JP2020146364A - Blood component measuring apparatus, blood component measuring apparatus control method, and blood component measuring apparatus control program - Google Patents

Abstract

To provide a technique capable of improving measurement accuracy of the concentration of blood components.SOLUTION: A blood component measuring apparatus 1 comprises: plural light-emitting devices which respectively irradiate a measurement portion of a living body with lights with different wavelengths; a light-receiving device which receives lights having passed through blood in the measured portion; and a control unit 10 which controls the light-emitting devices to irradiate the measurement portion with lights having wavelengths in increasing order of biological permeability in the measurement portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to a blood component measuring device, a control method of the blood component measuring device, and a control program of the blood component measuring device.

There is a technique of irradiating a measurement site (for example, a human finger) of a living body with light of a plurality of wavelengths to acquire a pulse wave signal, and analyzing the pulse wave signal to measure the concentration of a blood component. Patent Document 1 describes a blood analyzer including two Light-Emitting Diodes (LEDs) that emit near-infrared light having different wavelengths and a Photodiode (PD) that receives near-infrared light transmitted through a living body. Has been done. In the blood analyzer, two LEDs that emit light alternately irradiate the living body with near-infrared light, and the PD receives the near-infrared light transmitted through the living body, and a voltage signal corresponding to the intensity of the light is received. Is output. As a result, the blood analyzer detects the pulse wave generated by the absorption of near-infrared light by glucose in the living body from the change in the light receiving intensity in PD, and uses the magnitude of the pulse wave due to the absorption of hemoglobin as a reference signal. Calculate the ratio of glycated hemoglobin to the total amount of hemoglobin in the blood.

Japanese Unexamined Patent Publication No. 2004-248716

By the way, the output signal of the PD starts to change according to the optical input, but there is a delay until the output signal of the PD reaches the maximum value and the minimum value. Therefore, if another LED starts emitting light immediately after one LED stops emitting light, the PD will start emitting light from the other LED before the output signal component corresponding to the input light from the one LED becomes zero. Since the output signal starts to rise when the light is received, the output signal components of the PD corresponding to the input light from the two LEDs overlap each other. If each output signal component of the PD corresponding to the input light from the LED that irradiates light of two different wavelengths overlaps, the accurate output signal component for each wavelength cannot be separated and extracted and detected, so that it is accurate. The pulse wave signal cannot be detected. In the technique of analyzing the pulse wave signal to measure the concentration of the blood component, if the accurate pulse wave signal cannot be detected, the measurement accuracy of the blood component concentration will be lowered.

In view of the above circumstances, the present disclosure aims to provide a technique capable of improving the measurement accuracy of the concentration of blood components.

The blood component measuring device disclosed in the present invention includes a plurality of light emitting elements that irradiate a measurement site of a living body with light of different wavelengths, a light receiving element that receives the light that has passed through blood at the measurement site, and the measurement site. The present invention includes a control unit that controls the plurality of light emitting elements so as to irradiate light in the order of wavelength having low biopermeability. Here, the blood component measuring device irradiates the measurement site of the living body with light in the order of wavelength having the lowest biopermeability, but the biopermeability differs depending on the living body and the measuring site. The blood component measuring device accurately acquires the received light data corresponding to each wavelength by irradiating light in the order of wavelengths with low biopermeability, and thus obtains an accurate pulse wave signal from the accurate received data. , The measurement accuracy of the concentration of blood components can be improved.

In the blood component measuring device, the plurality of light emitting elements have wavelengths of 850 nm to 1150 n.
The control unit includes a first light emitting element that irradiates light having a peak wavelength in the wavelength range of m, and a second light emitting element that irradiates light having a peak wavelength in a wavelength range of 1150 nm to 1350 nm. The plurality of light emitting elements may be controlled so as to irradiate light in the order of the second light emitting element and the first light emitting element.

In the blood component measuring device, the plurality of light emitting elements further include a third light emitting element that irradiates light having a peak wavelength in a wavelength range of 1350 nm to 1500 nm, and the control unit is the third light emitting element. The plurality of light emitting elements may be controlled so as to irradiate light in the order of the second light emitting element and the first light emitting element.

In the blood component measuring device, the peak wavelengths of the first light emitting element, the second light emitting element, and the third light emitting element are appropriately selected according to the blood component to be measured in concentration. When measuring the value of triglyceride in blood (hereinafter referred to as "blood TG value"), for example, the blood component measuring device irradiates light having a peak wavelength at a wavelength of 1050 nm. It may include an element and a second light emitting element that irradiates light having a peak wavelength at a wavelength of 1300 nm. Further, for example, when measuring a value in which the ratio of glycated hemoglobin to the total hemoglobin concentration contained in blood is expressed as a percentage (hereinafter referred to as "HbA1c value"), the blood component measuring device has a wavelength of 1450 nm. A third light emitting element that irradiates light having a peak wavelength may be provided. An example of saccharified hemoglobin is hemoglobin produced by binding an amino group at the N-terminal of the β chain of hemoglobin to an aldehyde group of glucose having a chain structure in an aqueous solution. Here, when the measurement site of the living body is a human finger, the biopermeability is, in ascending order, light having a wavelength of 1450 nm, light having a wavelength of 1300 nm, and light having a wavelength of 1050 nm.

The blood component measuring device further includes a switching element that switches between a connected state in which the output terminal of the light receiving element is connected to the ground and a non-connected state in which the output terminal is disconnected from the ground, and the living body at the measurement site. A cycle is executed in which the plurality of light emitting elements irradiate light once each in the order of low transmission wavelength, and the light receiving element receives the light that has passed through the blood at the measurement site and acquires the received light data. In this case, the switching element may connect the output terminal of the light receiving element to the ground each time the cycle ends. As a result, the blood component measuring device can eliminate the influence of the output signal component in the previous cycle when the light receiving data is acquired in a plurality of cycles. Therefore, according to the blood component measuring device, the measurement accuracy of the blood component concentration can be improved by acquiring accurate light receiving data.

