JP2012065900A - Pulse wave sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse wave sensor to measure a pulse wave without restricting movements of an examinee, for it was difficult to continuously measure the pulse wave over a long period of time (several days to several months) although the pulse wave can be measured in a short period of time (several minutes to several hours) as the movements of the examinee have to be restricted so that the pulse wave sensor may not come off from a fingertip during the pulse-wave measurement since the pulse wave is measured on the fingertip of the examinee in prior arts.SOLUTION: The pulse wave sensor 1 has a structure to measure the pulse wave on a third joint of a finger 2 (finger-ring shape structure to be fit on the third joint of the finger 2 for the pulse-wave measurement). More concretely, the pulse wave sensor 1 includes a first unit 10 for measuring the pulse wave, a second unit 20 for supplying electric power to the first unit 10, a cable 30 for electrically connecting the first unit 10 and the second unit 20, and a finger-ring shape casing 40 for housing the first unit 10, the second unit 20 and the cable 30.

Description

  The present invention relates to a pulse wave sensor.

  As shown in FIG. 11, the pulse wave sensor having a conventional configuration has a structure (for example, a finger bag type) that measures a pulse wave with a fingertip of a subject. The conventional pulse wave sensor is configured to transmit measurement data to a main CPU [Central Processing Unit] in real time, and to analyze and store the measurement data on the main CPU side. In addition, the conventional pulse wave sensor is configured to connect to the main CPU by wire.

  In addition, Patent Document 1 and Patent Document 2 can be cited as examples of related art related to the above.

Japanese Patent Application Laid-Open No. 5-212016 International Publication No. 2002/066222 Pamphlet

  However, in the conventional structure in which the pulse wave is measured with the fingertip of the subject, it is necessary to restrict the behavior of the subject so that the pulse wave sensor does not drop from the fingertip during the measurement of the pulse wave. Therefore, with conventional pulse wave sensors, pulse waves can be measured for a short period (several minutes to several hours), but continuous pulse waves can be measured over a long period (several days to several months). Was difficult.

  In view of the above-described problems found by the inventors of the present application, an object of the present invention is to provide a pulse wave sensor capable of measuring a pulse wave without restricting the behavior of a subject.

  In order to achieve the above object, the pulse wave sensor according to the present invention has a structure (first structure) having a structure for measuring a pulse wave at a third joint of a finger.

  The pulse wave sensor having the first configuration may be configured to have a ring structure (second configuration) that is attached to the third joint of the finger and measures the pulse wave.

  The pulse wave sensor having the second configuration includes a first unit that measures a pulse wave, a second unit that supplies power to the first unit, the first unit, and the second unit. It is preferable to adopt a configuration (third configuration) that includes a cable that electrically connects between the first unit, the second unit, and a ring-shaped housing that houses the cable.

  Further, in the pulse wave sensor having the third configuration, the first unit is arranged on the ring-shaped housing so that the ring-shaped housing is on a belly side of the finger when the ring-shaped housing is attached to a third joint of the finger. The second unit is configured to be housed in the ring type housing so that the second unit is on the back side of the finger when the ring type housing is attached to the third joint of the finger (fourth unit). Configuration).

  Further, in the pulse wave sensor having the fourth configuration described above, the first unit includes a photosensor that irradiates light to the third joint of the finger and detects the intensity of the light transmitted through the living body (first configuration). 5 configuration).

  In the pulse wave sensor having the fifth configuration, the first unit may be configured to include a measurement window (sixth configuration) provided on the light emitting / receiving surface of the optical sensor.

  In the pulse wave sensor having the sixth configuration, the first unit may have a configuration (seventh configuration) including an amplifier circuit that amplifies the output signal of the optical sensor.

  In the pulse wave sensor having the seventh configuration, the first unit may include a calculation circuit (eighth configuration) including an arithmetic circuit that acquires information on the pulse wave based on the output signal of the amplifier circuit. .

  In the pulse wave sensor having the eighth configuration, the first unit may have a configuration (a ninth configuration) including a substrate on which the optical sensor is mounted.

