JP2017000415A - Information acquisition apparatus and information acquisition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information acquisition apparatus capable of accurately acquiring information of a subject even when a vessel is pressed by the measuring device.SOLUTION: A pulse measuring device 1 comprises: light receiving elements 26 for detecting the light intensity of reflected light transmitted through a vessel of a subject and outputting a pre-correction waveform; a pressure-sensitive conductive rubber member 12 for detecting a pressure by which the subject is pressed by a sensor module 8 and outputting the magnitude of the pressure; and a correction calculation unit 64 for correcting the pre-correction waveform using the magnitude of the pressure and outputting a post-correction waveform indicative of the light intensity when no pressure is applied to the vessel.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an information acquisition apparatus and an information acquisition method.

  A method of measuring the pulse and blood pressure by irradiating a blood vessel with light is used. As one of them, an apparatus for measuring blood pressure is disclosed in Patent Document 1. According to this, the measuring device is provided with a blood flow velocity sensor and a volume pulse wave sensor at a location facing the blood vessel. The blood flow velocity sensor irradiates the blood flow with ultrasonic waves and measures the blood flow velocity using the Doppler effect of the reflected wave. A volume pulse wave sensor irradiates light to a blood vessel. Then, the volume pulse wave is measured from the change in the light intensity absorbed by the light. Incidentally, the volume pulse wave shows a change in the blood vessel diameter.

  The measuring device is worn on the wrist. The blood flow velocity sensor measures the blood flow, and the volume pulse wave sensor measures the volume pulse wave. Next, the blood pressure signal calculation unit calculates the blood pressure from the blood flow velocity and the volume pulse wave.

JP 2004-154231 A

  When there is a gap between the measurement device and the subject, some light is repeatedly reflected between the measurement device and the subject. Since the light attenuates and fluctuates, the amount of light becomes inappropriate for blood measurement. On the other hand, when the measuring device presses the blood vessel, the cross-sectional shape of the blood vessel changes from a circular shape to an elliptical shape. At this time, since the cross-sectional area of the blood vessel decreases, the light intensity to be measured fluctuates as the pressure at which the light detection unit pushes the subject changes. When the light intensity is analyzed, an error due to the fluctuation of the light intensity occurs. Therefore, there has been a demand for an apparatus that can accurately acquire information on a subject even when the measurement apparatus presses a blood vessel.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

[Application Example 1]
An information acquisition apparatus according to this application example, wherein a light detection unit that detects a light intensity of light that has passed through a tube in a subject and outputs a first light intensity, and the subject presses the light detection unit A pressure detection unit that detects the pressure to be output and outputs the magnitude of the pressure, and the light intensity when the pressure is not applied to the tube by correcting the first light intensity using the pressure magnitude. And a correction unit that outputs the second light intensity.

  According to this application example, the information acquisition apparatus includes a light detection unit, a pressure detection unit, and a correction unit. The light detection unit detects the light intensity of the light that has passed through the tube in the subject and outputs the first light intensity. The pressure detector detects and outputs the pressure level at which the tube is pressed. The correction unit corrects the first light intensity using the magnitude of the pressure with which the tube is pressed. The correction unit outputs a second light intensity that is a light intensity when no pressure is applied to the tube.

  Since the tube of the subject is elastic, it deforms when pressed by the light detection unit. As the tube deforms, the amount of light passing through the tube changes. For this reason, the first light intensity varies with the variation of the pressure at which the light detection unit pushes the subject. The correction unit corrects the first light intensity using the magnitude of the pressure with which the tube is pressed, and outputs the second light intensity. The second light intensity is the light intensity when no pressure is applied to the tube. Therefore, since the information acquisition apparatus can analyze the information on the blood flowing through the tube with the light intensity when no pressure is applied to the tube, the information on the subject can be acquired with high accuracy.

[Application Example 2]
In the information acquisition device according to the application example described above, the time is t, the pressure at the time is P (t), the elasticity coefficient of the tube is E, the light absorption coefficient of the subject is μa _{T, and} the light absorption coefficient of blood is μa _B , where the first light intensity detected at the time is Im (t) and the second light intensity is I (t), the correction unit corrects using the following equation (1) It is characterized by.

  According to this application example, the correction unit corrects the first light intensity using (Equation 1) and the detected pressure. The tube is deformed by pressure, and the distance through which light passes is changed by deformation of the tube. The ratio of the distance that light passes through the subcutaneous tissue and the distance that light passes through the tube changes. (Equation 1) corrects the light intensity that changes with the change in the rate of light passing through the subcutaneous tissue and the tube due to pressure. Therefore, the correction unit can reliably correct the light intensity that varies depending on the pressure applied to the subject.

[Application Example 3]
In the information acquisition apparatus according to the application example, the correction unit uses the correlation table indicating a correlation between the second light intensity and the pressure detected by the pressure detection unit and the first light intensity. The light intensity is output.

  According to this application example, the second light intensity obtained by correcting the first light intensity is output using the correlation table and the detected pressure. The correlation table shows the correlation of the second light intensity with respect to the pressure detected by the pressure detector and the first light intensity. The correlation table shows the correlation that has been confirmed in advance. Therefore, the correction unit can reliably correct the first light intensity in the subject and obtain the second light intensity.

[Application Example 4]
In the information acquisition apparatus according to the application example, the pressure detection unit is positioned between the subject and the light detection unit, and the pressure detection unit includes a light passage unit that has elasticity and allows light to pass through. It is characterized by that.

  According to this application example, the pressure detection unit is located between the subject and the light detection unit. And a pressure detection part is provided with a light passage part, and a light passage part allows light to pass through. Therefore, the light detection unit can detect light output from the subject and passing through the pressure detection unit. When a hard member comes into contact with the subject, the hard member may partially press the subject. At this time, a high pressure is locally applied to the subject, and the subject may be marked. In this application example, the pressure detection unit has elasticity. Accordingly, it is possible to suppress the mark from being formed on the subject.

[Application Example 5]
In the information acquisition apparatus according to the application example described above, the pressure detection unit detects pressure applied to a place where light passing through the tube passes through the subject.

  According to this application example, the pressure detection unit detects the pressure applied to the place where the light passing through the tube passes through the subject. Thereby, the pressure detection part can detect the pressure added to the pipe | tube and the structure | tissue around a pipe | tube.

[Application Example 6]
In the information acquisition apparatus according to the application example described above, a light-shielding unit is installed in a place surrounding the light passage unit.

  According to this application example, the light shielding portion is installed at a place surrounding the light passage portion. The light-shielding part shields light that propagates repeatedly by reflection inside the pressure detection part. Therefore, it is possible to suppress light that does not pass through the subject from being input to the light detection unit.

[Application Example 7]
In the information acquisition apparatus according to the application example, the light detection unit is located between the subject and the pressure detection unit.

  According to this application example, the light detection unit is located between the subject and the pressure detection unit. Accordingly, since there is no pressure detection unit between the subject and the light detection unit, light output from within the subject is input to the light detection unit without passing through the pressure detection unit. Therefore, it is possible to prevent the light output from the subject from passing through the pressure detection unit and being attenuated.

[Application Example 8]
An information acquisition method according to this application example, wherein a first light intensity that is a light intensity of light that has passed through a tube in a subject is detected, a magnitude of a pressure with which the tube is pressed is detected, and the first The second light intensity, which is the light intensity when no pressure is applied to the tube, is calculated using one light intensity and the pressure with which the tube is pressed.

  According to this application example, the light intensity of the light passing through the tube in the subject is detected, and this light intensity is set as the first light intensity. Furthermore, the magnitude of the pressure with which the tube is pressed is detected. Then, the first light intensity and the pressure at which the tube is pressed are input to calculate the second light intensity. The second light intensity is the light intensity when no pressure is applied to the tube. Therefore, since the information acquisition method can analyze the information of blood flowing through the tube with the light intensity when no pressure is applied to the tube, the information of the subject can be acquired with high accuracy.

(A) is a schematic diagram for demonstrating the installation example of a pulse measuring device, (b) and (c) are schematic plan views which show the structure of a pulse measuring device in connection with 1st Embodiment. The disassembled perspective view which shows the structure of a pulse measuring device. (A) is a schematic plan view which shows the structure of a pressure detection part, (b) is a principal part schematic plan view which shows the structure of a pressure detection part, (c) is a schematic plan view which shows the structure of a sensor module. (A) is a partial schematic sectional side view for demonstrating operation | movement of a sensor module, (b) is a circuit diagram which shows a part of pressure sensor drive circuit. The electric control block diagram of a pulse measuring device. The flowchart of the pulse information acquisition method. The schematic diagram for demonstrating the pulse information acquisition method. The schematic diagram for demonstrating the pulse information acquisition method. The schematic diagram for demonstrating the pulse information acquisition method. The figure which shows the correlation table in connection with 2nd Embodiment, and a correction | amendment calculating part uses for correction | amendment. The electric control block diagram of the blood-pressure measuring device in connection with 3rd Embodiment. The electric sensor drive circuit and the electric control block diagram of a sensor module. The flowchart of the blood-pressure information acquisition method. The figure for demonstrating a volume pulse wave. The disassembled perspective view which shows the structure of the pulse measuring device concerning 4th Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. In addition, each member in each drawing is illustrated with a different scale for each member in order to make the size recognizable on each drawing.

(First embodiment)
In this embodiment, a characteristic example of a pulse measurement device and a pulse information acquisition method for measuring a pulse using the pulse measurement device will be described with reference to the drawings. The pulse measuring device according to the first embodiment will be described with reference to FIGS. Fig.1 (a) is a schematic diagram for demonstrating the installation example of a pulse measuring device. As shown to Fig.1 (a), the pulse measuring device 1 as an information acquisition apparatus is installed in the wrist of the subject 2 as a subject. The pulse measuring device 1 is a medical measuring device that measures the pulse of the subject 2 in a non-invasive manner, and is a medical device. The pulse measuring device 1 measures the pulse of blood flowing through the blood vessels of the wrist.

