JP2011055895A - Pulse wave measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulse wave measuring device which correctly measures the arterial pulse wave in the wrist by only wearing it in an approximate position of the artery in the wrist without being conscious of its precise fitting position to the artery of the wrist. <P>SOLUTION: A container 11 houses only an LED. Containers 21 and 31 house an LED and a PD. A container 41 houses only a PD. The pulse wave measuring device 1 sequentially drives the several LEDs, selects a pair of one of the several LEDs and one of the several PDs based on the change in output voltage value which is output by the several PDs receiving the reflection of the irradiation light of the LEDs and pulse waveform information stored in a memory, and measures the arterial pulse wave in the wrist of a subject by the selected LED and PD. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wristwatch-type pulse wave measuring device mounted on a wrist of a subject, and more particularly to a wristwatch-type pulse wave measuring device that measures a wrist pulse wave using a light emitting element and a light receiving element.

  Various wristwatch-type pulse wave measuring devices for measuring wrist pulse waves using a light emitting element (hereinafter referred to as LED) and a light receiving element (hereinafter referred to as PD) have been proposed. The pulse wave measuring apparatus includes an LED that irradiates light to the wrist artery and a PD that receives reflected light of the LED irradiation light to the wrist artery, and is based on a change in the output voltage value of the PD. The arterial volume displacement due to the pulsation of the wrist artery of the subject is detected and the pulse wave is measured.

  FIG. 9 is a diagram showing an ideal pulse waveform (about 2.5 beats) measured based on a change in the output voltage value of the PD, with the horizontal axis indicating time and the vertical axis indicating the output voltage value. The peak of the mountain shows the systole of the heart, and the bottom of the valley shows the arterial blood vessels contracting and expanding in synchronization with the diastole. The amplitude, shape, etc. of the pulse waveform change every moment depending on individual differences, physical condition, body movement, etc., the mounting force of the measuring device, the relative position between the blood vessel and the LED / PD.

By the way, the position of the wrist artery of the subject is different for each subject, and the shape of the wrist is complicated. Therefore, it is difficult to dispose the LED and PD at the wrist position where the pulse wave can be accurately measured.
Therefore, for example, in Patent Document 1, a pulse wave detection device including one LED and a plurality of PDs is wound around the wrist of the subject, and a PD that can obtain the maximum light reception output (maximum output voltage) is selected. A method for detecting a pulse wave based on the output voltage value is disclosed.
In Patent Document 2, a pulse wave measuring device including a plurality of LEDs and a plurality of PDs is mounted on the wrist of the subject, and an optimal combination of the plurality of LEDs and the plurality of PDs is paired with an optimal pair of LEDs and PDs. Is selected in real time based on the difference in pulse wave signal intensity (output voltage) from the PD, and the pulse wave is measured based on the output voltage value of the selected PD.

Japanese Patent Laid-Open No. 11-318840 JP 2006-271896 A

  In order to reliably receive the reflected light of the LED irradiation light with the PD, the LED and the PD must be brought into close contact with the human body surface (wrist). However, the above-mentioned patent document has a complicated shape and elasticity. No specific means for bringing the LED and PD into close contact with the wrist is disclosed, and it is difficult to accurately measure the pulse wave of the wrist artery of the subject. In particular, when the subject is exercising, the pulse wave measuring device worn on the wrist of the subject is displaced, making it more difficult to accurately measure the pulse wave of the wrist artery of the subject.

  Further, as disclosed in the patent document, simply increasing the number of LEDs and PDs hinders downsizing of the device and makes it difficult to attach the device to the wrist. In addition, the manufacturing cost and the manufacturing process increase, and the number of elements increases, so that the solder reliability tends to decrease.

  The present invention has been made in view of such circumstances, and in a wristwatch-type pulse wave measurement device that measures a wrist pulse wave using an LED and a PD, the wrist artery is conscious of a precise attachment position with respect to the wrist artery. An object of the present invention is to provide a pulse wave measuring device that accurately measures the pulse wave of the wrist artery simply by mounting the pulse wave measuring device at an approximate position.

