Blood glucose measuring device

Abstract

A blood glucose measuring device capable of measuring blood glucose levels using a green light source. [Solution] The blood glucose level measuring device includes a light output unit including a green light source that outputs incident light L1, a light detection unit that detects transmitted light L2 transmitted through the living body, and a calculation unit that calculates the blood glucose level of the living body. In the spectrum of the incident light L1, the central wavelength is located at 430 nm to 580 nm, the intensity at 600 nm to 615 nm is 0.01% or more of the intensity at the central wavelength, and the intensity at 480 nm to 515 nm is 1% or more of the intensity at the central wavelength. The light detection unit includes a first photodetector having a first detection wavelength range of 460 nm to 535 nm, and a second photodetector having a second detection wavelength range of 580 nm or more. The calculation unit calculates the blood glucose level of the living body based on the intensity of the transmitted light L2 detected by the first photodetector and the intensity of the transmitted light L2 detected by the second photodetector.

Description

[Technical field]

[0001] The present invention relates to a blood glucose measuring device. [Background technology]

[0002] A known example of a device for measuring biological information non-invasively is the device described in Patent Document 1. The device described in Patent Document 1 has a function of measuring the pulse rate of a living body by, for example, outputting light to the living body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-147469 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned device may be required to measure blood glucose levels. However, a green light source may be used to measure the pulse of a living body, and adding a new light source for measuring blood glucose levels, for example, may increase the size of the device or increase power consumption.

[0005] An object of the present invention is to provide a blood glucose measuring device that can realize blood glucose measurement using a green light source. [Means for solving the problem]

[0006] The blood glucose level measuring device of the present invention is, [1] "a blood glucose level measuring device for measuring a blood glucose level of a living organism, comprising: a light output unit including a green light source that outputs incident light to the living organism; a light detection unit that detects transmitted light that has passed through the living organism; and a calculation unit that calculates the blood glucose level of the living organism based on a detection result of the light detection unit, wherein the spectrum of the incident light has a central wavelength located in a first wavelength range of 430 nm to 580 nm, an intensity in a second wavelength range of 600 nm to 615 nm is 0.01% or more of the intensity at the central wavelength, and an intensity in a third wavelength range of 480 nm to 515 nm is 1% or more of the intensity at the central wavelength, the light detection unit has a first photodetector having a first detection wavelength range of 460 nm to 535 nm and a second photodetector having a second detection wavelength range of 580 nm or more, and the calculation unit calculates the blood glucose level of the living organism based on the intensity of the transmitted light detected by the first photodetector and the intensity of the transmitted light detected by the second photodetector."

[0007] In the blood glucose level measuring device described in [1] above, the spectrum of the incident light output to the living body has a central wavelength located in a first wavelength range of 430 nm to 580 nm, an intensity in a second wavelength range of 600 nm to 615 nm is 0.01% or more of the intensity at the central wavelength, and an intensity in a third wavelength range of 480 nm to 515 nm is 1% or more of the intensity at the central wavelength. When such incident light is incident on the living body, transmitted light having a spectrum with a central wavelength located in each of a wavelength range of 460 nm to 535 nm and a wavelength range of 580 nm or more is emitted from the living body. The calculation unit calculates the blood glucose level of the living body based on the intensity of the transmitted light detected in the first detection wavelength range of 460 nm to 535 nm and the intensity of the transmitted light detected in the second detection wavelength range of 580 nm or more. Therefore, according to this blood glucose level measuring device, it is possible to realize blood glucose level measurement using a green light source.

[0008] The blood glucose level measuring device of the present invention may be [2] "the blood glucose level measuring device according to the above [1], wherein in the spectrum of the incident light, the central wavelength is located in a fourth wavelength range of 470 nm to 540 nm, the intensity in a fifth wavelength range of 605 nm to 615 nm is 0.1% or more of the intensity at the central wavelength, and the intensity in a sixth wavelength range of 490 nm to 515 nm is 40% or more of the intensity at the central wavelength." This allows for the acquisition of transmitted light suitable for calculating blood glucose levels, thereby enabling more accurate calculation of the blood glucose level of a living body.

[0009] The blood glucose level measuring device of the present invention may be the blood glucose level measuring device according to the above [1] or [2], [3] "wherein the first photodetector includes a first photodetection region and a first optical filter having a first transmission wavelength range of 460 nm to 535 nm, the second photodetector includes a second photodetection region and a second optical filter having a second transmission wavelength range of 580 nm or more, and the calculation unit calculates the blood glucose level of the living body based on the intensity of the transmitted light that has passed through the first optical filter and detected by the first photodetection region, and the intensity of the transmitted light that has passed through the second optical filter and detected by the second photodetection region." As a result, the first optical filter and the second optical filter selectively transmit the transmitted light, so that the configuration of the first photodetection region and the second photodetection region can be made common.

