Wearable devices using near-infrared light sources

CAFC
  • US 10,098,546 B2
  • Filed: 01/02/2018
  • Issued: 10/16/2018
  • Est. Priority Date: 12/31/2012
  • Status: Active Grant
First Claim
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1. A wearable device, comprising:

  • a measurement device including a light source comprising a plurality of light emitting diodes (LEDs) for measuring one or more physiological parameters, the measurement device configured to generate, by modulating at least one of the LEDs having an initial light intensity, an optical beam having a plurality of optical wavelengths, wherein at least a portion of the optical beam includes a near-infrared wavelength between 700 nanometers and 2500 nanometers;

    the measurement device comprising one or more lenses configured to receive and to deliver at least a portion of the optical beam to tissue, wherein the tissue reflects at least a portion of the optical beam delivered to the tissue;

    the measurement device further comprising a receiver, the receiver having a plurality of spatially separated detectors and one or more analog to digital converters coupled to the spatially separated detectors, the one or more analog to digital converters configured to generate at least two receiver outputs, the receiver configured to;

    capture light while the LEDs are off and convert the captured light into a first signal andcapture light while at least one of the LEDs is on and to convert the captured light into a second signal, the captured light including at least a portion of the optical beam reflected from the tissue;

    the measurement device configured to improve a signal-to-noise ratio of the optical beam reflected from the tissue by differencing the first signal and the second signal and by differencing the two receiver outputs;

    the measurement device configured to further improve the signal-to-noise ratio of the optical beam reflected from the tissue by increasing the light intensity relative to the initial light intensity from at least one of the LEDs;

    the measurement device further configured to generate an output signal representing at least in part a non-invasive measurement on blood contained within the tissue, wherein the output signal is generated at least in part by using a Fourier transform of signals from the receiver including at least one of the first and second signals and signals from the at least two receiver outputs; and

    wherein the receiver further comprises one or more spectral filters positioned in front of at least some of the plurality of spatially separated detectors.

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