  In the pulse wave sensor having the ninth configuration, the amplifier circuit and the arithmetic circuit may be mounted on the back surface of the substrate (tenth configuration).

  In the pulse wave sensor having any one of the third to tenth configurations, the second unit may include a battery (an eleventh configuration).

  In the pulse wave sensor having the eleventh configuration, the second unit may include a power supply circuit that converts an input voltage from the battery into a desired output voltage (a twelfth configuration).

  In the pulse wave sensor having the eleventh or twelfth configuration, the second unit may have a configuration (a thirteenth configuration) including a charging circuit that controls charging of the battery.

  In the pulse wave sensor having the thirteenth configuration, the charging circuit may be configured to receive power from the outside by a contact method (fourteenth configuration).

  In the pulse wave sensor having the thirteenth configuration, the charging circuit may be configured to receive power from the outside in a non-contact manner (fifteenth configuration).

  Further, in the pulse wave sensor having any one of the third to fifteenth configurations, the second unit has a configuration (sixteenth configuration) including a memory for storing measurement data obtained by the first unit. Good.

  Further, in the pulse wave sensor having any one of the third to sixteenth configurations, the second unit includes a radio communication circuit that transmits the measurement data obtained by the first unit by radio (a seventeenth configuration). Configuration).

  In the pulse wave sensor having any one of the third to seventeenth configurations, the second unit may be configured to include a plurality of substrates vertically stacked via connectors (18th configuration).

  In the pulse wave sensor having any one of the third to eighteenth configurations, the ring-shaped housing may have a waterproof structure (19th configuration).

  In the pulse wave sensor having any one of the third to nineteenth configurations, the ring-shaped housing may have a configuration (a twentieth configuration) having an opening that is partially open in the circumferential direction.

  In the pulse wave sensor having the twentieth configuration, the ring-shaped housing may be formed of a flexible material (a twenty-first configuration).

  In the pulse wave sensor having the fourth configuration, the thickness of the second unit may be larger than the thickness of the first unit (22nd configuration).

  In the pulse wave sensor having the twenty-second configuration, the thickness of the second unit may be greater than twice the thickness of the first unit (a twenty-third configuration).

  With the pulse wave sensor according to the present invention, the pulse wave can be measured without restricting the behavior of the subject.

Schematic diagram for explaining the principle of pulse wave measurement Waveform diagram showing how the attenuation (absorbance) of light in a living body changes over time Sectional drawing which shows typically one structural example of the pulse wave sensor which concerns on this invention Sectional drawing which shows typically the modification of the pulse wave sensor which concerns on this invention First perspective view showing a state in which the pulse wave sensor 1 is attached to the third joint of the finger Second perspective view showing a state in which the pulse wave sensor 1 is attached to the third joint of the finger 3rd perspective drawing which shows a mode that the pulse wave sensor 1 is mounted | worn with the 3rd joint of a finger | toe Sectional drawing which shows one structural example of the 1st unit 10 typically Sectional drawing which shows one structural example of the 2nd unit 20 typically Sectional drawing which shows typically the modification of the 2nd unit 20 Schematic diagram showing a first conventional example of a pulse wave sensor

<Principle of pulse wave measurement>
FIG. 1 is a schematic diagram for explaining the principle of pulse wave measurement, and FIG. 2 is a waveform diagram showing how the attenuation (absorbance) of light in a living body changes with time.

In the pulse wave measurement by the volume pulse wave method, for example, as shown in FIG. 1, a light emitting unit (LED [Light Emitting] is directed toward a part of the living body pressed against the measurement window (the third joint of the finger in FIG. 1). The intensity of light transmitted through the body and coming out of the body is detected by a light receiving unit (such as a photodiode or a phototransistor). Here, as shown in FIG. 2, the attenuation (absorbance) of light due to living tissue and venous blood (deoxygenated hemoglobin Hb) is constant, but the attenuation of light due to arterial blood (oxygenated hemoglobin HbO ₂ ). (Absorbance) varies with time due to pulsation. Therefore, the volume pulse wave is measured by measuring the change in the absorbance of the peripheral artery using the “biological window” (wavelength range in which light is easily transmitted through the living body) from the visible region to the near infrared region. Can do.