[0010] The blood glucose measuring device of the present invention may be [4] "the blood glucose measuring device according to any one of the above [1] to [3], wherein the light detecting section further comprises a third photodetector having a third detection wavelength range of 500 nm to 600 nm, and the calculation section calculates the pulse rate of the living body based on the intensity of the transmitted light detected by the third photodetector." This makes it possible to realize measurement of both blood glucose level and pulse rate using a green light source, and suppresses the increase in size of the device and the increase in power consumption.

[0011] The blood glucose measuring device of the present invention may be [5] "the blood glucose measuring device according to the above [4], wherein the third photodetector further comprises a third photodetection region and a third optical filter having a third transmission wavelength range of 500 nm to 600 nm, which is provided on the third photodetection region, and the calculation unit calculates the pulse of the living body based on the intensity of the transmitted light that is transmitted through the third optical filter and detected by the third photodetection region." In this way, the first optical filter, the second optical filter, and the third optical filter each selectively transmit the transmitted light, so that the configurations of the first photodetection region, the second photodetection region, and the third photodetection region can be standardized.

[0012] The blood glucose measuring device of the present invention may be [6] "the blood glucose measuring device according to any one of the above [1] to [5], wherein the first photodetector is each of a plurality of first photodetectors, the second photodetector is each of a plurality of second photodetectors, and each of the plurality of first photodetectors and each of the plurality of second photodetectors are alternately arranged so as to surround the light output section." This reduces loss of incident light output from the light output section.

[0013] The blood glucose measuring device of the present invention may be [7] "the blood glucose measuring device according to any one of the above [1] to [5], wherein the green light source is each of a plurality of green light sources, and each of the plurality of green light sources is arranged so as to surround the light detecting unit." In this way, since the plurality of green light sources surrounds the light detecting unit, the intensity of the transmitted light incident on the light detecting unit is ensured. Effect of the Invention

[0014] According to the present invention, it is possible to provide a blood glucose measuring device that can realize blood glucose measurement using a green light source. [Brief description of the drawings]

[0015] [Figure 1] 1 is a conceptual diagram of a blood glucose measuring device according to an embodiment. [Diagram 2]FIG. 2 is a rear view of the blood glucose measuring device shown in FIG. [Diagram 3] 3 is a diagram showing the spectra of incident light output from a first light source shown in FIG. 2 and transmitted light having passed through a living body. FIG. [Figure 4] FIG. 4 is a diagram showing the spectrum of transmitted light shown in FIG. [Diagram 5] FIG. 13 is a rear view of a blood glucose measuring device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0017] Fig. 1 is a cross-sectional view of the blood glucose measuring device of this embodiment and a living body. Fig. 1 is merely a conceptual diagram for explaining the function of the blood glucose measuring device 1, and does not necessarily show an actual cross-section of the blood glucose measuring device 1.

[0018] The blood glucose measuring device 1 shown in Fig. 1 is, for example, a wearable device, a smartphone, or a pulse oximeter. Examples of wearable devices include a smart watch and a smart ring. In this embodiment, the blood glucose measuring device 1 is a smart watch that has a function of measuring the blood glucose level of a living body 6. The living body 6 has a superficial tissue 61 and an internal tissue 62 that is located inside the living body 6 with respect to the superficial tissue 61. A surface 61a of the superficial tissue 61 is the surface of the skin of the living body 6. The living body 6 is, for example, a human body.

[0019] The blood glucose measuring device 1 comprises a main body 2, a light output unit 3, a light detection unit 4, and an ECU [Electronic Control Unit] 5. The main body 2 has a front face 2a and a back face 2b facing the opposite side to the front face 2a. The front face 2a functions as a display screen (display) that displays various information of the blood glucose measuring device 1. The blood glucose measuring device 1 is attached to a living body 6 such that the back face 2b comes into contact with the skin of the living body 6.

[0020] The light output unit 3 is provided in the main body 2. The light output surface of the light output unit 3 is exposed from the rear surface 2b of the main body 2. The light output unit 3 outputs measurement light L. The measurement light L is emitted from the rear surface 2b. The measurement light L emitted from the light output unit 3 propagates inside the living body 6, and then is emitted from the living body 6 again. The light output unit 3 is controlled by the ECU 5.

[0021] The light detection unit 4 is provided in the main body 2. The light detection unit 4 is separated from the light output unit 3. The light detection surface of the light detection unit 4 is exposed from the rear surface 2b of the main body 2. The light detection unit 4 detects the measurement light L (transmitted light) that has passed through the living body 6. The light detection unit 4 transmits a signal related to the intensity of the measurement light L to the ECU 5.

