Faraday Cage Aperture Limits LED Light in Patient Sensor

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Solution Overview

Problem

Current patient monitoring sensors face challenges with light saturation due to advancements in LED technology, leading to detector saturation and potential inaccuracies in physiological parameter measurements.

Innovation Solution

The implementation of a faraday cage with an aperture in the patient monitoring sensor body helps control the amount of light reaching the detector, preventing saturation and providing protection against electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If brighter LED technology is used to improve signal strength, then the light emission intensity increases, but the detector becomes saturated leading to measurement inaccuracies

Engineering Contradiction:
Improvelight emission intensityVSAvoiddetection accuracy
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

A Faraday cage with a precisely configured aperture is introduced as an intermediary element between the LED and detector. This aperture acts as a mediator that selectively transmits light, allowing sufficient signal strength to reach the detector while preventing saturation by limiting the total light quantity. The aperture serves as a controlled interface that reconciles the conflicting requirements of high illumination intensity and accurate detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The Faraday cage aperture is designed with specific local geometric properties (size, shape, position) that are optimized to control light distribution. Rather than uniformly reducing light across the entire detector surface, the aperture creates a localized light path that maintains appropriate intensity levels at the detection zone while blocking excess light, thereby preserving measurement precision without completely diminishing signal strength.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the detector is exposed to more light to improve signal detection, then the light quantity increases, but electromagnetic interference affects measurement accuracy

Engineering Contradiction:
Improvelight quantityVSAvoidmeasurement reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The Faraday cage serves as a dual-function intermediary: its aperture structure controls light quantity while its conductive mesh structure simultaneously provides electromagnetic shielding. This single intermediary element addresses both the need for sufficient light quantity and the need to protect against electromagnetic interference that would compromise measurement reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The Faraday cage combines optical properties (aperture for light control) with electromagnetic shielding properties (conductive mesh structure) into a single composite structure. This composite design allows the device to simultaneously manage light quantity and block electromagnetic interference, resolving the contradiction between improving signal detection and maintaining measurement reliability.

Inventive Principle:
Principle #40Composite materials

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 solution effectively limits light exposure to the detector, maintaining accurate measurements of physiological parameters while safeguarding against electromagnetic interference.

Implementation Method 1

the faraday cage includes an aperture configured to limit an amount of light from the LED that the detector is able to detect

Methodology Applied
Scientific EffectLight absorption/limitation through aperture: Absorption (EM radiation)

Implementation Method 2

a faraday cage provided as a flap portion of the body extending from a portion of the body housing the detector

Methodology Applied
Scientific EffectFaraday cage electromagnetic shielding: Faraday Cage

Data Source

PatentEP4103050B1Controlling optical power in a sensor with the use of a faraday cage
Publication Date: 2025.04.23 COVIDIEN LP
  • EP4103050B1 patent drawingFigure 1
  • EP4103050B1 patent drawingFigure 2
  • EP4103050B1 patent drawingFigure 3

AI summary

A patient monitoring sensor having a communication interface, through which the patient monitoring sensor can communicate with a monitor is provided. The patient monitoring sensor includes a light-emitting diode (LED) communicatively coupled to the communication interface and a detector, communicatively coupled to the communication interface, capable of detecting light. The patient monitoring sensor also includes a faraday cage disposed around the detector, wherein the faraday cage includes an aperture configured to limit an amount of light from the LED that the detector is able to detect.