Bimorph Sensor for Intracranial Pressure Decoupling

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Solution Overview

Problem

Existing non-invasive intracranial pressure measurement devices struggle to accurately detect intracranial pressure pulsation due to the dominant influence of external carotid artery pulsation, leading to uncomfortable prolonged use and unreliable measurements.

Innovation Solution

A non-invasive measuring device featuring a bimorph piezoelectric bending sensor with antiparallel polarity, attached to a headband or cuff, which decouples the intracranial pressure pulsation from external arterial influences by using a C-shaped holder or elastic coupling, allowing precise detection of minimal skull deformations caused by intracranial pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a strain sensor is used to detect skull deformation for non-invasive intracranial pressure measurement, then the measurement can be performed non-invasively, but the external carotid artery pulsation dominates the signal making accurate intracranial pressure detection unreliable

Engineering Contradiction:
Improvenon-invasive measurementVSAvoidintracranial pressure detection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The sensor system is segmented into multiple independent strain sensors arranged in specific patterns on the skull surface. This segmentation allows the system to capture multiple components of skull deformation independently, enabling subsequent separation of intracranial pressure signals from arterial pulsation signals through differential analysis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies strain sensors at specific locations on the skull where intracranial pressure transmission is maximized while arterial pulsation influence is minimized. The local arrangement and orientation of sensors are optimized to detect radial skull expansion caused by intracranial pressure waves while filtering out tangential arterial pulsations.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the measuring device is attached directly to the skull without decoupling, then the measurement structure is simple, but the external carotid artery pulsation cannot be separated from the intracranial pressure signal

Engineering Contradiction:
Improvemeasurement structureVSAvoidsignal discrimination
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A specialized mounting structure acts as an intermediary between the skull and the strain sensors. This mounting structure includes elastic elements and damping components that selectively transmit intracranial pressure-induced skull deformations to the sensors while isolating them from high-frequency arterial pulsations. The intermediary structure serves as a mechanical filter that preserves the desired signal while attenuating the interfering signal.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the measuring device is padded for prolonged patient comfort, then patient comfort is improved, but the measurement sensitivity decreases due to cushioning effects

Engineering Contradiction:
Improvepatient comfortVSAvoidskull deformation detection sensitivity
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent employs thin, flexible mounting structures and minimal padding that maintain direct mechanical coupling between the skull and strain sensors. The flexible elements used are designed with specific stiffness characteristics that allow them to conform to the skull surface for comfort while remaining sufficiently rigid to transmit minute skull deformations caused by intracranial pressure waves without significant attenuation.

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enables reliable and comfortable long-term monitoring of intracranial pressure pulsation by effectively isolating external arterial pulsations, providing accurate vital parameter measurements and warnings.

Implementation Method 1

at least one bimorph piezoelectric bending sensor with antiparallel polarity

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

bimorph piezoelectric bending sensor with antiparallel polarity which is arranged symmetrically around the neutral fiber

Methodology Applied
Scientific EffectBimorph bending: Bi-Metallic Strip

Data Source

PatentEP4213710B1Measuring device for non-invasively detecting the intracranial pressure of a patient, and corresponding method
Publication Date: 2024.07.03 INDTACT
  • EP4213710B1 patent drawingFigure 1
  • EP4213710B1 patent drawingFigure 2
  • EP4213710B1 patent drawingFigure 3~4

AI summary

The invention relates to a measuring device for non-invasively detecting the intracerebral pressure pulsations of a patient, comprising a holding device which can be releasably attached to the exterior of the skull of the patient in a force- and/or form-fitting manner, at least one biomorphic bending sensor which is arranged in or on the holding device, an analog signal amplifier for amplifying the measurement data supplied by the bimorphic bending sensor, an A/D converter for converting the analog measurement data into digital data, and a computing unit for pre-processing the data and computing vital parameters, such as intracerebral pressure, using the digital data. The invention also relates to a corresponding method for non-invasively detecting an intracerebral pressure pulsation.