The present disclosure can also be grasped from the aspect of the control method of the blood component measuring device or the control program of the blood component measuring device. For example, the control method of the blood component measuring device disclosed in the present invention includes a plurality of light emitting elements that irradiate a measurement site of a living body with light of different wavelengths, and a light receiving element that receives the light that has passed through blood at the measurement site. A method for controlling a blood component measuring device comprising the above, the plurality of light emitting elements may be controlled so as to irradiate light in order of wavelength with low biopermeability at the measurement site.

According to the technique disclosed in the present invention, the measurement accuracy of the concentration of blood components can be improved.

It is a figure which shows an example of the structure of the blood component measuring apparatus which concerns on one Embodiment. It is a figure which shows typically the blood component measuring apparatus which concerns on one Embodiment. It is a figure which shows a part of the blood component measuring apparatus which concerns on one Embodiment schematically. It is a figure which shows a part of the blood component measuring apparatus which concerns on one Embodiment schematically. It is a circuit diagram of a part of the blood component measuring apparatus which concerns on one Embodiment. It is a graph which shows the response characteristic of PD. It is a graph which shows the response characteristic of PD. It is a graph which shows the output signal of PD which irradiates a human thumb with near-infrared light, and detected the light. It is a graph explaining the light-receiving data acquisition method by the blood component measuring apparatus which concerns on one Embodiment. It is a graph explaining the light-receiving data acquisition method by the blood component measuring apparatus which concerns on a comparative example. It is a graph explaining the method of acquiring the received light data in a plurality of cycles by the blood component measuring apparatus which concerns on one Embodiment. It is a graph explaining the method of acquiring the received light data in a plurality of cycles by the blood component measuring apparatus which concerns on a comparative example. It is a flowchart about the blood component measurement process using the blood component measuring apparatus which concerns on one Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configurations of the following embodiments are examples, and the present invention is not limited to the configurations of these embodiments.

First, the blood component measuring device according to the present embodiment will be described. The blood component measuring device 1 according to the present embodiment irradiates a measurement site that is a part of the body of the living body including blood with near-infrared light by a Light-Emitting Diode (LED) and passes through the blood in the measurement site. The near-infrared light is received by a Photodiode (PD) to acquire the received data. Since the living body is not transparent except for the eyeball, light is not transmitted. However, for example, the light that has entered the inside of a human finger is scattered by tissues, blood, etc. and does not travel straight, but a small part of the light that has entered reaches the PD and is detected. Of the detected light intensities, the component that fluctuates periodically is the pulse wave signal detected by the received data of the light that has passed through the blood.

Here, a human being can be mentioned as a living body to be measured by the blood component measuring device 1. When the measurement target is a human, the measurement site may be a site where pulsation can be easily detected by near-infrared light, and the finger, palm, wrist, inside of elbow, back of knee, sole of foot, foot. The fingers, ear flaps, anterior sides of the ears, lips, groove, etc. are preferable, and the thumb, index finger, and middle finger, which can clearly detect pulsation, are more preferable. In the following, the organism to be measured will be described as a human, and the measurement site will be described as a thumb. The organism to be measured and the measurement site are not limited to these.

FIG. 1 is a diagram showing a schematic configuration of a blood component measuring device 1 according to the present embodiment. As shown in FIG. 1, the blood component measuring device 1 includes a control unit 10, a storage unit 20, an irradiation unit 30, a light receiving unit 40, and a communication unit 50.

The control unit 10 includes a Central Processing Unit (CPU) and controls each unit in the blood component measuring device 1. For example, the control unit 10 controls the irradiation unit 30 so as to irradiate light in the order of wavelengths having low biopermeability at the measurement site. The storage unit 20 includes a non-volatile memory such as a flash memory and an electrically Erasable Programmable Read-Only Memory (EEPROM), and a Random Access Memory (RAM). The storage unit 20 stores the control program in the blood component measuring device 1 and the data obtained when various processes are executed.

The irradiation unit 30 irradiates the measurement site of the living body with near-infrared light. The blood component measuring device 1 according to the present embodiment measures the blood TG value and the HbA1c value by irradiating the thumb of a human being to be measured with near-infrared light by the irradiation unit 30.

The intensity of light passing through blood in the blood vessels of a human finger fluctuates periodically due to the pulsation of blood. The blood component measuring device 1 according to the present embodiment non-invasively adjusts the absorbance of blood at a plurality of wavelengths by utilizing a pulse wave signal which is a change over time in the light intensity passing through blood in a blood vessel of a human thumb. By measuring, the blood TG value and the HbA1c value are measured.

When the concentration of the TG value in blood increases and the turbidity of blood increases, the absorbance in near-infrared light having a wavelength of around 1050 nm increases. Therefore, in the present embodiment, the blood TG value is measured based on the difference between the absorbance of blood at a wavelength of 1050 nm and the absorbance of blood at a wavelength of 1300 nm.

Further, it has been found by the inventors of the present invention that the absorbance at a wavelength of around 1450 nm changes significantly as compared with other wavelengths depending on the HbA1c value. Further, since the absorbance in the vicinity of the wavelength of 900 nm to 1300 nm changes depending on the total hemoglobin concentration in the blood, in the present embodiment, the HbA1c value is measured using the absorbance at 1450 nm and the absorbance at wavelength 1050 nm or wavelength 1300 nm. ..

The irradiation unit 30 of the blood component measuring device 1 according to the present embodiment is the first to non-invasively measure the blood TG value and the HbA1c value by irradiating a human finger with near-infrared light having the above wavelength. The first light emitting element includes an LED having a peak wavelength of 1050 nm, the second light emitting element includes an LED having a peak wavelength of 1300 nm, and the third light emitting element includes an LED having a peak wavelength of 1450 nm. The details of these LEDs and the details of the method for measuring the blood TG value and the HbA1c value will be described later.

The light receiving unit 40 receives the light that has passed through the blood at the measurement site. The near-infrared light emitted by the irradiation unit 30 passes through the blood contained in the measurement site of the living body and is received by the light receiving unit 40. The light receiving unit 40 has a PD (photodiode), detects light that has passed through blood by the PD, and outputs the intensity as a voltage signal. Further, the blood component measuring device 1 has an AD (Analog Digital) converter (not shown), and after AD-converting the output signal as the received light data from the PD of the light receiving unit 40, it is output to the control unit 10. To do. The control unit 10 stores the received light data in the storage unit 20. The positional relationship between the irradiation unit 30 and the light receiving unit 40 will be described later.