[0022] The ECU 5 is provided in the main body 2. The ECU 5 is an electronic control unit having a CPU [Central Processing Unit] and a storage unit such as a ROM [Read Only Memory] or a RAM [Random Access Memory]. In the ECU 5, for example, a program stored in the storage unit is executed by the CPU. The ECU 5 functions as a calculation unit that calculates biological information of the living body 6. The ECU 5 calculates the blood glucose level, pulse rate, oxygen saturation concentration, etc. of the living body 6 based on a signal transmitted from the light detection unit 4 (detection result of the light detection unit 4).

[0023] Fig. 2 is a rear view of the blood glucose measuring device 1. Fig. 2 shows the light output unit 3 and the light detection unit 4 as viewed from the rear surface 2b of the main body unit 2. As shown in Fig. 2, the light output unit 3 has a first light source 31, a second light source 32, and a third light source 33. The first light source 31, the second light source 32, and the third light source 33 are arranged in a line. The first light source 31 is disposed between the second light source 32 and the third light source 33.

[0024] The first light source 31 is a green light source. The first light source 31 outputs green light as the measurement light L. The green light is, for example, a probe light having a central wavelength of about 515 nm. The green light is different from white light. When observed by the human eye, the green light appears green or green-blue. The color of the green light corresponds to, for example, 5G, 10G, 5BG, or 10BG of the Munsell color system. The first light source 31 outputs the green light at a predetermined pulse interval in response to a control signal transmitted from the ECU 5. That is, the green light output from the first light source 31 flashes at a predetermined pulse interval. The first light source 31 continues to output the green light. That is, the green light output from the first light source 31 flashes constantly. The first light source 31 is, for example, a light-emitting diode (LED), a laser diode (LD), a superluminescent diode (SLD), or the like.

[0025] The second light source 32 is a red light source. The second light source 32 outputs red light as the measurement light L. The red light is, for example, a probe light having a central wavelength of about 660 nm. The second light source 32 outputs red light at a predetermined pulse interval in response to a control signal transmitted from the ECU 5. That is, the red light output from the first light source 31 blinks at a predetermined pulse interval. The second light source 32 outputs red light intermittently. That is, the red light output from the second light source 32 blinks intermittently. The second light source 32 operates at predetermined intervals. During the period when the second light source 32 is operating, both the green light and the red light blink, and during the period when the second light source 32 is stopped, the green light blinks and the red light is turned off. The second light source 32 is, for example, a light emitting diode (LED), a laser diode (LD), a superluminescent diode (SLD), or the like.

[0026] The third light source 33 is an infrared light source. The third light source 33 outputs infrared light as the measurement light L. The infrared light is, for example, a probe light having a central wavelength of about 880 nm or about 910 nm. The third light source 33 outputs infrared light at a predetermined pulse interval in response to a control signal transmitted from the ECU 5. That is, the infrared light output from the third light source 33 blinks at a predetermined pulse interval. The third light source 33 outputs infrared light intermittently. That is, the infrared light output from the third light source 33 blinks intermittently. The third light source 33 operates at predetermined intervals. During the period when the third light source 33 is operating, both the green light and the infrared light blink, and during the period when the third light source 33 is stopped, the green light blinks and the infrared light is turned off. The third light source 33 is, for example, a light-emitting diode (LED), a laser diode (LD), a superluminescent diode (SLD), or the like.

[0027] The light detection unit 4 has a plurality of first light detectors 401, a plurality of second light detectors 402, and a plurality of third light detectors 403. The plurality of first light detectors 401, the plurality of second light detectors 402, and the plurality of third light detectors 403 are arranged in a circular ring shape so as to surround the light output unit 3. The first light detectors 401, the second light detectors 402, and the third light detectors 403 are alternately arranged so as to surround the light output unit 3. In this embodiment, the light detection unit 4 has two first light detectors 401, two second light detectors 402, and three third light detectors 403. In the circumferential direction of the light detection unit 4, one first light detector 401, one second light detector 402, one third light detector 403, one first light detector 401, one third light detector 403, one second light detector 402, and one third light detector 403 are arranged in order.

[0028] The first photodetector 401 has a first detection wavelength range S1 (see FIG. 4). That is, the first photodetector 401 detects light having a wavelength included in the first detection wavelength range S1. The first detection wavelength range S1 is 460 nm to 535 nm. The second photodetector 402 has a second detection wavelength range S2 (see FIG. 4). That is, the second photodetector 402 detects light having a wavelength included in the second detection wavelength range S2. The second detection wavelength range S2 is 580 nm or more. The third photodetector 403 has a third detection wavelength range S3 (see FIG. 4). That is, the third photodetector 403 detects light having a wavelength included in the third detection wavelength range S3. The third detection wavelength range S3 is 500 nm to 600 nm.