  FIGS. 1B and 1C are schematic plan views showing the structure of the pulse measuring device. FIG. 1B shows the surface of the pulse measuring device 1, and FIG. 1C shows the back surface of the pulse measuring device 1. As shown in FIG. 1 (b), the pulse measuring device 1 has a shape similar to a wristwatch. The pulse measuring device 1 includes an exterior part 3. Fixed bands 4 are installed on the left and right of the exterior part 3 in the figure, and the fixed band 4 fixes the pulse measuring device 1 to a measured part such as a wrist or an arm of the subject 2. A magic tape (registered trademark) is used for the fixed band 4. In the pulse measuring device 1, the direction in which the fixed band 4 extends is defined as the Y direction, and the direction in which the arm of the subject 2 extends is defined as the X direction. The direction in which the pulse measuring device 1 faces the subject 2 is defined as the Z direction. The X direction, the Y direction, and the Z direction are orthogonal to each other.

  The surface 3 a of the exterior portion 3 is a surface that faces outward when the patient 3 is attached to the subject 2. An operation switch 5, a touch panel 6, and a speaker 7 are installed on the surface 3 a of the exterior part 3. The subject 2 inputs a measurement start instruction using the operation switch 5 or the touch panel 6. Then, measurement result data is displayed on the touch panel 6. A warning sound for alerting the subject 2 is emitted from the pulse measuring device 1 from the speaker 7.

  As shown in FIG. 1C, a sensor module 8 as a light receiving unit and a light detection unit is installed on the back surface 3 b side of the exterior unit 3. The sensor module 8 is used by being brought close to the skin of the subject 2. The sensor module 8 is a device that irradiates the skin of the subject 2 with measurement light and receives reflected light. The sensor module 8 is a thin image sensor incorporating a light source and a photosensor array. A communication connector 9 for communicating with an external device is installed on the back surface 3 b of the exterior part 3. The communication connector 9 is arranged with contacts for communicating with a cord connected to an external device. In addition, a power connector 10 for filling a rechargeable storage battery (not shown) is provided. The power connector 10 is a connector for inputting electric power.

  FIG. 2 is an exploded perspective view showing the structure of the pulse measuring device. As shown in FIG. 2, the pulse measuring device 1 includes a back cover 11 from the Z direction side, a pressure-sensitive conductive rubber 12 as a pressure detection unit, a sensor module 8, a circuit unit 14, a spacer 15, a touch panel 6, a vibration device 16, The front case 17 is stacked in this order. The outer cover 3 is configured by the back cover 11 and the front case 17. The pressure-sensitive conductive rubber 12, the sensor module 8, the circuit unit 14, the spacer 15, the touch panel 6, the vibration device 16, and the like are housed in the exterior portion 3.

  The back cover 11 is a plate-like member and is a member facing the subject 2. The back cover 11 is provided with a rectangular first window portion 11a on the X direction side, and the first window portion 11a is a place where the pressure-sensitive conductive rubber 12 is exposed. The pressure-sensitive conductive rubber 12 prevents dust from entering the exterior portion 3. Further, the sensor module 8 is prevented from becoming dirty. A part of the pressure-sensitive conductive rubber 12 is bonded and fixed to the sensor module 8. A pressure detector 13 is constituted by the sensor module 8 and the pressure-sensitive conductive rubber 12 or the like.

  When a hard member comes into contact with the subject 2, the hard member may partially press the subject 2. At this time, a high pressure is locally applied to the subject, and the subject 2 may be marked. In the pulse measuring device 1, the pressure-sensitive conductive rubber 12 protrudes from the first window portion 11a, and the pressure-sensitive conductive rubber 12 has elasticity. Therefore, it can suppress that the subject 2 leaves a mark.

  The back cover 11 is provided with a rectangular second window portion 11 b and a third window portion 11 c on the −X direction side. The second window portion 11b is a place where the communication connector 9 is exposed, and the third window portion 11c is a place where the power connector 10 is exposed.

  The sensor module 8 is a sensor in which a light emitting element and a light receiving element are installed in a lattice shape, and irradiates the subject 2 with light to detect the light intensity of reflected light having a specific wavelength. The circuit unit 14 includes a circuit board 18. An electric circuit 21 that drives and controls the vibration device 16, the sensor module 8, and the touch panel 6 is installed on the circuit board 18. The electric circuit 21 is composed of a plurality of semiconductor chips. In addition, an operation switch 5, a speaker 7, a communication connector 9, a power connector 10, and a rechargeable storage battery 22 are installed on the circuit board 18. The rechargeable storage battery 22 is electrically connected to the power connector 10 and can be charged via the power connector 10.

  The spacer 15 is a structure that is installed between the circuit unit 14 and the touch panel 6. The surface on the −Z direction side of the circuit unit 14 is uneven because it is provided with a plurality of electric elements. The spacer 15 is placed over the circuit board 18 to flatten the surface on the touch panel 6 side. The spacer 15 is provided with a plurality of holes 15a, and the operation switch 5, the speaker 7, and the vibration device 16 pass through the holes 15a.

  The touch panel 6 has a structure in which an operation input unit 24 is installed on the display unit 23. The display unit 23 is not particularly limited as long as it can display electronic data as an image, and a liquid crystal display device or an OLED (Organic light-emitting diodes) display device can be used. In the present embodiment, for example, an OLED is used for the display unit 23.

  The operation input unit 24 is an input device in which transparent electrodes are arranged in a grid pattern on the surface of a transparent plate. When the operator touches the transparent electrode, a current flows between the intersecting electrodes, so that the place touched by the operator can be detected. The transparent plate may be a light-transmitting plate, and a resin sheet or a glass plate can be used. The transparent electrode only needs to be a light-transmitting and conductive film, and for example, IGO (Indium-gallium oxide), ITO (Indium Tin Oxide), or ICO (Indium-cerium oxide) can be used. The display unit 23 displays the measurement status, measurement results, and the like. The operation switch 5 is a switch for operating the pulse measuring device 1 similarly to the operation input unit 24. The operator operates the operation input unit 24 and the operation switch 5 to input various instructions such as a pulse measurement start instruction and measurement conditions.

  A vibration device 16 is installed on the + Z direction side of the front case 17. The vibration device 16 vibrates the exterior portion 3. The pulse measuring device 1 has a function of causing the subject 2 to be alerted by vibrating the exterior portion 3. The vibration device 16 is not particularly limited as long as it can vibrate the exterior portion 3 and members constituting the vibration device 16 are not particularly limited. In the present embodiment, for example, a piezoelectric element is used for the vibration device 16.

  The front case 17 is provided with a plurality of holes 17a through which the operation input unit 24, the operation switch 5, and the speaker 7 are exposed. Then, the back cover 11 and the front case 17 are accommodated with the sensor module 8 to the touch panel 6 interposed therebetween.

  FIG. 3A is a schematic plan view showing the structure of the pressure detector, and is a view of the sensor module 8 as seen from the back surface 3b side. FIG. 3B is a schematic plan view of the main part showing the structure of the pressure detection unit.

  As shown in FIG. 3A, in the sensor module 8, a light emitting element 25 and a light receiving element 26 as a light detection unit are installed in pairs, and the pair of the light emitting element 25 and the light receiving element 26 is two-dimensionally arranged in a lattice shape. It is arranged. In order to make the figure easy to see, the pairs of the light emitting elements 25 and the light receiving elements 26 are arranged in 5 rows and 10 columns in the drawing, but the number of rows and columns of the pair of the light emitting elements 25 and the light receiving elements 26 is not particularly limited. In this embodiment, for example, a pair of light emitting elements 25 and light receiving elements 26 of 250 rows × 250 columns is installed.

  The arrangement interval of the pair of the light emitting element 25 and the light receiving element 26 is preferably 1 to 1500 μm, and is preferably about 100 to 1500 μm, for example, in consideration of the manufacturing cost and the measurement accuracy. In the present embodiment, for example, the distance between the pair of the light emitting element 25 and the light receiving element 26 is 0.1 mm. The sensor module 8 also functions as an image sensor. The light emitting element 25 and the light receiving element 26 are arranged in the X direction and the Y direction.

  As shown in FIG. 3B, the pressure-sensitive conductive rubber 12 is provided with a light passage portion 12 a that allows light to pass through a location facing the light emitting element 25 and the light receiving element 26. Further, the pressure-sensitive conductive rubber 12 is provided with a pressure-sensitive portion 12b as a light-shielding portion that detects pressure at a location surrounding the light passage portion 12a. And the pressure sensitive conductive rubber 12 detects the pressure of the place surrounding the light passage part 12a. The pressure around the light passage portion 12a is close to the light passage portion 12a. Therefore, the pressure-sensitive part 12b can detect a pressure that is substantially equal to the pressure applied to the subject 2 where light passes.

  The material of the pressure-sensitive conductive rubber 12 is not particularly limited as long as it can pass light. In the present embodiment, for example, silicone rubber is adopted as the material of the pressure-sensitive conductive rubber 12. And the fine electroconductive particle is installed in the pressure sensitive part 12b by the uniform density. Carbon particles or metal particles can be used as the conductive particles. In the present embodiment, for example, carbon particles are employed as the conductive particles.

  The pressure sensitive part 12b has a shape in which one annular portion is cut. The first terminal 27a is connected to one end of the pressure sensitive part 12b, and the second terminal 27b is connected to the other end of the pressure sensitive part 12b. Carbon particles are connected to each other between the first terminal 27a and the second terminal 27b and function as an electrical resistor. When the pressure sensitive part 12b is pressurized and contracts, the number of places where the carbon particles are connected to each other increases. And resistance between the 1st terminal 27a and the 2nd terminal 27b becomes small. Therefore, the pressure applied to the pressure-sensitive conductive rubber 12 can be detected by detecting the resistance between the first terminal 27a and the second terminal 27b.

  The pressure sensitive part 12b is a light shielding part that does not transmit light. Thereby, the pressure-sensitive part 12b suppresses the light propagating through the pressure-sensitive conductive rubber 12. Therefore, light that does not pass through the subject 2 can be prevented from being input to the light receiving element 26.

  FIG. 3C is a schematic plan view showing the structure of the sensor module, in which the pressure-sensitive conductive rubber 12 is removed from the pressure detection unit 13. As shown in FIG. 3C, the sensor module 8 includes an element substrate 8a. A light emitting element 25 and a light receiving element 26 are installed on the element substrate 8a. A support member 8b that supports the light emitting element 25 and the light receiving element 26 is provided on the element substrate 8a. The support member 8b is provided with holes in a lattice shape, and the light emitting element 25 and the light receiving element 26 are provided in each hole. The surfaces of the light emitting element 25, the light receiving element 26, and the support member 8b on the + Z direction side are set to be the same plane. A first terminal 27a and a second terminal 27b are installed on the surface on the + Z direction side of the support member 8b. The first terminal 27a and the second terminal 27b are connected to the pressure sensitive part 12b.