  The first technical means includes: a light emitting element that emits light to the wrist artery of the subject; a light receiving element that receives reflected light of the irradiation light to the wrist artery; and drive control of the light emitting element to output the light receiving element And a pulse wave measuring device having an elastic belt for attaching to the wrist of the subject a control unit for measuring a pulse wave of the wrist artery of the subject based on a change in voltage value. The control unit stores in advance a reference pulse waveform information in a memory. The control unit stores the pulse waveform information as a reference in advance. The plurality of light emitting elements are sequentially driven, and a plurality of light receiving elements receiving the reflected light of the irradiated light outputs a change in voltage value and a plurality of pulse waveform information stored in the memory. Above A pulse wave measuring apparatus, wherein a pair of one of an optical element and one of a plurality of light receiving elements is selected, and a pulse wave of a wrist artery of a subject is measured by the selected light emitting element and light receiving element. .

  A second technical means is the first technical means, in which the containers are juxtaposed on both sides or one side of the two juxtaposed containers, and the light emitting element and the light receiving element are disposed in a storage chamber of the container. Or it is a pulse wave measuring device in which the light emitting element or the light receiving element is housed.

  A third technical means is the pulse wave measuring device according to the second technical means, wherein the light emitting element and the light receiving element are each stored in a checkered pattern in a storage chamber of the container provided side by side.

  According to the present invention, the subject can accurately measure the pulse wave of the wrist artery only by attaching the pulse wave measuring device to the approximate position of the wrist artery. Even if the position of the pulse wave measuring device is shifted after wearing, the wrist pulse wave can be measured accurately.

It is a figure which shows the state which mounted | wore the test subject's wrist with the pulse-wave measuring apparatus which concerns on this invention. 1 is an external view of a pulse wave measuring device according to the present invention. It is an external view of the container of the pulse wave measuring device according to the present invention. It is a figure explaining the state by which LED and PD are arrange | positioned in the state which mounted | wore the test subject's wrist with the pulse wave measuring device which concerns on this invention. It is a figure which shows a pulse waveform. It is a functional block diagram of the pulse wave measuring device concerning the present invention. It is a figure explaining the detail of the container of the pulse-wave measuring apparatus which concerns on this invention. It is a figure which shows a mode that the container of the pulse-wave measuring apparatus which concerns on this invention is attached to an elastic belt. It is a figure which shows the ideal pulse waveform measured based on the change of the output voltage value of PD.

FIG. 1 is a view showing a state in which a pulse wave measuring device 1 according to the present invention is attached to a wrist W of a subject.
11, 21, 31, and 41 are containers for storing LEDs that irradiate light to the wrist artery and / or PDs that receive reflected light of the LED irradiation light to the wrist artery. This container is a vertically long container having a long side in the wrist axis direction of the subject. The container 11 stores only the LED, the containers 21 and 31 store the LED and the PD, and the container 41 stores only the PD. Details will be described later.

  51 is an elastic belt used for attaching each container to a wrist, and each said container is fixed to the said elastic belt. The elastic belt 51 is wound around the subject's vein using a mounting belt (not shown). The elastic belt 51 is made of rubber or an elastomer material.

FIG. 2 is an external view of the pulse wave measuring device 1, and four containers (11, 21, 31, 41) are juxtaposed and fixed to the elastic belt 51.
11a and 21a are transparent covers that cover the emission surface of the LED and the light receiving surface of the PD housed in each container. With this transparent cover, the emitting surface of the LED and the light receiving surface of the PD do not touch the subject's body surface (skin), and the emitting surface and the light receiving surface are not soiled. Although the transparent covers of the containers 31 and 41 are not shown, the same transparent cover as that described above is provided.

  Reference numeral 52 denotes a single continuous flexible substrate on which electronic components for controlling the operation of the LEDs and PDs housed in each container are mounted. 51a and 51b are mounting holes formed in the elastic belt 51, and the mounting belt (not shown) is mounted in the holes. By the mounting belt, each container fixed to the elastic belt 51 is wound (mounted) on the wrist of the subject.

FIG. 3 is an external view of the containers 11, 21, 31, 41. In addition, illustration is abbreviate | omitted about the transparent cover 11a etc. for description.
As shown in FIG. 1, when the pulse wave measuring device 1 is attached to the wrist of a subject, an LED 11e is housed in a container 11 located on the little finger side of the subject. LED11e is located in a test subject's elbow side (refer FIG. 4) at the time of the said mounting | wearing. The LED 11e is arranged on the little finger side because, when the wrist ulnar artery is located between the LED 11e and the PD 21p (LED 21e), the PD output voltage value is smaller than the former when the PD is arranged on the little finger side. This is because it was obtained through experiments by the inventors.