[0029] The first photodetector 401 has a first photodetection region 41 and a first optical filter 44. The second photodetector 402 has a second photodetection region 42 and a second optical filter 45. The third photodetector 403 has a third photodetection region 43 and a third optical filter 46. Each of the photodetection regions 41, 42, and 43 detects transmitted light that has passed through the living body 6. Each of the photodetection regions 41, 42, and 43 has a photodetection element and a preamplifier. The photodetection element is, for example, a photodiode (PD) or the like. The preamplifier amplifies the photocurrent output from the photodetection element. In this embodiment, the configurations of the photodetection regions 41, 42, and 43 are the same as each other.

[0030] The first optical filter 44 is provided on the first light detection region 41. The first optical filter 44 is provided on the light detection surface of the first light detection region 41. The outer edge of the first optical filter 44 is located outside the outer edge of the first light detection region 41. The outer edge of the first optical filter 44 may be approximately coincident with the outer edge of the first light detection region 41. The first optical filter 44 has, for example, a film shape. The first optical filter 44 has a first transmission wavelength range T1 (see FIG. 4). The transmittance of light having a wavelength included in the first transmission wavelength range T1 through the first optical filter 44 is higher than the transmittance of light having a wavelength not included in the first transmission wavelength range T1 through the first optical filter 44. The first optical filter 44 transmits light in the first transmission wavelength range T1 and does not transmit light other than the first transmission wavelength range T1. The first transmission wavelength range T1 is 460 nm to 535 nm.

[0031] The second optical filter 45 is provided on the second light detection region 42. The second optical filter 45 is provided on the light detection surface of the second light detection region 42. The outer edge of the second optical filter 45 is located outside the outer edge of the second light detection region 42. The outer edge of the second optical filter 45 may be approximately coincident with the outer edge of the second light detection region 42. The second optical filter 45 has, for example, a film shape. The second optical filter 45 has a second transmission wavelength range T2 (see FIG. 4). The transmittance of light having a wavelength included in the second transmission wavelength range T2 through the second optical filter 45 is greater than the transmittance of light having a wavelength not included in the second transmission wavelength range T2 through the second optical filter 45. The second optical filter 45 transmits light in the second transmission wavelength range T2 and does not transmit light other than the second transmission wavelength range T2. The second transmission wavelength range T2 is 580 nm or more, and preferably 610 nm or more.

[0032] The third optical filter 46 is provided on the third light detection region 43. The third optical filter 46 is provided on the light detection surface of the third light detection region 43. The outer edge of the third optical filter 46 is located outside the outer edge of the third light detection region 43. The outer edge of the third optical filter 46 may be approximately coincident with the outer edge of the third light detection region 43. The third optical filter 46 has, for example, a film shape. The third optical filter 46 has a third transmission wavelength range T3 (see FIG. 4). The transmittance of light having a wavelength included in the third transmission wavelength range T3 through the third optical filter 46 is higher than the transmittance of light having a wavelength not included in the third transmission wavelength range T3 through the third optical filter 46. The third optical filter 46 transmits light in the third transmission wavelength range T3 and does not transmit light other than the third transmission wavelength range T3. The third transmission wavelength range T3 is 500 nm to 600 nm.

[0033] Each of the first optical filter 44, the second optical filter 45, and the third optical filter 46 is, for example, a dielectric multilayer filter. Each of the first optical filter 44, the second optical filter 45, and the third optical filter 46 may be, for example, a color filter for an image sensor formed from a color resist, or a color filter in which a dye is mixed into gelatin or triacetate. Each of the first optical filter 44, the second optical filter 45, and the third optical filter 46 may be the same as or different from each other.

[0034] Next, blood glucose measurement using green light output from the first light source 31 will be described in detail. Fig. 3 is a diagram showing the spectra of the incident light L1 (dashed line) output from the first light source 31 and the transmitted light L2 (solid line) that has passed through the living body 6. In Fig. 3, the horizontal axis represents wavelength and the vertical axis represents light intensity. In Fig. 3, the vertical axis is expressed as a log scale.

[0035] As shown in FIG. 3, the first light source 31 of the light output unit 3 outputs incident light L1 to the living body 6, and the light detection unit 4 detects transmitted light L2 that has passed through the living body 6. The incident light L1 is the above-mentioned green light. In the spectrum of the incident light L1, the central wavelength is located in a first wavelength range R1. In other words, the incident light L1 has a peak value in the first wavelength range R1. The central wavelength of the incident light L1 is an arbitrary value within the first wavelength range R1. The first wavelength range R1 is 430 nm to 580 nm.

