JP2008104751A - Blood-sugar level measuring instrument and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate a measurement by miniaturizing a blood-sugar level measuring instrument and non-invasively measuring the blood-sugar level; and attain an easy measurement by providing a non-invasive blood-sugar level measuring method. <P>SOLUTION: When measuring the blood-sugar level using a transmission light, a near-infrared laser absorbed by glucose at high absorption and a visible light non-absorbed by glucose are transmitted to a site to be measured. The transmission amount of the visible light is defined as a criterion to correct a change due to the state of the skin tissue of the site to be measured. In the measurement, the light path length is also calculated to correct a change in the transmission amount caused by the change in the light path length due to dispersion of the sites to be measured, thus enabling the highly precise measurement and the miniaturization and providing the non-invasive blood-sugar level measuring instrument and method therefor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a blood sugar level measuring apparatus and a blood sugar level measuring method, and more particularly to a blood sugar level measuring apparatus and a blood sugar level measuring method that are non-invasive, downsized, and easy to measure.

  Blood glucose level measurement methods include a blood sampling method (invasive method) and a non-blood sampling method (non-invasive method). As a blood sampling method, a method is generally used in which the collected blood is reacted with a reagent usually by glucose oxidase method, and a blood glucose level is obtained from the reaction color using a colorimetric method. Various methods have been reported for the bloodless method, and for example, a method for optical measurement is known.

As one of the optical measurement methods, there is a method for detecting a difference in absorption amount of near-infrared light by glucose. Specifically, it is a method in which near-infrared light is transmitted through a certain site and blood glucose level is measured from the amount of transmitted light. As the method, a fingertip corner is considered as the most useful part (for example, refer to Patent Document 1 and Patent Document 2).
Japanese Patent No. 3038771 (pages 2, 3 and 1) Japanese Patent No. 3692751 (page 3, FIG. 1)

  However, when transmitted light is used, the amount of transmitted light changes depending on the position of the part to be transmitted (measured part), resulting in an error in the measured value. In particular, since the amount of glucose absorbed is very small, the measurement value reproducibility is low due to changes in the position of the measurement site and the method of contacting the site. The reason for this change is that it is difficult to always keep the transmission site constant with a finger or the like, and there is a change in the optical path length of the transmission. In order to stabilize the measurement site, for example, a method may be considered in which a nail is provided on the nail to stabilize the measurement site, but it is not convenient. In addition, the transmitted light changes depending on the state of the skin tissue of the measurement site, and there is a problem that the reproducibility to the measurement subject cannot be maintained.

  The present invention is to solve the above-described problems.

  The present invention has been made in view of the various circumstances described above. First, a blood glucose level measuring apparatus for measuring a glucose concentration in a measurement site of a living body, which includes a display unit, a first waveguide, and a first waveguide. A measurement unit that sandwiches the measurement site by the first waveguide and the second waveguide, first emission light having a high absorption rate by glucose, and second emission light serving as a reference. Of the first emission light and the second emission light are transmitted through the measurement site and incident on the second waveguide. A light receiving unit that receives light as first transmitted light and second transmitted light, an optical path length detecting unit that detects an optical path length in the measurement site, and the target of the first outgoing light based on the first transmitted light The amount of transmission at the measurement site is calculated, and the amount of transmission is compensated based on the second transmitted light and the optical path length. And converted into blood glucose level data is the blood glucose level data solves By providing a control unit for displaying on the display unit.

  The first outgoing light is near infrared laser light, and the second outgoing light is visible light.

  The light emitting unit includes a first light emitting unit that outputs the first emitted light and a second light emitting unit that outputs the second emitted light, and synthesizes the first emitted light and the second emitted light. It is characterized by this.

  In addition, the light emitting unit includes a first light emitting unit that outputs the first emitted light and a second light emitting unit that outputs the second emitted light. The first emitted light and the second emitted light are sequentially and individually provided. Is output.

  The light receiving unit includes a first light receiving unit and a second light receiving unit, the first light receiving unit receives the first transmitted light, and the second light receiving unit receives the second transmitted light. It is characterized by.

  Further, the control unit calculates another transmission amount based on the second transmitted light, and corrects the transmission amount by the other transmission amount.

  In addition, the control unit corrects the transmission amount based on a change amount of the optical path length.

  Further, the control unit includes an angle detection unit that detects an angle formed by the first waveguide and the second waveguide, and calculates the optical path length based on the angle.

  Further, the maximum angle is set to be small enough to sandwich a predetermined part of the end of the living body.

  Second, a blood glucose level measuring method for measuring a glucose concentration in a measurement site of a living body, wherein the first emission light having a high absorption rate by glucose and the second emission light serving as a reference are emitted to the measurement site. A step of receiving, as the first transmitted light and the second transmitted light, the light transmitted through the measured portion of the first emitted light and the second emitted light, and the measured of the first emitted light. Blood glucose level data by detecting the optical path length in the site, calculating the transmission amount of the first emitted light through the site to be measured, and correcting the transmission amount based on the second transmitted light and the optical path length And the process of converting to the above.

  The first outgoing light is near infrared laser light, and the second outgoing light is visible light.

  Further, the first emitted light and the second emitted light are synthesized and emitted to the measurement site.

  Further, the first emitted light and the second emitted light are emitted individually and sequentially to the measurement site.

  The first transmitted light and the second transmitted light are separated and received.

  Further, another transmission amount based on the second transmission light is calculated, and the transmission amount is corrected by the other transmission amount.

