Matrix Sensor Pulse Oximeter for Accurate Pulsation Measurement
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Solution Overview
Problem
Pulse oximeters using photoplethysmography face challenges in acquiring accurate pulse waveforms with low user load, as transmissive types require tight body sandwiching for stability and reflective types have low light efficiency, making it difficult to obtain reliable measurements.
Innovation Solution
A measurement device with a light source emitting measurement light of specific wavelengths and a detection unit with a micro lens array of sensors, which analyzes temporal changes in light to specify measurement positions and calculate pulse waveforms, allowing for accurate pulsation information acquisition with reduced user load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transmissive pulse oximeter is used to obtain stable pulse waveforms, then measurement accuracy is improved, but user load increases due to tight body sandwiching requirement
Solution Approach 1:
The detection unit is divided into multiple sensors arranged in a matrix array, with each sensor independently detecting light at different positions. This segmentation allows the system to capture pulse waveform information from multiple locations simultaneously, maintaining measurement accuracy while reducing the need for tight body sandwiching.
Solution Approach 2:
The invention transitions from a single-point or linear detection approach to a two-dimensional matrix array detection. By arranging sensors in a matrix pattern, the system can analyze spatial distribution of light absorption across the measurement region, enabling accurate pulse waveform acquisition with more flexible contact requirements.
2Ease of operation
If a reflective pulse oximeter is used to reduce user load, then ease of operation is improved, but measurement accuracy deteriorates due to low light efficiency
Solution Approach 1:
The invention merges the advantages of both transmissive and reflective approaches by using multiple sensors in a matrix array that can detect light in reflective mode while maintaining high measurement accuracy. The combined detection capability of multiple sensors compensates for the lower light efficiency of reflective measurement.
Solution Approach 2:
The system changes the detection parameters by using multiple wavelengths and multiple sensor positions simultaneously. This allows the system to optimize the signal-to-noise ratio and improve measurement accuracy even in reflective mode with lower light efficiency.
3Measurement precision
If multiple sensors are arranged in a matrix array to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The matrix array of sensors serves multiple functions: detecting pulse waveforms, determining optimal measurement positions, and analyzing spatial distribution of blood flow. This multi-functionality justifies the increased device complexity by providing comprehensive measurement capabilities from a single detection unit.
Solution Approach 2:
The system automatically determines the optimal measurement position by analyzing the output signals from multiple sensors, eliminating the need for manual positioning or complex mechanical adjustment mechanisms. The sensors self-organize to identify the best measurement location based on signal quality.
4Ease of operation
If automatic measurement position determination is implemented to improve ease of operation, then ease of operation is improved, but analysis processing complexity increases
Solution Approach 1:
The system uses feedback from the detection unit to automatically determine the optimal measurement position. By analyzing the output signals from multiple sensors and identifying the position with the strongest or most stable pulse waveform signal, the system automatically adjusts or selects the best measurement location without user intervention.
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 high-accuracy pulse waveform measurement with reduced user load by optimizing light detection and analysis, improving temporal and spatial resolution for pulsation information, including oxygen saturation and other blood component analysis.
Implementation Method 1
a detection unit in which a plurality of sensors is regularly arranged in a predetermined arrangement and which detects the measurement light emitted from the light source and passing through the living body
Implementation Method 2
an analysis unit which performs an analysis processing of specifying a measurement position for measuring information on pulsation along with activities of the living body from the measurement region based on a temporal change in an amount of light of the detected measurement light
Implementation Method 3
a property that oxygenated hemoglobin absorbs infrared light (with a waveform of around 940 nm, for example) and reduction hemoglobin absorbs red light (with a waveform of around 660 nm, for example)
Data Source
AI summary
A measurement device according to the present disclosure includes a light source which emits at least one kind of measurement light belonging to a predetermined wavelength band toward a measurement region formed of at least part of a living body, a detection unit in which a plurality of sensors is regularly arranged in a predetermined arrangement and which detects the measurement light emitted from the light source and passing through the living body with the plurality of sensors, and an analysis unit which performs analysis processing of specifying a measurement position for measuring information on pulsation along with activities of the living body from the measurement region based on a temporal change in an amount of light of the detected measurement light by use of a detection result detected by the detection unit.