  The support member 8b is bonded and fixed to the element substrate 8a, and the pressure-sensitive conductive rubber 12 is bonded and fixed to the support member 8b. And the pressure detection part 13 is united. The light emitting element 25 and the light receiving element 26 are in close contact with the light passage portion 12a. Thereby, it is suppressed that light is repeatedly reflected between the light passage portion 12a and the light emitting element 25 and the light receiving element 26.

  The subject 2 is irradiated with light from the light emitting element 25 in order to detect the position of the blood vessel and the flow of blood. The wavelength of light emitted from the light emitting element 25 is 700 nm to 900 nm with 800 nm as the center. Hemoglobin in blood absorbs light with a wavelength of 800 nm. Accordingly, when the subject 2 is irradiated with light from the light emitting element 25 and imaged, the arrangement of blood vessels can be imaged.

  The light emitting element 25 is an irradiation unit that emits measurement light. The light emitting element 25 is not particularly limited as long as it can emit near-infrared light having transparency to the subcutaneous tissue. As the light emitting element 25, for example, an LED (Light Emitting Diode), an OLED (Organic light-emitting diode), or the like can be used.

  The light receiving element 26 outputs an electrical signal corresponding to the light intensity of receiving the reflected light 29 as light. The light receiving element 26 may be any element that can convert the intensity of light into an electrical signal. For example, an imaging element such as a charge coupled device sensor (CCD) or a complementary metal oxide semiconductor sensor (CMOS) can be used. One light receiving element 26 may include a plurality of elements that receive each wavelength component necessary for calibration. The sensor module 8 is installed on the back surface 3b side of the exterior portion 3 so that the surface on which the light emitting element 25 and the light receiving element 26 are installed is the front side, and the front side faces the skin surface of the subject 2. Has been.

  FIG. 4A is a partial schematic side sectional view for explaining the operation of the sensor module. As shown in FIG. 4A, the optical axis of the light emitting element 25 and the optical axis of the light receiving element 26 face the same direction. The light emitting element 25 emits measurement light 28 as light with a predetermined directivity. The direction with the highest light intensity among the directivity characteristics of the measurement light 28 is defined as the optical axis of the light emitting element. The light receiving element 26 has a predetermined directivity characteristic for detecting the reflected light 29. The direction with the highest sensitivity among the directivity characteristics of the sensitivity is defined as the optical axis of the light receiving element 26. In the sensor module 8, the direction in which the light intensity for emitting light is high and the direction in which the sensitivity for receiving light is highest are in the same direction. That is, the optical axis of the light emitting element 25 and the optical axis of the light receiving element 26 are in the same direction. Therefore, the sensor module 8 can receive the reflected light 29 with high sensitivity when the measured portion 2 a is installed in the direction of the optical axis of the light emitting element 25 and the optical axis of the light receiving element 26. The measured part 2a is a place where the pulse is measured.

  The portion to be measured 2a is set at a location facing the sensor module 8. Before detecting the blood pulse, the arrangement of the blood vessel 30 as a tube is detected. First, the arrangement of the blood vessel 30 is imaged. At this time, all the light emitting elements 25 of the sensor module 8 emit light simultaneously. Then, the measuring light 28 is irradiated to the entire area of the measured part 2 a of the subject 2. The measurement light 28 is irregularly reflected by the measured portion 2 a to become reflected light 29. Then, the reflected light 29 is received by all the light receiving elements 26, and an image of the measured portion 2a is acquired. Next, the measurement light 28 is output from some of the light emitting elements 25. The light receiving element 26 at a specific location receives the reflected light 29 and measures the pulse.

  A pressure-sensitive conductive rubber 12 is located between the subject 2 and the sensor module 8. Then, the pressure-sensitive conductive rubber 12 detects the distribution of pressure by which the sensor module 8 pressurizes the subject 2. And the pressure sensitive part 12b detects the pressure of the place to measure.

  FIG. 4B is a circuit diagram showing a part of the pressure sensor driving circuit. As shown in FIG. 4B, the pressure sensor drive circuit 31 includes a power supply wiring 32, and a voltage is applied to the power supply wiring 32 from the rechargeable storage battery 22. Although the voltage of the power supply wiring 32 is not particularly limited, in this embodiment, for example, the voltage of the power supply wiring 32 is set to 3V.

  A resistor 33 is connected to the power supply wiring 32 via the wiring. The opposite side of the power supply wiring 32 in the resistor 33 is connected to the first terminal 27 a of the pressure sensing unit 12 b and further connected to the input terminal of the amplifying element 34. The second terminal 27b located on the opposite side of the first terminal 27a in the pressure sensitive part 12b is grounded 35 via a wiring. An output terminal of the amplifying element 34 is connected to an input terminal of an AD conversion element 36 (Analog Digital) via a wiring. An output terminal of the AD conversion element 36 is connected to the control device 37 via a wiring.

  When pressure is applied to the pressure sensitive part 12b, the resistance value of the pressure sensitive part 12b decreases. Since the voltage between the first terminal 27a and the second terminal 27b is equal to the value obtained by multiplying the current and the resistance value of the pressure sensitive part 12b, the resistance of the first terminal 27a decreases when the resistance value of the pressure sensitive part 12b decreases. The voltage drops. As a result, the voltage at the input terminal of the amplifying element 34 decreases, and the voltage at the output terminal of the amplifying element 34 decreases. Accordingly, the pressure data value converted by the AD conversion element 36 and output to the control device 37 also decreases. As described above, the pressure sensor drive circuit 31 outputs pressure data corresponding to the pressure applied to the pressure sensing unit 12 b to the control device 37. Note that the same number of resistors 33, amplifying elements 34, and AD conversion elements 36 as the number of the pressure sensitive parts 12b may be installed, and a switching element is arranged between the amplifying element 34 and the AD converting element 36 to thereby convert the AD converting elements. The number of 36 may be less than the number of pressure-sensitive parts 12b.

  FIG. 5 is an electric control block diagram of the pulse measuring device. In FIG. 5, the pulse measuring device 1 includes a control device 37 that controls the operation of the pulse measuring device 1. The control device 37 includes a CPU 38 (Central Processing Unit) that performs various arithmetic processes as a processor, and a memory 41 that stores various types of information. The optical sensor drive circuit 42, the pressure sensor drive circuit 31, the operation input unit 24, the display unit 23, the operation switch 5, the speaker 7, the vibration device 16, the communication device 43, and the rechargeable storage battery 22 include an input / output interface 44 and a data bus 45. Via the CPU 38.

  The optical sensor drive circuit 42 is a circuit that drives the sensor module 8. The optical sensor driving circuit 42 drives the light emitting element 25 and the light receiving element 26 constituting the sensor module 8. In the sensor module 8, light emitting elements 25 and light receiving elements 26 are two-dimensionally arranged in a lattice pattern. The light sensor driving circuit 42 turns on and off the light emitting element 25 at a predetermined location in accordance with an instruction signal from the CPU 38. The optical sensor driving circuit 42 amplifies the light intensity signal of the light received by the light receiving element 26, converts it into a digital signal, and transmits it to the CPU 38.

  The pressure sensor drive circuit 31 AD converts a voltage signal corresponding to the pressure of the pressure sensing unit 12b at the location designated by the CPU. Then, the converted digital data is transmitted to the CPU 38.

  The display unit 23 displays predetermined information according to an instruction from the CPU 38. Based on the display content, the operator operates the operation input unit 24 and the operation switch 5 to input the instruction content. This instruction content is transmitted to the CPU 38.

  The speaker 7 is an audio output device, and performs various audio outputs according to instructions from the CPU 38. The speaker 7 outputs notification sounds such as pulse measurement start and measurement end, and error occurrence.

  The vibration device 16 is a device that vibrates the exterior portion 3. Since the exterior part 3 is in contact with the subject 2, the pulse measuring device 1 can alert the subject 2 by vibrating the exterior part 3. When sound cannot be emitted from the speaker 7 due to the usage environment of the pulse measuring device 1, the subject 2 can be alerted using the vibration device 16.

  The communication device 43 is a device configured by a circuit such as a wired communication circuit or a communication control circuit. The communication connector 9 performs communication with an external device. The communication device 43 may be used as a wireless communication circuit to perform wireless communication with an external device.

  The rechargeable storage battery 22 supplies power for driving the pulse measuring device 1. The rechargeable storage battery 22 outputs data indicating the amount of charge to the CPU 38. The CPU 38 can detect the electric power stored in the rechargeable storage battery 22. The rechargeable storage battery 22 is connected to the power connector 10 and is charged by a charging unit (not shown).

  The memory 41 is a concept including a semiconductor memory such as a RAM and a ROM, and an external storage device such as a hard disk and a DVD-ROM. Functionally, a storage area for storing a program 46 in which a control procedure of the operation of the pulse measuring device 1 is described and a storage area for storing a light emitting element list 47 that is data indicating the position of the light emitting element 25 are set. Is done.

  In addition, a storage area for storing a light receiving element list 48 that is data indicating the position of the light receiving element 26 is set. In addition, the memory 41 is set with a storage area for storing biological image data 49 obtained by photographing all the light emitting elements 25 and photographing the arrangement of the blood vessels 30. In addition, a storage area for storing blood vessel position data 50 indicating the position of the blood vessel 30 calculated from the biological image data 49 is set in the memory 41. In addition, a storage area for storing measurement position data 51 that is data indicating the position of the blood vessel 30 to be measured is set in the memory 41.

  In addition, the memory 41 is set with a storage area for storing pre-correction waveform data 52, which is data indicating a change in the measured light intensity. In addition, a memory area for storing pressure data 53 indicating the pressure applied to the pressure sensing unit 12b output from the pressure sensor drive circuit 31 is set in the memory 41. In addition, a storage area for storing the corrected waveform data 54 obtained by correcting the pre-correction waveform data 52 using the pressure data 53 is set in the memory 41. In addition, the memory 41 is set with a storage area for storing the pulse data 55 that is the pulse data calculated by the CPU 38. In addition, a work area for the CPU 38, a storage area that functions as a temporary file, and other various storage areas are set.