<What you can understand from the pulse wave>
Note that the pulse wave under the control of the heart and the independent nerve does not always exhibit a constant behavior, but causes various changes (fluctuations) depending on the condition of the subject. Accordingly, various body information of the subject can be obtained by analyzing the change (fluctuation) of the pulse wave. For example, from the heart rate, it is possible to know the exercise ability, the degree of tension, and the like of the subject, and from the heart rate variability, it is possible to know the fatigue level, the degree of sleep, the magnitude of stress, and the like. Further, from the acceleration pulse wave obtained by differentiating the pulse wave twice with respect to the time axis, the blood vessel age, arteriosclerosis degree, etc. of the subject can be known.

<Schematic configuration of pulse wave sensor>
FIG. 3 is a cross-sectional view schematically showing a configuration example of the pulse wave sensor according to the present invention. The pulse wave sensor 1 of this configuration example has a structure for measuring a pulse wave at the third joint of the finger 2, more specifically, a ring that is attached to the third joint of the finger 2 and measures the pulse wave. It has a structure. Focusing on the components, the pulse wave sensor 1 of this configuration example includes the first unit 10, the second unit 20, the cable 30, and the ring-shaped housing 40.

  The first unit 10 is a unit that mainly measures pulse waves, and the ring so that the ring-shaped housing 40 is on the ventral side (the palm side) of the finger 2 when the ring-shaped housing 40 is attached to the third joint of the finger 2. Housed in a mold housing 40. As described above, the belly of the finger 2 is thicker and has a better fit to the pulse wave sensor 1 than the back side (back side of the hand) of the finger 2 with a bone just under the skin and poor fit of the pulse wave sensor 1. By arranging the first unit 10 on the side (the palm side), the pulse wave can be measured stably, and the measurement accuracy of the pulse wave can be increased. In addition, the inventors of the present application have actually experimented that the pulse wave measurement at the third joint is sufficiently low compared with the pulse wave measurement at the fingertip, but the pulse wave can be measured sufficiently. Confirmed. The internal configuration and operation of the first unit 10 will be described in detail later.

  The second unit 20 is a unit that mainly supplies power to the first unit 10, and becomes the back side (back side of the hand) of the finger 2 when the ring-shaped housing 40 is attached to the third joint of the finger 2. As described above, it is housed in a ring type housing 40. Thus, by arranging the second unit 20 that can be a noise source for the first unit 10 as far as possible from the first unit 10, it is possible to improve the measurement accuracy of the pulse wave. The internal configuration and operation of the second unit 20 will be described in detail later.

  The cable 30 is accommodated in the ring type housing 40 so as to electrically connect the first unit 10 and the second unit 20. As the cable 30, in addition to a general covered electric wire, FPC [Flexible Printed Circuits] or the like can be suitably used.

  The ring-shaped housing 40 accommodates the first unit 10, the second unit 20, and the cable 30, and is attached to the third joint of the finger 2 when measuring a pulse wave.

  As described above, in the case of the pulse wave sensor 1 having a ring structure, the pulse wave sensor 1 drops from the finger 2 during measurement of the pulse wave unless the subject intentionally removes the pulse wave sensor 1 from the finger 2. Therefore, it is possible to measure the pulse wave without restricting the behavior of the subject.

  Further, if the pulse wave sensor 1 has a ring structure, it is not necessary to make the subject wear the pulse wave sensor 1 so much, so that it is continuous over a long period (several days to several months). Even when a simple pulse wave measurement is performed, it is not necessary to apply excessive stress to the subject.

  In particular, if the ring-shaped housing 40 is treated with jewels or the like, the pulse wave sensor 1 can be mounted as an ornament, so that the resistance to the mounting of the pulse wave sensor 1 can be further eliminated. It is possible to contribute to the development of new user groups.

  The thickness of the second unit 20 may be configured to be greater than the thickness of the first unit 10, and more preferably, the thickness of the second unit 20 may be configured to be greater than twice the thickness of the first unit 10. Is desirable. More specifically, the thickness of the first unit 10 may be about 1 to 5 mm, and the thickness of the second unit 20 may be about 4 to 20 mm.