  An LED 21e and a PD 21p are accommodated in a container 21 located on the left side of the container 11 in the drawing. The LED 21e is located on the palm side of the subject when the device is mounted, and the PD 21p is located on the elbow side of the subject. The container 31 contains an LED 31e and a PD 31p. The LED 31e is located on the elbow side of the subject at the time of wearing, and the PD 31p is located on the palm side of the subject.

  When the pulse wave measuring device 1 is worn on the wrist of the subject, the PD 41p is accommodated in the container 41 located on the subject's thumb side. The PD 41p is located on the elbow side of the subject at the time of wearing.

  As shown in FIG. 1, the pulse wave measuring device 1 of the present invention has LED irradiation light when the LED 11e, LED 21e, and LED 31e are sequentially driven (lighted) in a state where the device 1 is mounted on the wrist of the subject. One of a plurality of LEDs and one of the plurality of PDs based on the voltage value output by the PD 21p, the PD 31p, and the PD 41p that have received the reflected light, the change in the voltage value, and information (described later) relating to the reference pulse waveform A pair of LED and PD consisting of two LEDs is selected, and the pulse wave of the wrist artery of the subject is measured by the selected LED and PD.

The pulse wave measurement process executed by the pulse wave measurement device 1 of the present invention will be described in detail with reference to FIGS.
FIG. 4 is a diagram for explaining an arrangement state of the LED and the PD on the wrist in a state where the pulse wave measuring device 1 is mounted on the wrist of the subject.
The LED and PD are arranged in a checkered pattern. That is, the LED and PD are each stored in a checkered pattern in a storage chamber (described later) of containers arranged side by side.
At this time, it is assumed that the wrist artery A is located between the LED 31e and the PD 41p.

  In general, when the wrist artery is located approximately at the center between the LED and the PD, the output voltage value of the PD is large and the SNR (Signal-Noise Ratio) is also good. In the present invention, LEDs and PDs are arranged with substantially dimensional numerical values shown in FIG. In the experiments of the inventors, the wrist ulnar artery or the wrist radial artery is palpated with a finger, the eye is attached to the measurement point on the body surface, and then the pulse wave measuring device 1 arranged in the dimension value is attached to the wrist. It was confirmed that individual differences in both arterial positions could be covered.

  FIG. 5A is a diagram showing the voltage values output from the PD 21p, PD 31p, and PD 41p and the change (pulse waveform) of the voltage values when the LED 21e is turned on, and FIG. 5B is the LED 11e turned on. FIG. 5C shows a voltage value output from the PD when the LED 31 e is turned on, and FIG. 5C shows a voltage value output from the PD when the LED 31 e is turned on and a change in the voltage value. It is.

When the LED 21e shown in FIG. 5A is turned on, the pulse waveform obtained from the PD 21p, PD 31p, and PD 41p is clearly different from the pulse waveform shown in FIG. It turns out that it is a shape.
When the LED 11e shown in FIG. 5B is turned on, the pulse waveform obtained from the PD 21p and PD 31p substantially matches the pulse waveform shown in FIG. 9, but the pulse obtained from the PD 41p. The shape of the waveform is clearly different from the shape of the pulse waveform shown in FIG. 9, and it can be seen that the shape of the waveform is inaccurate.

  On the other hand, when the LED 31e shown in FIG. 5C is turned on, the pulse waveform shapes obtained from the PD 21p, PD 31p, and PD 41p all substantially coincide with the pulse waveform shape shown in FIG. ing. Of the pulse waveform values (output voltage values) obtained from PD21p, PD31p, and PD41p, the pulse waveform value obtained from PD41p is the highest. As described above, the optimum LED / PD pair can be determined to be the LED 31e / PD41p pair.

  As a method for determining whether the pulse waveform shapes obtained from PD21p, PD31p, and PD41p match the pulse waveform shapes shown in FIG. 9, various methods that have been proposed in the past can be used. For example, it relates to an ideal pulse waveform (see the pulse waveform diagram of FIG. 9) such as an inflection point obtained from a PD output value, a waveform SNR, and a twice-differential waveform of a pulse wave graph, and a threshold value related to the inflection point. Information may be stored in advance in a memory, and the determination may be performed using the information. Further, pattern matching may be executed on the shape of both pulse waveforms to calculate the similarity.

  Even if the wrist artery is positioned immediately above the LEDs 21e and PD21p, for example, the optimal LD / PD pair can be determined by executing the above-described determination process.

