Apparatus for measuring concentration of light-absorbing substance in blood
First Claim
1. An apparatus for measuring a concentration of a light-absorbing substance in blood, comprising:
- a light emitter, which emits light beams to irradiate a living tissue, each of the light beams being associated with one wavelength which is absorbed by the blood;
a first instrument, which measures first intensities of the light beams, which are to be incident on the living tissue;
a second instrument, which measures second intensities of the light beams, which are transmitted through the living tissue;
a first calculator, which calculates an attenuation variation ratio, which is a ratio of attenuation variations of the respective light beams due to variation of a volume of the blood caused by pulsation, based on the second intensities of the light beams; and
a second calculator, which calculates the concentration based on the first intensities, the second intensities, and the attenuation variation ratio.
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Accused Products
Abstract
An apparatus for measuring a concentration of a light-absorbing substance in blood is disclosed. A light emitter emits light beams to irradiate a living tissue, each of the light beams being associated with one wavelength which is absorbed by the blood. A first instrument measures first intensities of the light beams, which are to be incident on the living tissue. A second instrument measures second intensities of the light beams, which are transmitted through the living tissue. A first calculator calculates an attenuation variation ratio, which is a ratio of attenuation variations of the respective light beams due to variation of a volume of the blood caused by pulsation, based on the second intensities of the light beams. A second calculator calculates the concentration based on the first intensities, the second intensities, and the attenuation variation ratio.
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Citations
13 Claims
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1. An apparatus for measuring a concentration of a light-absorbing substance in blood, comprising:
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a light emitter, which emits light beams to irradiate a living tissue, each of the light beams being associated with one wavelength which is absorbed by the blood;
a first instrument, which measures first intensities of the light beams, which are to be incident on the living tissue;
a second instrument, which measures second intensities of the light beams, which are transmitted through the living tissue;
a first calculator, which calculates an attenuation variation ratio, which is a ratio of attenuation variations of the respective light beams due to variation of a volume of the blood caused by pulsation, based on the second intensities of the light beams; and
a second calculator, which calculates the concentration based on the first intensities, the second intensities, and the attenuation variation ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 11)
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9. An apparatus for measuring a concentration of a light-absorbing substance in blood, comprising:
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a light emitter, which emits (n) kinds of light beams to irradiate a living tissue, each of the light beams being associated with one wavelength which is absorbed by the blood;
a first instrument, which measures (n) kinds of first intensities of the light beams, which are to be incident on the living tissue;
a second instrument, which measures (n) kinds of second intensities of the light beams, which are transmitted through the living tissue;
a first calculator, which calculates, at most, (n−
1) kinds of attenuation variation ratios, which is a ratio of attenuation variations of the respective light beams due to variation of a volume of the blood caused by pulsation, based on the second intensities of the light beams; and
a second calculator, which calculates, at most, (n) kinds of DC components of attenuations of the light beams, based on the first intensities and the second intensities, and obtains the concentration based on the DC components and the attenuation variation ratio, wherein (n) is an integer which is three or more. - View Dependent Claims (12)
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10. An apparatus for measuring a concentration of a light-absorbing substance in blood, comprising:
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a light emitter, which emits (n) kinds of light beams to irradiate a living tissue, each of the light beams being associated with one wavelength which is absorbed by the blood;
a first instrument, which measures (n) kinds of first intensities of the light beams, which are to be incident on the living tissue;
a second instrument, which measures (n) kinds of second intensities of the light beams, which are transmitted through the living tissue;
a first calculator, which calculates, at most, (n−
1) kinds of attenuation variation ratios, which is a ratio of attenuation variations of the respective light beams due to variation of a volume of the blood caused by pulsation, based on the second intensities of the light beams; and
a second calculator, which calculates, at most, (n) kinds of DC components of intensities of the light beams transmitted through the living tissue, based on the first intensities and the second intensities, and obtains the concentration based on the DC components and the attenuation variation ratio, wherein (n) is an integer which is three or more. - View Dependent Claims (13)
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Specification