  In addition, the thickness of the first unit 10 includes the thickness of the translucent member (about 0.7 mm) forming the measurement window 13 in addition to the substrate 11, the optical sensor 12, the amplifier circuit 14, the arithmetic circuit 15, etc. The thickness of the ring-shaped housing 40 covering one unit 10 is included.

  The breakdown of the thickness of the second unit 20 includes the thickness of the battery 24 (2 to 5 mm), the thickness of the first substrate 21 and the power supply circuit 22 (1 to 3 mm (connector 2 mm)), and the second substrate 27. In addition to the thickness of the wireless communication circuit 28 (3 to 6 mm (connector 2 mm)), the thickness of the ring-shaped housing 40 covering the second unit 20 is included.

  In this way, the first unit 10 on the ventral side of the finger 2 is designed to be thin, and the second unit 20 on the back side of the finger 2 is designed to be thick, thereby enhancing the wearing feeling of the pulse wave sensor 1 on the finger 2. In addition, it is possible to make the pulse wave sensor 1 look like a general ring and to eliminate the uncomfortable appearance. In consideration of the attachment to the finger 2, the first unit 10 that is the ventral side of the finger 2 cannot be made too thick, but the second unit 20 that is the back side of the finger 2 is the first unit 20. Therefore, the degree of freedom of circuit mounting can be increased.

  Also, by designing the second unit 20 to be sufficiently thicker than the first unit 10, the pulse wave sensor 1 is less likely to rotate around the finger 2, so that the first unit 10 can be securely attached to the ventral side of the finger 2. (Side side suitable for pulse wave measurement), and it becomes possible to increase the measurement accuracy of the pulse wave. If the thickness of the first unit 10 and the thickness of the second unit 20 are different from each other at a glance, the pulse wave sensor 1 is reversed (that is, the first unit 10 is on the back side of the finger 2 and the second unit 20 is The risk of erroneous attachment to the ventral side of 2) can be reduced.

  In addition, in FIG. 3, the configuration in which the ring type housing 40 is a complete ring is illustrated, but the configuration of the present invention is not limited to this, and as shown in FIG. It is good also as a structure which has the opening part 41 by which a part of circumferential direction was open | released. By adopting such a configuration, it is possible to give a certain degree of freedom to the wearable size of the pulse wave sensor 1 (corresponding to the number of rings). In particular, if the ring-shaped housing 40 is made of a flexible material (silicon rubber, etc.) after the opening 41 is provided in the ring-shaped housing 40, the size that can be attached to the pulse wave sensor 1 is considerably large. It is possible to have a degree of freedom.

  Moreover, it is desirable that the ring-shaped housing 40 has a waterproof structure. With such a configuration, it is possible to measure a pulse wave without failure even when wet with water (rain) or sweat. Further, when the pulse wave sensor 1 is shared by a large number of people (for example, when used for lending in a gym), the pulse wave sensor 1 is kept clean by washing the ring-shaped housing 40 with water. Is possible.

  5 to 7 are perspective views showing the state in which the pulse wave sensor 1 is attached to the third joint of the finger. 5 shows the finger 2 seen through from the back side of the hand, FIG. 6 shows the finger 2 seen through from the palm side, and FIG. 7 shows the finger 2 seen through from the side. As shown in these drawings, the first unit 10 and the second unit 20 are not protruded from the third joint of the finger 2 so that the subject is not conscious of wearing the pulse wave sensor 1 (does not give a sense of incongruity). It is desirable to fit within a size.

<First unit>
FIG. 8 is a cross-sectional view schematically showing a configuration example of the first unit 10. The first unit 10 of this configuration example includes a substrate 11, an optical sensor 12, a measurement window 13, an amplifier circuit 14, and an arithmetic circuit 15.