The communication unit 50 wirelessly communicates with the terminal device 100 owned by the user by known short-range wireless communication such as Bluetooth (registered trademark), Bluetooth Low Energy (BLE), Wi-Fi, and transmits various data to the terminal device 100. can do.

Examples of the terminal device 100 include smartphones, feature phones, tablet-type personal computers, notebook-type personal computers, desktop-type personal computers, and various other electronic devices. The terminal device 100 is composed of a liquid crystal display device, an organic EL display device, and the like, and includes a display unit 100a that displays a blood TG value and an HbA1c value as measured values. In addition, the terminal device 100 stores a blood component measurement program and various data for executing various processes (see FIG. 13) in the blood component measurement described below. In this embodiment, the terminal device 100 is an example of a computer. In the present embodiment, the terminal device 100 calculates the blood TG value and the HbA1c value based on the pulse wave signal obtained by the blood component measuring device 1.

Next, a configuration example of the blood component measuring device 1 according to the present embodiment will be described in more detail with reference to FIG. FIG. 2 is an external perspective view of the blood component measuring device 1. The blood component measuring device 1 includes a housing 60 and an upper cover 61 that covers the upper part of the housing 60. In addition, blood component measuring device 1
An opening 62 for inserting the finger of the subject to be measured is provided between the housing 60 and the upper cover 61. When a subject inserts a finger into the opening 62, an irradiation unit 30 and a light receiving unit 40 are provided on the contact surface 60a that comes into contact with the finger in the housing 60.

FIG. 3 is a diagram schematically showing a state in which a subject inserts a thumb 101 into an opening 62 in the blood component measuring device 1 shown in FIG. In the blood component measuring device 1 according to the present embodiment, the irradiation unit 30 irradiates the ventral side of the thumb 101 with light, and the light that has passed through the blood is received by the light receiving unit 40 arranged on the ventral side of the finger. The reflected light method is adopted.

FIG. 4 is a plan view showing a contact surface 60a in which the irradiation unit 30 and the light receiving unit 40 are arranged in the blood component measuring device 1. The irradiation unit 30 includes a first LED 31 (an example of a "first light emitting element"), a second LED 32 (an example of a "second light emitting element"), and a third LED 33 (an example of a "third light emitting element"). The first LED 31 irradiates light having a peak wavelength at a wavelength of 1050 nm. The second LED 32 irradiates light having a peak wavelength at a wavelength of 1300 nm. The third LED 33 irradiates light having a peak wavelength at a wavelength of 1450 nm.

Further, in the present embodiment, the irradiation unit 30 irradiates light in the order of wavelength with low biopermeability at the measurement site of the living body. Here, the biopermeability is higher as the absorption rate of light in the living body is lower, and is lower as the absorption rate of light in the living body is higher. In general, near-infrared light having a wavelength of 850 nm to 1500 nm has a small absorption rate in a living body and high biopermeability. In the near-infrared light having the above wavelengths, the biopermeability in human fingers is, in ascending order, a wavelength of 1450 nm, a wavelength of 1300 nm, and a wavelength of 1050 nm. The irradiation unit 30 is controlled by the control unit 10 to irradiate light in the order of wavelength with low biopermeability, that is, in the order of the third LED 33, the second LED 32, and the first LED 31. Further, as shown in FIG. 4, the third LED 33 that irradiates light having a peak wavelength at a wavelength of 1450 nm, which is relatively low among these three wavelengths, is closest to the light receiving unit 40. It is arranged in the center of three LEDs 31 to 33 arranged side by side.

Further, the light receiving unit 40 has a PD 41 (an example of a “light receiving element”). The PD 41 receives light that is irradiated from the irradiation unit 30 to the finger and has passed through the blood. The PD 41 outputs a voltage signal as light receiving data by receiving light.

FIG. 5 is a partial circuit diagram of the blood component measuring device 1 according to the present embodiment. The blood component measuring device 1 includes a microcomputer 70 that constitutes a control unit 10 and a storage unit 20. The microcomputer 70 is operated by being supplied with electric power by a power source (for example, a secondary battery) (not shown) included in the blood component measuring device 1. One end side (output terminal) of PD41 is connected to the microcomputer 70 via an RC parallel circuit (R = 680kΩ, C = 3nF) in which a resistor 71 and a capacitor 72 are connected in parallel, and the other end side of PD41 is grounded. It is connected (grounded). Further, the blood component measuring device 1 includes a transistor 73 (NPN type). In the transistor 73, the collector terminal is connected to the output terminal of the PD 41, the emitter terminal is connected to the ground, and the base terminal is connected to the microcomputer 70. The transistor 73 is an example of a switching element that switches between a connected state in which the output terminal of the PD 41 is connected to the ground and a non-connected state in which the output terminal of the PD 41 is disconnected from the ground.

Further, the blood component measuring device 1 according to the present embodiment acquires light reception data for one cycle by irradiating light having different wavelengths in the order of the third LED 33, the second LED 32, and the first LED 31 within a predetermined time (100 msec). .. The transistor 73 connects the output terminal of the PD 41 to the ground after the light irradiation by the first LED 31 in a certain cycle, and disconnects the output terminal of the PD 41 from the ground before the light irradiation by the third LED 33 in the next cycle of the certain cycle. The switching control of the transistor 73 is executed by the microcomputer 70. The control program for executing this control is the storage unit of the microcomputer (Fig. 1).
It is stored in the storage unit 20) shown in.

