Piezoelectric Sensor Array for Pulse Wave Velocity Measurement

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Solution Overview

Problem

The existing measuring instrument for artery propagation velocity measurement is inaccurate due to uncertainties in the direct distance between the thin-film piezoelectric sensors attached to the wrist and ankle, which affects the reliability of the calculated propagation velocity.

Innovation Solution

A measuring instrument with a fixing part attachable to a subject, featuring a first and second piezoelectric sensor fixed at a prescribed distance, and an analyzing part that calculates the propagation velocity based on the time difference between peak voltage detections by these sensors, ensuring accurate measurement regardless of the sensor placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If thin-film piezoelectric sensors are attached to different limbs (wrist and ankle) to measure artery propagation velocity, then the measurement can be performed, but the accuracy of the measurement deteriorates due to uncertainties in the direct distance between sensors

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidpropagation velocity measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The invention divides the measurement system into multiple sensors attached to the same subject at different positions, with each sensor measuring local pulse pressure. The analyzing part then calculates propagation velocity based on the time difference between sensor readings and the known distance between sensors, eliminating the need for direct distance measurement between limbs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary analyzing part that processes the signals from multiple sensors. This intermediary component calculates the propagation velocity by determining the time difference between peak detections and using the prescribed distance between sensors, thereby mediating between the sensor readings and the final measurement result to eliminate direct distance measurement requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If direct distance measurement between sensors on different limbs is used, then propagation velocity can be calculated, but the reliability of the measurement deteriorates due to measurement uncertainties

Engineering Contradiction:

Improvepropagation velocity calculationVSAvoidmeasurement reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system uses the subject's own body as the reference framework for measurement. The sensors are attached to the subject at predetermined positions, and the analyzing part uses the known distance between these fixed positions (prescribed distance) rather than requiring external measurement. This self-service approach eliminates the need for external distance measurement equipment and reduces measurement uncertainties.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention changes the parameter used for distance measurement from direct physical distance measurement to prescribed distance based on subject-specific anatomical measurements. By using the subject's own body dimensions and predetermined sensor positions, the system transforms the measurement approach to eliminate external measurement uncertainties and improve reliability.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If multiple sensors are attached to the same subject at prescribed distances, then measurement accuracy improves, but the device complexity increases

Engineering Contradiction:

Improvevibration propagation velocity measurement accuracyVSAvoidsensor arrangement and analysis system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The analyzing part serves multiple functions: it detects peak voltages from multiple sensors, calculates time differences between detections, determines propagation velocity, and can assess local pulse wave characteristics. This multi-functionality consolidates what would otherwise require separate measurement systems into a single integrated device, reducing overall complexity while maintaining high measurement precision.

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

This solution allows for precise measurement of vibration propagation velocity, enabling early detection of arterial sclerosis risks and local pulse wave propagation velocity assessment without requiring sensors on different limbs.

Implementation Method 1

a first piezoelectric sensor fixed to the fixing part; a second piezoelectric sensor fixed to the fixing part at a prescribed distance from the first piezoelectric sensor

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11219377B2Measuring instrument and measuring system

Publication Date: 2022.01.11 RENESAS ELECTRONICS CORP

AI summary

A measuring device and measuring system which accurately measure a pulse wave propagation velocity. The measuring instrument includes: a fixing part attachable to and detachable from a subject; a first piezoelectric sensor fixed to the fixing part; a second piezoelectric sensor fixed to the fixing part at a prescribed distance from the first piezoelectric sensor; and an analyzing part for calculating a pulse wave propagation velocity in the subject according to time difference between time of detection of peak voltage by the first piezoelectric sensor and time of detection of peak voltage by the second piezoelectric sensor, and the prescribed distance.