Sensor Housing Variable Thickness Reduces Diaphragm Pressure
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Solution Overview
Problem
Implantable medical sensors, such as pressure sensors, experience baseline signal drift or offset due to tissue encapsulation and contraction, leading to erroneous measurements over time, particularly for chronically implanted sensors with flexible diaphragms.
Innovation Solution
The design of a housing for the sensor module includes lateral shoulders and a variable thickness outer layer to reduce contact pressure on the diaphragm, shifting the pressure away from the diaphragm area and minimizing the impact of tissue encapsulation-induced pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flexible diaphragm is used in the sensor housing, then the sensor can accurately detect pressure changes, but tissue encapsulation causes contact pressure on the diaphragm leading to baseline drift and measurement errors
Solution Approach 1:
The housing is designed with non-uniform wall thickness, creating regions of varying flexibility. The thinner regions allow controlled flexing to relieve contact pressure on the diaphragm, while thicker regions maintain structural integrity. This localized variation in mechanical properties protects the diaphragm from tissue encapsulation pressure without compromising pressure sensing capability.
Solution Approach 2:
The housing transitions from a rigid structure to a dynamically adaptable one through variable thickness design. The housing can flex and deform in response to tissue encapsulation forces, dynamically adjusting its shape to minimize contact pressure on the diaphragm while maintaining its protective enclosure function.
2Ease of manufacture
If the housing wall thickness is uniform, then manufacturing is simplified, but contact pressure from tissue encapsulation concentrates on the diaphragm causing baseline offset
Solution Approach 1:
The housing employs non-uniform wall thickness with specific regions designed thinner to reduce contact pressure on the diaphragm. This localized modification targets the problem area without requiring complete redesign of the entire housing structure, balancing manufacturing feasibility with performance improvement.
Solution Approach 2:
The wall thickness parameter is varied strategically throughout the housing structure. By changing this geometric parameter in specific regions, the housing achieves optimal mechanical characteristics for pressure distribution, reducing diaphragm contact pressure while maintaining overall structural functionality.
3Strength
If the housing is made more rigid to prevent deformation, then structural integrity is improved, but contact pressure from tissue encapsulation increases on the diaphragm
Solution Approach 1:
The housing achieves structural integrity through thicker walls in non-critical regions while maintaining flexibility in diaphragm-proximal regions through reduced thickness. This spatial differentiation allows the housing to be both strong where needed and compliant where it interacts with tissue encapsulation forces.
Solution Approach 2:
The housing exhibits dynamic mechanical behavior, transitioning between rigid and flexible states depending on the applied forces. It maintains rigidity for structural support while allowing controlled flexing in response to tissue encapsulation pressure, protecting the diaphragm from excessive contact forces.
Data Source
AI summary
An implantable sensor module and medical device includes a housing having an inner shell having a thickness extending between an inner wall and an outer wall and an outer layer, wherein the inner shell and the outer layer form a substantially flat portion. A shoulder extends adjacent to a diaphragm to extend the outer layer laterally away from a central medial line extending between edges of the diaphragm. A recess portion is formed between the diaphragm and an inner side of the outer layer, and an over-fill channel is formed by the outer layer extending through the outer layer from an opening formed at the outer wall to an opening formed along the inner side of the outer layer extending along the substantially flat portion.