PPG Sensing Module Movement Compensation via Optical Signal Classification

Solution Overview

Problem

Existing PPG sensing modules face accuracy issues due to movement-induced separation between the sensor and skin, leading to distorted optical signals and increased costs, area requirements, and power consumption when using separate acceleration and gyro sensors.

Innovation Solution

A PPG sensing module with integrated light sources, optical sensors, and signal processing circuits that perform analog-to-digital conversion and classify movement patterns to remove movement components from the PPG signal, eliminating the need for separate sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate acceleration sensor and gyro sensor are used to measure user movement, then movement detection accuracy is improved, but device complexity, cost, and power consumption increase

Engineering Contradiction:

Improvemovement detection accuracyVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the movement detection function into the existing PPG sensing module by using the optical sensors and signal processing circuits already present in the module. The signal processing circuit classifies read-out signals according to movement patterns and measures movement components using the same optical sensing infrastructure, eliminating the need for separate acceleration and gyro sensors.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical sensors in the PPG sensing module serve dual functions: they detect blood flow changes for heart rate measurement and simultaneously detect movement patterns for motion compensation. The signal processing circuit performs multiple functions including PPG signal generation, movement detection, and movement component removal using the same sensor array.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If separate acceleration sensor and gyro sensor are used to measure user movement, then movement detection accuracy is improved, but area and power consumption increase

Engineering Contradiction:

Improvemovement detection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent combines the movement detection function into the existing PPG sensing module by using the optical sensors and signal processing circuits already present in the module. The signal processing circuit classifies read-out signals according to movement patterns and measures movement components using the same optical sensing infrastructure, eliminating the need for separate acceleration and gyro sensors.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If separate acceleration sensor and gyro sensor are used to measure user movement, then movement detection accuracy is improved, but cost increases

Engineering Contradiction:

Improvemovement detection accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent combines the movement detection function into the existing PPG sensing module by using the optical sensors and signal processing circuits already present in the module. The signal processing circuit classifies read-out signals according to movement patterns and measures movement components using the same optical sensing infrastructure, eliminating the need for separate acceleration and gyro sensors.

Inventive Principle:

Principle #5Merging (Combining)

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 provides accurate PPG signals without movement distortion, reducing costs, design complexity, and power consumption by integrating movement measurement within the PPG sensing module.

Implementation Method 1

because a light absorption coefficient of a blood vessel changes according to change of a heart rate, a heart rate sensor module may be synchronized with a heart rate of a user (or a subject) and measure a heart rate or blood oxygen saturation by irradiating light on the skin of the user and sensing reflected light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a plurality of optical sensors configured to receive reflected light from the user and generate a plurality of sensing signals

Methodology Applied

Scientific EffectPhotodetection: Photoelectric Effect

Data Source

PatentUS11633157B2Photoplethysmogram (PPG) sensing module and device including the same

Publication Date: 2023.04.25 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided is a photoplethysmogram (PPG) sensing module including one or more light sources that emit light to a user; a plurality of optical sensors that receive reflected light from the user and generate sensing signals, each of the sensing signals being generated by one of the optical sensors; a read-out signal generating circuit that receives the sensing signals from the optical sensors and generate read-out signals by performing an analog-to-digital conversion on the sensing signals; and a signal processing circuit that receives the read-out signals, classifies the read-out signals according to one or more movement patterns of the user, measures a movement component of the user based on the classified read-out signals, and generates a PPG signal in which the movement component is removed.