  The optical sensor 12 is directly mounted on the front surface of the substrate 11, and the amplifier circuit 14 and the arithmetic circuit 15 are directly mounted on the rear surface thereof. In addition, a cable 30 for establishing an electrical connection with the second unit 20 is also connected to the substrate 11. An electrical connection is established between the front surface and the back surface of the substrate 11 through a through hole or a via. As described above, if the optical sensor 12, the amplifier circuit 14, and the arithmetic circuit 15 are all directly mounted on the substrate 11, the first unit 10 can be thinned. It is possible to enhance the feeling. Further, if only the optical sensor 12 is directly mounted on the surface of the substrate 11, the optical sensor 12 can be brought as close to the finger 2 as possible, so that the pulse wave measurement accuracy can be improved.

  The optical sensor 12 irradiates the third joint of the finger 2 with light from the light emitting unit, and acquires the pulse wave data by detecting the intensity of the light transmitted through the living body with the light receiving unit. The optical sensor 12 in this configuration example is not a configuration in which the light emitting unit and the light receiving unit are provided on opposite sides of the finger 2 (so-called transmission type, see the broken line arrow in FIG. 1), but the light emitting unit and the light receiving unit. Each part is configured to be provided on the same side with respect to the finger 2 (so-called reflection type, see solid line arrow in FIG. 1).

  The measurement window 13 is a translucent member (such as a glass plate or an acrylic plate) provided on the light emitting / receiving surface of the optical sensor 12, and the optical sensor 12 measures the pulse wave (finger 2 and the detection of the reflected light returning from the finger 2). The thickness of the measurement window 13 is preferably designed appropriately in view of the depth of focus of the optical sensor 12.

  The amplifier circuit 14 amplifies the output signal (detection signal of the light receiving unit) of the optical sensor 12 and outputs the amplified signal to the arithmetic circuit 15. In this way, with the configuration in which the amplifier circuit 14 is provided in the immediate vicinity of the optical sensor 12, the output signal of the optical sensor 12 can be amplified before noise is superimposed, and thus the signal S / N [Signal / Noise Ratio] can be increased, and as a result, the measurement accuracy of the pulse wave can be increased.

  The arithmetic circuit 15 comprehensively controls the operation of the entire pulse wave sensor 1 and performs various signal processing on the output signal of the amplifier circuit 14 to thereby provide various information on the pulse wave (pulse wave fluctuation, heart rate). , Heart rate variability, acceleration pulse wave, etc.). In addition, as the arithmetic circuit 15, CPU [Central Processing Unit] etc. can be used suitably. In this way, if the arithmetic circuit 15 is provided in the immediate vicinity of the optical sensor 12 and the amplifier circuit 14, the output signal of the amplifier circuit 14 can be processed before noise is superimposed. Can be increased.

<Second unit>
FIG. 9 is a cross-sectional view schematically showing a configuration example of the second unit 20. The second unit 20 of this configuration example includes a first board 21, a power supply circuit 22, a memory 23, a battery 24, a charging circuit 25, a connector 26, a second board 27, a wireless communication circuit 28, including.

  A power circuit 22 and a memory 23 are directly mounted on the front surface of the first substrate 21, and a battery 24 and a charging circuit 25 are directly mounted on the back surface of the first substrate 21. In addition, a cable 30 for establishing electrical connection with the first unit 10 is also connected to the first substrate 21. In addition, electrical connection is established between the front surface and the back surface of the first substrate 21 through through holes and vias. Thus, since the area of the first substrate 21 can be reduced by effectively using both surfaces of the first substrate 21, the second unit 20 does not protrude from the third joint of the finger 2. Therefore, it is not necessary for the subject to be aware of wearing the pulse wave sensor 1.

  The power supply circuit 22 converts the input voltage from the battery 24 into a desired output voltage and supplies it to each part of the pulse wave sensor 1. Thus, by arranging the power supply circuit 22 that can be a noise source for the first unit 10 as far as possible from the first unit 10, it is possible to improve the measurement accuracy of the pulse wave.

  The memory 23 may be measurement data obtained by the first unit 10 (raw data output from the amplifier circuit 14 or processed data after various processes are performed by the arithmetic circuit 15. May be stored volatilely or non-volatilely. As the memory 23, a volatile RAM [Random Access Memory], a nonvolatile flash memory, or the like can be suitably used. With such a configuration having measurement data storage means, the accumulated data in the memory 23 can be transmitted collectively at a predetermined interval, so that the wireless communication circuit 28 can be intermittently placed in a standby state. As a result, the battery drive time of the pulse wave sensor 1 can be extended.