[0036] In the spectrum of the incident light L1, the intensity in the second wavelength range R2 is 0.01% or more of the intensity at the central wavelength (peak intensity of the incident light L1). In the spectrum of the incident light L1, the intensity in the second wavelength range R2 is 10% or less of the intensity at the central wavelength, and preferably 5% or less of the intensity at the central wavelength. "Intensity in a wavelength range" refers to the intensity corresponding to an arbitrary wavelength value within the wavelength range. The second wavelength range R2 is 600 nm to 615 nm. At least a part of the inner region of the spectrum of the incident light L1 (the region between L1 and the horizontal axis in FIG. 3) overlaps with the region D1. In FIG. 3, the region D1 is a region within the second wavelength range R2 that is 0.01% or more of the intensity at the central wavelength.

[0037] In the spectrum of the incident light L1, the intensity in the third wavelength range R3 is 1% or more of the intensity at the central wavelength, and preferably 50% or more of the intensity at the central wavelength. In the spectrum of the incident light L1, the intensity in the third wavelength range R3 is 100% or less of the intensity at the central wavelength. The third wavelength range R3 is 480 nm to 515 nm. At least a part of the inner region of the spectrum of the incident light L1 overlaps with region D2. In FIG. 3, region D2 is a region within the third wavelength range R3 that has an intensity of 1% or more of the intensity at the central wavelength.

[0038] In the spectrum of the incident light L1, the central wavelength is preferably located in a fourth wavelength range R4. The fourth wavelength range R4 is included in the first wavelength range R1. That is, the minimum value of the fourth wavelength range R4 is equal to or greater than the minimum value of the first wavelength range R1, and the maximum value of the fourth wavelength range R4 is equal to or less than the maximum value of the first wavelength range R1. The fourth wavelength range R4 is, for example, 470 nm to 540 nm.

[0039] In the spectrum of the incident light L1, the intensity in the fifth wavelength range R5 is preferably 0.1% or more of the intensity at the central wavelength. The fifth wavelength range R5 is included in the second wavelength range R2. That is, the minimum value of the fifth wavelength range R5 is equal to or greater than the minimum value of the second wavelength range R2, and the maximum value of the fifth wavelength range R5 is equal to or less than the maximum value of the second wavelength range R2. The fifth wavelength range R5 is, for example, 605 nm to 615 nm. At least a part of the inner region of the spectrum of the incident light L1 preferably overlaps with the region D3. In FIG. 3, the region D3 is a region within the fifth wavelength range R5 that is 0.1% or more of the intensity at the central wavelength.

[0040] In the spectrum of the incident light L1, the intensity in the sixth wavelength range R6 is preferably 40% or more of the intensity at the central wavelength. The sixth wavelength range R6 is included in the third wavelength range R3. That is, the minimum value of the sixth wavelength range R6 is equal to or greater than the minimum value of the third wavelength range R3, and the maximum value of the sixth wavelength range R6 is equal to or less than the maximum value of the third wavelength range R3. The sixth wavelength range R6 is, for example, 490 nm to 515 nm. At least a part of the inner region of the spectrum of the incident light L1 overlaps with the region D4. In FIG. 3, the region D4 is a region within the sixth wavelength range R6 that is 40% or more of the intensity at the central wavelength.

[0041] The transmitted light L2 is the light of the incident light L1 that has been transmitted through the living body 6. Fig. 4 is a diagram showing the spectrum of the transmitted light L2 shown in Fig. 3. In Fig. 4, the horizontal axis represents wavelength, and the vertical axis represents light intensity. In Fig. 4, the vertical axis is expressed as a linear scale.

[0042] 3 and 4, in the spectrum of the transmitted light L2, the central wavelengths are located in the first transmitted wavelength range T1 (first detected wavelength range S1), the second transmitted wavelength range T2 (second detected wavelength range S2), and the third transmitted wavelength range T3 (third detected wavelength range S3). The transmitted light L2 has a first peak P1 in the first transmitted wavelength range T1, a second peak P2 in the second transmitted wavelength range T2, and a third peak P3 in the third transmitted wavelength range T3.

[0043] The transmitted light L2 having the first peak P1, the second peak P2, and the third peak P3 is incident on the first optical filter 44, the second optical filter 45, and the third optical filter 46, respectively. The transmitted light L2 (first peak P1) in the first transmission wavelength range T1 is transmitted through the first optical filter 44 and is detected by the first optical detection region 41. The transmitted light L2 (second peak P2) in the second transmission wavelength range T2 is transmitted through the second optical filter 45 and is detected by the second optical detection region 42. The transmitted light L2 (third peak P3) in the third transmission wavelength range T3 is transmitted through the third optical filter 46 and is detected by the third optical detection region 43.

