Hermetic Feedthrough via Oxidized Metal Islet in Medical Device Housing
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Solution Overview
Problem
Active implantable medical devices face challenges in forming feedthroughs that provide both electrical isolation and hermetic sealing, which are costly and limit miniaturization due to complex manufacturing processes and the use of ceramic/metal components, leading to reliability issues and increased costs.
Innovation Solution
A method is developed to create an electrically isolating zone within the metal housing wall by forming a non-through groove and using an isolating layer to support a metallic islet, eliminating the need for ceramic/metal components and reducing manufacturing complexity, with steps involving oxidation, etching, and deposition of insulating layers to ensure hermetic sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic or glass insulating materials are used to form feedthroughs with metal housing, then electrical isolation is achieved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent extracts the ceramic insulating material from the feedthrough structure and replaces it with the metal housing material itself. The housing wall is directly oxidized to form the insulating layer, eliminating the need for separate ceramic components and their associated brazing operations.
Solution Approach 2:
The patent merges the housing structure and insulating layer into a single integrated component. The insulating layer is formed directly on the housing wall through oxidation, combining what were previously separate parts (metal housing and ceramic insulator) into one monolithic structure.
2Reliability
If ceramic/metal feedthrough components are used, then hermetic sealing is achieved, but manufacturing cost increases by up to 10% of device total cost
Solution Approach 1:
The patent replaces expensive ceramic and gold brazing materials with a cost-effective oxidation process. The insulating layer is formed through direct oxidation of the metal housing, eliminating the need for costly ceramic components and precious metal brazing materials.
Solution Approach 2:
The housing material itself serves as the base for the insulating layer. The metal housing undergoes oxidation to form the insulating layer, meaning the housing serves dual purposes as both structural component and substrate for electrical isolation, eliminating the need for separate insulating components.
3Reliability
If laser welding is used to attach feedthroughs to titanium housing, then hermetic seal is formed, but gaps and reliability issues occur
Solution Approach 1:
The patent merges the housing and insulating layer into a single integrated component formed by direct oxidation. This eliminates the interfaces between separate parts that require welding or brazing, thereby eliminating the gaps and reliability issues associated with joining operations.
Solution Approach 2:
The patent removes the separate feedthrough component and its associated joining operations (laser welding, brazing) from the manufacturing process. The insulating layer is formed directly on the housing through oxidation, eliminating the need for joining operations entirely.
4Adaptability or versatility
If the number of electrodes is increased for multisite devices, then functionality is improved, but the number of feedthroughs and manufacturing complexity increase
Solution Approach 1:
The patent creates a universal feedthrough formation process that can accommodate any number of electrodes. The direct oxidation method allows for multiple pins to pass through the housing wall with insulating layers formed on each, providing a scalable solution that doesn't increase manufacturing complexity regardless of the number of contacts required.
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 reduces manufacturing costs and complexity, enhances hermetic sealing, and allows for miniaturization of medical devices by directly forming feedthroughs on the housing, avoiding the drawbacks of ceramic/metal brazing and laser welding, while maintaining electrical continuity and biocompatibility.
Implementation Method 1
forming an electrically isolating layer on each of the external and internal sides of the metallic electrically conductive housing wall of the device
Data Source
AI summary
A method for making an hermetic and electrically insulating feedthrough in the metal wall of a housing of a device, preferably of an active medical device, is disclosed. The method includes: a) forming electrically insulating layers (24, 26) on each of the internal and external sides of the wall (10), b) on the internal side of the wall, forming a non-through groove with a closed contour (30) defining in the wall a metal islet (28) that is physically and electrically isolated from the rest of the wall, by removing the entire thickness of the electrically insulating internal layer (26) and the wall (10), leaving intact a sufficient thickness of the electrically insulating external layer (24) so that the external layer mechanically supports the metal islet, and c) on the external and internal sides respectively, exposing pads (34, 36) for making an electrical contact to the metallic islet, by a localized removal of material of the electrically insulating external and internal layers (24, 26), respectively.