EP0426358B1
Expired / Lapsed
EP
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A non-invasive method and apparatus for measuring blood chemical concentration
Assignee: Individual
•
Filing: 1990-10-23
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Granted: 1999-05-12
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Expires: 2010-10-23
Abstract
Abstract A method and apparatus for measuring blood glucose concentration by irraditing blood vessels with electromagnetic radiation using near-infrared radiation diffuse-reflection laser spectroscopy. This invention uses electromagnetic radiation of a wavelength that is transmitted through the skin to the measurement part, for example, a blood vessel. Since skin is mostly composed of water (H2O), which absorbs IR radiation in nearly the entire IR spectral range, only radiation of a certain, narrow protion of the IR spectral range called the "water transmission window" is transmitted through the skin. The present invention uses electromagnetic radiation with a wavelength of 1.3 mu m SIMILAR 1.9 mu m radiation from a semiconductor diode laser (5). When electromagnetic radiation of these wavelengths irradiates the skin, light is transmitted through the skin to the blood vessel where the light interacts with the heterogeneous components of the blood. The light which reaches the blood is then diffusely reflected by the blood. The reflected light will have been modulated by the characteristic vibrations of the molecules which are major components of blood. The reflected light is detected and provided as a digital signal to a one-chip microcomputer (2). The one-chip microcomputer (2) calculates a blood glucose concentration from the digital signal by reference to a calibration curve stored in the memory of the one-chip microcomputer (2). The one-chip microcomputer (2) causes the calculated blood glucose concentration to be displayed on a digital display (3).
Inventors
- 👤 Won Suck Yang
- 👤 Yoon Ok Kim
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 22:22
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/145; A61B5/1455; A61B5/14532
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
149 words
A method of measuring the concentration of a chemical
carried in a blood stream, the method comprising the steps
of: irradiating a blood vessel carrying the blood stream
with near-infrared light having a wavelength of between
substantially 1.3µm and substantially 1.9µm; detecting radiation dispersed or diffusedly rejected
by the blood using a photodetector (7); and, analysing the detected radiation using diffuse-reflection
spectroscopy responsive to vibrational,
rotational and translational motion of the molecules of the
said chemical utilising overtone vibrations and a
combination of other types of vibration to determine the
concentration of the chemical in the blood, the method
characterised in that: the step of irradiating is carried out with light from
a laser diode (5); the step of analysing the detected radiation is
carried out by comparison of a detected value with a stored
calibration curve; and, the apparatus used to measure the concentration is a
portable apparatus.
Claim 2
Dependent Claim
16 words
A method according to claim 1 in which the chemical
concentration measured is blood glucose concentration.
Claim 3
Dependent Claim
323 words
A method according to claim 2 comprising the steps of: supplying a power source from a battery to a
processing means (2), a digital display (3), a laser diode
power supply (4), a detector (7) and an optical unit (6) by
means of a power switch (1); controlling said processing means (2) by means of
start/reset switch (8) so that said laser diode power
supply (4) gradually applies current to said laser diode
(5) at a stable voltage and temperature; controlling said processing means (2) so that a D/A
converter (10) coupled between said processing means (2)
and said laser diode power supply (5) converts a digital
control signal into an electrical control signal; emitting a wavelength sufficient for measurement in
said laser diode (5) by means of said laser diode power
supply (4); collimating the light emitted from the laser diode (5)
parallel to a corresponding object, or optically
controlling, separating and combining the light emitted
from said laser diode (5); irradiating through an integrating unit (9) said
optically controlled light to a blood vessel to measure
blood glucose concentration; integrating by means of said integrating unit (9) the
light absorbed, dispersed and diffusely reflected by the
blood after the light has passed through the skin to the
blood; transmitting the signal amplified by a preamplifier
connected to said detector to an A/D converter (11), after
converting photons integrated by said integrating unit (9)
and detected by said detector (7) into an electrical analog
measurement value the step of analysing the output
comprising: transmitting the signal to said processing means (2),
after converting said electrical analog measurement value
into a digital measurement value by means of said A/D
converter (11); calculating and computing blood glucose concentration
by comparing a calibration curve stored in memory region of
said processing means (2) with a digital measurement value
converted by said A/D converter (11); displaying a calculated blood glucose concentration on
said digital display (3).
