SMI Sensor Respiration Sensing in Head-Mounted Devices

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Solution Overview

Problem

Wearable devices face challenges in efficiently sensing respiration-related data, such as respiration rate, quality, nasal congestion, and snoring, while maintaining a small form factor and avoiding electromagnetic radiation exposure to sensitive nasal and eye tissues.

Innovation Solution

Incorporating self-mixing interferometry (SMI) sensors in head-mounted devices, such as smart eyewear or face masks, to emit electromagnetic radiation towards anatomical structures near the nasal passageway, generating SMI signals that provide respiration information, and using processing circuitry to determine appropriate emission and detection of radiation based on proximity and tissue movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If SMI sensors emit electromagnetic radiation toward anatomical structures to sense respiration data, then measurement precision is improved, but harmful factors to nasal and eye tissues worsen

Engineering Contradiction:

Improverespiration data accuracyVSAvoidelectromagnetic radiation exposure to tissues

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The SMI sensor emits electromagnetic radiation in periodic pulses rather than continuously. The processing circuitry controls the sensor to emit radiation only during specific time windows when respiration data acquisition is needed, thereby reducing overall tissue exposure while maintaining measurement precision during active sensing periods

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses feedback control where the processing circuitry monitors SMI signals in real-time and adjusts the emission timing and duration based on detected respiration patterns and facial movements. This feedback mechanism ensures radiation is emitted only when necessary for accurate measurement, minimizing harmful exposure

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If SMI sensors are positioned over the nose to detect respiration information, then sensing capability is improved, but ease of operation worsens due to detecting unintentional facial movements

Engineering Contradiction:

Improvesensing capabilityVSAvoidoperation reliability

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system dynamically adjusts its operation mode based on detected facial movements. When intentional movements are detected, the system pauses data acquisition; when the user is stationary, normal sensing resumes. This dynamic adaptation resolves the conflict between comprehensive sensing and operational reliability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system automatically detects and responds to facial movements without user intervention. The processing circuitry autonomously determines when to pause or resume sensing based on SMI signal analysis, making the device self-adjusting to usage conditions

Inventive Principle:

Principle #25Self-service

3Reliability

If multiple sensors are added to provide robust biometric data, then reliability is improved, but device complexity worsens

Engineering Contradiction:

Improvebiometric data robustnessVSAvoidsensor configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The SMI sensor serves multiple functions: it detects respiration rate, respiration quality, nasal congestion, snoring, and facial movements. By making the sensor multi-functional, the system achieves reliable comprehensive biometric data without adding multiple separate sensors, thus maintaining simplicity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 accurate determination of respiration data and intentional or unintentional facial movements, enhancing biometric data collection while ensuring safe operation by controlling electromagnetic radiation exposure.

Implementation Method 1

Each of the set of one or more sensors may include an interferometric sensor such as a self-mixing interferometry (SMI) sensor

Methodology Applied

Scientific EffectSelf-mixing interferometry: Interference

Implementation Method 2

emit electromagnetic radiation toward an anatomical structure adjacent a nasal passageway of a user and generate one or more SMI signals including information about movement of the anatomical structure

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS20240000337A1Wearable Device Including Optical Sensor Circuitry

Publication Date: 2024.01.04 APPLE INC

AI summary

A head mounted device includes a housing and a set of one or more SMI sensors. The set of one or more SMI sensors are disposed in the housing. The set of one or more SMI sensors are configured to emit electromagnetic radiation toward an anatomical structure adjacent a nasal passageway of a user and generate one or more SMI signals including information about movement of the anatomical structure.