Optically Transparent EMI Shielding for NIRS Sensors
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Solution Overview
Problem
Near-infrared spectroscopy (NIRS) sensors face challenges in accurately determining biological tissue oxygenation due to signal interference from electromagnetic interference (EMI) and high manufacturing costs, with existing methods failing to effectively account for signal attenuation through extra-cerebral tissue and lacking cost-effective solutions for repeated use.
Innovation Solution
A NIRS sensor assembly incorporating at least one light source, one or more light detectors, electromagnetic interference (EMI) shielding, and a light blocking sheet, which reduces noise from EMI and allows for improved signal quality and cost-effective manufacturing by using flexible components and EMI shielding configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional EMI shielding materials are used around light detectors, then EMI noise is reduced, but light signal attenuation occurs and manufacturing cost increases
Solution Approach 1:
The shielding structure is designed with spatially varying properties: the first portion provides EMI shielding while the second portion is optically transparent to allow light signal passage. This local differentiation resolves the contradiction by providing protection where needed while maintaining optical access where required.
Solution Approach 2:
The shielding member is divided into distinct functional segments: a first portion for EMI shielding and a second portion for optical transparency. This segmentation allows each portion to optimize its specific function without compromising the other, addressing both the EMI noise reduction and light signal detection requirements.
2Reliability
If sensor components are made more durable for repeated use, then reliability improves, but manufacturing cost increases
Solution Approach 1:
The shielding member combines materials with different properties in a single integrated component: one portion uses EMI-shielding material while another portion uses optically transparent material. This composite approach creates a durable, reusable component that maintains performance across multiple uses while being manufacturable through established techniques.
3Object-affected harmful factors
If shielding is added around light detectors, then EMI noise is reduced, but device complexity increases
Solution Approach 1:
The shielding member serves multiple functions simultaneously: it provides EMI shielding in its first portion while maintaining optical transparency in its second portion. This multi-functionality reduces overall device complexity by consolidating what would otherwise require separate components into a single integrated element.
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 proposed solution enhances signal quality by reducing EMI noise and improves the accuracy of tissue oxygenation monitoring while being more cost-effective and durable, enabling reliable non-invasive monitoring of blood oxygenation levels.
Implementation Method 1
The shielding, which is disposed around at least a portion of the light detector, attenuates local electromagnetic interference (EMI) and thereby reduces undesirable noise within the light detector signals
Implementation Method 2
light in the near-infrared range (700 nm to 1,000 nm) can pass easily through skin, bone and other tissues
Implementation Method 3
Hemoglobin exposed to light in the near-infrared range has specific absorption spectra that varies depending on its oxidation state
Data Source
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AI summary
A near infrared spectrophotometric sensor assembly for non-invasive monitoring of blood oxygenation levels in a subject's body is provided. The assembly includes at least one light source, at least one light detector operable to detect light emitted by the light source, an electromagnetic interference shielding disposed around at least a portion of the light detector, wherein the electromagnetic interference shielding includes an electrically conductive substrate that is optically transparent, and one or both of a light blocking sheet disposed relative to at least one of the light detectors and an encapsulating material.