  According to the present invention, it is possible to provide a blood sugar level measuring apparatus and a blood sugar level measuring method that can be miniaturized and are non-invasive and easily measurable.

  First, since the near-infrared laser beam is emitted and transmitted to the measurement site and the glucose concentration of the measurement site is measured based on the amount of transmission, the measurement apparatus can be downsized and non-invasive and easy measurement can be performed. Is possible. At this time, since the change due to the state of the skin tissue of the measurement site and the change in permeation amount due to the change (variation) of the measurement site can be automatically corrected, the optical blood glucose level measuring device can be easily adjusted. Measurement accuracy can be improved.

  More specifically, in addition to near-infrared laser light, reference visible light (visible laser light) is emitted to and transmitted through the measurement site, and the amount of visible light transmitted through the measurement site is measured. The transmission amount of the near infrared laser beam is corrected based on the amount. Thereby, the change of the permeation | transmission amount by the state of skin tissue can be reflected in a measured value, and a measurement error can be reduced. Further, the measurement accuracy can be further improved by detecting the optical path length of the light transmitted through the measurement site and correcting the measurement value based on the amount of change.

  Secondly, the measurement unit has a configuration in which the measurement site is sandwiched between the first waveguide and the second waveguide whose one end is fixed and the other end can be opened and closed. The angle when the is fully opened is fixed. Thereby, the part of the living body that can be clamped by the measurement unit can be substantially limited, and variations in measured values can be reduced.

  Third, the angle formed by the first waveguide and the second waveguide is detected, and the optical path length of near-infrared laser light that passes through the measurement site is calculated based on this angle to correct the transmission amount of the measurement site. . Thereby, the change of the transmission amount due to the variation of the measurement site can be reflected in the measurement value, and the measurement error can be reduced.

  Fourth, the maximum angle formed between the first waveguide and the second waveguide can be clamped by the measurement unit by setting the limited part of the living body end such as a fingertip or an earlobe, for example. The part of the living body can be limited in more detail, and the stability of the part to be measured is improved.

  Fifth, by irradiating the measurement site with the emitted light obtained by synthesizing near-infrared laser light and visible light (visible laser beam), the optical path through which the emitted light passes through the measurement site can be unified. Therefore, the basic amount of transmitted light can be measured at the site where blood glucose is actually measured.

  In addition, even measurements using near-infrared laser light and visible light with different wavelengths are only required to be performed once. Time can be shortened. Moreover, since near-infrared laser light cannot be visually recognized, it can recognize that it is measuring by having visible light emitted simultaneously.

  Sixth, in the case of individually emitting near-infrared laser light and visible light (visible laser light) (sequentially switching the emission wavelength of the laser), the photodetector is compared with the case of outputting the emitted light that is a combination of both. And optical parts such as dichroic mirrors can be omitted.

  Measurement and management of blood glucose levels are very important in the sense of preventing lifestyle-related diseases or future diseases in normal life. ADVANTAGE OF THE INVENTION According to this invention, the blood glucose level measuring apparatus and blood glucose level measuring method which can be measured easily and improved the measurement precision in normal life can be provided.

  Hereinafter, an example of an embodiment of a blood sugar level measuring apparatus and a blood sugar level measuring method according to the present invention will be described in detail with reference to FIGS.

  First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating an example of a blood sugar level measuring apparatus according to the first embodiment, in which FIG. 1A is an external plan view, and FIG. 1B is a cross-sectional view taken along the line aa in FIG. It is.

  The blood glucose level measuring apparatus 100 according to the present embodiment includes a display unit 2, a measuring unit 3, a light emitting unit 11, a light receiving unit 12, an optical path length detecting unit 19, and a control unit 6.

  For example, a power switch 4, a measurement start / stop button 5, a display unit 2, and the like are provided on one main surface of the external housing 8 of the blood glucose level measuring apparatus 100. At the upper part of the external housing 8, a measuring unit 3 is provided as a contact part with the part to be measured.

  The measurement unit 3 includes a first waveguide 31 and a second waveguide 32, and sandwiches a measurement site by these. Here, as an example, the first waveguide 31 and the second waveguide 32 are configured such that, for example, one end of each is fixed and the other end can be opened and closed. ) To clip.

  The measuring unit 3 is set small enough to hold a limited part of the living body end even when the first waveguide 31 and the second waveguide 32 are opened to the maximum. Moreover, the measurement part 3 is set as the structure which can always clamp a to-be-measured site | part with a predetermined load. By configuring the first waveguide 31 and the second waveguide 32 in a clip shape, it is possible to limit the part of the living body that can be sandwiched by the measurement unit 3, and the blood glucose level is measured by sandwiching the part to be measured by the measurement unit 3. The measurement stability is improved.

  One end of the first waveguide 31 is connected to the light emitting unit 11 in the optical unit 1, and a mirror 311 and a condenser lens 312 are provided at the other end, for example. The light output from the light emitting unit 11 (hereinafter referred to as outgoing light 21) is reflected by the mirror 311 through the first waveguide 31 as shown by the arrow, condensed by the condenser lens 312 and emitted to the measurement site. .

  One end of the second waveguide 32 is connected to the light receiving unit 12, and for example, a mirror 321 and a condenser lens 322 are provided at the other end. A part of the emitted light that has passed through the measurement site (hereinafter referred to as transmitted light 22) is collected by the condenser lens 322 as indicated by the dashed arrow, reflected by the mirror 321, and received by the light receiving unit 12 via the second waveguide 32. Received light.

