JP7589780B2 - Measurement device and biological information measurement device - Google Patents

Description

This application relates to a measurement device and a biological information measurement device.

In recent years, the number of diabetes patients has been increasing worldwide, and there is a demand for non-invasive blood glucose measurement that does not require blood sampling. Various methods have been proposed for measuring biological information such as blood glucose levels using light, including those using near-infrared, mid-infrared, and Raman spectroscopy. Of these, the mid-infrared region is the fingerprint region where glucose absorption is high, and can provide greater measurement sensitivity than the near-infrared region.

Light-emitting devices such as quantum cascade lasers (QCLs) can be used as light sources in the mid-infrared region, but a laser light source is required for each wavelength used. From the perspective of miniaturizing the device, it is desirable to narrow down the wavelengths in the mid-infrared region to just a few.

In order to measure glucose concentration accurately using the attenuated total reflection (ATR) method in a specific wavelength region such as the mid-infrared region, a method has been proposed that uses the wavelengths of the glucose absorption peaks (1035 cm-1, 1080 cm-1, 1110 cm-1) (see, for example, Patent Document 1).

When such a measuring device is used to perform measurements by contacting an optical part, such as a total reflection member, with the lips of a subject, etc., it may not be desirable from a safety or hygienic standpoint to use the same measuring device for different subjects. In addition, if dirt or residue adheres to the measuring device, or if it is scratched, the measurement accuracy may decrease. For this reason, it is preferable to make it possible to detach parts of the measuring device to perform maintenance such as cleaning or replacement.

As a device that allows parts of a measuring device to be detached, a device has been disclosed in which a light source such as a light-emitting element, an optical section such as an optical waveguide, and a photodetector such as a light-receiving element are formed on a single substrate and made replaceable (see, for example, Patent Document 2).

However, in the device of Patent Document 2, the light source, optical unit, and photodetector must all be replaced together, which can increase the cost of the device.

The objective of the present invention is to provide a measuring device that ensures safety while keeping device costs down.

A measuring device according to one aspect of the present invention comprises a light source that emits light, a total reflection member including a total reflection surface that totally reflects the incident light when in contact with an object to be measured, a light intensity detection unit that detects the light intensity of the outgoing light from the total reflection member, an output unit that outputs a measurement value obtained based on the light intensity, a first support unit that supports the light source and the light intensity detection unit, and a second support unit that supports the total reflection member and is detachably provided on the first support unit, wherein at least one of the first support unit and the second support unit supports a light guiding unit that causes the light from the light source to be incident on the total reflection member in an oblique direction with respect to the total reflection surface , and the second support unit supports a side portion of the total reflection member that is not parallel to the total reflection surface .

The present invention provides a measurement device that ensures safety while keeping device costs down.

1 is a diagram showing an example of the overall configuration of a blood glucose measuring device according to an embodiment; FIG. 2 is a diagram showing the action of an ATR prism. FIG. 2 is a perspective view showing the structure of an ATR prism. FIG. 2 is a perspective view showing the structure of a hollow fiber. FIG. 2 is a block diagram of an example of a hardware configuration of a processing unit according to the embodiment. 3 is a block diagram showing an example of a functional configuration of a processing unit according to the embodiment; FIG. 1A and 1B are diagrams showing an example of a probe light switching operation, in which (a) shows a case where a first probe light is used, (b) shows a case where a second probe light is used, and (c) shows a case where a third probe light is used. 4 is a flowchart showing an example of the operation of the blood glucose measuring device according to the embodiment. 1A and 1B are diagrams showing probe light intensities changed in three or more steps, in which (a) shows the probe light intensity of a comparative example, and (b) shows the probe light intensity changed in three or more steps. 1A and 1B are diagrams showing an example of correction of positional deviation of a probe light, in which (a) is a diagram showing a cross-sectional light intensity distribution of the probe light, (b) is a diagram showing the cross-sectional light intensity distribution of (a) after positional deviation, (c) is a diagram showing the cross-sectional light intensity distribution of the probe light including speckles, and (d) is a diagram showing the cross-sectional light intensity distribution of (c) after positional deviation. 1A and 1B are diagrams showing the function of the incident surface in an ATR prism, in which (a) shows the total reflection of the probe light when the incident surface is a flat surface, (b) shows the total reflection of the probe light when the incident surface is a diffusive surface, (c) shows the incident surface of a diffusive surface, (d) shows the incident surface of a concave surface, and (e) shows the incident surface of a convex surface. 1A and 1B are diagrams showing the relative positional deviation between the first and second hollow optical fibers and the ATR prism, in which (a) shows the case where the ATR prism is not in contact with the living body, (b) shows the case where the living body is in contact with the first total reflection surface of the ATR prism, and (c) shows the case where the living body is in contact with the second total reflection surface of the ATR prism. 4A and 4B are diagrams showing support members for the first and second hollow optical fibers and the ATR prism. 5A and 5B are diagrams showing an example of a light source drive current, in which FIG. 5A is a light source drive current of a comparative example, and FIG. 5B is a high-frequency modulated light source drive current. 1A, 1B, and 1C are diagrams showing an example of the configuration of a blood glucose measuring device according to a first embodiment, in which FIG. 10A to 10C are diagrams showing an example of the configuration of a blood glucose measuring device according to a second embodiment, in which (a) is a front view, (b) is a side view, and (c) is a detailed view of part A in (a). 17A to 17C are diagrams showing modified examples of the configuration of part A in FIG. 16, where (a) is a diagram of a first modified example, (b) is a diagram of a second modified example, and (c) is a diagram of a third modified example. 10A and 10B are diagrams showing a modified example of the light guiding section, in which FIG. 10A and 10B are diagrams showing another modified example of the light guiding section, in which FIG. 11A and 11B are diagrams showing an example of the configuration of a blood glucose measuring device according to a third embodiment, in which (a) is a front view and (b) is a cross-sectional view taken along the line BB of (a).

Below, a description of the embodiment of the invention will be given with reference to the drawings. In each drawing, the same components are given the same reference numerals, and duplicate explanations may be omitted.

<Explanation of terms in the embodiment>
(Mid-infrared region)
The mid-infrared region refers to a wavelength region of 2 to 14 μm, and is an example of a specific wavelength region.

(probe light)
The probe light refers to light used for measuring absorbance and biological information. In the embodiment, the probe light corresponds to light that is totally reflected by a total reflection member, attenuated by the living body, and then detected by a light intensity detection unit.

(ATR method)
The ATR (Attenuated Total Reflection) method is a technique for acquiring the absorption spectrum of an object to be measured by utilizing the field (evanescent wave) seeping out from a total reflection surface when total reflection occurs at a total reflection member such as an ATR prism placed in contact with the object to be measured.

(Absorbance)
The absorbance is a dimensionless quantity that indicates the degree to which the light intensity decreases when the light passes through an object. In the embodiment, the attenuation of the field leaking from the total reflection surface by the living body is measured as the absorbance by the ATR (Attenuated Total Reflection) method.

(Blood Glucose Levels)
Blood sugar level refers to the concentration of glucose in the blood.

(Detection value)
In the embodiment, it refers to a detection value by a light intensity detection unit.

(Wave number)
The relationship between wavelength λ (μm) and wave number k (cm −1 ) is k=10000/λ.

The following describes an embodiment using as an example a blood glucose level measuring device (an example of a biological information measuring device) that measures blood glucose levels (an example of biological information) based on absorbance measured using an ATR prism (an example of a total reflection member).

[Embodiment]
First, a blood glucose measuring device 100 according to an embodiment will be described.

In this embodiment, multiple probe lights with different wavelengths in the mid-infrared region are incident on a total reflection member placed in contact with a living body, and the absorbance of each of the multiple probe lights is obtained based on the ATR method, and the blood glucose level is measured based on the obtained absorbance.

<Example of overall configuration of blood glucose measuring device 100>
Fig. 1 is a diagram showing an example of the overall configuration of a blood glucose level measuring device 100. As shown in Fig. 1, the blood glucose level measuring device 100 includes a measuring section 1 and a processing section 2.

The measurement unit 1 is an optical head for performing the ATR method, and outputs a detection signal of the probe light attenuated by the living body to the processing unit 2. The processing unit 2 is a processing device that acquires absorbance data based on this detection signal, and also acquires and outputs a blood glucose level based on the absorbance data.