  The CPU 38 performs control for measuring the pulse according to the program 46 stored in the memory 41. As a specific function realization unit, the CPU 38 has a light emission control unit 56. The light emission control unit 56 performs control to selectively emit light and turn off the plurality of light emitting elements 25. In addition, the CPU 38 includes a light reception control unit 57. The light reception control unit 57 performs control to acquire digital data of light intensity received by the light receiving element 26. In addition, the CPU 38 includes a pressure detection control unit 58. The pressure detection control unit 58 performs control to detect the pressure applied to the pressure-sensitive conductive rubber 12.

  In addition, the CPU 38 includes a biological image acquisition unit 61. The biological image acquisition unit 61 acquires a biological image of the measurement target portion 2 a directly below the sensor module 8. Acquisition of a biometric image is realized by appropriately using a biometric image capturing technique such as a known vein authentication technique. That is, the light emitting elements 25 of the sensor module 8 are caused to emit light all at once, and all the light receiving elements 26 perform photographing. And the biometric image which is the image | photographed image is produced | generated. The biological image acquired by the biological image acquisition unit 61 is stored in the memory 41 as biological image data 49.

  In addition, the CPU 38 includes a measurement position calculation unit 62. The measurement position calculation unit 62 performs predetermined image processing on the biological image to acquire blood vessel position data. Specifically, a vein pattern is identified from a biological image using a known image processing technique. For example, binarization and filter processing are performed for each pixel of the biological image in comparison with the reference luminance. In the biological image after processing, a pixel having a luminance lower than the reference luminance indicates the blood vessel 30, and a pixel having a luminance higher than the reference luminance indicates a non-blood vessel region. The blood vessel position data acquired by the measurement position calculator 62 is stored in the memory 41 as blood vessel position data 50.

  The measurement position calculation unit 62 selects a blood vessel 30 at a location that satisfies a predetermined selection condition as a measurement target. Here, the number of blood vessels 30 at the location to be measured may be one or multiple. The data of the blood vessel 30 at the location selected as the measurement target is stored in the memory 41 as measurement position data 51.

  The measurement position calculation unit 62 selects the light emitting element 25 and the light receiving element 26 that are driven in the measurement of the blood vessel 30 at the measurement location. Specifically, the light emitting element 25 and the light receiving element 26 located on a straight line orthogonal to the center line of the blood vessel 30 at the measurement location are selected. At this time, the light emitting element 25 and the light receiving element 26 are selected so that the distance between the measurement place and the light emitting element 25 and the distance between the measurement place and the light receiving element 26 are close to the optimum distance. The selected light emitting element 25 is stored in the memory 41 as the light emitting element list 47. The selected light receiving element 26 is stored in the memory 41 as a light receiving element list 48.

  In addition, the CPU 38 includes a measurement control unit 63. The measurement control unit 63 causes the light sensor driving circuit 42 to light the light emitting element 25. Then, the light sensor drive circuit 42 drives the light receiving element 26 to detect the light intensity of the reflected light 29. This light intensity is the light intensity of light that has passed through the blood vessel 30. Further, the measurement control unit 63 selects a place where pressure is detected in the pressure-sensitive conductive rubber 12. And the measurement control part 63 makes the pressure sensor 12b of the place selected for the pressure sensor drive circuit 31 detect a pressure.

  In addition, the CPU 38 includes a correction calculation unit 64 as a correction unit. The correction calculation unit 64 corrects the measured pressure data, the waveform data indicating the transition of the light intensity detected by the sensor module 8, and the waveform data indicating the transition of the light intensity using an expression for correcting the light intensity using the pressure as a variable. . Thereby, the correction calculation unit 64 corrects the measured waveform data to waveform data in a state where there is no suppression of the blood vessel 30 due to the pressure applied to the measured portion 2a. The corrected waveform data is stored in the memory 41 as corrected waveform data 54.

  In addition, the CPU 38 has a pulse calculation unit 65. In the corrected waveform data 54, the pulse calculating unit 65 calculates the wave number existing for one minute. The calculated wave number is stored in the memory 41 as pulse data 55. In addition, the CPU 38 includes an input / output control unit 66. The input / output control unit 66 receives inputs from the operation input unit 24, the operation switch 5, and the communication connector 9. Then, a signal corresponding to the input response is transmitted to the functional units such as the calculation units and the control unit of the CPU 38. Further, the input / output control unit 66 outputs the display content to the display unit 23 and causes the display unit 23 to display the display content. Further, the input / output control unit 66 outputs audio information to the speaker 7 and causes the speaker 7 to utter the audio information. Further, the input / output control unit 66 outputs vibration pattern information to the vibration device 16 to vibrate the vibration device 16.

  In addition, the CPU 38 has an abnormal state determination unit 67. The abnormal state determination unit 67 determines the pulse calculated by the pulse calculation unit 65 by comparing it with the determination value. When the pulse is abnormal, a warning is given to the subject 2 using the display unit 23, the speaker 7, and the vibration device 16.

  In the present embodiment, each function of the pulse measuring device 1 is realized by program software using the CPU 38. However, each function described above is realized by a single electronic circuit (hardware) that does not use the CPU 38. If possible, such an electronic circuit can also be used.

  Next, a pulse information acquisition method using the pulse measuring device 1 described above will be described with reference to FIGS. FIG. 6 is a flowchart of the pulse information acquisition method. In the flowchart of FIG. 6, step S1 corresponds to a unit mounting process. In this step, the operator installs the pulse measuring device 1 on the subject 2. Step S2 corresponds to an image acquisition process. This process is a process in which the living body image acquisition unit 61 causes all the light emitting elements 25 to emit light at once, and the light receiving element 26 captures an image of the blood vessel 30. Next, the process proceeds to step S3. Step S3 is a blood vessel position acquisition step. This step is a step of acquiring the position of the blood vessel 30 using the image taken by the measurement position calculation unit 62. Next, the process proceeds to step S4.

  Step S4 is a measurement object selection process. In this step, the measurement position calculation unit 62 selects a place suitable for measurement in the blood vessel 30 of the measurement target portion 2a. Further, the measurement position calculation unit 62 selects a place to measure. Next, the process proceeds to step S5. Step S5 is a light emitting / receiving element selection step. This step is a step in which the measurement position calculation unit 62 selects the light emitting element 25 and the light receiving element 26 that are driven during measurement. Next, the process proceeds to step S6.

  Step S6 is a measurement process. In this step, the measurement light 28 is irradiated from the light emitting element 25 to the measured portion 2a, and the light intensity of the reflected light 29 received by the light receiving element 26 is measured. Further, it is a step of detecting the pressure applied to the pressure-sensitive conductive rubber 12. Next, the process proceeds to step S7. Step S7 is a correction process. In this step, the correction calculation unit 64 corrects the influence of the pressure on the waveform data indicating the transition of the detected light intensity. Next, the process proceeds to step S8. Step S8 is a pulse calculation step. This step is a step of calculating the wave number generated during one minute using the corrected waveform data. Next, the process proceeds to step S9. Step S <b> 9 is a pulse display step, which is a step of displaying the calculated pulse data on the display unit 23. The pulse information acquisition step is completed through the above steps.

  7 to 9 are schematic diagrams for explaining the pulse information acquisition method. Next, the pulse information acquisition method will be described in detail with reference to FIGS. 7 to 9 in association with the steps shown in FIG. FIG. 7A is a diagram corresponding to the unit mounting step of step S1. As shown in FIG. 7A, in step S1, the operator installs the pulse measuring device 1 on the subject 2. The pulse measuring device 1 is installed so that the pressure-sensitive conductive rubber 12 is in contact with the subject 2. At this time, it is installed so that the touch panel 6 can be seen. Next, the operator presses the operation switch 5 to start measurement, and proceeds to step S2.

  FIG. 7B and FIG. 7C are diagrams corresponding to the image acquisition process of step S2. As shown in FIG. 7B, the measured part 2a is photographed in step S2. The biological image acquisition unit 61 outputs an instruction signal for lighting the light emitting element 25 to the light emission control unit 56. The light emission control unit 56 outputs an instruction signal for lighting the light emitting element 25 to the optical sensor driving circuit 42. The optical sensor driving circuit 42 drives the light emitting element 25 to light it. The measurement light 28 emitted from the light emitting element 25 irradiates the measured portion 2a. The measurement light 28 is irregularly reflected by the measured portion 2 a and becomes reflected light 29.

  Next, the biological image acquisition unit 61 outputs an instruction signal for imaging to the light reception control unit 57. The light reception control unit 57 outputs an instruction signal for driving the light receiving element 26 to the optical sensor driving circuit 42. The optical sensor drive circuit 42 drives the light receiving element 26 to convert the light intensity of the input light into light reception data by AD (Analog Digital) and outputs it to the light reception control unit 57. Since the light receiving elements 26 are arranged in a lattice pattern, the light receiving elements 26 function as an imaging camera. As shown in FIG. 7C, the received light data forms a biological image 68 in which the shape of the blood vessel 30 is photographed. The light reception control unit 57 stores the biological image 68 in the memory 41 as the biological image data 49.

  FIG. 7C is a diagram corresponding to the image acquisition process in step S2 and the blood vessel position acquisition process in step S3. A biological image 68 shown in FIG. 7C is an image of the measured portion 2a output from the sensor module 8. The biological image 68 is obtained as a two-dimensional image with pixels corresponding to the arrangement of the light receiving elements 26 in the sensor module 8. The blood vessel 30 absorbs near infrared rays more easily than the non-blood vessel portion. For this reason, in the living body image 68, the blood vessel image 68a that is an image of the blood vessel 30 is darker and darker than the non-blood vessel image 68b that is an image of the non-blood vessel portion. In step S <b> 3, the measurement position calculation unit 62 extracts a blood vessel pattern by extracting a portion where the luminance is low in the biological image 68. That is, the measurement position calculation unit 62 calculates whether the luminance of each pixel constituting the biological image 68 is equal to or less than a predetermined threshold value. Then, the measurement position calculation unit 62 determines whether or not the blood vessel 30 exists immediately below the corresponding light receiving element 26. By this procedure, the measurement position calculation unit 62 detects the position of the blood vessel 30.

