Flexible Wrist Pulse Wave Sensor Housing Design
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Solution Overview
Problem
Existing biological information measuring devices attached to the wrist using auxiliary belts or S-like shaped housings often impede wrist motion and face challenges in accurately detecting pulse waves due to positional displacement of sensors, especially when trying to be close to the palmar crease.
Innovation Solution
A pulse wave detecting device with a housing that can be wound around the wrist, featuring a combination of high and low rigidity components to allow flexible attachment without obstructing wrist motion, and a band that is lower in rigidity than the housing to secure it, ensuring the sensor remains close to the radial artery for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressure sensor is positioned as close as possible to the palmar crease to improve detection accuracy, then the detection accuracy is improved, but the housing covers the wrist root portion and impedes wrist motion
Solution Approach 1:
The housing is constructed with a flexible material that allows it to stretch and deform, enabling the sensor to remain close to the palmar crease for accurate detection while the flexible nature prevents the housing from rigidly blocking wrist motion. The flexibility allows the housing to accommodate wrist movements without impeding operation.
Solution Approach 2:
The rigidity parameter of the housing is changed by using a flexible material instead of a rigid one. This parameter change allows the housing to maintain sensor positioning for detection accuracy while simultaneously allowing wrist motion through its flexible properties.
2Ease of operation
If a highly stretchable housing is used to prevent wrist motion limitation, then wrist motion is improved, but the positional displacement of the pressure sensor occurs due to extension or contraction of the housing
Solution Approach 1:
The housing uses a flexible material that can stretch and contract while maintaining the relative position of the pressure sensor. The flexibility allows wrist motion without causing sensor displacement, as the flexible housing moves uniformly with the wrist while keeping the sensor anchored near the palmar crease.
3Ease of manufacture
If the housing has uniform width in the circumferential direction for structural simplicity, then manufacturing is simplified, but the pressure sensor cannot be positioned close to the palmar crease without impeding wrist motion
Solution Approach 1:
The flexible housing material allows the structure to adapt its shape and width distribution to accommodate the sensor positioning requirement. Instead of requiring a complex non-uniform width design, the flexible housing can maintain a simpler form while still allowing the sensor to be positioned close to the palmar crease without blocking wrist motion, as the flexibility compensates for the simplified geometry.
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 device allows for unobstructed wrist motion while maintaining accurate pulse wave detection by positioning the sensor close to the palmar crease, improving detection accuracy and durability through a flexible attachment mechanism.
Implementation Method 1
a pulse wave detection sensor that detects a pulse wave from a radial artery of a subject
Data Source
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AI summary
A pulse wave detecting device in which the motion of the hand in a state where the detector is attached to the wrist can be prevented from being impeded, and which can accurately detect a pulse wave is provided. A biological information measuring device 100 includes: a housing 20 which accommodates a pulse wave detection sensor for detecting a pulse wave from the radial artery TD, and which is configured to be able to be wound along the circumferential direction X of the wrist H; and a band 30 which is used for fixing the housing 20 to the wrist, and which is lower in rigidity than the housing 20. The housing 20 is configured by: a back-side portion 2a which is to be wound around the back side of the hand; a palm side portion 2b which is to be wound around a palm side of the hand; and a coupling portion 2c which connects them together. In a state where the housing 20 is attached to the wrist H, the whole of a part which is in a hand side end portion 20a of the housing 20 that is on the side of the hand of the subject in a direction Y perpendicular to the circumferential direction X, and which constitutes the back-side portion 2a is closer to the side of the arm of the subject than the part constituting the palm side portion 2b in the direction Y.