Further, as shown in FIG. 5, the anode terminals of the first LED31, the second LED32, and the third LED33 are connected to a power supply circuit (not shown) that applies a DC voltage of 3.3 V, and their cathode terminals have a resistor. It is connected to the collector terminal of the transistors 74 to 76 (NPN type) via. Each emitter terminal of the transistors 74 to 76 is connected to the ground, and any base terminal of the transistors 74 to 76 is connected to the microcomputer 70 via a resistor. When the microcomputer 70 applies a voltage to each of the base terminals of the transistors 74 to 76 according to the light irradiation timing by the first LED 31, the second LED 32, and the third LED 33, a DC voltage of 3.3 V is applied to each LED. As a result, the blood component measuring device 1 can execute the light irradiation by the first LED 31, the second LED 32, and the third LED 33 at a predetermined timing. The control program for executing this control is stored in the storage unit (storage unit 20 shown in FIG. 1) of the microcomputer.

Next, the response characteristics of PD will be described with reference to FIGS. 6 and 7. FIG. 6 is a graph showing the response characteristics (response speed) of PD. The horizontal axis of the graph of FIG. 6 represents time (arbitrary unit). The response characteristics of PD are determined by factors such as the inter-terminal capacitance and the time constant of the load resistor (t1), the diffusion time of the generated carriers outside the depletion layer (t2), and the depletion layer running time of the carriers (t3). Will be done. The upper part of FIG. 6 shows the waveform of the input signal (voltage) to the LED, the middle part shows the waveform of the output signal (voltage) from PD when t1 and t3 are dominant, and the lower part shows the waveform of t2. The waveform of the output signal from the PD in the above case is shown. The light from the LED is received by the PD at the times s1 to s2 shown in FIG. 6, but the output signal from the PD rises to the maximum value and reaches the minimum value than the input signal to the LED. There is a delay in both the fall to.

FIG. 7 is a graph showing the waveform of the output signal from the PD when the resistance value of the load resistor is changed. The horizontal axis of the graph of FIG. 7 represents time (arbitrary unit). Further, the line a1 in the graph of FIG. 7 shows the waveform of the input signal to the LED, and the lines b1 to b5 show the waveform of the output signal from the PD. Lines b1 to b5 show an example of the waveform of the output signal when the resistance value of the load resistor increases in this order. As shown in the graph of FIG. 7, as the resistance value of the load resistor increases, the response delay increases both at the rising edge of the PD output signal until it reaches the maximum value and at the falling edge until it reaches the minimum value. As described above, the PD generally has a response characteristic in which the rise and fall of the output signal with respect to the optical input are delayed.

Next, the biopermeability of near-infrared light will be described with reference to FIG. Each of FIGS. 8A to 8C is a graph showing a PD output signal obtained by irradiating a human thumb with near-infrared light and receiving the light. The horizontal axis of FIGS. 8A to 8C represents time (msec).

In the graph of FIG. 8A, line c1 shows the waveform of the input signal to the LED that irradiates light with a peak wavelength at a wavelength of 1050 nm, and line d1 is the PD that receives the light that has passed through the blood in the human thumb. The waveform of the output signal from is shown. Similarly, in the graph of FIG. 8B, line c2 shows the waveform of the input signal to the LED that irradiates light with a peak wavelength at a wavelength of 1300 nm, and line d2 receives the light that has passed through the blood in the human thumb. The waveform of the output signal from the PD is shown. Similarly, in the graph of FIG. 8C, line c3 shows the waveform of the input signal to the LED that irradiates light with a peak wavelength at a wavelength of 1450 nm, and line d3 receives the light that has passed through the blood in the human thumb. The waveform of the output signal from the PD is shown.

As shown in FIGS. 8A to 8C, in the near-infrared light having three wavelengths of 1050 nm, 1300 nm, and 1450 nm, the output signal from the PD increases in this order. The larger the output signal from the PD, the higher the biotransparency of light, and the smaller the output signal from the PD, the lower the biotransmission of light. Therefore, it can be seen that the biopermeability of these three wavelengths of near-infrared light in the human thumb is, in ascending order, a wavelength of 1450 nm, a wavelength of 1300 nm, and a wavelength of 1050 nm. The same applies to the biopermeability of the human index finger and middle finger.

Next, a method of acquiring light-receiving data in the blood component measuring device 1 according to the present embodiment will be described with reference to FIG. In the present embodiment, the blood component measuring device 1 is used to irradiate the thumb of the subject with near-infrared light in ascending order of wavelength with low biopermeability, and the light that has passed through the blood is received by the PD41. FIG. 9 is a graph illustrating a method of acquiring light receiving data in the present embodiment. In the graph of FIG. 9, line e shows the waveform of the output signal from PD41, line f1 shows the waveform of the input signal to the third LED 33, line f2 shows the waveform of the input signal to the second LED 32, and line f3 shows the waveform of the input signal to the second LED 32. The waveform of the input signal to the first LED 31 is shown. The horizontal axis of the graph in FIG. 9 represents time (msec).

The irradiation time of light by each LED is set longer as the peak wavelength is lower in biotransparency. Specifically, the third LED 33 irradiates light in a time of about 50 msec, the second LED 32 irradiates light in a time of about 25 msec, and the first LED 31 irradiates light in a time of about 7 msec. As a result, the blood component measuring device 1 sets the predetermined time corresponding to the human pulse wave (100 ms in the present embodiment) as one cycle, and the wavelength order of low biopermeability, that is, the order of the third LED 33, the second LED 32, and the first LED 31. The light reception data is acquired by the PD 41 of the light receiving unit 40.

Further, as described above with reference to FIGS. 6 and 7, the PD generally has a response characteristic in which the rise and fall of the output signal corresponding to the input light is delayed. The output signal of PD41 is stable during the period when the slope of the line indicating the waveform becomes substantially zero. As shown in the graph of FIG. 9, in the period in which the third LED 33 irradiates the light, the output signal of the PD 41 is stable in the period p1 in which the slope of the line e becomes substantially zero. Similarly, in the period in which the second LED 32 irradiates light, the output signal of the PD 41 is stable in the period p2 in which the slope of the line e becomes substantially zero. Similarly, in the period in which the first LED 31 irradiates light, the output signal of the PD 41 is stable in the period p3 in which the slope of the line e becomes substantially zero. The blood component measuring device 1 acquires the output signal as light receiving data during the period when the output signal of the PD 41 is stable.