  FIG. 7D is a diagram corresponding to the measurement object selection step in step S4 and is a schematic diagram showing blood vessel position information obtained based on the biological image 68. The information on the blood vessel position is information indicating whether the blood vessel 30 is a non-blood vessel portion 69 for each pixel constituting the living body image 68. In step S <b> 4, the measurement position calculation unit 62 selects the measurement site 70 that is the measurement location of the blood vessel 30. The measurement position calculation unit 62 selects the measurement site 70 so as to satisfy the following selection condition. The selection condition is “a part other than a branching part or a joining part of the blood vessel 30 or an end part of the image, and has a predetermined length and width”.

  In the branching / merging portion 30a of the blood vessel 30, the rate of change that changes according to the pressure changes more complicatedly than the straight line portion, so that it is difficult to correct. Therefore, it is difficult to correct with high accuracy. For this reason, the measurement site 70 is selected from the portion of the blood vessel 30 excluding the branching / merging portion 30a.

  Further, in the end portion 30b of the blood vessel 30 in the living body image 68, the structure of branching or merging of blood vessels in the vicinity of the outside of the image is unknown. For this reason, in order to avoid the possibility of a decrease in measurement accuracy due to the same reason as described above, the measurement site 70 is selected from the blood vessel 30 excluding the end 30b of the biological image 68.

  FIG. 8A is a diagram corresponding to the light emitting / receiving element selecting step in step S5. As shown in FIG. 8A, in step S5, the measurement position calculator 62 selects the light emitting element 25 and the light receiving element 26 that are driven during measurement. At this time, the light emitting element 25 and the light receiving element 26 are selected so that the measurement site 70 is positioned between the light emitting element 25 and the light receiving element 26. The light receiving element 26 detects light transmitted through the measurement site 70.

  The measurement position calculation unit 62 sets the positions of the light emitting element 25 and the light receiving element 26 so that the measurement site 70 is located at the center between the light emitting element 25 and the light receiving element 26. Further, the measurement position calculation unit 62 sets the positions of the light emitting element 25 and the light receiving element 26 so that the distance between the light emitting element 25 and the light receiving element 26 approaches a predetermined optimum distance 71.

  FIG. 8B and FIG. 8C are diagrams corresponding to the measurement process of step S6. This figure is a schematic diagram for explaining the propagation of light in a living tissue, and shows a cross-sectional view along the depth direction. Hatching is omitted for easy viewing of the figure. As shown in FIG. 8B, in step S6, the light emitting element 25 emits the measurement light 28 with a predetermined directivity characteristic. A cell tissue surrounding the blood vessel 30 in the subject 2 is defined as a general tissue 2d. The general tissue 2d is a skin tissue, a fat element, a muscle tissue or the like, and is a cell tissue located around the blood vessel 30 to be measured. A part of the measurement light 28 passes through the blood vessel 30 through the general tissue 2d. A part of the measurement light 28 passes through the blood vessel 30 after being scattered by the general tissue 2d. A part of the measurement light 28 passes through the blood vessel 30 and then enters the light receiving element 26 as reflected light 29. A part of the measurement light 28 does not pass through the blood vessel 30 and is input to the light receiving element 26 as reflected light 29.

  FIG. 8C is a diagram in which light input to the light receiving element 26 among the light emitted from the light emitting element 25 is simulated by the ray tracing method. As shown in FIG. 8C, the measurement light 28 irradiated from the light emitting element 25 is diffusely reflected in the living tissue, and a part of the irradiated light reaches the light receiving element 26. An optical path, which is a light propagation path, mainly passes through a banana-shaped region sandwiched between two arcs. The optical path has a maximum width and a deeper width in the vicinity of the approximate center between the light emitting element 25 and the light receiving element 26. As the distance between the light emitting element 25 and the light receiving element 26 increases, the depth through which light passes increases.

  In order to improve the measurement accuracy, it is desirable that light transmitted through more blood vessels 30 is received by the light receiving element 26. For this reason, it is desirable that the measurement site 70 to be measured is located approximately at the center between the light emitting element 25 and the light receiving element 26. When the depth from the skin surface to the measurement site 70 is the blood vessel depth 72, an optimum distance 71 corresponding to the assumed blood vessel depth 72 is determined. The optimum distance 71, which is the optimum distance between the light emitting element 25 and the light receiving element 26, is a distance approximately twice the blood vessel depth 72. For example, when the blood vessel depth 72 is about 3 mm, the optimum distance 71 is about 5 to 6 mm.

  The wavelength of the measurement light 28 emitted from the light emitting element 25 is a wavelength that is absorbed by blood. Since a part of the reflected light 29 detected by the light receiving element 26 passes through the blood vessel 30, a part of the reflected light 29 is absorbed by the blood in the blood vessel 30. The pressure in the blood vessel 30 changes according to the movement of the heart of the subject 2. When the pressure in the blood vessel 30 increases, the diameter of the blood vessel 30 increases. Thereby, since the distance that the measurement light 28 passes through the blood becomes long, the amount of light absorbed by the blood becomes large. And the light intensity which the light receiving element 26 detects becomes small. On the other hand, when the pressure in the blood vessel 30 decreases, the diameter of the blood vessel 30 decreases. As a result, the amount of light absorbed by the blood is reduced, and the light intensity detected by the light receiving element 26 is increased. Accordingly, the waveform of the light intensity detected by the light receiving element 26 is a waveform reflecting the motion of the heart.

  In step S <b> 6, the pressure detection control unit 58 detects the pressure applied to the pressure-sensitive conductive rubber 12 by driving the pressure sensor drive circuit 31. At this time, the pressure sensor drive circuit 31 detects the pressure in the pressure-sensitive part 12b located between the light emitting element 25 and the light receiving element 26 driven by the optical sensor drive circuit 42. Then, the pressure applied to the subject 2 is detected in the optical path through which the measurement light 28 and the reflected light 29 pass. The measurement light 28 and the reflected light 29 are light that passes through the blood vessel 30, and the pressure sensing unit 12 b detects the pressure applied to the place where the light that passes through the blood vessel 30 passes through the subject 2. Thereby, the pressure sensitive part 12b can detect the pressure applied to the blood vessel 30 and the tissue around the blood vessel 30.

  FIG. 9A to FIG. 9C are diagrams corresponding to the correction process in step S7. In FIG. 9A, the vertical axis indicates the light intensity detected by the light receiving element 26, and the upper side in the figure is stronger than the lower side. The horizontal axis shows the passage of time, and the time changes from the left side to the right side in the figure. A pre-correction waveform 73 as the first light intensity indicates the output of the light receiving element 26. The pre-correction waveform 73 is a combination of a short cycle waveform and a long cycle waveform. The short-cycle waveform is affected by the heartbeat. The long cycle waveform is a waveform due to the influence of the blood vessel 30 being pressed by the pulse measuring device 1.

  In FIG. 9B, the vertical axis indicates the pressure detected by the pressure-sensitive conductive rubber 12, and the pressure is higher on the upper side than on the lower side in the figure. The horizontal axis shows the passage of time, and the time changes from the left side to the right side in the figure. A pressure transition line 74 as a pressure indicates an output of the pressure sensor drive circuit 31. When the pressure transition line 74 is high, the blood pressure of the blood vessel 30 being pressed against the pulse measuring device 1 is high. At this time, since the cross-sectional area of the blood vessel 30 is reduced, the measurement light 28 is hardly absorbed by blood. Accordingly, the light intensity of the pre-correction waveform 73 is increased.

ここで、μ_aT：生体組織の光吸収係数、μ_aB：血液の光吸収係数、ｄ_T：圧力がかからない状態で生体組織を通過する光の光路長、ｄ_B：圧力がかからない状態で血液を通過する光の光路長とする。 In step S <b> 7, the correction calculation unit 64 corrects the pre-correction waveform 73 using the pressure transition line 74. Next, a correction method using mathematical formulas will be described. The incident light intensity output from the light emitting element 25 is defined as _Io . The detected light intensity detected by the light receiving element 26 when no pressure is applied to the blood vessel 30 is I. (Equation 2) is established according to Lambert-Beer's law.

Here, μ _aT : light absorption coefficient of biological tissue, μ _aB : light absorption coefficient of blood, d _T : optical path length of light passing through the biological tissue without pressure, d _B : blood without pressure Let it be the optical path length of the light passing through.

ここで、Δｄ_B：圧力がかかった状態で血液を通過する光の光路長の変化分とする。 The detection light intensity of the light receiving element 26 detects when the pressure applied to the vessel 30 and I _m. Uncorrected waveform 73 shows the transition of I _m. According to Lambert-Beer's law, (Equation 3) further holds.

Here, Δd _B is a change in the optical path length of light passing through blood in a state where pressure is applied.

(Equation 3) can be transformed as (Equation 4).

(Expression 5) is obtained by substituting (Expression 2) into (Expression 4).

On the other hand, the pressure applied to the blood vessel 30 is P, and the elastic coefficient of the blood vessel 30 is E. (Equation 6) is established by Hooke's law.

Substituting [Delta] d _B by modifying (equation 6) [Delta] d _B of the second term on the right side of (Equation 5) (Equation 7) is obtained.

Substituting (Equation 7) into (Equation 5) and transforming it yields (Equation 8).

（式１）における係数μａＴ、μａＢ、Ｅを予め実験を行って求めておく。（式１）において、Ｐ（ｔ）が大きくなると実際に計測で得られるＩｍ（ｔ）は大きくなるが、これに乗算され指数関数で表現される補正項が小さくなるので、Ｉ（ｔ）の変動は小さくなる。圧力推移線７４及び（式１）を用いて補正前波形７３を補正する。 Let I be I (t), which is a function of time, and Im be Im (t), which is a function of time. Further, P is also assumed to be P (t) that is a function of time. (Expression 8) becomes (Expression 1).

The coefficients μaT, μaB, and E in (Expression 1) are obtained by conducting experiments in advance. In (Equation 1), when P (t) increases, Im (t) actually obtained by measurement increases, but the correction term expressed by an exponential function when multiplied by this decreases, so I (t) The fluctuation will be smaller. The pre-correction waveform 73 is corrected using the pressure transition line 74 and (Equation 1).

  In FIG. 9C, the vertical axis indicates the corrected light intensity, and the light intensity is higher on the upper side than on the lower side in the figure. The horizontal axis shows the passage of time, and the time changes from the left side to the right side in the figure. A corrected waveform 75 as the second light intensity is a waveform obtained by correcting the uncorrected waveform 73. In the corrected waveform 75, a waveform having a short period is affected by the heartbeat. In the corrected waveform 75, the waveform due to the effect of the blood vessel 30 being pressed by the pulse measuring device 1 is excluded.