The measurement unit 1 includes a first light source 111, a second light source 112, a third light source 113, a first shutter 121, a second shutter 122, and a third shutter 123. It also includes a first half mirror 131, a second half mirror 132, a coupling lens 14, a first hollow optical fiber 151, an ATR prism 16, a second hollow optical fiber 152, and a photodetector 17.

The processing unit 2 includes an absorbance acquisition unit 21 and a blood glucose level acquisition unit 22. The absorbance measurement device 101 includes a measurement unit 1 and an absorbance acquisition unit 21, as shown surrounded by a dashed line.

The first light source 111, the second light source 112, and the third light source 113 in the measurement unit 1 are each electrically connected to the processing unit 2, and are quantum cascade lasers that emit laser light in the mid-infrared region in response to a control signal from the processing unit 2.

In this embodiment, the first light source 111 emits laser light with a wave number of 1050 cm-1 as the first probe light, the second light source 112 emits laser light with a wave number of 1070 cm-1 as the second probe light, and the third light source 113 emits laser light with a wave number of 1100 cm-1 as the third probe light.

Laser light with wave numbers of 1050 cm-1, 1070 cm-1, and 1100 cm-1 each correspond to the wave numbers of the glucose absorption peaks, and by measuring the absorbance using these wave numbers, it is possible to accurately measure the glucose concentration based on the absorbance.

The first shutter 121, the second shutter 122, and the third shutter 123 are each electrically connected to the processing unit 2, and are electromagnetic shutters whose opening and closing are controlled in response to a control signal from the processing unit 2.

When the first shutter 121 is opened, the first probe light from the first light source 111 passes through the first shutter 121 and reaches the first half mirror 131. On the other hand, when the first shutter 121 is closed, the first probe light is blocked by the first shutter 121 and does not reach the first half mirror 131.

When the second shutter 122 is opened, the second probe light from the second light source 112 passes through the second shutter 122 and reaches the first half mirror 131. On the other hand, when the second shutter 122 is closed, the second probe light is blocked by the second shutter 122 and does not reach the first half mirror 131.

Similarly, when the third shutter 123 is opened, the third probe light from the third light source 113 passes through the third shutter 123 and reaches the second half mirror 132. On the other hand, when the third shutter 123 is closed, the third probe light is blocked by the third shutter 123 and does not reach the second half mirror 132.

The first half mirror 131 and the second half mirror 132 are optical elements that transmit a portion of the incident light and reflect the remainder. Such optical elements can be constructed by providing an optical thin film that transmits a portion of the incident light and reflects the remainder on a substrate that is transparent to the incident light.

However, the present invention is not limited to optical thin films, and may be configured by forming a diffractive structure on a substrate that is transparent to incident light, which transmits part of the incident light and reflects (diffracts) the rest. The use of a diffractive structure is advantageous in that it can suppress light absorption.

The first half mirror 131 transmits the first probe light that has passed through the first shutter 121 and reflects the second probe light that has passed through the second shutter 122. The second half mirror 132 transmits both the first and second probe lights and reflects the third probe light that has passed through the third shutter 123.

It is preferable to configure the first half mirror 131 and the second half mirror 132 so that the light intensity ratio between the transmitted light and the reflected light is approximately 1:1, but the light intensity ratio can also be adjusted depending on the probe light intensity emitted by each light source.

The first to third probe lights that have passed through the first half mirror 131 or the second half mirror 132 are guided into the first hollow optical fiber 151 via the coupling lens 14, propagate through the first hollow optical fiber 151, and are guided into the ATR prism 16 via the entrance surface 161 of the ATR prism 16.

The ATR prism 16 is an optical prism that causes the first to third probe light beams incident on the entrance surface 161 to propagate toward the exit surface 164 while totally reflecting the light beams, and emits the light beams from the exit surface 164. As shown in FIG. 1, the ATR prism 16 is placed with the first total reflection surface 162 in contact with the living body S (an example of an object to be measured).

The first to third probe lights guided into the ATR prism 16 are repeatedly totally reflected by the first total reflection surface 162 and the second total reflection surface 163 opposite the first total reflection surface 162, and are guided into the second hollow optical fiber 152 via the exit surface 164.

The first to third probe lights guided by the second hollow optical fiber 152 reach the photodetector 17. The photodetector 17 is a detector capable of detecting light with a wavelength in the mid-infrared region, and photoelectrically converts the received first to third probe lights, outputting an electrical signal according to the light intensity as a detection signal to the processing unit 2. The photodetector 17 is composed of an infrared PD (Photo Diode) or MCT (Mercury Cadmium Telluride) detection element, a bolometer, etc. Here, the photodetector 17 is an example of a light intensity detection unit. In the following, when the first to third probe lights are not differentiated, they may be simply referred to as probe lights.

The processing unit 2 is constructed by an information processing device such as a PC (Personal Computer). The absorbance acquisition unit 21 in the processing unit 2 acquires absorbance data of each probe light based on the detection signal of the photodetector 17, and outputs the data to the blood glucose level acquisition unit 22. The blood glucose level acquisition unit 22 acquires blood glucose level data of the living body based on the absorbance data of each probe light.

In FIG. 1, in order to clearly show the configuration of the measurement unit 1 and the components included in the absorbance measurement device 101, the measurement unit 1 is surrounded by a solid line frame and the absorbance measurement device 101 is surrounded by a dashed line frame, but these do not indicate a housing. The ATR prism 16 is not stored in a housing, and at least one of the first total reflection surface 162 or the second total reflection surface 163 can be brought into contact with any part of a living body.

<Function and configuration of ATR prism 16 etc.>
Next, the function of the ATR prism 16 will be described with reference to Fig. 2. As shown in Fig. 2, the ATR prism 16 of the measurement unit 1 is placed in contact with the living body S. The probe light incident on the ATR prism 16 is attenuated corresponding to the infrared absorption spectrum of the living body S. The attenuated probe light is received by the photodetector 17, and the light intensity of each probe light is detected. The detection signal is input to the processing unit 2, which acquires and outputs absorbance data and blood glucose level data based on the detection signal.

The infrared attenuated total reflection (ATR) method is effective for spectroscopic detection in the mid-infrared region where the absorption light intensity of glucose is obtained. The infrared ATR method uses the "seepage" of the field that appears when infrared probe light is incident on the high refractive index ATR prism 16 and total reflection occurs at the interface between the ATR prism 16 and the outside world (e.g., living organism S). If measurement is performed with the living organism S, which is the object to be measured, in contact with the ATR prism 16, the seeped-out field is absorbed by the living organism S.

If infrared light in a wide wavelength range of 2 to 12 μm is used as the probe light, the light with wavelengths caused by the molecular vibrational energy of the living body S is absorbed, and the light absorption appears as a dip at the corresponding wavelength of the probe light transmitted through the ATR prism 16. This method is particularly advantageous for infrared spectroscopy using a probe light with a weak power, as it allows a large amount of energy to be obtained from the detection light transmitted through the ATR prism 16.

When infrared light is used, the light seeps into the living body S from the ATR prism 16 to a depth of only a few microns, and does not reach the capillaries that exist at a depth of several hundred microns. However, it is known that components such as blood plasma in blood vessels seep into skin and mucous membrane cells as tissue fluid (interstitial fluid). By detecting the glucose components present in this tissue fluid, it is possible to measure blood glucose levels.

It is believed that the concentration of glucose components in tissue fluid increases the closer it is to the capillaries, and so during measurement, the ATR prism is always pressed with a constant pressure. In order to facilitate such pressing, the embodiment employs a multiple reflection ATR prism with a trapezoidal cross section.

Here, FIG. 3 is a perspective view showing the structure of the ATR prism according to the embodiment. As shown in FIG. 3, the ATR prism 16 is a trapezoidal prism. The more multiple reflections occur within the ATR prism 16, the higher the glucose detection sensitivity. In addition, since the contact area with the living body S can be made large, the fluctuation in the detection value due to changes in the pressure pressing the ATR prism 16 can be kept small. The length L of the bottom surface of the ATR prism 16 is, for example, 24 mm. The thickness t is set to a small value, such as 1.6 mm or 2.4 mm, so that multiple reflections occur.