[0044] The ECU 5 measures the blood glucose level of the living body 6 based on the intensity of the transmitted light L2 detected by the first photodetector 401 and the intensity of the transmitted light L2 detected by the second photodetector 402. The ECU 5 calculates the blood glucose level of the living body 6 based on the intensity of the transmitted light L2 (first peak P1) that has passed through the first optical filter 44 and been detected by the first photodetector region 41, and the intensity of the transmitted light L2 (second peak P2) that has passed through the second optical filter 45 and been detected by the second photodetector region 42.

[0045] Specifically, the ECU 5 calculates the relative change in O2Hb (ΔO2Hb) and the relative change in HHb (ΔHHb) based on the difference between the intensity of the first peak P1 at the first time and the intensity of the first peak P1 at the second time (the amount of change in the intensity of the first peak P1 over time), the difference between the intensity of the second peak P2 at the first time and the intensity of the second peak P2 at the second time (the amount of change in the intensity of the second peak P2 over time), the absorption coefficients of oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) relative to the first peak P1, and the absorption coefficients of O2Hb and HHb relative to the second peak P2. The ECU 5 continues to calculate ΔO2Hb and ΔHHb at a predetermined time interval (for example, about 16 milliseconds). The ECU 5 calculates the blood glucose level of the living body 6 based on the time difference between a characteristic point (e.g., a peak point) of ΔO2Hb and a characteristic point (e.g., a peak point) of ΔHHb. The ECU 5 may calculate a differential value (first differential value) of ΔO2Hb with respect to the time series, and a differential value (second differential value) of ΔHHb with respect to the time series. The ECU 5 may calculate the blood glucose level of the living body 6 based on the time difference between a first characteristic point (e.g., a peak point of the first differential value) of the first differential value and a second characteristic point (e.g., a peak point of the second differential value) of the second differential value. In this embodiment, the methods shown in Japanese Patent No. 6846152 are used as a method of calculating the blood glucose level.

[0046] The ECU 5 calculates the pulse of the living body 6 based on the intensity of the transmitted light L2 detected by the third photodetector 403. The ECU 5 calculates the pulse of the living body 6 based on the intensity of the transmitted light (third peak P3) that has passed through the third optical filter 46 and been detected by the third photodetection region 43. The ECU 5 calculates the pulse of the living body 6 based on the time interval between adjacent third peaks P3. For example, if the time interval between adjacent third peaks P3 is 0.8 seconds (for example, an average value), the ECU 5 calculates the value obtained by dividing 60 seconds by 0.8 seconds (75 BPM [Beat Per Minute]) as the pulse of the living body 6.

[0047] The red light output from the second light source 32 and the infrared light output from the third light source 33 are each detected by the third photodetector 403. The red light output from the second light source 32 and the infrared light output from the third light source 33 are each transmitted through the third optical filter 46 and detected by the third photodetection region 43. The ECU 5 calculates the blood oxygen saturation concentration of the living body 6 based on the intensities of the red light and the infrared light (the transmitted light of the red light and the infrared light) transmitted through the third optical filter 46 and detected by the third photodetection region 43. In this embodiment, a known method is used as a method for calculating the blood oxygen saturation concentration. The ECU 5 may calculate the blood glucose level of the living body 6 based on the intensities of the red light and the infrared light detected by the third photodetection region 43 by the same method as the method using the green light described above.

[0048] As described above, in the blood glucose measuring device 1, the spectrum of the incident light L1 output to the living body 6 has a central wavelength in a first wavelength range R1 of 430 nm to 580 nm, an intensity in a second wavelength range R2 of 600 nm to 615 nm is 0.01% or more of the intensity at the central wavelength, and an intensity in a third wavelength range R3 of 480 nm to 515 nm is 1% or more of the intensity at the central wavelength. When such incident light L1 is incident on the living body 6, transmitted light L2 having a spectrum (a spectrum having a first peak P1 and a second peak P2) with central wavelengths in the wavelength range of 460 nm to 535 nm and the wavelength range of 580 nm or more is emitted from the living body 6. The ECU 5 calculates the blood glucose level of the living body 6 based on the intensity of the transmitted light L2 detected in a first detection wavelength range S1 of 460 nm to 535 nm (the intensity of the first peak P1) and the intensity of the transmitted light L2 detected in a second detection wavelength range S2 of 580 nm or more (the intensity of the second peak P2). Therefore, the blood glucose level measuring device 1 can realize blood glucose level measurement using a green light source.

