickened wall while achieving electrical insulation through the oxide layer, resolving the contradiction between hermeticity and mechanical strength.
2Reliability
If filtering is added to the bushing, then electrical signal filtering is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the filtering function with the existing bushing structure by forming a capacitive filter directly within the wall layers. The insulating oxide layer (12) and conductive metal layer (28) are structured to create capacitor plates, integrating filtering capability into the feedthrough itself rather than adding separate filtering components, thus improving signal filtering without increasing device complexity.
Solution Approach 2:
The bushing structure is designed to perform multiple functions simultaneously: the insulating oxide layer (12) provides both electrical insulation and serves as one plate of a capacitive filter, while the conductive metal layer (28) provides mechanical reinforcement and serves as the other plate of the capacitor. This multi-functionality achieves signal filtering without adding separate filtering components.
3Adaptability or versatility
If additional functional elements like RF antennas are integrated, then device functionality is enhanced, but device volume increases
Solution Approach 1:
The patent merges the RF antenna function with the existing conductive metal layer (28) of the bushing structure. The metal layer is extended and shaped to function both as a structural reinforcement and as an RF antenna element, integrating multiple functions into a single component rather than adding separate antenna elements, thus enhancing functionality without significantly increasing device volume.
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 enhances the mechanical robustness and hermeticity of the feedthroughs, integrates capacitive filtering and additional functional elements, and reduces the overall device volume, while maintaining biocompatibility and industrial feasibility.
Implementation Method 1
an electrically conductive external layer (28) formed above the external insulating layer (12)
Implementation Method 2
on the external side, in superficially oxidizing the titanium of the case or depositing an insulating layer (for example of silicon dioxide) thereon
Implementation Method 3
the conductive outer layer (28) may extend beyond the region of the bushing to an extent defining a first armature of a parallel filter capacitor of the bushing
Data Source
AI summary
In the feedthrough region, the housing wall has, on its inner side, a closed-contour groove (16) defining a physically and electrically isolated metallic island (14), this groove extending through the entire thickness of the wall. On its outer side, an electrically insulating outer layer (12) includes a recess (18) formed at the edge of the island, extending through the entire thickness of the insulating outer layer. On the outer side of the wall, there is also an electrically conductive outer layer (28) formed above the insulating outer layer and extending at least to the edge of the groove and beyond it on both sides. The island is mechanically supported and sealed by both the insulating and conductive outer layers. Furthermore, parallel (C1) and series (C2) filtering capacitors integrated into the structure can be defined for the feedthrough.