NIRS Sensor Contact Layer for Tissue Comfort

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Solution Overview

Problem

Non-invasive medical devices, such as near-infrared spectroscopy (NIRS) sensors, often cause discomfort and irritation to subjects due to prolonged contact with biological tissue.

Innovation Solution

A NIRS sensor assembly with a subject contact layer that is optically transmissive and includes materials like silicone foam, polyethylene foam, or fabrics, which covers both the light source and detector, reducing discomfort by acting as a cushion and thermal barrier, and a processor that accounts for the optical transmissivity of the contact layer to accurately measure tissue characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a non-invasive medical device is in contact with the subject over a period of time, then measurements can be taken, but discomfort and irritation are experienced by the subject

Engineering Contradiction:
Improveduration of contactVSAvoiddiscomfort and irritation
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

A subject contact layer is provided that covers the light source and light detector. This contact layer acts as a cushioning element between the sensor components and the subject's skin, reducing pressure and discomfort during prolonged contact while allowing the device to remain in place for extended measurement periods

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Object-affected harmful factors

If a contact layer is added to reduce discomfort, then subject comfort is improved, but the optical path is affected

Engineering Contradiction:
Improvesubject comfortVSAvoidmeasurement accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The subject contact layer serves as an intermediary element that mediates between the need for comfort and the need for accurate optical measurements. The layer is specifically designed to be optically transmissive, allowing light to pass through while providing the cushioning effect needed for subject comfort during prolonged contact

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical properties of the contact layer are carefully selected and characterized. The processor is configured to account for the specific optical transmissivity parameters of the contact layer material, compensating for any attenuation or scattering effects to maintain measurement accuracy

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

The solution effectively reduces discomfort and irritation while maintaining accurate measurements of tissue characteristics, such as blood oxygen parameters, by using an optically transmissive contact layer that minimizes pressure and thermal discomfort, and a processor that compensates for the contact layer's optical properties.

Implementation Method 1

a light source operable to emit light at one or more predetermined wavelengths... The light detector has an active area for detecting light emitted by the light source and passed through the biological tissue

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

The subject contact layer has at least one optically transmissive portion... acting as a cushion and thermal barrier

Methodology Applied
Scientific EffectOptical transmissivity: Light

Implementation Method 3

The light detector has an active area for detecting light emitted by the light source and passed through the biological tissue. The detector is operable to produce signals representative of the detected light

Methodology Applied
Scientific EffectPhotodetection: Photoelectric Effect

Data Source

PatentEP2928371B1Method for spectrophotometrically determining a blood oxygen parameter
Publication Date: 2021.06.02 EDWARDS LIFESCIENCES CORP
  • EP2928371B1 patent drawingFigure 1
  • EP2928371B1 patent drawingFigure 2
  • EP2928371B1 patent drawingFigure 3

AI summary

According to an aspect of the present invention, a near infrared spectroscopy (NIRS) sensor assembly, system, and method for measuring a characteristic of a biological tissue is provided. The NIRS sensor assembly includes a light source, at least one light detector, and a subject contact layer. The light source is operable to emit light at one or more predetermined wavelengths. The light detector has an active area for detecting light emitted by the light source and passed through the biological tissue. The detector is operable to produce signals representative of the detected light. The subject contact layer is disposed to cover one or both of the light detector and the light source. The subject contact layer has at least one optically transmissive portion.