  FIG. 9D is a diagram corresponding to the pulse calculation step of step S8. In FIG. 9D, the vertical axis indicates the intensity of the spectrum, and the upper side in the figure indicates a higher intensity than the lower side. The horizontal axis indicates the frequency, and the right side in the figure is higher than the left side. In step S8, the corrected waveform 75 is Fourier transformed. As a result, a frequency distribution 76 is obtained. The pulse frequency 77 is obtained by obtaining the frequency at the apex of the frequency distribution 76. Since the pulse is the number of pulses per minute and the pulse frequency 77 is the number of pulses per second, the pulse frequency 77 is calculated by multiplying the pulse frequency 77 by 60 times.

  In the pulse display step of step S9, the pulse is displayed on the display unit 23. The display unit 23 may display the change in pulse over time in the form of a graph. In addition, the pulse may be compared with the determination value, and a warning sound may be emitted from the speaker 7 when the pulse exceeds the determination value. The process of acquiring pulse information from the subject 2 is completed by the above process.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, the pulse measuring device 1 includes the light receiving element 26, the pressure sensitive unit 12 b, and the correction calculation unit 64. The light receiving element 26 detects and outputs the light intensity of the reflected light 29 that has passed through the blood vessel 30 in the subject 2. The pressure sensing unit 12b detects and outputs the magnitude of the pressure with which the blood vessel 30 is pressed. The correction calculation unit 64 corrects the light intensity using the magnitude of the pressure with which the blood vessel 30 is pressed. Then, the correction calculation unit 64 outputs the light intensity when no pressure is applied to the blood vessel 30.

  The blood vessel 30 of the subject 2 is elastic and deforms when pressed by the pulse measuring device 1. When the blood vessel 30 is deformed, the amount of light passing through the blood vessel 30 changes. For this reason, the light intensity output from the light receiving element 26 varies as the pressure at which the pulse measuring device 1 pushes the subject 2 varies. The correction calculation unit 64 corrects and outputs the light intensity using the magnitude of the pressure with which the blood vessel 30 is pressed. The corrected light intensity is the light intensity when no pressure is applied to the blood vessel 30. That is, the corrected light intensity is a measurement value obtained by removing the influence of the blood vessel 30 being pressed and deformed by the pulse measuring device 1. Therefore, since the pulse measuring device 1 analyzes the information of the blood flowing through the blood vessel 30 using the transition data of the light intensity when no pressure is applied to the blood vessel 30, the information of the subject 2 can be obtained with high accuracy. .

  (2) According to the present embodiment, the correction calculation unit 64 corrects the pre-correction waveform 73 using (Equation 1) and the detected pressure transition line 74. The blood vessel 30 is deformed by the pressure, and the distance through which the light passes is changed by the deformation of the blood vessel 30. The ratio between the distance that light passes through the non-blood vessel portion 69 and the distance that light passes through the blood vessel 30 changes. (Equation 1) corrects the light intensity that changes with the change in the ratio of light passing through the non-blood vessel portion 69 and the blood vessel 30 by pressure. Therefore, the correction calculation unit 64 can reliably correct the light intensity that changes due to the pressure applied to the subject 2.

  (3) According to this embodiment, the pressure-sensitive conductive rubber 12 is located between the subject 2 and the light receiving element 26. Therefore, when the light receiving element 26 presses the subject 2, the pressure-sensitive conductive rubber 12 receives a pressing force. Therefore, the pressure-sensitive conductive rubber 12 can detect the force with which the subject 2 is pressed. The pressure-sensitive conductive rubber 12 includes a light passage portion 12a, and the light passage portion 12a allows the measurement light 28 and the reflected light 29 to pass therethrough. Therefore, the light receiving element 26 can detect the reflected light 29 output from the subject 2 and passing through the pressure-sensitive conductive rubber 12.

  (4) According to this embodiment, the pressure-sensitive conductive rubber 12 is located between the subject 2 and the light receiving element 26. When a hard member comes into contact with the subject 2, the hard member may partially press the subject 2. At this time, a high pressure is locally applied to the subject 2, and the subject 2 may be marked. In the present embodiment, the pressure-sensitive conductive rubber 12 has elasticity. Therefore, it can suppress that the subject 2 leaves a mark.

  (5) According to the present embodiment, the pressure sensitive part 12b detects the pressure at the place surrounding the light passage part 12a. Since the sensor module 8 is a rigid plate-like member, the pressure applied to the pressure-sensitive portion 12b is substantially the same as the pressure applied to the light passage portion 12a. When the light emitting element 25 used for measurement and the light receiving element 26 are separated from each other, the pressure applied to the subject 2 is detected by using the pressure sensitive part 12b disposed between the light emitting element 25 used and the light receiving element 26. To do. Thereby, the pressure-sensitive conductive rubber 12 can detect the pressure applied to the subject 2 at the place where the measurement light 28 and the reflected light 29 pass through the subject 2. Accordingly, it is possible to detect the pressure applied to the subject 2 where light passes.

  (6) According to this embodiment, the pressure sensitive part 12b is installed around the light passage part 12a. The pressure sensitive part 12b is a light shielding part that shields light. Then, the pressure-sensitive portion 12 b blocks light that propagates repeatedly by reflection inside the pressure-sensitive conductive rubber 12. Therefore, light that does not pass through the subject 2 can be prevented from being input to the light receiving element 26.

  (7) According to the present embodiment, the light intensity of light that has passed through the blood vessel 30 in the subject 2 is detected. This light intensity waveform is a pre-correction waveform 73. Furthermore, the magnitude of the pressure with which the blood vessel 30 is pressed is detected. The corrected waveform 75 is calculated by correcting the uncorrected waveform 73 using the pressure with which the blood vessel 30 is pressed. The corrected waveform 75 is a waveform of light intensity when no pressure is applied to the blood vessel 30. Therefore, in this embodiment, since the pulse of the blood flowing through the blood vessel 30 can be detected with the corrected waveform 75 when no pressure is applied to the blood vessel 30, the pulse of the subject 2 can be detected with high accuracy.

(Second Embodiment)
Next, an embodiment of a pulse measuring device will be described with reference to FIG. FIG. 10 is a diagram showing a correlation table used for correction by the correction calculation unit. This embodiment is different from the first embodiment in that the correction calculation unit 64 corrects the pre-correction waveform 73 using a correlation table instead of (Equation 1). Note that description of the same points as in the first embodiment is omitted.

  That is, in the present embodiment, the correction calculation unit 64 corrects the pre-correction waveform 73 using the correlation table 80 shown in FIG. In the correlation table 80, pressure values 81 of P0 to P100 are described in the leftmost column of the table. In the correlation table 80, light intensities 82 of Im0 to Im100 are described in the top row of the table. In the column of the place where the row of the predetermined pressure value 81 and the column of the predetermined light intensity 82 intersect, the light intensity 83 obtained by correcting each light intensity 82 at the predetermined pressure value 81 is described. The light intensity 83 is a value obtained by estimating the light intensity 82 when the pressure value 81 is 0. The pressure value 81 of 0 indicates a state in which the pressure applied to the measured portion 2a is only atmospheric pressure.

  The correction calculation unit 64 inputs the pre-correction waveform 73 and the pressure transition line 74 from the memory 41. The correction calculation unit 64 sets the pre-correction waveform 73 at a measured time as the light intensity 82 and the pressure transition line 74 as the pressure value 81. Then, the correction calculation unit 64 calculates the light intensity 83 at the place where the row of the pressure value 81 and the column of the light intensity 82 intersect to obtain the light intensity of the corrected waveform 75 at a certain time. The correction calculation unit 64 calculates the light intensity 83 obtained by correcting the pre-correction waveform 73 by changing the measured time. Then, the correction calculation unit 64 corrects all the measured light intensities to complete the corrected waveform 75.

  The data described in the correlation table 80 is data measured in advance through experiments. Therefore, the corrected waveform 75 can be calculated by using the pre-correction waveform 73, the pressure transition line 74, and the correlation table 80.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, the pre-correction waveform 73 is corrected using the correlation table 80 and the detected pressure transition line 74. The correlation table 80 shows the correlation of the corrected light intensity 83 with respect to the pressure value 81 detected by the pressure-sensitive conductive rubber 12 and the light intensity 82 detected by the light receiving element 26. The correlation table 80 shows the correlation that has been confirmed in advance. Therefore, the correction calculation unit 64 can reliably correct the pre-correction waveform 73 and obtain the corrected waveform 75.

(Third embodiment)
Next, an embodiment of the blood pressure measurement device will be described with reference to FIGS. This embodiment is different from the first embodiment in that a laser Doppler blood flow meter is installed instead of the sensor module 8, and a control device having a function of calculating blood pressure is installed instead of the control device 37. It is in. Note that description of the same points as in the first embodiment is omitted.

  FIG. 11 is an electrical control block diagram of the blood pressure measurement device. In the present embodiment, the blood pressure measurement device 86 in FIG. 11 includes a control device 87 that controls the operation of the blood pressure measurement device 86. The control device 87 includes a CPU 88 that performs various arithmetic processes as a processor, and a memory 89 that stores various information. The optical sensor drive circuit 90, the pressure sensor drive circuit 31, the operation input unit 24, the display unit 23, the operation switch 5, the speaker 7, the vibration device 16, the communication device 43, and the rechargeable storage battery 22 include an input / output interface 44 and a data bus 45. Via the CPU 88.

  The optical sensor drive circuit 90 is a circuit that drives the sensor module 91. The optical sensor driving circuit 90 drives the light emitting element 92 and the light receiving element 93 that constitute the sensor module 91. In the sensor module 91, light emitting elements 92 and light receiving elements 93 are two-dimensionally arranged in a lattice pattern. The optical sensor driving circuit 90 turns on and off the light emitting element 92 in accordance with an instruction signal from the CPU 88. The optical sensor driving circuit 90 amplifies the light intensity signal received by the light receiving element 93, separates it into a high frequency component and a low frequency component, converts it into a digital signal, and transmits it to the CPU 88.

