Pocket-type instrument for non-invasive measurement of blood glucose concentration
First Claim
1. A method for determining non-invasively the concentration of glucose in a blood-carrying body part of a patient comprising the steps of:
- (a) splitting a laser beam into two polarized components and phase modulating one of the components with a modulation frequency above a range of mechanical vibrations and a phase, thereby providing a modulated component and an unmodulated component;
(b) combining the modulated and unmodulated components and forming therefrom a reference optical beam and a measurement optical beam, each of which is a polarized-modulated laser beam;
(c) passing the reference optical beam through a polarizer, sensing the polarized reference optical beam with a photodetector, and producing an electrical reference signal corresponding to the phase of the polarized-modulated optical beam;
(d) passing the measurement optical beam through a blood carrying body part having glucose to be measured and a thickness to provide a passed measurement optical beam having a phase and(i) splitting the passed measurement optical beam into a polarized component and a depolarized component;
(ii) converting the depolarized component into a depolarized component electric signal;
(iii) converting the polarized component into a polarized component electric signal;
(iv) subtracting the depolarized component electric signal from the polarized component electric signal to provide a first subtracted signal;
(v) low-pass filtering the depolarized component electric signal to provide a low-pass filtered signal; and
(vi) dividing the first subtracted signal by the lowpass filtered signal, thereby providing an electrical measurement signal corresponding to the phase of the passed measurement optical beam;
(e) determining a phase difference between the electrical reference and measurement signals; and
(f) determining the concentration of the glucose in the blood carrying body part illuminated by the measurement optical beam based on the determined phase difference.
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Accused Products
Abstract
A pocket-type apparatus for non-invasive measurement of blood glucose concentration based on producing a polarized-modulated laser beam via an optical phase shifter (32), measuring a phase difference introduced, e.g., by a finger (F) or a ear lobule (E) of a subject, measuring phase difference between a reference signal (SR) and a measurement signal (SM), and processing the obtained data which are then presented as blood glucose concentration. The optical phase shifter (32) comprises a pair of fiber-optic arms (40 and 42). The laser beam is fed to one of the fiber-optic arms (4), then both arms are guided through an input optical coupler (44) which splits the laser beam into a first component, which further propagates through the first optic-fiber arm (40), and a second component, which propagates through second optic-fiber arm (42). An optical phase shifter (48) which is attached to the first fiber-optic arm (40) modulates the first component of the laser beam. Both arms are then guided through an output optical coupler (46) which coherently mixes the light-propagating modes of the fiber-optic arms so that the output of each arm has a complementary coherent mixture of the beam first and second components with an orthogonal direction of polarization. An output of one of the fiber-optic arms is used as a reference optical signal and an output of the other fiber-optic arm is used as a measuring optical signal.
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Citations
27 Claims
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1. A method for determining non-invasively the concentration of glucose in a blood-carrying body part of a patient comprising the steps of:
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(a) splitting a laser beam into two polarized components and phase modulating one of the components with a modulation frequency above a range of mechanical vibrations and a phase, thereby providing a modulated component and an unmodulated component; (b) combining the modulated and unmodulated components and forming therefrom a reference optical beam and a measurement optical beam, each of which is a polarized-modulated laser beam; (c) passing the reference optical beam through a polarizer, sensing the polarized reference optical beam with a photodetector, and producing an electrical reference signal corresponding to the phase of the polarized-modulated optical beam; (d) passing the measurement optical beam through a blood carrying body part having glucose to be measured and a thickness to provide a passed measurement optical beam having a phase and (i) splitting the passed measurement optical beam into a polarized component and a depolarized component; (ii) converting the depolarized component into a depolarized component electric signal; (iii) converting the polarized component into a polarized component electric signal; (iv) subtracting the depolarized component electric signal from the polarized component electric signal to provide a first subtracted signal; (v) low-pass filtering the depolarized component electric signal to provide a low-pass filtered signal; and (vi) dividing the first subtracted signal by the lowpass filtered signal, thereby providing an electrical measurement signal corresponding to the phase of the passed measurement optical beam; (e) determining a phase difference between the electrical reference and measurement signals; and (f) determining the concentration of the glucose in the blood carrying body part illuminated by the measurement optical beam based on the determined phase difference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification