Method and device for non-invasive in vivo determination of blood constituents
First Claim
1. Method for non-invasive in vivo determination of a blood constituent in a body part by measuring the light absorption in the body part comprising the steps of harmonically modulating the body part in thickness with a pressure modulation frequency, and with a second pressure modulation frequency differing from zero and irradiating the thickness-modulated body part with light of at least two monochromatic wavelengths, at least one but not all of said wavelengths being lie in a range of optical absorption of the blood constituent, acquiring at least four measured signals that are dependent on an influence of the light as well as on a mechanical change in thickness, and determining a concentration of the blood constituent from the at least four measured signals.
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Accused Products
Abstract
The body part under examination has its thickness modulated by mechanical influence with at least two pressure modulation frequencies. At least four measured signals that are dependent both on the influence of the light as well as on the mechanical thickness change are acquired by irradiating the body part with light.
149 Citations
21 Claims
- 1. Method for non-invasive in vivo determination of a blood constituent in a body part by measuring the light absorption in the body part comprising the steps of harmonically modulating the body part in thickness with a pressure modulation frequency, and with a second pressure modulation frequency differing from zero and irradiating the thickness-modulated body part with light of at least two monochromatic wavelengths, at least one but not all of said wavelengths being lie in a range of optical absorption of the blood constituent, acquiring at least four measured signals that are dependent on an influence of the light as well as on a mechanical change in thickness, and determining a concentration of the blood constituent from the at least four measured signals.
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17. An apparatus for non-invasive in vivo determination of blood constituents in a body part, comprising:
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a light source adapted to emit light into a body part;
a detector disposed to detect light from said light source after passing through said body part;
a compression unit adapted for placement on said body part for harmonically modulating said body part in thickness; and
a first pressure modulation frequency generator, operating at a first pressure modulation frequency, and a second modulation frequency generator, operating at a second modulation frequency, connected to said compression unit, and said compression unit harmonically modulating said body part in thickness with said first and second pressure modulation frequencies. - View Dependent Claims (18, 19, 20, 21)
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Specification