  The memory 89 is a concept including a semiconductor memory such as a RAM and a ROM, and an external storage device such as a hard disk and a DVD-ROM. Functionally, a storage area for storing a program 94 in which a control procedure of the operation of the blood pressure measurement device 86 is described and a storage area for storing a light emitting element list 47 that is data indicating the position of the light emitting element 92 are set. Is done. In addition, a storage area for storing a light receiving element list 48 that is data indicating the position of the light receiving element 93 is set. The arrangement of the light emitting element 92 and the light receiving element 93 is the same as the arrangement of the light emitting element 25 and the light receiving element 26 in the first embodiment.

  In addition, a memory area for storing the biological image data 49, the blood vessel position data 50, the measurement position data 51, the pre-correction waveform data 52, the pressure data 53, and the post-correction waveform data 54 is set in the memory 89. In addition, a memory area for storing volume pulse wave data 95 that is data of the peak value of the volume pulse wave obtained from the corrected waveform is set in the memory 89. In addition, the memory 89 is set with a storage area for storing blood flow data 96 that is blood flow data calculated by the CPU 88. In addition, a storage area for storing blood pressure data 97 that is blood pressure data calculated by the CPU 88 is set. In addition, a work area for the CPU 88, a storage area that functions as a temporary file, and other various storage areas are set.

  The CPU 88 performs control for measuring blood pressure in accordance with a program 94 stored in the memory 89. As a specific function realization unit, the CPU 88 has a light emission control unit 98. The light emission control unit 98 performs control to selectively emit light and turn off the plurality of light emitting elements 92. In addition, the CPU 88 includes a light reception control unit 99. The light reception control unit 99 performs control to acquire digital data of light intensity received by the plurality of light receiving elements 93. In addition, the CPU 88 includes a pressure detection control unit 58. The pressure detection control unit 58 performs control to detect the pressure applied to the pressure-sensitive conductive rubber 12.

  In addition, the CPU 88 includes a biological image acquisition unit 61 and a measurement position calculation unit 62. The biological image acquisition unit 61 and the measurement position calculation unit 62 have the same functions as those in the first embodiment, and select the light emitting element 92 and the light receiving element 93 at appropriate locations for measurement. The selected light emitting element 92 is stored in the memory 89 as the light emitting element list 47. The selected light receiving element 93 is stored in the memory 89 as the light receiving element list 48.

  In addition, the CPU 88 includes a measurement control unit 100. The measurement control unit 100 causes the light sensor driving circuit 90 to light the light emitting element 92. Then, the optical sensor driving circuit 90 drives the light receiving element 93 to detect the light intensity of the reflected light 29. This light intensity is the light intensity of light that has passed through the blood vessel 30. Further, the measurement control unit 100 selects a place where pressure is detected in the pressure-sensitive conductive rubber 12. And the measurement control part 100 makes a pressure sensor 12b of the place selected for the pressure sensor drive circuit 31 detect a pressure.

  In addition, the CPU 88 includes a correction calculation unit 64. The waveform data corrected by the correction calculation unit 64 is stored in the memory 89 as corrected waveform data 54.

  In addition, the CPU 88 includes a volume pulse wave calculation unit 101. The volume pulse wave calculation unit 101 detects two peaks in one cycle of the corrected waveform 75. Then, the ratio of the light intensity at the two peaks is calculated. The calculation result is stored in the memory 89 as volume pulse wave data 95. In addition, the CPU 88 includes a blood flow rate calculation unit 102. The blood flow calculation unit 102 calculates the blood flow using the laser Doppler method. The calculation result is stored in the memory 89 as blood flow data 96. In addition, the CPU 88 includes a blood pressure calculation unit 103. The blood pressure calculation unit 103 calculates blood pressure using the volume pulse wave data 95 and the blood flow data 96. The calculation result is stored in the memory 89 as blood pressure data 97. In addition, the CPU 88 includes an input / output control unit 66 and an abnormal state determination unit 67.

  In the present embodiment, each function of the blood pressure measurement device 86 is realized by program software using the CPU 88. However, each function described above is realized by a single electronic circuit (hardware) that does not use the CPU 88. If possible, such an electronic circuit can also be used.

  FIG. 12 is an electric control block diagram of the optical sensor driving circuit and the sensor module. The optical sensor driving circuit 90 includes a light emission amplification circuit 106, and an input terminal of the light emission amplification circuit 106 is connected to the light emission control unit 98 of the control device 87 by wiring. The sensor module 91 includes a light emitting element 92, and an output terminal of the light emitting amplifier circuit 106 is connected to the light emitting element 92 by wiring.

  The number of light emitting amplifier circuits 106 is the same as the number of light emitting elements 92, and the optical sensor driving circuit 90 can individually turn on and off the light emitting elements 92. And the light emission control part 98 controls lighting of the light emitting element 92 separately. The light emitting element 92 is a laser diode, and the measurement light 107 that emits light is laser light. The wavelength of the measurement light 107 is not particularly limited, but is preferably 700 nm to 900 nm with 800 nm as the center. Since the measurement light 107 is easily absorbed by blood at wavelengths in this range, the sensor module 91 can easily detect the blood flow waveform. In the present embodiment, for example, the wavelength of the measurement light 107 is set to 780 nm.

  The optical sensor driving circuit 90 includes a light receiving amplification circuit 108. The sensor module 91 includes a light receiving element 93, and an input terminal of the light receiving amplification circuit 108 is connected to the light receiving element 93 by wiring. The number of light receiving amplifier circuits 108 is the same as the number of light receiving elements 93, and the optical sensor driving circuit 90 can drive the light receiving elements 93 individually. Then, the light receiving amplifier circuit 108 inputs the output of the light receiving element 93 individually.

  The output terminal of the light receiving amplifier circuit 108 is connected to the high-frequency bandpass filter 109 and the lowpass filter 110 by wiring. The high-pass bandpass filter 109 is a filter that passes a frequency of several kHz to several tens of kHz. The output terminal of the high-frequency bandpass filter 109 is connected to the blood flow amplification circuit 111 by wiring. The output terminal of the blood flow amplification circuit 111 is connected to the blood flow AD conversion circuit 112 by wiring. The sampling frequency of the blood flow AD conversion circuit 112 is set to several hundred kHz. The output terminal of the blood flow AD conversion circuit 112 is connected to the light reception control unit 99 of the control device 87 by wiring.

  The low-pass filter 110 is a filter that passes a frequency of several kHz or less. The output terminal of the low-pass filter 110 is connected to the volume wave amplification circuit 113 by wiring. The output terminal of the volume wave amplification circuit 113 is connected to the volume wave AD conversion circuit 114 by wiring. The sampling frequency of the volumetric wave AD converter circuit 114 is set to several kHz. The output terminal of the volume wave AD conversion circuit 114 is connected to the light reception control unit 99 of the control device 87 by wiring.

  The measurement light 107 emitted from the light emitting element 92 to the measured part 2a is scattered by the general tissue 2d. The light scattered by the general tissue 2d is defined as first scattered light. The frequency of the first scattered light is the same as that of the measurement light 107. On the other hand, the measurement light 107 scattered in the blood vessel 30 is set as the second scattered light. The wavelength of the second scattered light slightly changes according to the blood flow velocity. The change in the wavelength of the second scattered light is caused by the influence of the Doppler effect due to blood flow. Since the first scattered light and the second scattered light have slightly different wavelengths, the first scattered light and the second scattered light interfere with each other and a beat occurs. This beat is called a light beat.

  The frequency of the measuring beam 107 is about 400 THz, which exceeds the response speed of the light receiving element 93. The frequency of the optical beat is several kHz to several tens kHz, and the light receiving element 93 is a frequency that can be converted into an electric signal. The high band pass filter 109 extracts an optical beat signal from the reflected light 29. Then, the blood flow amplification circuit 111 amplifies the optical beat, and the blood flow AD conversion circuit 112 converts the optical beat into digital data. The blood flow amplification circuit 111 and the blood flow AD conversion circuit 112 have a resolution for processing an optical beat signal, and the optical sensor driving circuit 90 outputs optical beat waveform data to the control device 87.

  The diameter of the blood vessel 30 varies according to the movement of the heart. Thereby, the blood vessel 30 repeats contraction and expansion to become a pulse. A waveform capable of observing the pulse of the blood vessel 30 is referred to as a volume pulse wave. The low-pass filter 110 extracts a volume pulse wave signal. Then, the volume wave amplification circuit 113 amplifies the volume pulse wave, and the volume wave AD conversion circuit 114 converts the volume pulse wave into digital data. The optical sensor driving circuit 90 outputs the volume pulse wave waveform data to the control device 87.

  Next, a blood pressure information acquisition method using the above-described blood pressure measurement device 86 will be described with reference to FIGS. FIG. 13 is a flowchart of the blood pressure information acquisition method. In the flowchart of FIG. 13, Steps S1 to S5 are the same as those in the first embodiment, and a description thereof will be omitted. After step S5, the process proceeds to step S11.

  Step S11 is a measurement process. In this step, the measurement light 107 is irradiated from the light emitting element 92 to the measured portion 2 a, and an optical beat is extracted from the reflected light 29 received by the light receiving element 93. Further, it is a step of extracting a volume pulse wave from the reflected light 29. Next, the process proceeds to step S7. Step S7 is a correction process. In this step, the correction calculation unit 64 corrects the influence of pressure on the detected waveform data of the volume pulse wave. In step S7, the same calculation as in the first embodiment is performed. And the correction calculating part 64 correct | amends a volume pulse wave using the pressure transition line 74. FIG. Next, the process proceeds to step S12. Step S12 is a blood pressure calculation step. This step is a step of calculating blood pressure using the corrected waveform data and optical beat data.

  In the blood pressure calculation step in step S12, first, the blood flow is calculated from the waveform data of the optical beat. The blood flow calculation unit 102 performs Fourier transform on the optical beat waveform. As a result, an optical beat power spectrum is obtained. The power spectrum shows the frequency distribution of the square value of the amplitude in the optical beat waveform. Let the power spectrum be P (f). f indicates a frequency, and P (f) is a function having the frequency as a parameter.

ここで、ｆ１、ｆ２：高域バンドパスフィルター１０９の遮断周波数、Ｋ_Q：実験から得られた定数である。 Next, the blood flow rate calculation unit 102 calculates the mean square of the light intensity in one cycle of the volume pulse wave. This calculation result is defined as <I ² >. Next, the blood flow rate calculation unit 102 calculates the blood flow rate Q of the blood vessel 30 using (Equation 9).

