Composite Titanium Housing for Implantable Stimulation Modules
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Solution Overview
Problem
Implantable electrical stimulation systems face inefficiencies in signal penetration and charging due to low resistance materials used in their construction, which lead to reduced efficiency in inductive charging and telemetry communication.
Innovation Solution
A composite metal container for the control module is developed, utilizing a combination of low resistance materials like Grade 1 titanium for curved portions and higher resistance titanium alloys like Grade 23 for surface and edge areas to minimize eddy currents and enhance signal penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low resistance materials are used in the control module housing, then electrical conductivity is improved, but eddy currents increase causing reduced efficiency in inductive charging and telemetry
Solution Approach 1:
The housing is divided into different material zones: curved portions use low resistance material (Grade 1 titanium) while flat surface portions use high resistance material (Grade 23 titanium alloy). This local differentiation allows each zone to perform its optimal function - curved portions maintain structural integrity and conductivity, while flat portions minimize eddy currents and improve charging efficiency.
Solution Approach 2:
The housing combines two different titanium materials with distinct electrical resistance properties. Grade 1 titanium provides low resistance for structural portions, while Grade 23 titanium alloy provides high resistance for surface portions. This composite construction resolves the contradiction by allowing both low resistance and high resistance characteristics to coexist in different locations.
2Loss of energy
If high resistance materials are used in the control module housing, then eddy currents are reduced improving charging efficiency, but signal penetration and telemetry communication are weakened
Solution Approach 1:
Different material zones are strategically placed: high resistance material covers flat surfaces to minimize eddy currents, while low resistance material is used in curved portions to maintain signal penetration and telemetry functionality. This spatial differentiation resolves the contradiction between reducing energy loss and maintaining communication reliability.
Solution Approach 2:
The composite housing structure combines Grade 23 titanium alloy (high resistance) for eddy current reduction in flat areas with Grade 1 titanium (low resistance) for signal penetration in curved areas. This material combination allows both opposing requirements to be satisfied simultaneously in different locations.
3Ease of manufacture
If a single material is used for the control module housing, then manufacturing is simplified, but performance in both inductive charging and telemetry cannot be optimized
Solution Approach 1:
The housing employs different materials in different locations based on functional requirements. Curved portions use Grade 1 titanium for structural integrity and signal properties, while flat portions use Grade 23 titanium alloy for eddy current reduction. This localized material selection optimizes overall system performance while maintaining manufacturability through standardized titanium materials.
Solution Approach 2:
The housing is constructed as a composite of two titanium-based materials that are chemically similar but have different electrical properties. This approach balances manufacturing ease (both materials are titanium and can be joined using standard titanium fabrication techniques) with performance optimization (different electrical characteristics in different locations).
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 design improves the efficiency of inductive battery charging and telemetry communication by reducing eddy currents, allowing better signal penetration and communication within the control module.
Implementation Method 1
utilizing a combination of low resistance materials like Grade 1 titanium for curved portions and higher resistance titanium alloys like Grade 23 for surface and edge areas to minimize eddy currents and enhance signal penetration
Implementation Method 2
improves the efficiency of inductive battery charging
Data Source
AI summary
An implantable control module for an electrical stimulation system includes a connector to couple to a lead or lead extension; an electronics housing coupled to the connector and having a first major surface, a second major surface, and at least one side surface; and an electronic subassembly disposed within the electronics housing. The electronics housing includes a first portion formed of a first conductive material and a second portion formed of a second conductive material. The second portion forms at least part of the first major surface and extends to form an adjacent region of the side surface or the second major surface. In some embodiments, the first conductive material has a resistivity that is no more than 50% of a resistivity of the second conductive material. In some embodiments, the first conductive material is titanium and the second conductive material is a titanium alloy.