[0049] The inventors of the present application came up with the idea of ​​using a green light source for measuring blood glucose levels in order to reduce the size and power consumption of the device. As a result of intensive research based on the idea, the inventors of the present application found that biospectroscopic analysis is possible when green light having a spectrum in which the central wavelength is located in the wavelength range of 430 nm to 580 nm, the intensity in the wavelength range of 600 nm to 615 nm is 0.01% or more of the intensity at the central wavelength, and the intensity in the wavelength range of 480 nm to 515 nm is 1% or more of the intensity at the central wavelength is used. That is, the inventors of the present application found that when green light having such a spectrum is incident on a living body, transmitted light having a spectrum in which the central wavelength is located in each of the wavelength ranges of 460 nm to 535 nm and the wavelength range of 580 nm or more, and the intensity at each central wavelength is at the same level, is obtained. The inventors of the present application succeeded in measuring blood glucose levels using these transmitted lights.

[0050] In the spectrum of the incident light L1, the central wavelength is preferably located in a fourth wavelength range R4 of 470 nm to 540 nm, the intensity in a fifth wavelength range R5 of 605 nm to 615 nm is 0.1% or more of the intensity at the central wavelength, and the intensity in a sixth wavelength range R6 of 490 nm to 515 nm is 40% or more of the intensity at the central wavelength. This provides transmitted light L2 suitable for calculating blood glucose levels, allowing the blood glucose level of the living body 6 to be calculated more accurately.

[0051] The first photodetector 401 includes a first photodetection region 41 and a first optical filter 44 having a first transmission wavelength range T1 of 460 nm to 535 nm, which is provided on the first photodetection region 41, and the second photodetector 402 includes a second photodetection region 42 and a second optical filter 45 having a second transmission wavelength range T2 of 580 nm or more, which is provided on the second photodetection region 42. The ECU 5 calculates the blood glucose level of the living body 6 based on the intensity (intensity of the first peak P1) of the transmitted light L2 transmitted through the first optical filter 44 and detected by the first photodetection region 41, and the intensity (intensity of the second peak P2) of the transmitted light L2 transmitted through the second optical filter 45 and detected by the second photodetection region 42. As a result, the transmitted light L2 is selectively transmitted by each of the first optical filter 44 and the second optical filter 45, so that the first photodetection region 41 and the second photodetection region 42 can have a common configuration.

[0052] The light detection unit 4 has a third photodetector 403 having a third detection wavelength range S3 of 500 nm to 600 nm. The ECU 5 calculates the pulse rate of the living body 6 based on the intensity of the transmitted light L2 detected by the third photodetector 403. This makes it possible to measure both the blood glucose level and the pulse rate using a green light source, and prevents the device from becoming larger and the power consumption from increasing.

[0053] The third photodetector 403 has a third photodetection region 43 and a third optical filter 46 provided on the third photodetection region 43 and having a third transmission wavelength range T3 of 500 nm to 600 nm. The ECU 5 calculates the pulse of the living body 6 based on the intensity of the transmitted light L2 (third peak P3) that has passed through the third optical filter 46 and been detected by the third photodetection region 43. As a result, the first optical filter 44, the second optical filter 45, and the third optical filter 46 each selectively transmit the transmitted light L2, so that the first photodetection region 41, the second photodetection region 42, and the third photodetection region 43 can have a common configuration.

[0054] The first photodetectors 401, the second photodetectors 402, and the third photodetectors 403 are alternately arranged to surround the light output unit 3. This reduces loss of the measurement light L emitted from the light output unit 3.

[0055] Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

[0056] FIG. 5 is a rear view of a blood glucose measuring device according to a modified example. As shown in FIG. 5, in the blood glucose measuring device 1 according to the modified example, the light output unit 3 has a plurality of first light sources 31, a plurality of second light sources 32, and a plurality of third light sources 33. The first light sources 31, the second light sources 32, and the third light sources 33 are arranged in a circular ring shape so as to surround the light detection unit 4. The first light sources 31, the second light sources 32, and the third light sources 33 are alternately arranged so as to surround the light detection unit 4. The light output unit 3 has, for example, three first light sources 31, two second light sources 32, and two third light sources 33. In the circumferential direction of the light output unit 3, one first light source 31, one third light source 33, one second light source 32, one first light source 31, and one second light source 32 are arranged in order. In this case, the photodetectors of the photodetector 4 may be alternately arranged in a matrix. Each photodetector of the photodetector 4 may have a CCD image sensor or a CMOS image sensor instead of a PD. According to this configuration, the first light sources 31, the second light sources 32, and the third light sources 33 surround the photodetector 4, so that the intensity of the transmitted light L2 incident on the photodetector 4 is ensured. In the blood glucose measuring device 1 according to the modified example, the light output unit 3 may have the first light source 31 instead of each of the second light source 32 and the third light source 33. The light output unit 3 may be composed of the first light sources 31 surrounding the photodetector 4. In this case, the second transmission wavelength range T2 may be 580 nm to 635 nm, and may preferably be 610 nm to 635 nm.