Claim 4
Dependent Claim
62 words
A method for measuring blood glucose concentration
according to claim 3 wherein in the step of calculating and
computing blood glucose concentration by comparing a
calibration curve stored in the memory of said processing
means (2) with a digital measurement value converted by
said A/D converter (11), utilizes a mathematical method
based on a multiple linear regression analysis and a
multivariate analysis.
Claim 5
Independent Claim
372 words
An apparatus for measuring non-invasively blood
glucose concentration, the apparatus comprising: means to irradiate a blood vessel carrying the blood
stream with light at a wavelength of between substantially
1.3µm and substantially 1.9µm; an integrating unit (9) which integrates light
dispersed and diffusedly reflected from the blood; a detector (7) which amplifies a signal by means of a
preamplifier after converting photons integrated by said
integrating element into an electrical analog measurement
value; an A/D converter (11) for converting said electrical
analog measurement value into a digital measurement value;
and processing means (2) including means for calculating
and computing blood glucose concentration; characterised in that: the apparatus has a width x length x height less than
170 mm x 80 mm x 25 mm; the apparatus is arranged to irradiate the blood with
light from a laser diode (5); the processing means (2) are adapted for controlling
the flow of current supplied from a laser diode power
supply (4) to the laser diode (5); and, the means for calculating and computing are adapted
for comparing an electrical analog measurement value
detected and converted by the detector (7) with a
calibration curve stored in memory of said processing means
(2), and in that the apparatus further comprises: a D/A converter (10) for controlling the laser diode
power supply by converting a digital control signal to an
analog control signal, said laser diode (5) consisting of
a plurality of diodes for emitting light of different
wavelengths or emitting light of the same wavelength in
accordance with the current supplied from said laser diode
power supply, the processing means (2) and A/D converter
(11) being arranged in combination to control the power
supply to apply current gradually and at stable voltage and
temperature levels to the laser diode (5), a temperature controller (13) which controls the
temperature of said laser diode (15), said temperature
controller being connected between said laser diode power
supply (4) and said laser diode (15); an optical unit (6) which collimates light emitted
from said laser diode (5) parallel to a corresponding
object or optically controls, separates and combines the
light emitted from said laser diode; and, a digital display (3) connected for displaying the
calculated and computed blood glucose concentration.
Claim 6
Dependent Claim
62 words
An apparatus for measuring blood glucose concentration
according to claim 5, wherein the wavelength of the
electromagnetic radiation emitted from said laser diode (5)
is in the near-infrared region, in the range from
substantially 1.4µm to substantially 1.8µm and the light
emitted from said laser diode (5) simultaneously irradiates
the blood through the skin, or sequentially irradiates the
blood through the skin.
Claim 7
Dependent Claim
83 words
An apparatus for measuring blood glucose concentration
according to claim 5 or 6, wherein said integrating unit
(9) is globular or like shape, oval or half oval or other
shape, and said integrating unit has a width, length and height
less than 2.56 cm, but preferably 1.28cm or less, and more
particularly 0.64cm or less, and said measurement apparatus
has a width x length x height less than 150mm x 75mm x
22mm, and more particularly 130mm x 70mm x 20mm or less.
Claim 8
Dependent Claim
56 words
An apparatus for measuring blood glucose concentration
according to claim 5, 6 or 7 including an input/output port
separable from the measurement apparatus and connected to
the measurement apparatus by means of an optic fibre, and
the distance between port and measurement apparatus is
100∼1,000mm and preferably 500mm or less, and more
preferably is substantially 300mm.
Claim 9
Independent Claim
89 words
An apparatus for measuring blood glucose concentration
according to claims 5, 6, 7 or 8 wherein a photo diode is
utilized as said detector (7) which detects photons
integrated by said integrating unit (9) and a Ge detector,
and preferably is coupled to a preamplifier and said D/A converter (10) and A/D converter (11) are
separated from said processing means, or are included in
said processing means (2), and said battery used as a power source is 4.5 to 9V, and
is suitable for a charging battery of 6V.
References Cited (Backward Citations)
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