Implantable Pressure Sensor Non-Coplanar Membrane Design

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Solution Overview

Problem

Conventional implantable pressure sensors experience distortion in measured pressure values due to temperature-induced volume and pressure changes, leading to material stress and potential failure, with existing solutions failing to minimize these distortions effectively and being costly and prone to manufacturing defects.

Innovation Solution

The design incorporates a housing with multiple non-coplanar pressure transfer membranes and reversibly deformable regions, distributing stresses uniformly and increasing the housing's flexibility, which reduces the risk of deformation and enhances robustness against temperature fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the housing walls are made thick to provide structural stability, then the housing strength is improved, but the flexibility and elasticity are reduced, leading to higher pressure changes during temperature fluctuations

Engineering Contradiction:

Improvehousing strengthVSAvoidflexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The housing is divided into multiple segments with different wall thicknesses. The first housing portion has a first wall thickness and the second housing portion has a second wall thickness, allowing each segment to be optimized for its specific function - structural support versus flexibility and stress distribution

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the housing have different mechanical properties through varying wall thicknesses. The first housing portion provides structural stability while the second housing portion provides flexibility to accommodate volume changes, creating local quality variations that resolve the contradiction

Inventive Principle:

Principle #3Local quality

2Device complexity

If a single pressure transfer membrane is used, then the device complexity is reduced, but the ability to balance stresses from volume changes is insufficient

Engineering Contradiction:

Improvemembrane structure complexityVSAvoidstress balance capability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The pressure transfer function is segmented across multiple membranes rather than relying on a single membrane. The first and second pressure transfer membranes are positioned on opposite sides of the housing, creating a segmented approach that distributes and balances stresses more effectively

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first and second pressure transfer membranes act as counterbalancing elements positioned on opposite sides of the housing. When volume changes occur, the membranes on opposite sides experience opposing forces that balance each other out, reducing net stress on the housing structure

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Strength

If the housing is made rigid to maintain structural integrity, then the housing strength is improved, but the ability to withstand material stresses from volume changes is reduced

Engineering Contradiction:

Improvehousing strengthVSAvoidmaterial stress

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The housing structure is segmented into portions with different rigidity characteristics. The first housing portion maintains structural integrity while the second housing portion has enhanced flexibility to accommodate volume changes, allowing the system to withstand material stresses without failing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wall thickness parameter is varied between different housing portions to change their mechanical properties. By adjusting the wall thickness parameter locally, the housing achieves both structural integrity and stress accommodation capability

Inventive Principle:

Principle #35Parameter changes

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 significantly reduces temperature-induced pressure fluctuations, enhances the sensor's robustness, and maintains measurement accuracy, while minimizing manufacturing costs and material stress, thereby improving the reliability of implantable pressure sensors.

Implementation Method 1

The liquid (for example oil) here serves as a pressure transfer medium so that the external pressure can be conducted via the housing (often via a thin membrane on the housing), through the liquid, and to the MEMS chip

Methodology Applied

Scientific EffectPressure transfer: Pascal's Law

Implementation Method 2

In the patient's blood, temperature changes of a few degrees Celsius can usually occur, thus resulting in volume and pressure changes of the pressure transfer medium within the housing

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

The housing has at least one reversibly deformable region, with the reversibly deformable region comprising a region of an outer wall of the housing and/or a region of the inner volume of the housing

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10524673B2Implantable pressure sensor

Publication Date: 2020.01.07 BIOTRONIK SE & CO KG

AI summary

The invention describes an implantable pressure sensor having a housing, wherein the housing has walls and two or more pressure transfer membranes bounding an internal volume, wherein the pressure transfer membranes are not coplanar.