  The first waveguide 31 and the second waveguide 32 have a shape (for example, a cylindrical shape) and a material so that the emitted light 21 and the transmitted light 22 do not leak to the outside, and together with the light emitting unit 11 and the light receiving unit 12, Part of it.

  In order to measure the blood glucose level, it is efficient to detect the glucose concentration in the living body. In addition, when measuring blood sugar levels non-invasively (without blood sampling), light in a wavelength band that is transparent to the human body is used. In the case of glucose, some spectra of near-infrared light are used. It is known to have light absorption characteristics. Therefore, the blood glucose level is measured by transmitting near-infrared laser light to the measurement site and detecting the absorption rate by glucose.

  The light emitting unit 11 outputs first emitted light having a high absorption rate by glucose and second emitted light serving as a reference. Although details will be described later, the light emitting unit 11 includes a semiconductor laser and outputs a near-infrared laser beam having a single wavelength as the first emitted light. The near-infrared laser beam employs a wavelength of, for example, 1580 nm, which has a high absorption rate by glucose in the transmitted light.

  The light emitting unit 11 includes another semiconductor laser or LED (Light Emitting Diode), and outputs visible light as the second emitted light. In the present embodiment, for example, laser light having a wavelength of 660 nm (visible laser light) is employed as visible light. This wavelength is a wavelength that has no or very little absorption with respect to glucose, is long to some extent, and is a wavelength at which a certain amount of attenuation is recognized by the skin tissue of the measurement site. By using the visible light as a reference, it is possible to correct “variation” of the near-infrared laser light due to the measurement site.

  The light receiving unit 12 includes, for example, a photo detector, and firstly transmits light that has passed through the measurement site and is incident on the second waveguide 32 out of the first emitted light (near-infrared laser light). Light is received as light (hereinafter referred to as laser transmitted light). In addition, light that has passed through the measurement site and is incident on the second waveguide 32 in the second emitted light (visible light) is received as second transmitted light (hereinafter, visible transmitted light).

  By detecting the visible transmitted light, the light receiving unit 12 can calculate the transmission amount (transmittance) of visible light in the measurement site. Therefore, the transmission amount of near-infrared laser light can be corrected based on this.

  The optical path length detection unit 19 detects the optical path length of the light transmitted through the measurement site by the first waveguide 31 and the second waveguide 32, and is, for example, an angle detection unit.

  The angle detector 19 detects an angle θ formed by the first waveguide 31 and the second waveguide 32. The angle detector 19 is configured by, for example, a digital counter that counts pulses from the encoder, a rotating plate provided with a slit, and the like, and the first waveguide 31 and the second waveguide 32 sandwich the measurement site. These movement amounts are converted into distances according to the angle θ.

  The optical path length detection unit is not limited to the angle detection unit 19 and may be a unit that converts the amount of movement between the first waveguide 31 and the second waveguide 32 into a distance, such as a micrometer. In the case where the measurement unit 3 is not in a clip shape and is configured such that the measurement site is sandwiched by the slide of the first waveguide 31 and the second waveguide 32, for example, the optical path length of the measurement site is detected by the slide amount. it can. However, it is possible to stabilize the load on the part to be measured by making the measuring unit 3 a clip. Considering the advantage that the measurement site 3 can be clamped and limited to some extent, the present embodiment will be described by taking the case where the angle detection unit 19 is employed as an example.

  The control unit 6 is configured by, for example, a semiconductor integrated circuit integrated on a printed circuit board, and includes an arithmetic processing unit. The arithmetic processing unit calculates the transmission amount (or transmittance) of the near-infrared laser light at the measurement site from the light amount of the laser transmission light detected by the light receiving unit 12.

  Further, the arithmetic processing unit calculates the transmission amount (or transmittance) of visible light in the measurement site from the light amount of the visible transmission light detected by the light receiving unit 12.

  Further, the arithmetic processing unit calculates the optical path length of the near-infrared laser light in the measurement site based on the angle θ formed by the first waveguide 31 and the second waveguide 32 detected by the angle detection unit 19.

  Then, the transmission amount of near-infrared laser light (hereinafter referred to as laser transmission amount) is corrected based on the transmission amount of visible light (hereinafter referred to as visible transmission amount) and the optical path length.

  Although details will be described later, based on the amount of change in visible transmission, by correcting the amount of laser transmission that has passed through the same site to be measured, changes in the site to be measured and changes in skin tissue at the site to be measured The measurement error due to “variation” can be reduced.

  Further, by correcting the laser transmission amount based on the optical path length of the measurement site, it is possible to reduce measurement errors due to “variation” of the measurement site.

  Further, as described above, the arithmetic processing unit converts the corrected laser transmission amount into blood glucose level data, and the control unit 6 displays the blood glucose level data on the display unit 2 by the display driver.

  The display unit 2 is connected to a display driver that is a part of the control unit 6. The display unit 2 is, for example, an LCD (Liquid Crystal Display) panel, an organic EL (Electronic Luminescent) display panel, etc., and displays a blood glucose level and other measurement information (for example, notification of measurement error, date and time) so that the measurer can recognize it. Anything can be used. In addition, a power supply unit (not shown) connected to the control unit 6 is provided. The power source is charged by an AC adapter, a battery, or a combination thereof.

  Note that a contact detection sensor may be provided in the first waveguide 31 and the second waveguide 32, and the measurement apparatus may be operated after normal contact is detected.