[0057] In the embodiment, the light output section 3 has the second light source (red light source) 32 and the third light source (infrared light source) 33, but the light output section 3 does not have to have the second light source 32 and the third light source 33. The light output section 3 may be constituted by the first light source 31. In this case, the second transmission wavelength range T2 may be 580 nm to 635 nm, and may be preferably 610 nm to 635 nm.

[0058] In the embodiment, the light detection section 4 has the third optical filter 46, but the light detection section 4 does not necessarily have to have the third optical filter 46.

[0059] In the embodiment, the first photodetector 401 has the first optical filter 44, but when the first photodetection region 41 has selective sensitivity to the first detection wavelength range S1, the first photodetector 401 may not have the first optical filter 44. In the embodiment, the second photodetector 402 has the second optical filter 45, but when the second photodetection region 42 has selective sensitivity to the second detection wavelength range S2, the second photodetector 402 may not have the second optical filter 45. In the embodiment, the third photodetector 403 has the third optical filter 46, but when the third photodetection region 43 has selective sensitivity to the third detection wavelength range S3, the third photodetector 403 may not have the third optical filter 46. [Explanation of symbols]

[0060] 1...blood glucose measuring device, 3...light output section, 4...light detection section, 5...ECU (calculation section), 6...living body, 31...first light source (green light source), 41...first light detection area, 42...second light detection area, 43...third light detection area, 44...first optical filter, 45...second optical filter, 46...third optical filter, 401...first light detector, 402...second light detector, 403...third light detector, L1...incident light, L2...transmitted light, R1...first wavelength range, R2...second wavelength range, R3...third wavelength range, R4...fourth wavelength range, R5...fifth wavelength range, R6...sixth wavelength range, S1...first detection wavelength range, S2...second detection wavelength range, S3...third detection wavelength range, T1...first transmitted wavelength range, T2...second transmitted wavelength range, T3...third transmitted wavelength range.

Claims

1. A blood glucose measurement device for measuring a blood glucose level of a living body, comprising: a light output unit including a green light source, the green light source outputting incident light to the living body; a light detection unit that detects transmitted light, which is light that has passed through the living body, out of the incident light; A calculation unit that calculates a blood glucose level of the living body based on a detection result of the light detection unit, In the spectrum of the incident light, a central wavelength is located in a first wavelength range of 430 nm to 580 nm, an intensity in a second wavelength range of 600 nm to 615 nm is 0.01% or more of the intensity at the central wavelength, and an intensity in a third wavelength range of 480 nm to 515 nm is 1% or more of the intensity at the central wavelength; The light detection unit includes a first light detector having a first detection wavelength range of 460 nm to 535 nm and a second light detector having a second detection wavelength range of 580 nm or more; A blood glucose measuring device, wherein the calculation unit calculates the blood glucose level of the living body based on the intensity of the transmitted light detected by the first photodetector and the intensity of the transmitted light detected by the second photodetector.

2. 2. The blood glucose measurement device of claim 1, wherein, in the spectrum of the incident light, the central wavelength is located in a fourth wavelength range of 470 nm to 540 nm, an intensity in a fifth wavelength range of 605 nm to 615 nm is 0.1% or more of the intensity at the central wavelength, and an intensity in a sixth wavelength range of 490 nm to 515 nm is 40% or more of the intensity at the central wavelength.

3. the first photodetector includes a first photodetection region and a first optical filter provided on the first photodetection region and having a first transmission wavelength range of 460 nm to 535 nm; the second photodetector includes a second photodetection region and a second optical filter provided on the second photodetection region and having a second transmission wavelength range of 580 nm or more; The blood glucose measuring device of claim 1, wherein the calculation unit calculates the blood glucose level of the living body based on the intensity of the transmitted light that passes through the first optical filter and is detected by the first optical detection region, and the intensity of the transmitted light that passes through the second optical filter and is detected by the second optical detection region.

4. The light detection unit further includes a third light detector having a third detection wavelength range of 500 nm to 600 nm, The blood glucose measuring device according to claim 1 , wherein the calculation unit calculates the pulse rate of the living body based on the intensity of the transmitted light detected by the third photodetector.

5. the third photodetector includes a third photodetection region and a third optical filter provided on the third photodetection region and having a third transmission wavelength range of 500 nm to 600 nm; The blood glucose measuring device according to claim 4 , wherein the calculation unit calculates a pulse rate of the living body based on an intensity of the transmitted light that is transmitted through the third optical filter and detected by the third light detection region.

6. the first photodetector is each of a plurality of first photodetectors; the second photodetector is each of a plurality of second photodetectors; The blood glucose measuring device according to claim 1 , wherein the first photodetectors and the second photodetectors are alternately arranged to surround the optical output section.

7. the green light source is each of a plurality of green light sources; The blood glucose measuring device according to claim 1 , wherein the plurality of green light sources are arranged so as to surround the light detecting section.

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