Pulse Wave Sensor Light Intensity Optimization
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Solution Overview
Problem
Conventional pulse wave sensors face challenges in optimizing light emission intensity for accurate pulse wave detection due to individual variations in light attenuation and the time required for amplitude adjustment processes, which can be lengthy and not directly related to actual detection.
Innovation Solution
A pulse wave sensor with a light emission intensity adjusting unit that rapidly sets optimal light emission intensity by sequentially emitting light with different test intensities during a short test period, using a reference light reception intensity to determine the normal emission intensity, allowing for quick optimization without interrupting the detection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light emission intensity is increased to increase pulse wave signal amplitude, then signal amplitude is improved, but saturation of the pulse wave signal occurs making accurate detection difficult
Solution Approach 1:
The system dynamically changes the light emission intensity parameter based on individual attenuation characteristics. By adjusting the emission intensity to match each user's specific light absorption properties, the system achieves optimal signal amplitude without saturation, resolving the contradiction between signal strength and detection accuracy.
Solution Approach 2:
The system uses feedback from the detected light reception intensity to adjust the light emission intensity. The light emission intensity adjusting unit modifies the emission level based on the actual reception intensity, creating a closed-loop control system that maintains optimal signal levels while preventing saturation.
2Reliability
If light emission intensity is decreased to avoid signal saturation, then detection accuracy is improved, but pulse wave signal amplitude becomes too small for accurate information extraction
Solution Approach 1:
The system dynamically adjusts the light emission intensity parameter upward for users with low attenuation characteristics. This ensures that the signal amplitude is sufficient for accurate detection while remaining below saturation levels, resolving the contradiction between signal strength and detection accuracy.
3Measurement precision
If sequential reading of amplitudes with multiple test light emission intensities is performed to optimize light emission intensity setting, then light emission intensity optimization accuracy is improved, but adjustment time becomes excessively long
Solution Approach 1:
The system performs preliminary measurement of the light reception intensity at a single test emission intensity before actual pulse wave detection. This preliminary action provides sufficient information to calculate the optimal emission intensity setting, avoiding the need for time-consuming sequential measurements at multiple intensities while still achieving accurate optimization.
Solution Approach 2:
The system uses a simplified measurement approach that copies the essential information needed for optimization from a single test measurement. By deriving the optimal setting from one test point rather than requiring multiple sequential measurements, the system achieves accurate optimization in significantly reduced time.
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 efficient optimization of light emission intensity for accurate pulse wave detection in a shorter time compared to traditional methods, reducing the overall detection time and improving the accuracy of pulse wave information acquisition.
Implementation Method 1
a light receiving unit configured to receive light, which is transmitted through or is reflected from the living body based on the light from the light emitting unit
Implementation Method 2
an intensity of the received light varies with a pulsation of the living body, pulse wave information can be obtained based on characteristics of the pulse wave signal corresponding to the intensity of the received light
Data Source
AI summary
A pulse wave sensor includes: a light emitting unit configured to emit light onto a living body; a light receiving unit configured to receive light transmitted through or reflected from the living body based on the light from the light emitting unit; a pulse wave detecting unit configured to detect a pulse wave of the living body based on a result of light reception by the light receiving unit when the light is emitted from the light emitting unit with a normal light emission intensity; and a light emission intensity adjusting unit configured to cause the light emitting unit to emit light with a predetermined test light emission intensity in a test period prior to the detection of the pulse wave, and set the normal light emission intensity using detection light reception intensity in the light receiving unit by the light emission and a predetermined reference light reception intensity.