  FIG. 2 is a schematic diagram showing the blood glucose level measurement site 25 and the blood glucose level measuring device 100.

  The measurement site 25 sandwiched by the blood sugar level measuring apparatus 100 of the present embodiment will be described. For example, the thickness is relatively thin, such as between the fingers of the hand (FIG. 2A) or the earlobe (FIG. 2B). It is preferable that the pleated portion is the measurement site 25. This is because the measurement error can be reduced when the optical path length of the light passing through the measurement site is shorter. Although not shown, the measurement site may be the fingertip. In this way, the glucose concentration in the dermis layer of the site to be measured 25 and in the capillaries is measured.

  Each of the first waveguide 31 and the second waveguide 32 has a clip-like configuration in which one end is fixed by, for example, the angle detection unit 19 and the other end is openable and closable. At this time, reproducibility can be improved by always applying a predetermined load to the measurement site 25.

  In addition, the angle θ formed by the first waveguide 31 and the second waveguide 32 is set to be small enough that the limited portion of the living body end can be clamped. More specifically, even when the measuring unit 3 is opened to the maximum, the measurement site can be limited to some extent by adopting a configuration in which only a thin and limited site such as a fold-like part of a living body can be sandwiched. For example, as the maximum opening angle between the first waveguide 31 and the second waveguide 32, the condensing lens 312 located at the tip of the first waveguide 31 and the condensing lens 322 located at the tip of the second waveguide 32. The measurement area sandwiched between them is limited to a specific part such as a finger or earlobe, and is a fingertip. In addition, it is possible to avoid the occurrence of a large “variation” in the measurement value depending on the measurement site, such as being limited to the tip portion. Further, since the optical path length is shortened, the measurement error can be reduced.

  FIG. 3 is a diagram showing an outline of the blood sugar level measuring apparatus 100 and the optical unit 1 of the present embodiment. FIG. 3A is an example of a circuit block diagram, and the optical unit 1 is indicated by a broken line. FIG. 3B is a schematic diagram showing a state in which the emitted light 21 and the transmitted light 22 pass through the measurement site 25 in a state where the measurement site 25 is sandwiched by the measurement unit 3.

  The light emitting unit 11 includes a first light emitting unit LD1, a second light emitting unit LD2, and a dichroic mirror 17. The first light emitting unit LD1 is, for example, a semiconductor laser, and the second light emitting unit LD2 is a semiconductor laser or an LED. Here, a case where a semiconductor laser is employed as the second light emitting unit LD2 will be described as an example.

  The first light emitting unit LD1 is driven by the laser driver 63a of the control unit 6 and outputs first emitted light (near infrared laser light) 211 having an emission wavelength of, for example, 1580 nm. The second light emitting unit LD2 is driven by the laser driver 63b of the control unit 6, and outputs second emitted light (visible light: laser light) 212 having an emission wavelength of, for example, 660 nm. Note that the emission wavelength of the second light emitting unit LD2 is a wavelength different from that of the near-infrared laser light 211, and has a wavelength that does not absorb or extremely little absorbs glucose, and is attenuated to some extent by skin tissue. Although not limited, a semiconductor laser having an emission wavelength of 660 nm is common and inexpensive.

  Part of the near-infrared laser beam 211 output from the first light emitting unit LD1 is input to an APC (Auto Power Control) 13a via a half mirror 15a and an FMD (Front Monitor Diode) 16a.

  Part of the visible light 212 output from the second light emitting unit LD2 is input to an APC (Auto Power Control) 13b via a half mirror 15b and an FMD (Front Monitor Diode) 16b.

  The APCs 13a and 13b perform control such as maintaining the power of the near-infrared laser light 211 and the visible light 212 constant, respectively.

  Further, the near-infrared laser beam 211 and the visible light 212 are combined by the dichroic mirror 17 that transmits one and reflects the other, and is converted into parallel light by the lens 18 and the first waveguide 31 as one outgoing light 21. Led in.

  The emitted light 21 is reflected by the mirror 311 at the end of the first waveguide 31, condensed by the condenser lens 312, and emitted to the measurement site 25. A part of the emitted light 21 in the measurement site 25 is absorbed by glucose and slightly attenuated by the skin tissue, and collected as transmitted light 22 by the condenser lens 322 at the end of the second waveguide 32. The light is reflected by the mirror 321 and detected by the light receiving unit 12.

  In this way, by irradiating the measurement site 25 with the emitted light 21 obtained by synthesizing the near-infrared laser beam 211 and the visible light 212, the optical path through which the emission light 21 passes through the measurement site 25 can be unified. Therefore, the amount of basic transmitted light 22 can be measured at a site where blood glucose is actually measured.

  In addition, even in the measurement using the near-infrared laser beam 211 and the visible light 212 having different wavelengths, the measurement only needs to be performed once. Compared to the case where the near-infrared laser beam 211 and the visible light 212 are sequentially switched and measured. Thus, the measurement time can be shortened. Moreover, since the near-infrared laser beam 211 cannot be visually recognized, it can be recognized that the visible light 212 is emitted at the same time, and measurement is being performed.

  The light receiving unit 12 includes a first light receiving unit PD1, a second light receiving unit PD2, and a dichroic mirror 23. The transmitted light 22 is separated into a first transmitted light (laser transmitted light) 221 and a second transmitted light (visible transmitted light) 222 by the dichroic mirror 23 via the lens 24. The laser transmitted light 221 is detected by the first light receiving unit PD1, and the visible transmitted light 222 is detected by the second light receiving unit PD2. The detected amount of received laser transmitted light 221 (hereinafter referred to as laser transmission amount N) is an actual measurement value.