Candidate materials for the ATR prism 16 are those that are non-toxic to the human body and exhibit high transmission characteristics around the 10 μm wavelength band of glucose. As an example, from among materials that satisfy these conditions, a prism made of ZnS (zinc sulfide) with a refractive index of 2.2 can be used, which has a large light penetration rate and allows detection at deeper depths. Unlike ZnSe (zinc selenide), which is commonly used as an infrared material, ZnS has been shown to be non-carcinogenic and is also used in dental materials as a non-toxic dye (lithopone).

In a typical ATR measurement device, the ATR prism is fixed to a relatively large device, so the part of the body to be measured is limited to the body surface, such as the fingertip or forearm. However, the skin in these areas is covered with a stratum corneum that is about 20 μm thick, so the detected glucose concentration is low. In addition, the stratum corneum is affected by the secretion state of sweat and sebum, so the reproducibility of the measurement is limited. Therefore, the blood glucose measurement device 100 uses a first hollow optical fiber 151 and a second hollow optical fiber 152 that can transmit the probe light, which is infrared light, with low loss, and one end of each is abutted against the ATR prism 16.

The first hollow optical fiber 151 is optically connected to the incident surface 161 of the ATR prism 16 by abutting one end against the ATR prism 16, so that the emitted light from the first hollow optical fiber 151 is incident on the incident surface 161 of the ATR prism 16.

The second hollow optical fiber 152 is optically connected to the exit surface 164 of the ATR prism 16 by abutting one end against the ATR prism 16, so that the light emitted from the exit surface 164 of the ATR prism 16 is guided into the second hollow optical fiber 152.

By using the ATR prism 16, it is possible to measure on the earlobe, where capillaries are located relatively close to the skin surface and are less affected by sweat and sebum, and on the oral mucosa, where there is no keratin.

Figure 4 is a perspective view showing an example of the structure of a hollow optical fiber used in the blood glucose measuring device 100. Mid-infrared light, which has a relatively long wavelength and is used for glucose measurement, cannot be transmitted through a quartz glass optical fiber because the light is absorbed by the glass. Up until now, various types of optical fibers for infrared transmission using special materials have been developed, but the materials have problems such as toxicity, hygroscopicity, and chemical durability, making them difficult to use in the medical field.

On the other hand, the first hollow optical fiber 151 and the second hollow optical fiber 152 have a metal thin film 242 and a dielectric thin film 241 arranged in this order on the inner surface of a tube 243 made of a harmless material such as glass or plastic. The metal thin film 242 is made of a low-toxicity material such as silver, and is coated with the dielectric thin film 241 to impart chemical and mechanical durability. In addition, the core 245 is made of air, which does not absorb mid-infrared light, making it possible to transmit mid-infrared light with low loss over a wide wavelength range.

<Configuration of Processing Unit 2>
Next, the configuration of the processing unit 2 will be described with reference to FIGS.

FIG. 5 is a block diagram showing an example of the hardware configuration of the processing unit 2 according to the embodiment. As shown in FIG. 5, the processing unit 2 includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, a HD (Hard Disk) 504, a HDD (Hard Disk Drive) controller 505, and a display 506. It also includes an external device connection I/F (Interface) 508, a network I/F 509, a data bus 510, a keyboard 511, a pointing device 512, a DVD-RW (Digital Versatile Disk Rewritable) drive 514, a media I/F 516, a light source drive circuit 517, a shutter drive circuit 518, and a detection I/F 519.

Of these, the CPU 501 controls the operation of the entire processing unit 2. The ROM 502 stores programs used to drive the CPU 501, such as an IPL (Initial Program Loader). The RAM 503 is used as a work area for the CPU 501.

The HDD 504 stores various data such as programs. The HDD controller 505 controls the reading and writing of various data from the HDD 504 under the control of the CPU 501. The display 506 displays various information such as a cursor, menu, window, text, or image.

The external device connection I/F 508 is an interface for connecting various external devices. In this case, the external devices are, for example, a USB (Universal Serial Bus) memory or a printer. The network I/F 509 is an interface for data communication using a communication network. The bus line 510 is an address bus, a data bus, or the like for electrically connecting each component such as the CPU 501 shown in FIG. 5.

The keyboard 511 is a type of input means equipped with multiple keys for inputting characters, numbers, various instructions, etc. The pointing device 512 is a type of input means for selecting and executing various instructions, selecting a processing target, moving the cursor, etc. The DVD-RW drive 514 controls the reading and writing of various data from the DVD-RW 513, which is an example of a removable recording medium. Note that this is not limited to a DVD-RW, and may be a DVD-R, etc. The media I/F 516 controls the reading and writing (storing) of data from the recording medium 515, such as a flash memory.

The light source drive circuit 517 is an electric circuit that is electrically connected to each of the first light source 111, the second light source 112, and the third light source 113, and outputs a drive voltage for causing these light sources to emit infrared light in response to a control signal. The shutter drive circuit 518 is an electric circuit that is electrically connected to each of the first shutter 121, the second shutter 122, and the third shutter 123, and outputs a drive voltage for driving these shutters to open and close in response to a control signal.

The detection I/F 519 is an electrical circuit such as an A/D (Analog/Digital) conversion circuit that serves as an interface for acquiring the detection signal of the photodetector 17. The detection I/F 519 also functions as an interface for acquiring detection signals from various sensors, such as a pressure sensor and a temperature sensor, not shown in FIG. 5, in addition to the photodetector 17.

Next, FIG. 6 is a block diagram showing an example of the functional configuration of the processing unit 2 according to the embodiment. As shown in FIG. 6, the processing unit 2 includes an absorbance acquisition unit 21 and a blood glucose level acquisition unit 22.

The absorbance acquisition unit 21 also includes a light source drive unit 211, a light source control unit 212, a shutter drive unit 213, a shutter control unit 214, a data acquisition unit 215, a data recording unit 216, and an absorbance output unit 217.

Of these, the function of the light source drive unit 211 is realized by the light source drive circuit 517 etc., the function of the shutter drive unit 213 is realized by the shutter drive circuit 518 etc., the function of the data acquisition unit 215 is realized by the detection I/F 519 etc., and the function of the data recording unit 216 is realized by the HD 504 etc. In addition, each function of the light source control unit 212, the shutter control unit 214 and the absorbance output unit 217 is realized by the CPU 501 executing a predetermined program etc.

The light source driving unit 211 outputs a driving voltage based on a control signal input from the light source control unit 212, and causes each of the first light source 111, the second light source 112, and the third light source 113 to emit infrared light. The light source control unit 212 controls the emission timing and light intensity of the infrared light based on the control signal.

The shutter drive unit 213 outputs a drive voltage based on a control signal input from the shutter control unit 214 to drive the first shutter 121, the second shutter 122, and the third shutter 123 to open and close. The shutter control unit 214 controls the timing and period for opening the shutter using the control signal. Here, the shutter control unit is an example of an entrance control unit.

The data acquisition unit 215 outputs the light intensity detection values acquired by sampling the detection signal continuously output by the photodetector 17 at a predetermined period to the data recording unit 216. The data recording unit 216 records the detection values input from the data acquisition unit 215.

The absorbance output unit 217 performs a predetermined calculation process based on the detection value read from the data recording unit 216 to obtain absorbance data, and outputs the obtained absorbance data to the blood glucose level acquisition unit 22.

However, the absorbance output unit 217 may output the acquired absorbance data to an external device such as a PC via the external device connection I/F 508, or to an external server or the like via the network I/F 509 and the network. The data may also be output to the display 506 (see FIG. 5) for display.

The blood glucose level acquisition unit 22 also includes a bioinformation output unit 221 as an example of an output unit. The bioinformation output unit 221 executes a predetermined calculation process based on the absorbance data input from the absorbance acquisition unit 21 to acquire blood glucose level data, and outputs the acquired blood glucose level data to the display 506 or the like for display.

However, the bioinformation output unit 221 may output the blood glucose level data to an external device such as a PC via the external device connection I/F 508, or may output the blood glucose level data to an external server or the like via the network I/F 509 and the network. The bioinformation output unit 221 may also be configured to output the reliability of the blood glucose level measurement as well.

The technology disclosed in JP 2019-037752 A and other publications can be applied to the process for obtaining blood glucose level data from absorbance data, so further detailed explanation will be omitted here.

<Example of operation of blood glucose measuring device 100>
Next, the operation of the blood glucose measuring device 100 will be described with reference to FIGS.

