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US 7,613,487 B2Granted
Instrument for noninvasively measuring blood sugar level
AssigneeNagasaki Prefectural Government
InventorYoshiaki Shimomura
Life of this patent
Estimating the term…
Abstract
A small and portable instrument for measuring blood sugar level of a human body noninvasively with no error comprising a light source control section for irradiating the measurement part of a finger with irradiation lights in two different near-infrared wavelength regions, photodetectors for receiving lights and of the irradiation lights quantities of transmitted lights. A relative transmittance, i.e. the ratio of the quantities of transmitted lights of the same wavelength detected at the two positions, is calculated for each wavelength and the blood sugar level is determined using the relative transmittance of each wavelength.
Claims8
An instrument for noninvasively measuring a blood sugar level comprising:
- an irradiation device configured to irradiate a measurement part of a human body with the light of two different wavelengths;
- a transmitted light quantity detecting device configured to receive transmitted light, which is the light from the irradiation device transmitted through the measurement part of the human body, at two positions spaced at different distances so as to detect the quantity of the transmitted light;
- and
- a calculation device configured to calculate coefficients k0 and k1 by the use of the pre-measured blood sugar level and relative transmittances Rλ1 and Rλ2, and calculates the blood sugar level C in accordance with the following formula:
- C=k0+k1*ln(Rλ1)/ln(Rλ2),
- in which, of the quantities of the transmitted light detected at the two positions, the quantity of the light transmitted through a shorter distance is represented as I1.λ1 and I1.λ2, the quantity of the light transmitted through a longer distance is represented as I2.λ1 and I2.λ2, and the relative transmittances Rλ1 and Rλ2 of the two different wavelengths are represented by the following formulae:
- Rλ1=I2.λ1/I1.λ1 and Rλ2=I2.λ2/I1.λ2.
4 more elements
An instrument for noninvasively measuring a blood sugar level comprising:
- an irradiation device configured to irradiate a measurement part of a human body with the light of two different wavelengths;
- a transmitted light quantity detecting device configured to receive the transmitted light, which is the light from the irradiation device transmitted through the measurement part of the human body, at two positions spaced at different distances so as to detect the quantity of the transmitted light;
- and
- a calculation device configured to calculate coefficients k0 and k1 by the use of a pre-measured blood sugar level and absorbances A1 and A2, and calculates the blood sugar level C in accordance with the following formula:
- C=k0k1*A1/A2,
- in which, of the quantities of the transmitted light detected at the two positions, the quantity of the light transmitted through a shorter distance is represented as I1.λ1 and I1.λ2, the quantity of the light transmitted through a longer distance is represented as I2.λ1 and I2.λ2, the relative transmittances Rλ1 and Rλ2 of the two different wavelengths are represented by the following formulae:
- Rλ1=I2.λ1/I1.λ1 and Rλ2=I2.λ2/I1.λ2, and
- the absorbances of the two different wavelengths A1 and A2 are represented as the following formulae on the basis of the relative transmittances Rλ1 and Rλ2:
- A1=−ln(Rλ1) and A2=−ln(Rλ2).
6 more elements
An instrument for noninvasively measuring a blood sugar level comprising:
- an irradiation device configured to irradiate a measurement pan of a human body with the light of three different wavelengths;
- a transmitted light quantity detecting device configured to receive the transmitted light, which is the light from the irradiation device transmitted through the measurement pan of the human body, at two positions spaced at different distances so as to detect the quantity of the transmitted light;
- and
- a calculation device configured to calculate coefficients k0 and k1 by the use of a pre-measured blood sugar level and relative transmittances Rλ1, Rλ2, and Rλ3, and calculates the blood sugar level C in accordance with the following formula:
- C=k0+k1*ln(R80 1/Rλ3)/ln(Rλ2/Rλ3),
- in which, of the quantities of the transmitted light detected at the two positions, the quantity of the light transmitted through a shorter distance is designated as I1.λ1, I1.λ2, and I1.λ3, the quantity of the light transmitted through a longer distance is designated as I2.λ1, I2.λ2, and I2.λ3, and the relative transmittances Rλ1, Rλ2, and Rλ3 of the three wavelengths are represented by the following formulae:
- Rλ1=I2.λ1/I1.λ1, Rλ2=I2.λ2/I1.λ2, and Rλ3=I2.λ3/I1.λ3.
4 more elements
An instrument for noninvasively measuring a blood sugar level comprising:
- an irradiation device configured to irradiate a measurement part of a human body with the light of three different wavelengths;
- a transmitted light quantity detecting device configured to receive the transmitted light, which is the light from the irradiation device transmitted through the measurement part of the human body, at two positions spaced at different distances so as to detect the quantity of the transmitted light;
- and
- a calculation device configured to calculate coefficients k0 and k1 by the use of a pre-measured blood sugar level and absorbances A1, A2, and A3, and calculates the blood sugar level C in accordance with the following formula:
- C=k0+k1*(A1−A3)/(A2−A3),
- in which, of the quantities of the transmitted light detected at the two positions, the quantity of the light transmitted through a shorter distance is designated as I1.λ1, I1.λ2, I1.λ3, the quantity of the light transmitted through a longer distance is designated as I2.λ1, I2.λ2, and I2.λ3, the relative transmittances Rλ1, Rλ2, and Rλ3 of the three different wavelengths are represented by the following formulae:
- Rλ1=I2.λ1/I1.λ1, Rλ2=I2.λ2/I1.λ2, and Rλ3=I2.λ3/I1.λ3, and
- the absorbances of the three different wavelengths A1, A2, and A3 are represented by the following formulae on the basis of the relative transmittances Rλ1, Rλ2, and Rλ3:
- A1=−ln(Rλ1), A2=−ln(Rλ2), and A3=−ln(Rλ3).
6 more elements
Dependencies are inferred from the claim text.