  Each of the first light receiving part PD1 and the second light receiving part PD2 is, for example, an InGaAs photodiode or the like, and converts each received transmitted light 22 into an electric signal. The electric signal is proportional to the intensity of the received light, is amplified by the amplifiers 14 a and 14 b, and is output to the A / D converter 62 of the control unit 6.

  The control unit 6 includes a DSP (Digital signal processor) 61, an A / D conversion circuit 62, laser drivers 63 a and 63 b, and an arithmetic processing unit 65. The control unit 6 also includes a display driver 64 for outputting data such as measurement results to the display unit, other circuits (not shown) necessary for other controls, and the like.

  A signal (reception signal) based on the amount of received light amplified by the optical unit 1 is converted into a digital signal by the A / D conversion circuit 62 and input to the arithmetic processing unit 65 in the DSP 61.

  The arithmetic processing unit 65 calculates the glucose concentration at the measurement site based on the received signal. In the present embodiment, the glucose concentration is calculated based on the absorbance I using near-infrared laser light 211 having a wavelength that is largely absorbed by glucose. The absorptance I can be obtained from the amount of emitted light (intensity) of the near-infrared laser light 211 emitted from the light emitting unit 11 and the amount of received light (intensity) of the laser transmitted light 221 that has passed through the measurement site 25. If the intensity of the emitted light 21 having the wavelength λ emitted to the measurement site 25 is L0 (λ), and the intensity of the transmitted light 22 having the received wavelength λ is L (λ), the absorbance I ( λ) is obtained by ln (L (λ) / L0 (λ)) (in the case where the emitted light 21 is constant, the received light intensity itself is equivalent to the absorbance).

  The absorbance I has a predetermined correlation with the glucose concentration. Therefore, the glucose concentration of the measurement site 25 can be calculated by causing the control unit 6 to hold the correlation function between the absorbance I and the glucose concentration.

  Furthermore, in this embodiment, the control unit 6 corrects the change in the laser transmission amount N (measured value) accompanying the change in the state of the skin tissue of the measurement site 25. Further, the change in the laser transmission amount N accompanying the change in the optical path length due to the change in the measurement site 25 is corrected. This will be described below.

  The change in the laser transmission amount N accompanying the change in the state of the skin tissue is corrected by the transmission amount of the visible light 212 emitted to the same measurement site 25 (hereinafter referred to as the visible transmission amount V).

  As described above, the visible light 212 is a wavelength at which a certain amount of attenuation is recognized by the skin tissue without absorption by glucose. Therefore, the reference transmission state can be measured by the change amount of the visible transmission amount V.

  More specifically, the permeation amount (hereinafter referred to as reference permeation amount) of a specific part of the living body is measured in advance and held in the control unit 6, and this is compared with the visible permeation amount V. Thereby, the change amount of the visible transmission amount V (difference between the visible transmission amount and the reference transmission amount) is the change (deviation) of the measured region 25 itself, the change of the state of the skin tissue, or the tissue change of the skin tissue. It can be measured as the first shift amount shown.

  Since the near-infrared laser beam 211 passes through the same site to be measured 25 as the visible light 212, the measured laser transmission amount N (measured value) includes the first reference shift amount. Therefore, the arithmetic processing unit 65 performs a calculation for correcting the laser transmission amount N based on the first shift amount.

  In addition, the arithmetic processing unit 65 determines the optical path length L of the near-infrared laser light 211 in the measurement site 25 based on the angle θ formed by the first waveguide 31 and the second waveguide 32 detected by the angle detection unit 19. Calculate (see FIG. 3B). If the part to be measured 25 varies, the amount of laser transmission N transmitted through the part to be measured 25 also changes, causing a measurement error. In the present embodiment, an expected value is stored in the control unit 6 in advance, and by calculating the amount of change (second shift amount) of the optical path length L of the measured region 25 from the expected value, Even if there is "variation" in the measurement site, this can be corrected.

  As a result, even when the measurement site 25 changes, for example, with a fingernail portion, between fingers, or an earlobe, the laser is always corrected with the amount of change peculiar to that site and the change in optical path length. A transmission amount N can be obtained.

  More specifically, the arithmetic processing unit 65 calculates the first shift amount and the second shift amount according to the following equation (1), and the laser transmission amount N due to the change in the state of the skin tissue or the like or the change in the optical path length. The blood glucose level data G from which the measurement error is eliminated is calculated.

G = f (N, A, V) (1)
Here, N: laser transmission amount, A: angle (θ) formed by the first waveguide 31 and the second waveguide 32, and V: visible transmission amount.

  The control unit 6 causes the display driver 64 to display the blood glucose level data G on the display unit 2 as a measurement result. Further, the measurement unit 6 performs various known controls corresponding to pressing of a measurement start / stop button, monitoring of a measurement state, and the like. When a contact detection sensor is provided in the measurement unit 3, the control unit 6 performs a process related to detection of a contact state, such as starting a measurement process (laser drive or the like) after detecting normal contact.

  The miniaturized clip-type optical simple blood sugar level measuring device 100 shown in FIGS. 1 to 3 is used to measure the blood sugar level of the living body, thereby easily measuring the blood sugar level of the living body. Can be done.