Next, a method of acquiring light-receiving data with the blood component measuring device according to the comparative example will be described with reference to FIG. In the comparative example, a blood component measuring device having the same configuration as the blood component measuring device 1 according to the present embodiment is used to irradiate the thumb of the subject with near-infrared light in order of wavelength having high biopermeability, and pass through the blood. The light is received by the PD. FIG. 10 is a graph illustrating a method of acquiring light receiving data in a comparative example. In the graph of FIG. 10, line g shows the waveform of the output signal from PD, line h1 shows the waveform of the input signal to the LED that irradiates light with a peak wavelength of 1050 nm, and line h2 shows the light with a peak wavelength of 1300 nm. The waveform of the input signal to the LED that irradiates the light is shown, and the line h3 shows the waveform of the input signal to the LED that irradiates the light having a peak wavelength of 1450 nm. The horizontal axis of the graph in FIG. 10 represents time (msec).

The irradiation time of light by each LED is the same as that of the present embodiment described above. Therefore, the LED that irradiates the light having a peak wavelength of 1050 nm irradiates the light in a time of about 7 msec. An LED that irradiates light with a peak wavelength of 1300 nm irradiates light in a time of about 25 msec. An LED that irradiates light with a peak wavelength of 1450 nm irradiates light in a time of about 50 msec. As a result, the blood component measuring device according to the comparative example irradiates light in the order of wavelengths with high biopermeability in a predetermined time (100 ms in the present embodiment) corresponding to a human pulse wave as one cycle and acquires light receiving data. ..

Further, as described above, the output signal of the PD is stable during the period when the slope of the line indicating the waveform of the output signal from the PD becomes substantially zero. As shown in the graph of FIG. 10, the output signal of PD is stable during the period q1, q2, and q3 when the slope of the line g is substantially zero.

As described above, in the blood component measuring device 1 according to the present embodiment, light is irradiated in the order of wavelengths having low biopermeability. In addition, the PD has a response characteristic in which the rising and falling edges of the output signal are delayed. Further, as described with reference to FIGS. 8A to 8C, when the thumb of the subject is irradiated with light having a wavelength of 1450 nm and the light is received by the PD, the output signal of the PD is light having a wavelength of 1300 nm. Is smaller than the output signal of the PD when the subject's thumb is irradiated with the light and the light is received by the PD. Therefore, after stopping the light irradiation by the third LED 33 (peak wavelength: 1450 nm), the light irradiation by the second LED 32 (peak wavelength: 1300 nm) is immediately started, and each output of the PD 41 corresponding to the input light from these two LEDs is started. Even if the signal components overlap, the effect on the output signal component of the PD 41 corresponding to the input light from the second LED 32 is small. Similarly, when the subject's thumb is irradiated with light having a wavelength of 1300 nm and the light is received by the PD, the output signal of the PD is such that the subject's thumb is irradiated with light having a wavelength of 1050 nm and the light is received by the PD. It is smaller than the output signal of the PD in the case. Therefore, after stopping the light irradiation by the second LED 32 (peak wavelength: 1300 nm), the light irradiation by the first LED 31 (peak wavelength: 1050 nm) is immediately started, and each output of the PD 41 corresponding to the input light from these two LEDs is started. Even if the signal components overlap, the effect on the output signal component of the PD 41 corresponding to the input light from the first LED 31 is small.

On the other hand, in the blood component measuring device according to the comparative example, light is irradiated in the order of wavelength having high biopermeability. The output signal of the PD when the subject's thumb is irradiated with light having a wavelength of 1050 nm and the light is received by the PD is the corresponding when the subject's thumb is irradiated with light having a wavelength of 1300 nm and the light is received by the PD. It is larger than the output signal of PD. Therefore, when the light irradiation having a wavelength of 1300 nm is immediately started after the light irradiation having a wavelength of 1050 nm is stopped, the output signal component of the PD corresponding to the input light having a wavelength of 1300 nm becomes the output signal component of the PD corresponding to the input light having a wavelength of 1050 nm. It overlaps with and is buried. Therefore, the period q2 in the comparative example in which the accurate output signal component of the PD corresponding to the input light having a wavelength of 1300 nm can be obtained is shorter than the period p2 in the present embodiment. Similarly, when the subject's thumb is irradiated with light having a wavelength of 1300 nm and the light is received by the PD, the output signal of the PD is such that the subject's thumb is irradiated with light having a wavelength of 1450 nm and the light is received by the PD. It is larger than the output signal of the PD in the case. Therefore, when the light irradiation having a wavelength of 1300 nm is stopped and then the light irradiation having a wavelength of 1450 nm is immediately started, the output signal component of the PD corresponding to the input light having a wavelength of 1450 nm becomes the output signal component of the PD corresponding to the input light having a wavelength of 1300 nm. It overlaps with and is buried. Therefore, the period q3 in the comparative example in which the accurate output signal component of the PD corresponding to the input light having a wavelength of 1450 nm can be obtained is shorter than the period p1 in the present embodiment.

As described above, the period p1 in which the accurate output signal component of PD is obtained in the period of irradiating light having a wavelength of 1450 nm is longer than the period q3, and the accurate output signal component of PD is obtained in the period of irradiating light having a wavelength of 1300 nm. The obtained period p2 is longer than the period q2. Therefore, in the present embodiment, the periods p1 and p2 in which the output signal of PD41 is stable can be obtained longer than in the comparative example, and accurate light receiving data for performing signal processing for acquiring the pulse wave signal is compared. You can get more than the example. In the period of irradiating light with a wavelength of 1050 nm, the period p3 in which the accurate output signal component of PD is obtained should also be long enough to obtain accurate received light data for signal processing to acquire the pulse wave signal. Can be done.