(Example of probe light switching operation)
7A and 7B are diagrams for explaining an example of the switching operation of the probe light, in which (a) shows the state of the measurement unit 1 when the first probe light is used, (b) shows the state of the measurement unit 1 when the second probe light is used, and (c) shows the state of the measurement unit 1 when the third probe light is used.

In this embodiment, the incidence of the probe light from each light source on the ATR prism 16 is controlled by opening and closing each shutter, so that when measuring absorbance and blood glucose level, the first light source 111, the second light source 112, and the third light source 113 constantly emit infrared light.

In FIG. 7(a), the first shutter 121 is opened in response to a control signal. The first probe light emitted by the first light source 111 passes through the first shutter 121, passes through the first half mirror 131 and the second half mirror 132, and is guided to the first hollow optical fiber 151 via the coupling lens 14. After that, the light propagates through the first hollow optical fiber 151 and then enters the ATR prism 16.

On the other hand, since the second shutter 122 and the third shutter 123 are both closed, the second probe light and the third probe light do not enter the ATR prism 16. Therefore, in this state, the absorbance of the first probe light due to attenuation in the ATR prism 16 is measured.

In FIG. 7(b), the second shutter 122 is opened in response to a control signal. The second probe light emitted by the second light source 112 passes through the second shutter 122, is reflected by the first half mirror 131, passes through the second half mirror 132, and is guided to the first hollow optical fiber 151 via the coupling lens 14. After that, the light propagates through the first hollow optical fiber 151 and enters the ATR prism 16.

On the other hand, since the first shutter 121 and the third shutter 123 are both closed, the first probe light and the third probe light do not enter the ATR prism 16. Therefore, in this state, the absorbance of the second probe light due to attenuation in the ATR prism 16 is measured.

In FIG. 7(c), the third shutter 123 is opened in response to a control signal. The third probe light emitted by the third light source 113 passes through the third shutter 123, is reflected by the second half mirror 132, and is guided to the first hollow optical fiber 151 via the coupling lens 14. After that, the light propagates through the first hollow optical fiber 151 and enters the ATR prism 16.

On the other hand, since the first shutter 121 and the second shutter 122 are both closed, the first probe light and the second probe light do not enter the ATR prism 16. Therefore, in this state, the absorbance of the third probe light due to attenuation in the ATR prism 16 is measured.

When the first shutter 121, the second shutter 122, and the third shutter 123 are all closed, the first probe light, the second probe light, and the third probe light do not enter the ATR prism 16 and do not reach the photodetector 17.

In this way, the shutter control unit 214 (see FIG. 6) as an incidence control unit can control the opening and closing of each shutter to switch between a state in which the first to third probe lights are sequentially incident on the ATR prism 16 and a state in which none of the first to third probe lights are incident on the ATR prism 16.

(Example of operation of blood glucose measuring device 100)
FIG. 8 is a flowchart showing an example of the operation of the blood glucose measuring device 100.

First, in step S81, the first light source 111, the second light source 112, and the third light source 113 all emit infrared light in response to a control signal from the light source control unit 212. However, in this initial state, the first shutter 121, the second shutter 122, and the third shutter 123 are all closed.

Next, in step S82, the shutter control unit 214 opens the first shutter 121 and closes the second shutter 122 and the third shutter 123.

Next, in step S83, the data recording unit 216 records the detection value (first detection value) by the photodetector 17 acquired by the data acquisition unit 215.

Next, in step S84, the shutter control unit 214 opens the second shutter 122 and closes the first shutter 121 and the third shutter 123.

Next, in step S85, the data recording unit 216 records the detection value (second detection value) by the photodetector 17 acquired by the data acquisition unit 215.

Next, in step S86, the shutter control unit 214 opens the third shutter 123 and closes the first shutter 121 and the second shutter 122.

Next, in step S87, the data recording unit 216 records the detection value (third detection value) by the photodetector 17 acquired by the data acquisition unit 215.

Next, in step S88, the absorbance output unit 217 acquires absorbance data of the first to third probe lights based on the first to third detection values, and outputs the data to the bioinformation output unit 221.

Next, in step S89, the bioinformation output unit 221 performs a predetermined calculation process based on the absorbance data of the first to third probe lights to obtain blood glucose level data, and outputs the obtained blood glucose level data to the display 506 (see Figure 5) for display.

In this way, the blood glucose measuring device 100 can acquire and output blood glucose data.

In the embodiment, an example has been shown in which the incidence of the probe light on the ATR prism 16 is switched by controlling the first shutter 121, the second shutter 122, and the third shutter 123, which are electromagnetic shutters, but this is not limited to the above. The incidence of the probe light on the ATR prism 16 may be switched by controlling multiple light sources to switch on (emission) and off (non-emission). Also, a single light source that emits light of multiple wavelengths may be used, and the light source may be switched on and off for each wavelength.

In the embodiment, an example is shown in which a first half mirror and a second half mirror are used as elements that transmit part of the probe light and reflect the rest, but this is not limited to this, and a beam splitter, a polarizing beam splitter, etc. may also be used.

In addition, high refractive index materials that transmit the probe light, such as germanium, have a high surface reflectance due to their material properties. For example, when light polarized perpendicular to the surface direction of the substrate (s-polarized) is incident on the substrate at an incident angle of 45 degrees, the ratio of transmission to reflection is nearly 1:1. Taking advantage of this, a germanium plate can be installed at an incident angle of 45 degrees to act as a half mirror. Note that the back surface also has a 50% reflection component, so an anti-reflection film is applied to the back surface.

<Various modified examples according to the embodiment>
Here, since each component in the embodiment can be modified in various ways, various modifications will be described below.

(Suppression of the effect of linearity error of the photodetector 17)
The photodetector 17 used in the blood glucose level measuring device 100 may contain linearity errors, which cause blood glucose level measurement errors. Therefore, the probe light intensity is changed into three or more predetermined steps, and the probe light intensity is compared with the detection value by the photodetector 17, thereby reducing the effect of the linearity errors.

Figure 9 is a diagram illustrating an example of probe light intensity changed in three or more steps in this manner, where (a) is a diagram showing the probe light intensity according to a comparative example, and (b) is a diagram showing the probe light intensity changed in three or more steps. In Figure 9, the parts shown with diagonal hatching represent the first probe light intensity, the parts shown with grid hatching represent the second probe light intensity, and the parts without hatching represent the third probe light intensity.

In FIG. 9(a), the intensity of each probe light is constant, whereas in FIG. 9(b), the intensity of each probe light is gradually decreased in three or more stages. By changing the drive voltage or drive current of the light source in three or more predetermined stages (six stages in FIG. 9(b)), the intensity of the emitted probe light can be changed in three or more stages. Note that the light intensity of the probe light in this case changes in a cycle shorter than the probe light switching control cycle by the shutter control unit 214 (for example, the cycle from steps S82 to S84 in FIG. 8).

When the photodetector 17 does not include a linearity error, the detection value by the photodetector 17 changes linearly with respect to changes in the probe light intensity. On the other hand, when the photodetector 17 includes a linearity error, the detection value by the photodetector 17 changes nonlinearly with respect to changes in the probe light intensity.

Therefore, the probe light is emitted while changing the light intensity in three or more stages, the detection value by the photodetector 17 at each stage is obtained, and the emitted probe light intensity data is compared with the detection value by the photodetector 17 to identify the light intensity range where linearity is ensured. Then, of the probe light intensity that changes in three or more stages, only the part where linearity is ensured is used to measure the absorbance and blood glucose level. This makes it possible to measure the absorbance and blood glucose level while reducing the effect of linearity error in the photodetector 17.

The operation of identifying the light intensity range in which linearity is ensured may be performed prior to blood glucose measurement, or may be performed in real time during blood glucose measurement.

In addition, since there are multiple probe lights but only one photodetector 17, the process of reducing the effect of linearity error in the photodetector 17 does not have to be performed using all of the multiple probe lights, but can be performed using at least one of the multiple probe lights.

(Detection of probe light by image sensor)
The photodetector 17 is not limited to one that uses a single pixel (light receiving element), but may also be a line-shaped image sensor in which pixels are arranged in a line, or an area-shaped image sensor in which pixels are arranged two-dimensionally.

Here, the detection signal of the photodetector 17 is the integral value of the intensity of the received probe light, so if the optical path of the incident light or outgoing light in the ATR prism 16 changes when the living body S comes into contact with the ATR prism 16, the probe light intensity before and after the change is integrated, causing a detection error, which may result in accurate absorbance data not being obtained.