Here, f1 and f2 are cutoff frequencies of the high-frequency bandpass filter 109, and K _Q are constants obtained from experiments.

  FIG. 14 is a diagram for explaining volume pulse waves. In FIG. 14, the horizontal axis indicates the passage of time, and the time changes from the left side to the right side in the figure. The vertical axis indicates the blood vessel diameter, and the upper side in the figure is thicker than the lower side. The plethysmogram 115 shows a change in blood vessel diameter over time. When the blood vessel diameter is large, the amount of measurement light 107 absorbed is larger than when the blood vessel diameter is thin. Therefore, the output of the volume wave amplifying circuit 113 and the blood vessel diameter have a negative correlation. The volume pulse wave calculation unit 101 calculates the volume pulse wave 115 using the output waveform of the volume wave amplification circuit 113.

  A first peak 117 and a second peak 118 exist during one period 116 of the volume pulse wave 115. The first peak 117 is a change caused when the blood vessel 30 swells when blood is pumped from the heart. The second peak 118 is a change that occurs when the blood pumped from the heart propagates to the periphery of the blood vessel 30 and is reflected back to return the blood vessel 30 to swell.

The blood vessel diameter 119 of the first peak 117 is P1, and the blood vessel diameter 120 of the second peak 118 is P2. The vascular resistance is R. The vascular resistance is a fluid resistance of blood flowing through the blood vessel 30. At this time, R is calculated by (Equation 10).
R = K (P2 / P1) (Formula 10)
Here, K is a constant obtained from an experiment.

When the blood pressure of the subject 2 is Pr, Pr is calculated by (Equation 11).
Pr = Q × R (Formula 11)
As described above, the blood pressure measurement device 86 measures the blood pressure of the subject 2 using the optical beat and volume pulse wave output from the optical sensor drive circuit 90. Returning to FIG. 13, after step S12, the process proceeds to step S13. Step S <b> 13 is a blood pressure display step, which is a step of displaying the calculated blood pressure data on the display unit 23. In the blood pressure display step of step S13, the blood pressure of the subject 2 is displayed on the display unit 23. The process of acquiring blood pressure information from the subject 2 is completed by the above process.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, the same calculation as that of the first embodiment is performed in the correction process of step S7. And the correction calculating part 64 correct | amends a volume pulse wave using the pressure transition line 74. FIG. Therefore, the volume pulse wave calculation unit 101 can accurately detect P1 and P2. As a result, the blood pressure measurement device 86 can accurately measure the blood pressure of the subject 2.

(Fourth embodiment)
Next, an embodiment of a pulse measuring device will be described with reference to FIG. FIG. 15 is an exploded perspective view showing the structure of the pulse measuring device. This embodiment is different from the first embodiment in that the sensor module 8 is located between the subject 2 and the pressure-sensitive conductive rubber. Note that description of the same points as in the first embodiment is omitted.

  That is, in this embodiment, as shown in FIG. 15, the pulse measuring device 123 includes a back cover 11, a sensor module 8, a pressure-sensitive conductive rubber 124 as a pressure detection unit, a circuit unit 14, a spacer 15, The touch panel 6, the vibration device 16, and the front case 17 are stacked in this order. The sensor module 8, the pressure-sensitive conductive rubber 124, the circuit unit 14, the spacer 15, the touch panel 6, the vibration device 16, and the like are housed in the exterior portion 3.

  The pressure-sensitive conductive rubber 124 has a low resistance when subjected to pressure in the same manner as the pressure-sensitive conductive rubber 12 of the first embodiment. Accordingly, the pressure applied to the pressure-sensitive conductive rubber 124 can be detected by detecting the resistance of the pressure-sensitive conductive rubber 124. The terminal of the pressure sensitive conductive rubber 124 is connected to the element substrate 8 a of the sensor module 8, and the pressure sensor driving circuit 31 detects a change in electric resistance in the pressure sensitive conductive rubber 124. A pressure detector 125 is constituted by the sensor module 8 and the pressure-sensitive conductive rubber 124 and the like.

  The sensor module 8 is connected to the circuit board 18 by a flexible cable 126. A signal is transmitted between the pressure-sensitive conductive rubber 124 and the circuit unit 14 by the flexible cable 126. Then, the light intensity data of the reflected light 29 output from the optical sensor driving circuit 42 and the pressure data applied to the pressure-sensitive conductive rubber 124 output from the pressure sensor driving circuit 31 are input to the circuit board 18 via the flexible cable 126. Is done.

  The sensor module 8 is exposed from the first window portion 11 a of the back cover 11. The sensor module 8 is located between the subject 2 and the pressure-sensitive conductive rubber 124. Accordingly, since the pressure-sensitive conductive rubber 124 does not exist between the subject 2 and the sensor module 8, the reflected light 29 is input to the sensor module 8 without passing through the pressure-sensitive conductive rubber 124. Accordingly, it is possible to prevent the reflected light 29 output from the subject 2 from passing through the pressure-sensitive conductive rubber 124 and attenuated.

Note that the present embodiment is not limited to the above-described embodiment, and various changes and improvements can be added by those having ordinary knowledge in the art within the technical idea of the present invention. A modification will be described below.
(Modification 1)
In the first embodiment, the pressure applied by the pressure-sensitive conductive rubber 12 to the measured portion 2a is detected. A piezoelectric rubber may be used instead of the pressure-sensitive conductive rubber 12. Piezoelectric rubber is obtained by dispersing piezoelectric particles in an elastic material such as silicone rubber. Piezoelectric materials such as lead zirconate titanate, lead zirconate titanate, and polyvinylidene fluoride are used for the piezoelectric particles. In addition, a piezoelectric material in which a polylactic acid film is laminated may be used. Also at this time, the piezoelectric rubber can detect the pressure applied to the measured portion 2a.

(Modification 2)
In the first embodiment, the light passage portion 12 a is installed in the pressure-sensitive conductive rubber 12 of the pressure detection portion 13. The pressure-sensitive conductive rubber 12 was made of a material that can transmit light. In addition, a through-hole may be provided in the light passage portion 12a so that the measurement light 28 and the reflected light 29 pass. The pressure sensitive conductive rubber 12 can prevent the measurement light 28 and the reflected light 29 from being attenuated.

(Modification 3)
In the said 1st Embodiment, although the pulse measuring device 1 was installed in the wrist, it is not specifically limited. It can be installed in places where you want to detect pulse, such as chest, abdomen, and limbs.

(Modification 4)
In the first embodiment, the pulse measuring device 1 measures the pulse of the subject 2. However, the present invention is not limited to this, and it may be used for inspection of animals other than the human body. Furthermore, pressure correction may be used to measure fluid flowing inside plants and elastic bodies other than animals. The pulsating flow of the fluid flowing in the subject can be measured. At this time, the fluid is colored so that the fluid absorbs the measurement light 28. A tube through which fluid flows corresponds to a blood vessel. The contents of Modifications 1 to 4 may be applied to the second to fourth embodiments.

(Modification 5)
In the third embodiment, the same number of light receiving amplifier circuits 108 as the light receiving elements 93 are provided. A switching circuit may be provided between the light receiving element 93 and the light receiving amplifier circuit 108. The number of light receiving amplifier circuits 108 can be reduced. In addition, the area occupied by the wiring can be reduced. Thereby, the optical sensor drive circuit 90 can be reduced in size.

(Modification 6)
In the first to third embodiments, a plurality of light emitting elements 25 (or light emitting elements 92) and light receiving elements 26 (or light receiving elements 93) are arranged in a matrix. A simple configuration in which one light emitting element 25 (or light emitting element 92) and one light receiving element 26 (or light receiving element 93) are provided may be employed. Thereby, an information acquisition apparatus can be simplified and reduced in size.

  DESCRIPTION OF SYMBOLS 1 ... Pulse measuring apparatus as information acquisition apparatus, 2 ... Subject as subject, 8 ... Sensor module as light detection part, 12, 124 ... Pressure-sensitive conductive rubber as pressure detection part, 12a ... Light passage , 12b... Pressure sensitive part as a light shielding part, 26. Light receiving element as a light detection part, 28... Measuring light as light, 29... Reflected light as light, 30. 73: Pre-correction waveform as first light intensity, 74: Pressure transition line as pressure, 75: Waveform after correction as second light intensity, 80: Correlation table.

Claims (8)

A light detector that detects the light intensity of light that has passed through the tube in the subject and outputs a first light intensity;
A pressure detection unit that detects a pressure with which the subject is pressed by the light detection unit and outputs a magnitude of the pressure; and
A correction unit that corrects the first light intensity using the magnitude of the pressure and outputs a second light intensity that is the light intensity when no pressure is applied to the tube. Acquisition device. The information acquisition device according to claim 1,
The time detected at the time t, the pressure at the time P (t), the elasticity coefficient of the tube E, the light absorption coefficient of the subject μa _T, the light absorption coefficient of blood μa _B , and the time detected When the first light intensity is Im (t) and the second light intensity is I (t),
The correction unit corrects using the following equation (1), the information acquisition device.

The information acquisition device according to claim 1,
The correction unit outputs the second light intensity using a correlation table indicating a correlation of the second light intensity with respect to the pressure detected by the pressure detection unit and the first light intensity. Information acquisition device. The information acquisition device according to any one of claims 1 to 3,
The pressure detection unit is located between the subject and the light detection unit,
The information acquisition apparatus according to claim 1, wherein the pressure detection unit includes a light passage unit that has elasticity and allows light to pass therethrough. The information acquisition device according to claim 4,
The information acquisition apparatus, wherein the pressure detection unit detects a pressure applied to a place where light passing through the tube passes through the subject. The information acquisition device according to claim 5,
An information acquisition apparatus, wherein a light-shielding part is installed at a location surrounding the light passage part. The information acquisition device according to any one of claims 1 to 3,
The information acquisition apparatus, wherein the light detection unit is located between the subject and the pressure detection unit. Detecting a first light intensity which is a light intensity of light passing through a tube in a subject;
Detecting the pressure of the tube being pressed;
An information acquisition method comprising: calculating a second light intensity, which is the light intensity when no pressure is applied to the tube, using the first light intensity and a pressure with which the tube is pressed.

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