As described above, the blood component measuring device 1 according to the present embodiment irradiates light in the order of wavelengths with low biopermeability in the human thumb, that is, in the order of the third LED 33, the second LED 32, and the first LED 31 within 100 msec. The received data for one cycle is acquired. When acquiring the received light data, the blood component measuring device 1 detects the output signal as many times as the number of times corresponding to the magnitude of each output signal during the period p1, p2, and p3 in which the output signal from the PD 41 is stable. For example, the blood component measuring device 1 detects a signal value for 900 times during the period p1 in which the third LED 33, which has a small output signal of the PD 41, irradiates light. Further, the blood component measuring device 1 detects the signal values for 300 times during the period p2 in which the second LED 32, which has an intermediate magnitude of the output signal of the PD 41, irradiates the light. Further, the blood component measuring device 1 detects the signal values for 100 times during the period p1 in which the first LED 31 having a large output signal of the PD 41 irradiates the light. The control unit 10 of the blood component measuring device 1 acquires the received light data for each wavelength for one cycle by adding the detected values for each wavelength and then dividing by the number of detections. As a result, the blood component measuring device 1 can remove noise from the output signal of the PD and acquire accurate received light data. The blood component measuring device 1 performs this cycle a plurality of times (for example, one cycle of 100 msec is performed 200 times), and acquires the received light data for a time sufficient to obtain a human pulse wave signal (for example, 20 seconds). According to the blood component measuring device 1 according to the present embodiment, it is possible to obtain a long period in which the output signal of the PD 41 is stable, and it is possible to obtain a large amount of accurate received light data for signal processing for acquiring a pulse wave signal. , The measurement accuracy of the concentration of blood components contained in blood can be improved.

Further, the blood component measuring device 1 according to the present embodiment can temporarily reset the output signal of the PD 41 every cycle by connecting the output terminal of the PD 41 to the ground by providing the transistor 73 shown in FIG. .. The effect of resetting the output signal of PD41 once will be described with reference to FIGS. 11 and 12. 11 and 12 are graphs showing the output signal of the PD, and the line j of FIG. 11 and the line k of FIG. 12 show the waveform of the output signal of the PD. Further, the horizontal axis of FIGS. 11 and 12 represents time (msec).

FIG. 11 shows an example in which the output signal of the PD 41 is once reset every cycle in the blood component measuring device 1 according to the present embodiment, that is, an example in which the output terminal of the PD 41 is connected to the ground every cycle. ing. As shown in FIG. 11, when the output terminal of the PD 41 is connected to the ground after the light irradiation by the first LED 31 in the N (N is a natural number) cycle and before the start of the light irradiation by the third LED 33 in the N + 1th cycle, Since the output signal component of the PD 41 corresponding to the Nth light irradiation of the first LED 31 is temporarily reset to zero, the output signal component of the PD 41 corresponding to the Nth light irradiation of the first LED 31 is the N + 1th light of the third LED 33. It is possible to prevent the PD41 from overlapping with the output signal component corresponding to the irradiation.

FIG. 12 shows an example in which the output signal of the PD is not reset once every cycle in the blood component measuring device according to the comparative example, that is, an example in which the output terminal of the PD is not connected to the ground every cycle. .. As shown in FIG. 12, the output terminal of the PD is connected to the ground after the light irradiation by the LED having the peak wavelength at the wavelength of 1050 nm in the Nth cycle and before the start of the light irradiation by the LED having the peak wavelength at the wavelength of 1450 nm in the N + 1 cycle. If not, due to the above response characteristics of the PD, the output signal component of the PD (indicated by the broken line k1 in the figure) corresponding to the light irradiation at the wavelength of 1050 nm in the Nth cycle is the light irradiation at the wavelength of 1450 nm in the N + 1 cycle. There is a risk that it will overlap with the output signal component of the PD corresponding to (indicated by the broken line k2 in the figure).

The blood component measuring device 1 according to the present embodiment irradiates light of each wavelength once by the first LED 31, the second LED 32, and the third LED 33 of the irradiation unit 30, and receives the light that has passed through the blood in the human thumb. When the PD 41 of 40 receives light and executes a cycle of acquiring light reception data a plurality of times, the output terminal of the PD 41 is temporarily connected to the ground each time one cycle is completed by the transistor 73. As a result, the blood component measuring device 1 can eliminate the influence of the output signal component in the previous cycle when the light receiving data is acquired by the PD 41 in a plurality of cycles. Therefore, according to the blood component measuring device 1, the measurement accuracy of the concentration of the blood component contained in the blood can be further improved by acquiring more accurate light receiving data.

Next, the blood TG value and the HbA1c value measurement process in the blood component measuring device 1 according to the present embodiment will be described with reference to FIG. FIG. 13 is a flowchart relating to the measurement process of the blood TG value and the HbA1c value in the blood component measuring device 1.

First, in OP101, the blood component measuring device 1 irradiates the thumb of the subject with light in the order of the third LED 33, the second LED 32, and the first LED 31, and receives the light passing through the blood in the finger with the PD 41 to receive the received data. To get. The blood component measuring device 1 acquires, for example, light-receiving data for 20 seconds (200 cycles), and uses the light-receiving data for 20 seconds as pulse wave signal data.

In the present embodiment, the blood component measuring device 1 acquires the pulse wave signal data, and the terminal device 100 analyzes the pulse wave data signal to calculate the blood TG value and the HbA1c value. The acquired pulse wave signal data is transmitted to the terminal device 100, and the terminal device 100 receives the pulse wave signal data from the blood component measuring device 1.

In the next OP 102, the terminal device 100 calculates the absorbance corresponding to each wavelength from the pulse wave signal data. For example, the change width of the pulsating signal corresponding to each wavelength can be appropriately converted into absorbance. The terminal device 100 determines the absorbance of blood corresponding to light irradiation at a wavelength of 1050 nm (hereinafter referred to as “first absorbance”) and light irradiation at a wavelength of 1300 nm from the change width of the pulse wave signal corresponding to irradiation at each wavelength. The absorbance of the corresponding blood (hereinafter referred to as "second absorbance") and the absorbance of blood corresponding to light irradiation at a wavelength of 1450 nm (hereinafter referred to as "third absorbance") are calculated. According to this embodiment, since the accurate pulse wave signal of each wavelength can be separated and extracted by the light receiving data acquisition method described with reference to FIG. 9, the first to third absorbances corresponding to each wavelength are accurately calculated. be able to.