  Although not shown, the optical unit 1 may be provided with a temperature detection unit (for example, a temperature sensor). The temperature sensor measures the temperature of the measurement site 25 (or in addition to the outside air temperature). The light absorption characteristics of glucose by the near-infrared laser light 211 change with temperature. Therefore, the temperature is measured by the temperature sensor before the blood glucose level is measured, and the wavelength of the near infrared laser beam 211 is corrected within a minute range from the measurement result. Note that visible light is not affected by temperature and does not require temperature correction.

  For example, since the oscillation wavelength of the near-infrared laser beam 211 emitted from the first light emitting unit LD1 has a characteristic that varies depending on the current supplied to the first light emitting unit LD1 or the temperature of the first light emitting unit LD1, it is measured in advance. The temperature or drive current of the first light emitting unit LD1 that emits the near-infrared laser light 211 is controlled based on the temperature dependence of the absorption characteristics of glucose. For example, when controlling with the drive current of the near-infrared laser beam 211, the laser drive amount is calculated and fed back to the laser driver 63a. Thereby, the near-infrared laser beam 211 is selected with the most efficient wavelength within the range satisfying the wavelength condition of the present embodiment according to the temperature of the measurement site 25, and is shifted by, for example, several nm. Thereby, a more accurate blood glucose level can be measured.

  Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is different from the first embodiment in the configuration of the light emitting unit 11 of the optical unit 1, and is otherwise the same as the first embodiment. Is omitted.

  FIG. 4 is an example of a circuit block diagram illustrating an outline of the optical unit 1 in the second embodiment.

  The near-infrared laser beam 211 and the visible light 212 output from the light emitting unit 11 may be individually emitted to the measurement site 25 without being synthesized. As long as the measurement target part 25 is sandwiched by the measurement unit 3, the near-infrared laser light 211 and the visible light 212 may be emitted with a predetermined time difference. The laser transmitted light 221 can be corrected.

  In this case, since it is not necessary to synthesize the emitted light 21, the dichroic mirror 17 is unnecessary. For example, when parallel light is used as measurement light (light received by the light receiving unit 12), the semiconductor laser is diffused light, and thus a collimator lens is required. However, when measuring diffused light as it is, the lens is It is unnecessary.

  Then, near-infrared laser light 211 and visible light 212 are output from the first light-emitting portion LD1 and the second light-emitting portion LD2 with a predetermined time difference at the timing created by the CPU that controls light emission, respectively.

  In the light receiving unit 12 also, the laser transmitted light 221 and the visible transmitted light 222 are individually received, so that the dichroic mirror 23 is unnecessary.

  Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the first embodiment in the configuration of the light emitting unit 11 and the light receiving unit 12 of the optical unit 1, and the other components are the same as those in the first embodiment. The description of is omitted.

  FIG. 5 is an example of a circuit block diagram illustrating an outline of the optical unit 1 according to the third embodiment.

  The light receiving unit 12 includes one photodiode PD that can receive and detect two wavelengths of the laser transmitted light 221 (1580 nm) and the visible transmitted light 222 (660 nm). When a photodiode is used for the light receiving unit 12, generally, the photodiode has a narrow light receiving sensitivity. Therefore, as in the first embodiment (FIG. 3), the photodiodes PD1 and PD2 correspond to the two wavelengths, respectively. Is provided. However, as shown in FIG. 5, if light can be received by one photodiode, it is not necessary to separate them, and only one amplifier 14 is required, which can contribute to reduction in the number of components and downsizing of the apparatus.

  Note that here, the emitted light 21 output from the light emitting unit 11 is illustrated as being output separately, and the dichroic mirror 23 is not provided as in the second embodiment, and the first light emitting unit LD1 and the second light emitting unit LD1 are provided. Near-infrared laser light 211 and visible light 212 are output from the light emitting unit LD2 at a predetermined time difference. However, the present invention is not limited to this, and the emitted light 21 synthesized as in the first embodiment (FIG. 3) may be output.

  In the present embodiment, for example, a long optical path length required for a spectroscopic analyzer, an FTIR analyzer, or the like, or an operating unit such as a mirror is unnecessary, and the size can be reduced. In addition, since the transmitted light of the laser light having a single wavelength is received, it is not necessary to split the light with a diffraction grating or the like, and the light receiving side can be composed of, for example, a lens and a photo detector. Therefore, the blood sugar level measuring apparatus 100 can be reduced in size and weight, and the portability can be greatly improved. The size is small enough to fit in the palm of the hand and can be carried and operated with one hand.

  Furthermore, in the present embodiment, only the absorption spectrum of glucose is measured, and unnecessary spectrum is not measured, so that the measurement time can be shortened.

  Next, an embodiment of a blood glucose level measuring method according to the present invention will be described with reference to FIG.

  The blood glucose level measurement method of the present embodiment is a blood glucose level measurement method for measuring the glucose concentration at a measurement site of a living body, and receives the first emitted light having a high absorption rate by glucose and the second emitted light as a reference. A step of emitting to the measurement site; a step of receiving, as the first transmitted light and the second transmitted light, the light transmitted through the measurement site among the first emitted light and the second emitted light; and the measurement of the first emitted light A step of detecting an optical path length in the site, a step of calculating a transmission amount of the first emitted light through the measurement site, correcting the transmission amount based on the second transmitted light and the optical path length, and converting the blood glucose level data Is composed of.