Figures 10(a) and (b) show such a positional shift of the probe light, and region 171 is the region where the probe light is received by the photodetector 17. When the probe light is shifted in the direction of the white arrow in Figure 10(b), the probe light intensity distribution in region 171 changes, and the detection signal by the photodetector 17 changes.

In contrast, if an image sensor is used for the photodetector 17, the amount of misalignment of the probe light can be determined from the probe light image captured by the image sensor, and the effect of the misalignment of the probe light can be corrected by using the integral value of the light intensity distribution of the probe light after the misalignment as the detection signal. Region 172 in FIG. 10(b) shows the region where the integral value of the light intensity distribution of the probe light after the misalignment is obtained.

Furthermore, when coherent light such as laser light is used as the probe light, a fine patchy light intensity distribution called speckle may be superimposed on the probe light. FIG. 10(c) shows an example of the cross-sectional light intensity distribution of the probe light including speckle. Numeral 174 indicates a light intensity singularity that may be included in the speckle image, and singularity 174 is included in region 173.

Figure 10(d) shows a case where the probe light in Figure 10(c) is displaced in the direction of the white arrow. In this state, singular point 174 is no longer included in region 173, and the change in the detection signal before and after the displacement becomes significant. In response to this, the effect of the displacement of the probe light can be more suitably corrected by using the integral value of the light intensity distribution in region 175 as the detection signal according to the amount of displacement of the probe light detected from the probe light image.

In addition, it is possible to reduce measurement variation errors by estimating the contact area between the living body S and the ATR prism 16 based on the probe light intensity distribution on the image sensor and correcting the detection value based on the detection signal of the image sensor from the sensitivity distribution within the surface of the ATR prism 16 that was acquired and stored before the start of measurement.

(Surface of incidence to total reflection member)
In the above-described embodiment, an example was shown in which the incident surface 161 of the ATR prism 16 is a flat surface, but this is not limited to this, and the incident surface 161 may have various shapes such as a diffusing surface or a surface having a curvature.

As shown in FIG. 11(a), when the incident surface 161 is flat, the direction of travel of the probe light within the ATR prism 16 is uniform according to the angle of incidence on the incident surface 161. Therefore, on the total reflection surface of the ATR prism 16 with which the living body S comes into contact, there may be a region dependency in which the measurement sensitivity differs from region to region.

The detection signal of the photodetector 17 depends on the contact state, such as the size of the contact area of the living body S with the ATR prism 16. In particular, when the object to be measured is a living body S such as lips or a finger, the reproducibility of the contact state tends to be low, and measurement variability may increase due to the area dependency of the measurement sensitivity.

In response to this, by making the incident surface 161 a diffusing surface and randomly varying the direction of travel of the probe light within the ATR prism 16, it is possible to mitigate the area dependency of the measurement sensitivity and reduce measurement variability, as shown in FIG. 11(b).

In addition to the diffusing surface shown in FIG. 11(c), the incident surface 161 can also be a concave surface shown in FIG. 11(d) or a convex surface shown in FIG. 11(e). The concave surface in FIG. 11(d) and the convex surface in FIG. 11(e) are examples of incident surfaces with curvature. In this case, as with the diffusing surface, the optical path of the probe light can be made different, and the area dependency of the measurement sensitivity can be alleviated, reducing measurement variation.

The same effect can be obtained by arranging a diffuser plate or lens on the optical path before the probe light enters the ATR prism 16. However, in this case, the number of components of the device increases, which may lead to differences in measurement values between devices (machine differences) due to assembly errors and higher costs. Making the entrance surface 161 of the ATR prism 16 a diffuser or curved surface is more preferable, as it can reduce such machine differences and higher costs.

(Light guide section and support section for total reflection member)
When the living body S comes into contact with the ATR prism 16, if the relative positions of the first hollow optical fiber 151 and the second hollow optical fiber 152 and the ATR prism 16 are shifted, the incidence efficiency and emission efficiency of the probe light to the ATR prism 16 may fluctuate, resulting in increased measurement variation.

Figure 12 is a diagram explaining the relative positional deviation between the first hollow optical fiber 151 and the second hollow optical fiber 152 and the ATR prism 16. (a) shows the case where the ATR prism 16 is not in contact with the living body S, (b) shows the case where the living body S is in contact with the first total reflection surface 162 of the ATR prism 16, and (c) shows the case where the living body S is in contact with the second total reflection surface 163 of the ATR prism 16.

As shown in FIG. 12(b), when the living body S comes into contact with the first total reflection surface 162 of the ATR prism 16, a downward pressure force is applied in the direction indicated by the white arrow, and the ATR prism 16 shifts downward. As a result, the ATR prism 16' is in the state shown, and the relative positions of the first hollow optical fiber 151 and the second hollow optical fiber 152 and the ATR prism 16' change.

Also, as shown in FIG. 12(c), when the living body S comes into contact with the second total reflection surface 163 of the ATR prism 16, a pressing force is applied in the upward direction indicated by the white arrow, and the ATR prism 16 shifts upward. As a result, the state shown in the ATR prism 16" is reached, and the relative positions of the first hollow optical fiber 151 and the second hollow optical fiber 152 and the ATR prism 16" change.

This relative position shift causes fluctuations in the incidence efficiency and emission efficiency of the probe light with respect to the ATR prism 16. In particular, when the object to be measured is a living organism, it is not easy to maintain a constant contact pressure, and measurement variability due to relative position shifts is particularly likely to increase.

Therefore, in order to suppress relative positional deviation, it is preferable that the first hollow optical fiber 151, the second hollow optical fiber 152, and the ATR prism 16 are supported by the same support member.

Figure 13 is a diagram illustrating an example of the configuration of the members that support the first hollow optical fiber 151, the second hollow optical fiber 152, and the ATR prism 16. The light guide support member 153 in Figure 13 is a member that supports the first hollow optical fiber 151 and the ATR prism 16 together. The output support member 154 is a member that supports the second hollow optical fiber 152 and the ATR prism 16 together.

By supporting the first hollow optical fiber 151 and the ATR prism 16 as a single unit, even when the living body S is brought into contact with the ATR prism 16, the two move together as a single unit, and no relative positional deviation occurs. Also, by supporting the second hollow optical fiber 152 and the ATR prism 16 as a single unit, even when the living body S is brought into contact with the ATR prism 16, the two move together as a single unit, and no relative positional deviation occurs. This makes it possible to suppress fluctuations in the incidence efficiency and emission efficiency of the probe light that accompany contact of the living body S with the ATR prism 16, and to reduce measurement variability.

In the above example, the light guide support member 153 and the output support member 154 are separate members, but the first hollow optical fiber 151, the second hollow optical fiber 152, and the ATR prism 16 may be supported by a single support member.

Even if the light guide section is not formed using the first hollow optical fiber 151 as the light guide section, but is formed using optical elements such as mirrors and lenses, the same effect as described above can be obtained by supporting the optical elements and the ATR prism 16 integrally.

In addition to the light guide section, the first light source 111, the second light source 112, the third light source 113, and the photodetector 17 are supported integrally by the same support member, which has the effect of reducing measurement variation.

(High frequency modulation of light source driving current)
When speckles are included in the probe light, the detection value by the photodetector 17 may vary depending on the speckle pattern, which may increase the measurement variation. Since this speckle is generated by the interference of scattered light of the probe light, etc., the generation of speckles can be suppressed by reducing the coherence of the probe light. Therefore, in the embodiment, the coherence of the light source included in the blood glucose measuring device is reduced by superimposing a high-frequency modulation component on the current that drives the light source, and the measurement variation of the absorbance caused by the speckle of the probe light can also be reduced.

Figure 14 is a diagram illustrating an example of a light source drive current, where (a) shows the light source drive current in a comparative example, and (b) shows the high-frequency modulated light source drive current.

The light source control unit 212 (see FIG. 6) periodically outputs a pulsed driving current as shown in FIG. 14(a) to each of the first light source 111, the second light source 112, and the third light source 113, causing them to emit pulsed probe light.

In the embodiment, a high-frequency modulation component is superimposed on the pulsed drive current of FIG. 14(a) and output to the first light source 111, the second light source 112, and the third light source 113. The waveform of the high-frequency modulation component may be sinusoidal or rectangular. The modulation frequency can be selected from any frequency ranging from 1 MHz (megahertz) to several GHz (gigahertz).