  The battery 24 is a power supply source necessary for driving the pulse wave sensor 1, and a lithium ion secondary battery, an electric double layer capacitor, or the like can be suitably used. Thus, with the battery-driven pulse wave sensor 1, it is not necessary to connect an external power supply cable when measuring the pulse wave, and thus the pulse wave can be measured without restricting the behavior of the subject. It becomes possible. In this configuration example, since the battery 24 with high flatness is arranged immediately above the finger 2, it is possible to increase the affinity when the pulse wave sensor 1 is attached to the finger 2, and as a result, It is not necessary for the subject to be aware of wearing the pulse wave sensor 1.

  The charging circuit 25 performs charging control of the battery 24 by receiving external power supply. The external power supply method may be a contact method using a USB [Universal Serial Bus] cable or the like, or a non-contact method such as an electromagnetic induction method, an electric field coupling method, and a magnetic field resonance method. It may be. With such a configuration having the battery 24 charging means, battery replacement work is not required, and the convenience of the pulse wave sensor 1 can be enhanced.

  The connector 26 is a conductive member for vertically stacking the first substrate 21 and the second substrate 22. A wireless communication circuit 28 is directly mounted on the front surface of the second substrate 27, and a connector 26 is connected to the back surface thereof. Note that an electrical connection is established between the front surface and the back surface of the second substrate 27 through a through hole or a via. As described above, by adopting a laminated structure of a plurality of substrates, the area of the first substrate 21 and the area of the second substrate 22 can be reduced as compared with the configuration in which all circuit elements are mounted on one substrate. Therefore, the second unit 20 can be stored in a size that does not protrude from the third joint of the finger 2, and the subject does not need to be aware of wearing the pulse wave sensor 1. In addition, since the 2nd unit 20 used as the back side of the finger | toe 2 can be designed thicker than the 1st unit 10 used as the belly side of the finger | toe 2, the laminated structure of several board | substrates can be employ | adopted without any problem. It is.

  The wireless communication circuit 28 uses any one of the measurement data obtained by the first unit 10 (raw data output from the amplifier circuit 14, processed data output from the arithmetic circuit 15, and stored data output from the memory 23). May be transmitted wirelessly to an external personal computer or mobile phone. The wireless communication circuit 28 can be a noise source for the first unit 10, like the power supply circuit 22. As the wireless communication circuit 28, for example, a Bluetooth (registered trademark) module IC can be suitably used. With such a configuration having the wireless communication circuit 28, when the measurement data is transmitted to the external device, a wired connection is not required. For example, the measurement data is transmitted in real time without restricting the behavior of the subject. Can be performed.

  When the ring-type housing 40 has a waterproof structure, a non-contact method is adopted as a power supply method to the charging circuit 25 from the viewpoint of completely eliminating external terminals, and further, external transmission of measurement data is performed. It is desirable to adopt a wireless transmission method as the method.

  In the above configuration example, the configuration in which the battery 24 is disposed immediately above the finger 2 is taken as an example. However, the configuration of the present invention is not limited to this, and the first substrate 21 is arranged as shown in FIG. The battery 24 may be disposed directly above the finger 2 and the battery 24 may be attached above the wireless communication circuit 28. At that time, the power supply circuit 22, the memory 23, and the charging circuit 25 are directly mounted on the front surface of the first substrate 21, while no circuit elements are mounted on the back surface (flat state). Is desirable. By adopting such a configuration, as in the configuration example of FIG. 9, it becomes possible to increase the affinity when the pulse wave sensor 1 is attached to the finger 2. As a result, the pulse wave sensor 1 is attached to the subject. You don't have to be aware of

<Other variations>
The configuration of the present invention can be variously modified in addition to the above-described embodiment without departing from the gist of the invention. That is, the above-described embodiment is an example in all respects and should not be considered as limiting, and the technical scope of the present invention is not the description of the above-described embodiment, but the claims. It should be understood that all modifications that come within the meaning and range of equivalents of the claims are included.