In the next OP103, the terminal device 100 calculates the blood TG value from the first absorbance and the second absorbance. The terminal device 100 calculates the non-invasive blood absorbance by, for example, performing the difference between the first absorbance and the second absorbance, and converts the non-invasive blood absorbance into a blood TG value using a predetermined conversion table. As a result, the blood TG value is calculated.

In the next OP 104, the terminal device 100 normalizes the third absorbance and converts the normalized third absorbance into an HbA1c value. As an example of standardization, for example, the third absorbance is divided by the first absorbance or the second absorbance. By normalizing the third absorbance, the HbA1c value can be calculated more accurately without depending on the total hemoglobin concentration. Further, as a method of converting the standardized third absorbance into the HbA1c value, for example, the terminal device 100 stores a calibration curve data representing the relationship between the absorbance and the HbA1c value, which is prepared in advance, and is standardized. The HbA1c value can be calculated by comparing the third absorbance later with the calibration curve. It is preferable to use human hemoglobin and glycated hemoglobin to be measured for preparing the calibration curve.

The terminal device 100 calculates the blood TG value and the HbA1c value by the above method according to the blood component measurement program.

In the next OP 105, the terminal device 100 displays the blood TG value and the HbA1c value as measured values on the display unit 100a. As a result, the subject can know the blood TG value and the HbA1c value. According to this embodiment, since an accurate pulse wave signal can be detected, the measurement accuracy of the blood component concentration can be improved.

The above is the description of the present embodiment, but the configuration of the blood component measuring device 1, the calculation process of the blood TG value and the HbA1c value, etc. are not limited to the above embodiment, and the technique of the present invention is not limited to the above embodiment. Various changes can be made within the range that does not lose the identity with the idea.

Further, in the above embodiment, the measurement site of the living body is irradiated with light in the order of wavelength having the lowest biopermeability, but the biopermeability differs depending on the living body and the measurement site. Therefore, the order of wavelengths with low biopermeability is not limited to wavelengths of 1450 nm, 1300 nm, and 1050 nm. The control of irradiating light in the order of wavelength with low biopermeability may be executed based on the control signal from the terminal device 100. For example, the terminal device 100 stores biopermeability information of each wavelength at various measurement sites of a living body, and the terminal device 100 irradiates light in ascending order of biopermeability at the measurement site of the living body to be measured. The blood component measuring device 1 may be controlled so as to do so.

Further, in the present embodiment, the terminal device 100 calculates and displays the blood TG value and the HbA1c value based on the pulse wave signal data obtained by the blood component measuring device 1, but the present invention is not limited to this. For example, the blood component measuring device 1 may calculate the blood TG value and the HbA1c value based on the pulse wave signal data, and the display unit included in the blood component measuring device 1 may display the blood TG value and the HbA1c value. .. Further, the blood component measuring device 1 may calculate the blood TG value and the HbA1c value based on the pulse wave signal data, and the terminal device 100 may display the blood TG value and the HbA1c value. In this case, the blood component measuring device 1 is an example of a computer, in which the blood component measuring program is stored in the storage unit 20, and the control unit 10 expands the blood component measuring program into the RAM in the storage unit 20. By executing the various processes shown in FIG. 13 (for example, the processes of OP102 to OP105) are executed.

Further, the terminal device 100 transmits the pulse wave signal data obtained by the blood component measuring device 1 to an external server via a communication line, and the external server calculates the blood TG value and the HbA1c value based on the pulse wave signal data. Then, information including the blood TG value and the HbA1c value may be transmitted to the terminal device 100 via the communication line, and the terminal device 100 may display the blood TG value and the HbA1c value on the display unit 100a.

Further, although the reflected light method is adopted for the blood component measuring device 1 in the above embodiment, the transmitted light method may be adopted. In the transmitted light type blood component measuring device 1, for example, the irradiation unit 30 is arranged on the upper cover 61 so that the irradiation unit 30 and the light receiving unit 40 sandwich the thumb 101 of the subject inserted through the opening 62, and the thumb 101 The irradiation unit 30 may irradiate light from the back side (nail side) of the thumb, and the light receiving unit 40 may receive the light that has passed through the thumb.

Further, in the blood component measuring device 1 according to the above embodiment, the irradiation unit 30 acquires the output signal from the PD 41 by irradiating the third LED 33, the second LED 32, and the first LED 31 with light having different wavelengths in this order within a predetermined time. This may be regarded as one cycle, and a plurality of cycles may be performed continuously or intermittently. In this case, the irradiation unit 30 may be controlled by the control unit 10 or by the blood component measuring device 1 based on the control signal from the terminal device 100.

The number of LEDs included in the irradiation unit 30, the peak wavelength of the irradiation light of each LED, and the arrangement pattern are not limited to the above embodiment. For example, when measuring only the blood TG value, the irradiation unit 30 may have the first LED 31 and the second LED 32. Further, in this case, when the blood component measuring device 1 acquires the output signal from the PD 41 in a plurality of cycles, the transistor 73 performs P after the light irradiation by the first LED 31 in the Nth cycle.
The output terminal of the D41 may be connected to the ground, and the output terminal of the PD41 may be disconnected from the ground before the light irradiation by the second LED 32 in the N + 1 cycle. Further, when measuring only the HbA1c value, the irradiation unit 30 may have either the first LED 31 or the second LED 32 and the third LED 33. Further, in this case, when the blood component measuring device 1 acquires the output signal from the PD 41 in a plurality of cycles, the output terminal of the PD 41 is grounded by the transistor 73 after the light irradiation by the first LED 31 or the second LED 32 in the Nth cycle. The output terminal of the PD 41 may be disconnected from the ground before the light irradiation by the third LED 33 in the N + 1 cycle. As described above, the blood component measuring device 1 may connect the output terminal of the PD 41 to the ground after each cycle, regardless of the blood component to be measured.

Further, although the living body to be measured in the above embodiment is a human, the living body to be measured is not limited to human. Mammals and birds are examples of specific living organisms to be measured. Of these, it is more preferable to measure humans who may be diagnosed with diseases caused by hyperglycemia (for example, diabetes), and mammals and birds which can be pets and livestock.