By superimposing the high-frequency modulation components, the first light source 111, the second light source 112, and the third light source 113 can each emit a pseudo multimode laser light as the probe light, thereby reducing the coherence of the probe light. This reduces the speckle of the probe light due to the reduced coherence, and reduces the measurement variation caused by the speckle.

[First embodiment]
Next, the blood glucose measuring device according to the first embodiment will be described.

In this embodiment, the device includes a light source that emits a probe light, a total reflection member that totally reflects the incident probe light when it is in contact with the object to be measured, a light intensity detection unit that detects the light intensity of the probe light emitted from the total reflection member, and an output unit that outputs blood glucose level information obtained based on the light intensity. The light source and the light intensity detection unit are supported by a first support unit, and the total reflection member is supported by a second support unit that is detachably provided on the first support unit.

This configuration allows only the total reflection member that comes into contact with the living body to be replaced, without replacing the light source and light intensity detection unit, providing a blood glucose measurement device that ensures safety while reducing device costs.

<Configuration example of blood glucose level measuring device 100a>
First, the configuration of the blood glucose level measuring device 100a according to this embodiment will be described. Fig. 15 is a diagram for explaining an example of the configuration of the blood glucose level measuring device 100a, where (a) is a top view, (b) is a front view, and (c) is a side view.

As shown in FIG. 15, the blood glucose measuring device 100a includes a measuring unit 1a, which includes a first support unit 31, a QCL (Quantum Cascade Laser) 110, and a second support unit 32. The second support unit 32 is detachable from the first support unit 31. FIG. 15 shows the second support unit 32 attached to the first support unit 31.

The first support section 31 comprises a box-shaped member 311 and a back plate 312. The box-shaped member 311 is a member that supports the QCL 110, the first hollow optical fiber 151, the second hollow optical fiber 152, and the photodetector 17 therein. The back plate 312 is fixed to a part of the surface on the +Z direction side of the box-shaped member 311, and is a portion that functions as a connection section with the second support section 32. Here, the front view in FIG. 15(b) shows a see-through view of the inside of the box-shaped member 311.

The box-shaped member 311 has a light source support base 181 and a photodetector support base 182 fixed to the surface on the +Z direction side of the bottom plate inside. The light source support base 181 fixes the QCL 110 to its sloping surface, and the photodetector support base 182 fixes the photodetector 17 to its sloping surface. These can be fixed with adhesive, screws, etc. This point will also apply when the term "fixed" is used hereinafter.

QCL110 is a wavelength-tunable quantum cascade laser that emits laser light with a wave number of 1050 cm-1 as the first probe light, laser light with a wave number of 1070 cm-1 as the second probe light, and laser light with a wave number of 1100 cm-1 as the third probe light.

In other words, the QCL 110 has the functions of the first light source 111, the second light source 112, and the third light source 113 in the embodiment described above (see FIG. 1). In this embodiment, the emission of the first to third probe light by the QCL 110 can be switched by a control signal, so the configuration for switching the wavelength of the first shutter 121, the second shutter 122, the third shutter 123, the first half mirror 131, the second half mirror 132, etc. in FIG. 1 is omitted. In the following, the first to third probe light are collectively referred to as probe light P.

One end of the first hollow optical fiber 151 is fixed to the QCD 110 so as to be capable of guiding the probe light P, and is supported by the QCD 110. A portion of the first hollow optical fiber 151 on the side connected to the QCD 110 in the longitudinal direction is housed within the first support 31. Meanwhile, the remaining portion protrudes from the first support 31 toward the ATR prism 16, and the other end of the first hollow optical fiber 151 corresponding to the end on the protruding side abuts against the incident surface 161 of the ATR prism 16. However, this other end is not fixed to the ATR prism 16, and the ATR prism 16 can be separated from the first hollow optical fiber 151.

One end of the second hollow optical fiber 152 is fixed to the photodetector 17 so as to be capable of guiding the probe light P to the photodetector 17, and is supported by the photodetector 17. A portion of the second hollow optical fiber 152 on the side connected to the photodetector 17 in the longitudinal direction is housed within the first support portion 31, and the remaining portion protrudes from the first support portion 31 toward the ATR prism 16. The other end of the second hollow optical fiber 152, which corresponds to the end on the protruding side, abuts against the exit surface 164 of the ATR prism 16. However, this other end is not fixed to the ATR prism 16, and the ATR prism 16 can be separated from the other end of the second hollow optical fiber 152.

As shown in FIG. 15(c), the second support portion 32 is an L-shaped member when viewed from the X-direction side, and the end portion of the L-shape on the -Z-direction side abuts the upper surface of the box-shaped member 311. In addition, two through holes 321 that penetrate in the Y-direction are formed and aligned in the X-direction on the flat portion of the second support portion 32 that is aligned along the XZ plane. Meanwhile, two tap holes 313 are provided on the back plate 312 of the first support portion 31 at positions that correspond one-to-one to the two through holes 321.

The -Y side face of the ATR prism 16 abuts against the +Y side end of the L-shape of the second support part 32, and the ATR prism 16 is fixed in place. The second support part 32 thus fixes the side face of the ATR prism 16, thereby supporting the ATR prism 16.

The +Y and -Y faces of the ATR prism 16 are perpendicular to the first total reflection surface 162 and the second total reflection surface 163 of the ATR prism 16, respectively, and the -Y face of the ATR prism 16 corresponds to "one side portion perpendicular to the total reflection surface of the total reflection member."

The through hole 321 is formed at a position that has a predetermined relationship with the ATR prism 16 supported by the second support portion 32. More specifically, when the apex angle formed by the entrance surface 161 and the first total reflection surface 162 of the ATR prism 16 is used as a position reference, the through hole 321 is formed at a position that has a predetermined relationship with this apex angle when the second support portion 32 supports the ATR prism 16.

Therefore, when the second support part 32 is attached to the first support part 31 so that the through hole 321 and the tap hole 313 are aligned, the ATR prism 16 is positioned at a predetermined position relative to the first support part 31, and the first total reflection surface 162 and the second total reflection surface 163 are positioned at predetermined positions relative to the first support part 31. Here, the two through holes 321 are each an example of a coupled part, and the two tap holes 313 are each an example of a coupling part.

When attaching the second support part 32 to the first support part 31, the second support part 32 is lowered in the -Z direction so that the end of the L-shape of the second support part 32 on the -Z direction side abuts against the upper surface of the box-shaped member 311. In addition, the surface on the -Y direction side of the second support part 32 abuts against the surface on the +Y direction side of the back plate 312.

In this state, the second support part 32 is more precisely aligned so that the two through holes 321 of the second support part 32 are aligned with the two tapped holes 313 of the back plate 312. Then, with the alignment complete, a screw is inserted into each of the two through holes 321 and the inserted screws are screwed into the tapped holes 313, thereby joining the second support part 32 and the first support part 31. In this way, the second support part 32 can be attached to the first support part 31.

The positions of the first hollow optical fiber 151 and the second hollow optical fiber 152 are determined in advance so that, when the second support part 32 is attached to the first support part 31, the end of the first hollow optical fiber 151 abuts against the incident surface 161 of the ATR prism 16, and the end of the second hollow optical fiber 152 abuts against the incident surface 161 of the ATR prism 16.

In addition, in Figure 15, the screw that is inserted into the through hole 321 and screwed into the tap hole 313 is not shown.

<Effects of the blood glucose measuring device 100a>
When measuring biological information such as blood glucose levels using a total reflection member such as the ATR prism 16, the measurement is performed by contacting the subject's lips, which serves as the measurement object, with at least one of the first total reflection surface 162 or the second total reflection surface 163 of the ATR prism 16.

This contact may cause residue or dirt to adhere to the first total reflection surface 162 or the second total reflection surface 163, or may cause scratches, which may result in an inability to accurately detect the attenuation of the probe light due to the object being measured, making it impossible to accurately measure the blood glucose level. In addition, since the blood glucose level measuring device is brought into contact with the subject's lips, etc., it may be undesirable from the standpoint of safety and hygiene to share the same blood glucose level measuring device among multiple subjects.

For this reason, it is preferable to perform maintenance such as cleaning and replacement by detaching a part of the measuring device. Conventionally, a measuring device has been disclosed in which a light source such as a light-emitting element, an optical section such as an optical waveguide, and a photodetector such as a light-receiving element are formed on a single substrate to make the part detachable and replaceable.

