Combination of reflective and transmissive sensors with characteristic wavelengths for physiological monitoring
Inventors
MOODY, DEREK L. • DOVE, Jacob D. • Addison, Paul S. • Sethi, Rakesh K. • Galen, Peter M. • Reustle, Linden
Assignees
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Publication Number
US-12616399-B2
Publication Date
2026-05-05
Expiration Date
Abstract
A light sensing device includes a first light source configured to emit light within a first wavelength range, a second light source configured to emit light within a second wavelength range, detector circuitry, a first photodetector in the detector circuitry configured to detect the light within the first wavelength range, and a second photodetector in the detector circuitry configured to detect the light within the second wavelength range. The first photodetector and the second photodetector are in parallel in the detector circuitry such that the detector circuitry sums electrical signals outputted by the first photodetector and the second photodetector.
Core Innovation
The invention provides a light sensing system for regional oximetry that uses a first light source and a second light source configured to emit light within a first wavelength range and a second wavelength range, respectively. The system includes a first pair of photodetectors in a reflective position with respect to the first and second light sources and a second pair of photodetectors in a transmission position with respect to the first and second light sources, and the reflective and transmission photodetectors generate electrical signals corresponding to the first and second wavelength ranges.
In the reflective position, the first pair of photodetectors includes a first photodetector and a second photodetector having different responsivities to wavelengths of light, where the first photodetector detects the light within the first wavelength range and the second photodetector detects the light within the second wavelength range. In the transmission position, the second pair includes a third photodetector and a fourth photodetector having different responsivities, where the third photodetector detects the first wavelength range and the fourth photodetector detects the second wavelength range.
Detector circuitry sums electrical signals outputted by the photodetectors in each pair and outputs the summed signals to a regional oximetry device. The transmission optical path is longer than the reflective optical path.
The disclosure frames the problem as improving regional oxygen saturation and total hemoglobin signal quality in the presence of confounders associated with hemoglobin-related sensing in tissue, including superficial tissue and pigmentation/interstitial-fluid effects.
Claims Coverage
The document includes two independent claims: one directed to a light sensing system and one directed to a method. Across these independent claims, the main inventive features concern dual-wavelength light emission, reflective and transmission optical-path detection using photodetector pairs with different responsivities, summing of corresponding electrical signals, and output of the summed signals to a regional oximetry device.
Dual wavelength light sensing with reflective and transmission photodetector pairs
A light sensing system comprising a first light source configured to emit light within a first wavelength range and a second light source configured to emit light within a second wavelength range, with a first pair of photodetectors located in a reflective position and a second pair of photodetectors located in a transmission position with respect to the first and second light sources.
Photodetector pairs having different responsivities for the wavelength ranges
The first pair of photodetectors comprises a first photodetector and a second photodetector having different responsivities, where the first photodetector detects the light within the first wavelength range and the second photodetector detects the light within the second wavelength range; the second pair comprises a third photodetector and a fourth photodetector having different responsivities, where the third photodetector detects the light within the first wavelength range and the fourth photodetector detects the light within the second wavelength range.
Parallel photodetector arrangement and paired summing of electrical signals
The first photodetector and the second photodetector are in parallel with each other and the third and fourth photodetectors are in parallel with each other, and detector circuitry is configured to sum electrical signals outputted by the first photodetector and the second photodetector and to sum electrical signals outputted by the third photodetector and the fourth photodetector.
Output of summed signals to a regional oximetry device
Detector circuitry is configured to output the summed signals to a regional oximetry device.
Reflective and transmission detection with optical path length difference
A method comprising emitting light within the first wavelength range and emitting light within the second wavelength range, detecting by a first pair of photodetectors through a reflective optical path and detecting by a second pair of photodetectors through a transmission optical path that is longer than the reflective optical path.
Electrical signal generation and summing for each wavelength band
Detecting by the first pair of photodetectors generates a first electrical signal corresponding to light within the first wavelength range and a second electrical signal corresponding to light within the second wavelength range, detecting by the second pair generates a third electrical signal corresponding to light within the first wavelength range and a fourth electrical signal corresponding to light within the second wavelength range, and the method sums the first electrical signal and the second electrical signal and sums the third electrical signal and the fourth electrical signal.
Output of summed signals to a regional oximetry device
The method outputs the summed signals to a regional oximetry device.
Claim coverage centers on using two wavelength ranges with corresponding photodetector pairs arranged for reflective and transmission detection, where photodetectors within each pair have different responsivities for the respective wavelength ranges and the system sums the corresponding electrical signals for output to a regional oximetry device.
Stated Advantages
Improves signal quality and noise reduction by using reflective short optical path detectors and transmission long optical path detectors to address confounders including superficial tissue and pigmentation/interstitial-fluid effects.
Documented Applications
Determining regional oxygen saturation (rSO2) and related hemoglobin/water-derived measures relevant to hemoglobin disorders.
Regional blood oxygen saturation determination using the summed signals output to a regional oximetry device.
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