  The present invention can be used as a technology for enhancing the convenience of a pulse wave sensor, and includes various devices such as healthcare support devices, game devices, music devices, pet communication tools, and driver's sleep control devices. It can be applied to various fields.

DESCRIPTION OF SYMBOLS 1 Pulse wave sensor 10 1st unit 11 Board | substrate 12 Optical sensor 13 Measurement window (translucent member)
14 Amplifying circuit 15 Arithmetic circuit (CPU)
20 Second unit 21 First substrate 22 Power supply circuit (DC / DC converter)
23 memory 24 battery 25 charging circuit 26 connector 27 second substrate 28 wireless communication circuit 30 cable 40 ring-shaped housing 41 opening

Claims (23)

  A pulse wave sensor having a structure for measuring a pulse wave at a third joint of a finger.   The pulse wave sensor according to claim 1, wherein the pulse wave sensor has a ring structure that is attached to a third joint of a finger and measures a pulse wave. A first unit for measuring a pulse wave;
A second unit for supplying power to the first unit;
A cable for electrically connecting the first unit and the second unit;
A ring-shaped housing for housing the first unit, the second unit, and the cable;
The pulse wave sensor according to claim 2, further comprising: The first unit is housed in the ring-shaped housing so that the ring-shaped housing is on the ventral side of the finger when the ring-shaped housing is attached to a third joint of a finger;
The said 2nd unit is accommodated in the said ring type housing | casing so that it may become the back side of a finger when the said ring type housing | casing is mounted | worn with the 3rd joint of a finger | toe. Pulse wave sensor.   5. The pulse wave sensor according to claim 4, wherein the first unit includes an optical sensor that detects the intensity of light transmitted through the living body by irradiating the third joint of the finger with light. 6.   The pulse wave sensor according to claim 5, wherein the first unit includes a measurement window provided on a light emitting / receiving surface of the optical sensor.   The pulse wave sensor according to claim 6, wherein the first unit includes an amplifier circuit that amplifies an output signal of the optical sensor.   The pulse wave sensor according to claim 7, wherein the first unit includes an arithmetic circuit that acquires information related to a pulse wave based on an output signal of the amplifier circuit.   The pulse wave sensor according to claim 8, wherein the first unit includes a substrate on which the optical sensor is mounted.   The pulse wave sensor according to claim 9, wherein the amplifier circuit and the arithmetic circuit are mounted on a back surface of the substrate.   The pulse wave sensor according to any one of claims 3 to 10, wherein the second unit includes a battery.   The pulse wave sensor according to claim 11, wherein the second unit includes a power supply circuit that converts an input voltage from the battery into a desired output voltage.   The pulse wave sensor according to claim 11 or 12, wherein the second unit includes a charging circuit that controls charging of the battery.   The pulse wave sensor according to claim 13, wherein the charging circuit is supplied with electric power from the outside by a contact method.   The pulse wave sensor according to claim 13, wherein the charging circuit is supplied with electric power from the outside in a non-contact manner.   The pulse wave sensor according to any one of claims 3 to 15, wherein the second unit includes a memory that stores measurement data obtained by the first unit.   The pulse wave sensor according to any one of claims 3 to 16, wherein the second unit includes a wireless communication circuit that wirelessly transmits measurement data obtained by the first unit.   The pulse wave sensor according to any one of claims 3 to 17, wherein the second unit includes a plurality of boards stacked vertically through connectors.   The pulse wave sensor according to any one of claims 3 to 18, wherein the ring-shaped housing has a waterproof structure.   The pulse wave sensor according to any one of claims 3 to 19, wherein the ring-shaped housing has an opening part of which is opened in a circumferential direction.   The pulse wave sensor according to claim 20, wherein the ring-shaped housing is formed of a flexible material.   The pulse wave sensor according to claim 4, wherein the thickness of the second unit is larger than the thickness of the first unit.   The pulse wave sensor according to claim 22, wherein the thickness of the second unit is larger than twice the thickness of the first unit.

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