  FIG. 6 is a flowchart showing an example of the blood sugar level measuring method of the present embodiment, and will be described with reference to this figure and the circuit block (FIG. 3) of the first embodiment.

  1st process (step S1): The process of radiate | emitting the 1st emitted light with the high absorption factor by glucose, and the 2nd emitted light used as a reference | standard to a to-be-measured site | part.

  First, the body temperature (and outside air temperature) of the measurement site is measured. Based on the measurement temperature and the temperature dependence characteristics of glucose, a laser driving amount that emits a wavelength that satisfies the specified laser wavelength condition (in this embodiment) or a wavelength closest to the specified laser wavelength condition is calculated (step S11). . Note that visible light may not be corrected by temperature.

  First emission light (near-infrared laser light) 211 having high absorptance due to glucose is output from the first light emitting part LD1 (according to the calculated laser driving amount), and second emission light (visible light) serving as a reference ) 212 is output from the second light emitting unit LD2, and the measurement target 25 is irradiated with the emitted light 21 via the first waveguide 31. In FIG. 3, the emitted light 21 is synthesized by the dichroic mirror 17. However, as in the second embodiment (FIG. 4), the near-infrared laser light 211 and the visible light 212 are individually separated with a predetermined time difference. You may output (step S12).

  Second step (step S2): A step of receiving, as the first transmitted light and the second transmitted light, the light transmitted through the measurement site among the first emitted light and the second emitted light.

  The first light receiving part PD1 of the light receiving part 12 separates and receives the transmitted light 22 incident on the second waveguide 32. More specifically, the first light receiving portion PD1 of the light receiving portion 12 converts the light that has passed through the measurement site 25 and entered the second waveguide 32 out of the near-infrared laser light 211 into the first transmitted light (laser transmitted light). ) 221 is received. In addition, the second light receiving unit PD2 of the light receiving unit 12 receives, as the second transmitted light (visible transmitted light) 222, the light that has passed through the measurement site 25 and entered the second waveguide 32 in the visible light 212. .

  As in the third embodiment (FIG. 5), the two transmitted lights may be received by one photodiode PD without being separated.

  Third step (step S3): a step of detecting the optical path length in the measurement site of the first emitted light.

  In a state where the measurement unit 3 sandwiches the measurement site 25, the angle detection unit 19 (FIG. 3) detects the angle θ formed by the first waveguide 31 and the second waveguide 32. The angle detection unit 19 includes a digital counter and a rotating plate provided with a slit. The angle detection unit 19 has a clip-like shape in which one end of each of the first waveguide 31 and the second waveguide 32 is fixed to the angle detection unit 19. With this configuration, the angle θ formed by the first waveguide 31 and the second waveguide 32 can be measured at the same time that the measurement site 25 is sandwiched by the measurement unit 3. The control unit 6 calculates the optical path length L in the measurement site by measuring the angle θ.

  Instead of detecting the angle θ by the angle detector 19, the optical path length may be measured by converting the movement amount of the first waveguide 31 and the second waveguide 32 into a distance, for example, like a micrometer. .

  Fourth step: (Step S4): A step of calculating the transmission amount of the first emitted light at the measurement site, correcting the transmission amount based on the second transmitted light and the optical path length, and converting it to blood glucose level data.

  Based on the transmission amount (laser transmission amount) N of the laser transmitted light 221 detected by the first light receiving unit PD1, the control unit 6 determines the absorbance of the near-infrared laser light 211 absorbed by glucose in the measurement site 25. The measured glucose concentration G ′ at the site to be measured is calculated from the calculated correlation function between the absorbance and the glucose concentration (step S41).

  At this time, the control unit 6 corrects the change of the laser transmission amount N based on the change in the state of the skin tissue of the measurement site 25, and changes the laser transmission amount N based on the optical path length L accompanying the change of the measurement site 25. to correct.

  Specifically, the transmission amount (visible transmission amount) V of the visible light 212 detected by the second light receiving unit PD2, and the transmission amount (reference transmission amount) of a specific part of the living body that is measured in advance and held in the control unit 6 , The first shift amount indicating the change (deviation) of the measurement site 25 itself, the change in the state of the skin tissue, or the tissue change of the skin tissue is calculated.

  Since the measured laser transmission amount N includes the first reference shift amount, the arithmetic processing unit 65 performs an operation for correcting the laser transmission amount N based on the first shift amount (step S42). .

  In addition, the arithmetic processing unit 65 calculates the optical path length of the near-infrared laser beam 211 in the measurement site 25 based on the angle θ formed by the first waveguide 31 and the second waveguide 32 detected by the angle detection unit 19. To do. And the 2nd shift amount based on the change of the optical path length L of the to-be-measured site | part 25 is calculated, and laser transmission amount N is further correct | amended by this (step S43).

  More specifically, the arithmetic processing unit 65 calculates blood glucose level data G by the following equation (1).

G = f (N, A, V) (1)
Here, N: laser transmission amount, A: angle (θ) formed by the first waveguide 31 and the second waveguide 32, and V: visible transmission amount.

  As a result, blood glucose level data G from which the measurement error of the laser transmission amount N due to the change in the state of the skin tissue or the like or the change in the optical path length is eliminated from the measured glucose concentration G ′.

By measuring the blood glucose level of the living body using the miniaturized clip-type optical simple blood glucose level measuring apparatus 100, the blood glucose level measuring method of the living body can be easily performed in a non-invasive manner.