Further, in the above embodiment, the blood TG value and the HbA1c value are measured as the blood component concentrations, but the concentrations of other blood components may be measured. For example, hemoglobin, glucose, cholesterol (total cholesterol, HDL- or LDL-cholesterol, free cholesterol), urea, bilirubin, lipoprotein, phospholipid, ethyl alcohol and the like in blood may be measured. In this case, the living body is irradiated with light having a wavelength whose absorbance changes depending on the concentration of each blood component, and the concentration of each blood component is calculated from the absorbance.

Further, in the above embodiment, an example in which three LEDs having different emission wavelengths are used has been shown, but by changing or increasing the blood component to be measured, the required number of LEDs and the light emission of the LEDs are shown. The type of wavelength is changed as appropriate. In this case, it is assumed that the wavelength further reduces the biopermeability, and it is possible that the lighting order of the plurality of LEDs must be controlled more strictly. Even in such a case, according to the technique disclosed in the present invention, it is possible to improve the measurement accuracy of the concentration of blood components.

1 Blood component measuring device 10 Control unit 20 Storage unit 30 Irradiation unit 40 Light receiving unit 50 Communication unit 100 Terminal device

Claims (12)

Multiple light emitting elements that irradiate the measurement site of the living body with light of different wavelengths,
A light receiving element that receives the light that has passed through the blood at the measurement site, and
A control unit that controls the plurality of light emitting elements so as to irradiate light in the order of wavelengths having low biopermeability at the measurement site.
A blood component measuring device characterized by comprising. The plurality of light emitting elements include a first light emitting element that irradiates light having a peak wavelength in a wavelength range of 850 nm to 1150 nm, and a second light emitting element that irradiates light having a peak wavelength in a wavelength range of 1150 nm to 1350 nm. Have,
The blood component measuring device according to claim 1, wherein the control unit controls the plurality of light emitting elements so as to irradiate light in the order of the second light emitting element and the first light emitting element. The plurality of light emitting elements further include a third light emitting element that irradiates light having a peak wavelength in a wavelength range of 1350 nm to 1500 nm.
2. The second aspect of the present invention, wherein the control unit controls the plurality of light emitting elements so as to irradiate light in the order of the third light emitting element, the second light emitting element, and the first light emitting element. Blood composition measuring device. A switching element for switching between a connected state in which the output terminal of the light receiving element is connected to the ground and a non-connected state in which the output terminal is disconnected from the ground is further provided.
A cycle in which the plurality of light emitting elements irradiate light once each in the order of wavelength having low biopermeability at the measurement site, and the light receiving element receives the light that has passed through blood at the measurement site to acquire light receiving data. When the switching element is executed a plurality of times, the switching element connects the output terminal of the light receiving element to the ground each time the cycle ends, according to any one of claims 1 to 3. The blood component measuring device according to item 1. A control method for a blood component measuring device including a plurality of light emitting elements that irradiate a measurement site of a living body with light having different wavelengths, and a light receiving element that receives the light that has passed through blood at the measurement site. ,
A control method for a blood component measuring device, characterized in that the plurality of light emitting elements are controlled so as to irradiate light in order of wavelength having low biopermeability at the measurement site. The plurality of light emitting elements include a first light emitting element that irradiates light having a peak wavelength in a wavelength range of 850 nm to 1150 nm, and a second light emitting element that irradiates light having a peak wavelength in a wavelength range of 1150 to 1350 nm. Have,
The control method for a blood component measuring device according to claim 5, wherein the plurality of light emitting elements are controlled so as to irradiate light in the order of the second light emitting element and the first light emitting element. The plurality of light emitting elements further include a third light emitting element that irradiates light having a peak wavelength in a wavelength range of 1350 nm to 1500 nm.
The blood component measuring device according to claim 6, wherein the plurality of light emitting elements are controlled so as to irradiate light in the order of the third light emitting element, the second light emitting element, and the first light emitting element. Control method. The blood component measuring device further includes a switching element that switches between a connected state in which the output terminal of the light receiving element is connected to the ground and a non-connected state in which the output terminal is disconnected from the ground.
In the control method, the plurality of light emitting elements irradiate light once each in the order of wavelength having low biopermeability at the measurement site, and the light receiving element receives and receives the light that has passed through blood at the measurement site. When the cycle of acquiring data is executed a plurality of times, the switching element is controlled, and the output terminal of the light receiving element is connected to the ground each time the cycle is completed. The control method for a blood component measuring device according to any one of claims 5 to 7. A control program for a blood component measuring device including a plurality of light emitting elements that irradiate a measurement site of a living body with light of different wavelengths and a light receiving element that receives the light that has passed through blood at the measurement site. ,
A control program for a blood component measuring device, wherein a computer is made to control the plurality of light emitting elements so as to irradiate light in order of wavelength having low biopermeability at the measurement site. The plurality of light emitting elements include a first light emitting element that irradiates light having a peak wavelength in a wavelength range of 850 nm to 1150 nm, and a second light emitting element that irradiates light having a peak wavelength in a wavelength range of 1150 nm to 1350 nm. Have,
The control program for a blood component measuring device according to claim 9, wherein the computer controls the plurality of light emitting elements so as to irradiate the second light emitting element and the first light emitting element in this order. .. The plurality of light emitting elements further include a third light emitting element that irradiates light having a peak wavelength in a wavelength range of 1350 nm to 1500 nm.
The blood according to claim 10, wherein the computer is made to control the plurality of light emitting elements so as to irradiate light in the order of the third light emitting element, the second light emitting element, and the first light emitting element. Control program for component measuring device. The blood component measuring device further includes a switching element that switches between a connected state in which the output terminal of the light receiving element is connected to the ground and a non-connected state in which the output terminal is disconnected from the ground.
In the control program, the plurality of light emitting elements irradiate light once each in the order of wavelength having low biopermeability at the measurement site, and the light receiving element receives and receives the light that has passed through blood at the measurement site. When the cycle of acquiring data is executed a plurality of times, the computer is made to control the switching element, and the output terminal of the light receiving element is connected to the ground each time the cycle is completed. The control program of the blood component measuring device according to any one of claims 9 to 11, characterized by this.

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