Method and Apparatus for Sensing Blood Oxygen
First Claim
Patent Images
1. A method for determining at least one circulatory related characteristic of a person, comprising:
- generating an oscillating light having an intensity that oscillates at an oscillating light frequency, the oscillating light including an electromagnetic wavelength which causes the oscillating light to be absorbed by some tissue of the person in amounts that are proportional to a volume of oxygenated blood in the tissue of the person;
directing the oscillating light towards the tissue of the person to cause the oscillating light to enter the tissue and pass through the tissue along a light path from which a first portion of the oscillating light exits the tissue and along which a second portion of the oscillating light is absorbed by the oxygenated blood in the light path such that the first portion is modulated by a volume of oxygenated blood that is present in said light path;
detecting levels of light near the tissue and creating a detector signal which is related to the detected light levels, the detected light including at least some of the first portion of the oscillating light exiting from the tissue and a secondary light from other sources, the detector signal including a first component caused by detection of the first portion of the oscillating light exiting the tissue, and a second component caused by the detection of the secondary light;
filtering the detector signal to attenuate at least a part of the second component of the detector signal and to pass the first component of the detector signal substantially un-attenuated; and
determining at least said circulatory characteristic based on a volume of oxygenated blood in the light path through the tissue as characterized by the modulation of the first component of the detector signal.
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Abstract
An exemplary embodiment providing one or more improvements includes a blood oxygen sensing apparatus and method in which an infra-red light is absorbed blood in portions that are related to levels of oxygen in the blood along a path.
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Citations
52 Claims
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1. A method for determining at least one circulatory related characteristic of a person, comprising:
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generating an oscillating light having an intensity that oscillates at an oscillating light frequency, the oscillating light including an electromagnetic wavelength which causes the oscillating light to be absorbed by some tissue of the person in amounts that are proportional to a volume of oxygenated blood in the tissue of the person; directing the oscillating light towards the tissue of the person to cause the oscillating light to enter the tissue and pass through the tissue along a light path from which a first portion of the oscillating light exits the tissue and along which a second portion of the oscillating light is absorbed by the oxygenated blood in the light path such that the first portion is modulated by a volume of oxygenated blood that is present in said light path; detecting levels of light near the tissue and creating a detector signal which is related to the detected light levels, the detected light including at least some of the first portion of the oscillating light exiting from the tissue and a secondary light from other sources, the detector signal including a first component caused by detection of the first portion of the oscillating light exiting the tissue, and a second component caused by the detection of the secondary light; filtering the detector signal to attenuate at least a part of the second component of the detector signal and to pass the first component of the detector signal substantially un-attenuated; and determining at least said circulatory characteristic based on a volume of oxygenated blood in the light path through the tissue as characterized by the modulation of the first component of the detector signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A blood oxygen sensor for determining at least one circulatory related characteristic of a person, comprising:
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an oscillating light generator for generating an oscillating light having an intensity that oscillates at an oscillating light frequency, the oscillating light including an electromagnetic wavelength which causes the oscillating light to be absorbed by some tissue of the person in amounts that are proportional to a volume of oxygenated blood in the tissue toward which the oscillating light is directed; a light directing apparatus for directing the oscillating light toward the tissue of the person to cause the oscillating light to enter the tissue and pass through the tissue along a light path from which a first portion of the oscillating light exits the tissue and along which a second portion of the light is absorbed by the oxygenated blood in the light path such that the first portion is modulated by a volume of oxygenated blood that is present in said light path; a light detector for detecting levels of light near the tissue in a spaced apart relationship to the light directing apparatus, and for creating a detector signal which is related to the detected light levels, the detected light including at least some of the first portion of the oscillating light exiting from the tissue and a secondary light from sources other than the oscillating light generator, the detector signal including a first component caused by detection of the first portion of the oscillating light exiting the tissue, and a second component caused by the detection of the secondary light; a filter for filtering the detector signal to attenuate at least part of the second component of the detector signal and to pass the first component of the detector signal substantially un-attenuated; and a computing device for receiving the filtered detector signal and for determining at least said circulatory characteristics relating to the person based on a volume of oxygenated blood in the light path through the tissue as characterized by the modulation of the first component of the detector signal. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A method for determining at least one circulatory related characteristic of a person, comprising:
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generating light at a wavelength which causes the light to be absorbed by some tissue of the person in amounts that are proportional to a volume of oxygenated blood in the tissue towards which the light is directed; directing the light towards the tissue of the person to cause the light to enter the tissue; guiding the light to cause to light to pass through the tissue along a light path which includes the light entering and exiting the tissue a plurality of times, a first portion of the light exiting the tissue and a second portion of the light is absorbed by the oxygenated blood in the light path such that the first portion is modulated by a volume of oxygenated blood that is present in said light path; detecting levels of light near the tissue after the light has passed through the light path and creating a detector signal which is related to the detected light levels, the detected light including at least some of the first portion of light exiting from the tissue and a secondary light from other sources, the detector signal including a first component caused by detection of a first portion of light exiting the tissue, and a second component caused by the detection of the secondary light; and determining at least said circulatory characteristic based on a volume of oxygenated blood in the light path through the tissue as characterized by the modulation of the first component of the detector signal. - View Dependent Claims (39, 40, 41, 42, 43, 44)
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45. A blood oxygen sensor for determining at least one circulatory related characteristic of a person, comprising:
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a light generator for generating a light at a wavelength which causes the light to be absorbed by some tissue of the person in amounts that are proportional to a volume of oxygenated blood in the tissue toward which the light is directed; a light directing apparatus for directing the light toward the tissue of the person to cause the light to enter the tissue; a light guide for guiding the light to pass through the tissue along a light path which includes the light entering and exiting the tissue a plurality of times, a first portion of the light exiting the tissue and a second portion of the light is absorbed by the oxygenated blood in the light path such that the first portion is modulated by a volume of oxygenated blood that is present in said light path; a light detector for detecting levels of light near the light guide which includes at least some of the first portion of light exiting from the tissue and for creating a detector signal which is related to the detected light levels; and a computing device for receiving the detector signal and for determining at least said circulatory characteristic based on a volume of oxygenated blood in the light path through the tissue as characterized by the modulation of the first portion of the light exiting the tissue. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52)
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Specification