However, in conventional technology, the light source, optical unit, and photodetector must all be replaced at the same time, which can increase the cost of the device. In particular, light sources and photodetectors compatible with probe light in the mid-infrared region, which is suitable for measuring blood glucose levels, are expensive, which makes the increase in device costs even more noticeable.

In contrast, in this embodiment, the QCL 110 that emits the probe light P and the photodetector 17 that detects the light intensity of the probe light P emitted from the ATR prism 16 are supported by a first support part 31, and the ATR prism 16 is supported by a second support part that is detachably provided on the first support part 31.

This makes it possible to replace the ATR prism 16 without replacing the QCL 110 and the photodetector 17. Since the QCL 110 and the photodetector 17 are not replaced, the cost of the device can be reduced, and since the ATR prism 16 is replaced, good safety and hygienic conditions can be ensured. In this way, a measurement device that ensures safety while reducing the cost of the device can be provided.

In addition, in this embodiment, the second support portion 32 supports the ATR prism 16 at a surface on the -Y direction side of the ATR prism 16, which is one of the surfaces perpendicular to the first total reflection surface 162 or the second total reflection surface 163 of the ATR prism 16.

By supporting the ATR prism 16 in this manner, when the subject's lips are brought into contact with the first total reflection surface 162 or the second total reflection surface 163 for measurement, the subject can place the +Y direction side of the ATR prism 16 facing his or her mouth and bring his or her lips into contact with the first total reflection surface 162 or the second total reflection surface 163. In addition, the entrance surface 161, the first total reflection surface 162, the second total reflection surface 163, and the exit surface 164 are not used to support the ATR prism 16. Therefore, blood glucose level measurement can be performed accurately using the subject's lips as the measurement object without impeding the function of the ATR prism 16.

In addition, in this embodiment, the through hole 321 is formed at a position that has a predetermined relationship with the ATR prism 16 supported by the second support part 32. Therefore, when the second support part 32 is attached to the first support part 31 by aligning the positions of the through hole 321 and the tap hole 313, the ATR prism 16 is positioned at a predetermined position with respect to the first support part 31, and the first total reflection surface 162 and the second total reflection surface 163 are positioned at predetermined positions with respect to the first support part 31. As a result, even if the second support part 32 is detached from the first support part 31, the ATR prism 16 is always positioned in the same position, ensuring reproducibility of blood glucose measurement.

In this embodiment, the first support 31 supports the QCL 110, the photodetector 17, and the first hollow optical fiber 151 as a light guide. This allows the probe light P emitted by the QCL 110 to be properly guided toward the ATR prism 16, allowing blood glucose levels to be measured properly.

In this embodiment, the method of connecting the first support part 31 and the second support part 32 is described as connecting the through hole 321 and the tap hole 313 via a screw, but the present invention is not limited to this. For example, a knock pin (fitting part) is provided on the back plate 312 of the first support part 31 instead of the tap hole 313, and a knock hole (fitted part) is provided on the flat part of the second support part 32 along the XZ plane instead of the through hole 321. The first support part 31 and the second support part 32 can also be connected by fitting a knock pin into this knock hole.

[Second embodiment]
Next, a blood glucose level measuring device 100b according to a second embodiment will be described. Figure 16 is a diagram for explaining an example of the configuration of the blood glucose level measuring device 100b, where (a) is a front view, (b) is a side view, and (c) shows details of part A in (a) (part indicated by a dashed line). Note that Fig. 16(a) shows a perspective view of the blood glucose level measuring device 100b. This also applies to the front views of the following figures. Also, 32u in Fig. 16(c) is a view of the second support part 32b as seen from the -Z direction side.

As shown in FIG. 16, the blood glucose measuring device 100b has a first support part 31b and a second support part 32b.

Of these, the first support 31b is a box-shaped member that supports the QCL 110, the first hollow optical fiber 151, the second hollow optical fiber 152, and the photodetector 17 inside. The first support 31b has a light source support base 181 and a photodetector support base 182 fixed to the surface on the +Z direction side of the bottom plate inside. The light source support base 181 fixes the QCL 110 to its inclined surface, and the photodetector support base 182 fixes the photodetector 17 to its inclined surface. Furthermore, two knock pins 314 are provided on the surface on the +Z direction side of the first support 31b.

The second support part 32b is a block-shaped member that is hexagonal when viewed from the Y direction side. The second support part 32b is formed with a recess 16v for inserting and fixing the ATR prism 16, an entrance through hole 327 through which the probe light P entering the ATR prism 16 passes, and an exit through hole 328 through which the probe light P exiting from the ATR prism 16 passes. In addition, two knock holes 322 are provided on the surface on the -Z direction side of the second support part 32b at positions that correspond one-to-one to the two knock pins 314 in the first support part 31.

As shown in FIG. 16(a), the entrance through-hole 327 is a hole that penetrates in an oblique direction and is formed so that the probe light P from the QCL 110 can reach the entrance surface 161 of the ATR prism 16. The exit through-hole 328 is also a hole that penetrates in an oblique direction and is formed so that the probe light P that exits the ATR prism 16 can reach the photodetector 17.

The knock hole 322 in the second support portion 32b is formed at a position that has a predetermined relationship with the ATR prism 16 supported by the second support portion 32b. Therefore, when the second support portion 32b is attached to the first support portion 31b so that the knock pin 314 and the knock hole 322 fit together, the ATR prism 16 is positioned at a predetermined position with respect to the first support portion 31b, and the first total reflection surface 162 and the second total reflection surface 163 are positioned at predetermined positions with respect to the first support portion 31b. Here, the two knock holes 322 are each an example of a coupled portion, and the two knock pins 314 are each an example of a coupling portion.

When attaching the second support part 32b to the first support part 31b, the second support part 32b is lowered in the -Z direction to engage the two knock holes 322 with the two knock pins 314. This allows the second support part 32b to be attached to the first support part 31b.

The configuration of the blood glucose measuring device 100b makes it easy to attach the second support part 32b to the first support part 31b. Other effects are the same as those described in the first embodiment.

In this embodiment, the configuration for connecting the second support portion 32b and the first support portion 31b can be modified in various ways.

Figure 17 shows modified examples of the configuration of part A in Figure 16, where (a) shows a first modified example, (b) shows a second modified example, and (c) shows a third modified example.

In the example of FIG. 17(a), two knock holes 315 are provided in the first support portion 31b, and two knock pins 323 are provided in the second support portion 32b at positions that correspond one-to-one to the two knock holes 315. With this configuration, the same effect as in the second embodiment can be obtained. Here, the knock holes 315 are an example of a connecting portion, and the knock pins 323 are an example of a connected portion.

In the example of FIG. 17(b), three knock pins 316 are provided on the first support portion 31b. Furthermore, these three knock pins 316 are provided at positions asymmetric with respect to the center C on the surface on the +Z direction side of the first support portion 31b. Specifically, the distance from the middle knock pin of the three knock pins to the center C is different from the distance from the left knock pin of the three knock pins to the center C. As a result, the position of the middle knock pin is asymmetric with respect to the center C from the position of the left knock pin.

On the other hand, the second support portion 32b has three knock holes 324 at positions that correspond one-to-one to the three knock pins 316. Here, the knock pins 316 are an example of a connecting portion, and the knock holes 324 are an example of a connected portion. Also, the three knock pins 316 are an example of multiple connecting portions.

With this configuration, the same effect as in the second embodiment can be obtained. Furthermore, by providing at least two of the three knock pins 316 in asymmetric positions with respect to the center C, it is possible to prevent the second support part 32b from being attached to the first support part 31b in the wrong direction. By correcting the attachment direction, the side of the ATR prism 16 supported by the second support part 32b can be positioned on the opposite side to the side facing the living body S, thereby allowing blood glucose levels to be measured appropriately.

In the example of FIG. 17(c), the first support portion 31b is provided with a latch protrusion 317, and the second support portion 32b is provided with a latch recess 325. By aligning the latch recess 325 with the latch protrusion 317 and pressing the second support portion 32b, the latch protrusion 317 and the latch recess 325 are joined, and the second support portion 32b can be attached to the first support portion 31b. The latch between the latch protrusion 317 and the latch recess 325 can be released by pressing the latch protrusion 317 inward.