It is explanatory drawing which shows one Embodiment of the blood glucose level measuring apparatus which concerns on this invention, (A) is an external appearance top view, (B) is the sectional view on the aa line of (A). It is explanatory drawing which shows the state by which the to-be-measured site | part was pinched | interposed with the blood glucose level measuring apparatus, (A) is the schematic which made the to-be-measured part between the fingers of the hand, and (B) made the earlobe the to-be-measured part. FIG. It is a figure which shows 1st Embodiment of the blood glucose level measuring apparatus which concerns on this invention, (A) is a circuit block diagram, (B) is a schematic diagram of a measurement part. It is a circuit block diagram which shows 2nd Embodiment of the blood glucose level measuring apparatus which concerns on this invention. It is a circuit block diagram which shows 3rd Embodiment of the blood glucose level measuring apparatus which concerns on this invention. It is a flowchart which shows one Embodiment of the blood glucose level measuring method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical unit 2 Display part 3 Measuring part 4 Power switch 5 Measurement start / stop button 6 Control part 8 External housing 11 Light emitting part 12 Light receiving part 13a, 13b APC
14a, 14b Amplifier 15a, 15b Half mirror 16a, 16b FMD
17, 23 Dichroic mirror 18, 24 Lens 19 Optical path length detector (angle detector)
21 outgoing light 211 first outgoing light 212 second outgoing light 22 transmitted light 221 first transmitted light 222 second transmitted light 25 part to be measured 31 first waveguide 32 second waveguide 311 321 mirror 312 322 condenser lens 61 DSP
62 A / D converter circuit (A / D converter)
63a, 63b Laser driver 64 Display driver 65 Arithmetic processing unit 100 Blood glucose level measuring device LD1 First light emitting unit LD2 Second light emitting unit PD Photodiode (light receiving unit)
PD1 photodiode (first light receiving part)
PD2 photodiode (second light receiving part)

Claims (15)

A blood glucose level measuring device for measuring the concentration of glucose in a measurement site of a living body,
A display unit;
A measurement unit having a first waveguide and a second waveguide, and sandwiching the measurement site by the first waveguide and the second waveguide;
A light emitting section for emitting the first emitted light having a high absorption rate by glucose and the second emitted light serving as a reference to the measurement site through the first waveguide;
A light receiving unit that receives, as the first transmitted light and the second transmitted light, the light transmitted through the measurement site and incident on the second waveguide among the first emitted light and the second emitted light;
An optical path length detection unit for detecting an optical path length in the measurement site;
Based on the first transmitted light, calculate the transmission amount of the first emitted light in the measurement site, correct the transmission amount based on the second transmitted light and the optical path length, and convert it to blood glucose level data; A control unit for displaying the blood glucose level data on the display unit;
A blood glucose level measuring apparatus comprising:   The blood glucose level measuring apparatus according to claim 1, wherein the first emitted light is near-infrared laser light, and the second emitted light is visible light.   The light emitting unit includes a first light emitting unit that outputs the first emitted light and a second light emitting unit that outputs the second emitted light, and synthesizes the first emitted light and the second emitted light. The blood sugar level measuring device according to claim 1, wherein   The light emitting unit includes a first light emitting unit that outputs the first emitted light and a second light emitting unit that outputs the second emitted light, and sequentially outputs the first emitted light and the second emitted light individually. The blood glucose level measuring apparatus according to claim 1, wherein:   The light receiving unit includes a first light receiving unit and a second light receiving unit, the first light receiving unit receives the first transmitted light, and the second light receiving unit receives the second transmitted light. The blood glucose level measuring apparatus according to claim 1.   The blood glucose level measuring apparatus according to claim 1, wherein the control unit calculates another transmission amount based on the second transmitted light, and corrects the transmission amount based on the other transmission amount.   The blood glucose level measuring apparatus according to claim 1, wherein the control unit corrects the transmission amount based on an amount of change in the optical path length.   2. The control unit according to claim 1, wherein the control unit includes an angle detection unit that detects an angle formed by the first waveguide and the second waveguide, and calculates the optical path length based on the angle. Blood glucose level measuring device.   9. The blood sugar level measuring apparatus according to claim 8, wherein the maximum angle is set to be small enough to sandwich a predetermined part of the end of the living body. A blood glucose level measuring method for measuring a glucose concentration at a measurement site of a living body,
Emitting a first emitted light having a high absorption rate by glucose and a second emitted light serving as a reference to the measurement site;
Receiving the light transmitted through the portion to be measured among the first emitted light and the second emitted light as first transmitted light and second transmitted light;
Detecting an optical path length in the measurement site of the first emitted light;
Calculating the amount of transmission of the first emitted light through the measurement site, correcting the amount of transmission based on the second transmitted light and the optical path length, and converting to blood glucose level data;
A blood glucose level measuring method comprising:   The blood glucose level measuring method according to claim 10, wherein the first emitted light is near-infrared laser light, and the second emitted light is visible light.   The blood glucose level measuring method according to claim 10, wherein the first emitted light and the second emitted light are synthesized and emitted to the measurement site.   The blood glucose level measuring method according to claim 10, wherein the first emitted light and the second emitted light are emitted individually and sequentially to the measurement site.   The blood glucose level measuring method according to claim 10, wherein the first transmitted light and the second transmitted light are separated and received.   The blood glucose level measuring method according to claim 10, wherein another transmission amount based on the second transmitted light is calculated, and the transmission amount is corrected by the other transmission amount.

Images