Flexible Pulse Wave Detector with Deformation Stop Timing Calibration
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Solution Overview
Problem
Existing biological information measurement devices struggle to accurately detect pressure pulse waves when a flexible sensor is pressed against the body surface, as the difference in strain across magnetoresistance effect elements affects measurement accuracy, and there is no established method for controlling this in existing technologies.
Innovation Solution
A pulse wave detector with a flexible strain sensor, a flexible pressing member, a drive section, a pressing control section, a deformation stop timing determination section, a calibration section, and a pressure generation section, which determines the deformation stop timing of the strain sensor, sets a reference level for strain detection signals, and generates a pressure signal from calibrated signals to accurately detect pressure pulse waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flexible sensor is pressed against the body surface to improve measurement capability, then the feeling of wearing the sensor becomes excellent and more elements can be used for calculation, but the difference in strain applied to each element affects measurement accuracy
Solution Approach 1:
The patent applies preliminary action by determining the deformation stop timing of the flexible sensor before actual pressure pulse wave detection. The pressing control section controls the pressing member to press the sensor against the body surface, and the deformation stop timing determination section identifies when the sensor has fully deformed and stopped. This preliminary deformation phase allows the system to establish a baseline state, ensuring that subsequent measurements are taken from a known reference point, thereby resolving the contradiction between using flexible sensors for comfort and maintaining measurement accuracy.
2Measurement precision
If a pressing mechanism and drive section are added to enable tonometry method detection, then pressure pulse wave detection becomes possible, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing the pressing member to serve multiple functions: it provides the necessary pressing force for tonometry method detection, controls the deformation of the flexible sensor, and establishes the baseline state for accurate measurement. The pressing control section and deformation stop timing determination section work together to automate this multi-functional component, reducing the need for separate dedicated mechanisms and thereby managing device complexity while enabling pressure pulse wave detection.
3Reliability
If the flexible sensor is pressed against the body surface to achieve proper tonometry state, then pressure pulse wave detection becomes possible, but the strain difference across elements cannot be ignored
Solution Approach 1:
The patent applies feedback by using the strain detection signals from multiple elements to determine when the sensor deformation has stopped. The deformation stop timing determination section monitors the strain detection signals and identifies the timing when all elements have reached their final deformed state. This feedback mechanism allows the system to adapt to the actual deformation behavior of the flexible sensor, ensuring that measurements are taken when the sensor is in a stable, consistent state, thereby resolving the strain difference issue while maintaining proper tonometry state.
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 detection of pressure pulse waves by calibrating strain detection signals and generating reliable pressure signals, improving the accuracy and reliability of biological information measurement, particularly in tonometry states.
Implementation Method 1
a blood pressure sensor having a plurality of magnetoresistance effect elements disposed in a two-dimensional form on a flexible substrate to detect strains as resistance values
Data Source
AI summary
A pulse wave detection method includes: increasing a pressing force of a pressing member for pressing a strain sensor fixed thereto against a body surface, the flexible strain sensor having a plurality of strain detection elements arranged on a substrate; determining a deformation stop timing at which deformation of a detection face of the strain sensor has been stopped based on the strain detection signal detected by each of the plurality of strain detection elements in a pressure raising process in which the pressing force is increased; setting a level of the strain detection signal detected at the deformation stop timing as a reference level; calibrating the first strain detection signal detected after the deformation stop timing based on the reference level; and generating a pressure signal from the calibrated first strain detection signal.