The latch-equipped protrusion 317 is an example of a coupling portion, and the latch-equipped recess 325 is an example of a coupled portion. With this configuration, the same effect as in the second embodiment can be obtained.

On the other hand, various modifications are possible for the configuration for guiding the probe light P from the QCL 110 to the ATR prism 16, and the configuration for guiding the probe light P exiting the ATR prism 16 to the photodetector 17.

Figure 18 is a diagram illustrating a modified example of such a light guide section, where (a) is a front view and (b) is a side view. In the example of Figure 18, a lens 155 is provided in the entrance through hole 327 in the second support section 32b, and a lens 156 is provided in the exit through hole 328. This configuration can further improve the efficiency of the probe light P reaching the ATR prism 16 and the efficiency of the probe light P reaching the photodetector 17.

Figure 19 is a diagram illustrating another modified example of the light guide section, (a) being a front view and (b) being a side view. In the example of Figure 19, a third hollow optical fiber 157 is provided in the entrance through hole 327 in the second support section 32b, and a fourth hollow optical fiber 158 is provided in the exit through hole 328. A lens 159 is provided on the entrance side of the probe light P to the ATR prism 16 of the first support section 31b, and a lens 160 is provided on the exit side of the probe light P. Even with this configuration, the efficiency of the probe light P reaching the ATR prism 16 and the efficiency of the probe light P reaching the photodetector 17 can be improved.

[Third embodiment]
Next, a blood glucose level measuring device 100c according to a third embodiment will be described. Figure 20 is a diagram illustrating an example of the configuration of the blood glucose level measuring device 100c. (a) is a front view, and (b) is a cross-sectional view taken along line B-B of (a). As shown in Figure 20, the blood glucose level measuring device 100c includes a second support section 32c, and the second support section 32c includes an opening 326.

The ATR prism 16 is fixed by abutting its -Y side against the +Y side of the recess 16v provided in the second support portion 32c. The open portion 326 is a gap provided below (on the -Z side) the ATR prism 16 fixed to the second support portion 32c.

In blood glucose level measurement in which the subject's lips are brought into contact with the ATR prism 16, providing such an opening 326 allows the upper lip to come into contact with the first total reflection surface 162 and the lower lip to be inserted into the opening 326 and brought into contact with the second total reflection surface 163. As a result, even when a block-shaped member is used for the second support portion 32c, blood glucose levels can be measured by bringing the lips into contact with both the first total reflection surface 162 and the second total reflection surface 163. Other effects are the same as those described in the first embodiment.

Although the embodiments have been described above, the present invention is not limited to the specifically disclosed embodiments above, and various modifications and variations are possible without departing from the scope of the claims.

In the embodiment, an example has been shown in which the functions of the absorbance acquisition unit 21, blood glucose level acquisition unit 22, drive control unit 23, etc. are realized by one processing unit 2, but this is not limited to this. These functions may be realized by separate processing units, or the functions of the absorbance acquisition unit 21 and blood glucose level acquisition unit 22 may be distributed and realized by multiple processing units. It is also possible to configure the functions of the processing unit and the functions of storage devices such as the data recording unit 216 to be realized by an external device such as a cloud server.

In addition, in the embodiment, an example of measuring blood glucose level as biological information is shown, but this is not limited to this, and the embodiment can also be applied to measuring other biological information as long as it can be measured based on the ATR method.

Also, an optical element such as a beam splitter that branches off a portion of the probe light after it is emitted by the light source or after it is emitted from the hollow optical fiber, and a detection element that detects the intensity of the branched portion of the probe light may be provided, and the drive voltage or drive current of the light source may be feedback-controlled to suppress fluctuations in the probe light intensity. This suppresses output fluctuations of the light source, enabling more accurate measurement of biological information.

The embodiments can also be applied when the blood glucose measuring device has one light source and measures by emitting probe light of one wavelength from the one light source.

Furthermore, each function of the embodiments described above can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and devices such as an ASIC (Application Specific Integrated Circuit), DSP (digital signal processor), FPGA (field programmable gate array), and conventional circuit modules designed to execute each function described above.

1, 1a Measurement unit 100, 100a Blood glucose level measuring device (an example of a biological information measuring device)
101 Absorbance measuring device 110 QCL (an example of a light source)
111 First light source (an example of a light source)
112 Second light source (an example of a light source)
113 Third light source (an example of a light source)
121 First shutter 122 Second shutter 123 Third shutter 131 First half mirror 132 Second half mirror 14 Coupling lens 151 First hollow optical fiber 152 Second hollow optical fiber 153 Light guide support member 154 Output support member 16 ATR prism 161 Incident surface 162 First total reflection surface 163 Second total reflection surface 164 Output surface 17 Photodetector (an example of a light intensity detection unit)
181 Light source support base 182 Photodetector support base 2 Processing unit 21 Absorbance acquisition unit 211 Light source driving unit 212 Light source control unit 213 Shutter driving unit 214 Shutter control unit 215 Data acquisition unit 216 Data recording unit 217 Absorbance output unit 22 Blood glucose level acquisition unit 221 Biological information output unit (an example of an output unit)
31 First support portion 311 Box-shaped member 312 Back plate 313 Tap hole (an example of a connecting portion)
314 Knock pin (an example of a joint)
315 Knock hole (an example of a joint)
316 Knock pin (an example of multiple joints)
317 Latch-equipped protrusion (an example of a coupling part)
32 Second support portion 321 Through hole (an example of a joined portion)
322, 324 Knock hole (an example of a coupled part)
323 Knock pin (an example of a joint)
325 Latch recess (an example of a coupled part)
326 Open part 501 CPU
506 Display 519 Detection I/F
S Living body (an example of an object to be measured)
P Probe light θ ₀ Incident angle θ ₁ ~ θ ₄ Inclination angle θ _C Critical angle φ Brewster angle

Patent No. 5376439 Japanese Patent Application Publication No. 06-281568

Claims (10)

A light source that emits light;
a total reflection member including a total reflection surface that totally reflects the incident light in a state of contact with the object to be measured;
a light intensity detection unit that detects the light intensity of the light emitted from the total reflection member;
an output unit that outputs a measurement value obtained based on the light intensity;
a first support portion that supports the light source and the light intensity detection portion ;
a second support portion that supports the total reflection member and is detachably provided on the first support portion;
At least one of the first support portion and the second support portion supports a light guiding portion that causes the light from the light source to be incident on the total reflection member in a direction oblique to the total reflection surface ,
The second support portion supports a side portion of the total reflection member that is not parallel to the total reflection surface.
Measuring equipment. A light source that emits light;
a total reflection member including a total reflection surface that totally reflects the incident light in a state of contact with the object to be measured;
a light intensity detection unit that detects the light intensity of the light emitted from the total reflection member;
an output unit that outputs a measurement value obtained based on the light intensity;
a first support portion that supports the light source and the light intensity detection portion ;
a second support portion that supports the total reflection member and is detachably provided on the first support portion;
The second support portion has an incident through hole that passes the light traveling in an oblique direction with respect to the total reflection surface and causes the light to be incident on the total reflection member in the oblique direction, and supports a side portion of the total reflection member that is not parallel to the total reflection surface.
Measuring equipment. The measuring device according to claim 2 , wherein at least one of the first support portion and the second support portion supports a light guiding portion that causes the light from the light source to be incident on the total reflection member in the oblique direction. The measuring device according to claim 1 , wherein the light guide portion includes at least one of an optical fiber, a mirror, and a lens. The measuring device according to claim 1 , wherein the second support portion supports the total reflection member such that a second total reflection surface facing the total reflection surface of the total reflection member is open. The measurement device described in any one of claims 1 to 5, wherein the second support portion includes a plurality of surfaces that are non-parallel to the total reflection surface, and is coupled to the first support portion such that at least one of the plurality of surfaces does not contact the first support portion and at least one of the plurality of surfaces contacts the first support portion. the second support portion includes a coupled portion that is coupled to the coupling portion of the first support portion when the second support portion is in a first orientation;
The measuring device according to claim 1 , wherein the coupled portion is not coupled to the coupling portion when the second support portion is in a second orientation opposite to the first orientation. The measurement device according to claim 1 , wherein the first support portion supports the light source and the light intensity detector. A measuring device according to any one of claims 1 to 8 ,
The output unit is a biological information measuring device that outputs biological information acquired based on the light intensity. The biological information measuring device according to claim 9 , wherein the biological information is blood glucose level information.

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