  FIG. 6 is a functional block diagram of the pulse wave measuring apparatus 1 according to the present invention. An LED / PD unit 61 includes an LED 11e, an LED 21e, an LED 31e, a PD 21p, a PD 31p, a PD 41p, a flexible substrate 52 connected to the LED and the PD, and the like. The LED / PD unit 61 outputs the output voltage value of each PD to the output data processing unit 62.

  The output data processing unit 62 includes an amplifier, an analog switch, an AD converter, and the like. The output data processing unit 62 performs various data processing on the output voltage values of the PD 21p, PD 31p, and PD 41p, and outputs the data to the unit control unit 63.

  The unit control unit 63 includes a dimming circuit, a driver, an analog switch, and the like, and executes drive control of each LED of the LED / PD unit 61 and control of each PD.

  The memory 63a of the unit control unit 63 stores the ideal pulse waveform (FIG. 9) such as the inflection point obtained from the PD output value, the waveform SNR, and the twice differential waveform of the pulse wave, and the threshold value related to the inflection point. The information relating to the pulse waveform diagram of FIG.

  When the LED 11e, LED 21e, and LED 31e are sequentially driven (lighted), the selection unit 63b of the unit control unit 63 outputs the voltage value output by the PD 21p, PD 31p, and PD 41p that has received the reflected light of the LED irradiation light and the voltage value. Based on the change and pulse waveform information (stored in advance in the memory 63a) as a reference for PD selection processing, a pair of LED and PD consisting of one of a plurality of LEDs and one of a plurality of PDs is selected, The pulse wave of the wrist artery of the subject is measured by the selected LED and PD. Thereafter, the LED driving / PD selection process is periodically executed. The selection process may be executed when the output voltage value of the PD falls below a predetermined threshold value.

  The output voltage value or the like of the selected PD is output to a storage medium (not shown) such as a display device or a flash memory.

Next, the details of the container, for example, the container 31 will be described with reference to FIG. FIG. 7A is a perspective view of the container 31, and FIG. 7B is a cross-sectional view of the container 31.
Reference numeral 32 in FIG. 7A denotes a storage member that stores the LED 31e and the PD 31p (see FIG. 7B). The storage member 32 is formed with a storage chamber 32a for storing the LED 31e and a storage chamber 32b for storing the PD 31p, which are partitioned by a partition wall 32c.
Since each storage chamber is separated by the partition wall 32c, the PD 31p receives only the reflected light of the LED 31e irradiation light and does not directly receive the irradiation light of the LED 31e.

  Reference numeral 33 denotes a reinforcing member that reinforces the flexible substrate 52 connected to the LED 31e and the PD 31p housed in the housing member 32. The emission surface of the LED 31e and the light receiving surface of the PD 31p are covered with a transparent cover 31a (see FIG. 7B).

  A belt fastening member 34 is used when the storage member 32 is attached to the elastic belt 51 (see FIG. 2). Reference numeral 35 denotes a first screw used when the fixing member 37 (see FIG. 7B) is fixed to the storage member 32, and reference numeral 36 denotes a second screw used when the storage member 32 is fixed to the elastic belt 51. is there.

  As shown in the cross-sectional view of the container 31 in FIG. 7B, the LED 31 e and the PD 31 p are connected to the wiring of the flexible substrate 52. The flexible substrate 52 is pressed against and fixed to the bottom side of the storage member 32 from above by the fixing member 37 via the reinforcing member 33, and the fixing member 37 is fixed to the storage member 32 by the first screw 35.

  FIG. 8 is a diagram illustrating a state in which the container 31 is attached to the elastic belt 51. This figure shows a state in which the flexible substrate 52 is fixed to the storage member 32 of the container 31 via the fixing member 37. The photoelectric elements (LED 31e, PD 31p, etc.) housed in the containers (11, 21, 31, 41) are unit control units 63 (see FIG. 6) connected to the connection terminals 52a of the flexible substrate 52, etc. It is electrically connected to the electronic components. The containers are fixed (connected) integrally and continuously via the flexible substrate 52.

  The attachment of the container 31 to the elastic belt 51 will be described. First, the attachment portion 34 a of the belt fastening member 34 is passed through the fastening hole 51 c of the elastic belt 51 and the belt fastening member 34 is attached to the fixing member 37. Then, the second screw 36 is inserted into the screw hole 34 b of the belt fastening member 34 and the screw hole 37 a of the fixing member 37, and the elastic belt 51 is sandwiched between the storage member 32 and the belt fastening member 34 by the second screw 36. Fix it.

  Other containers (11, 21, 41) are similarly attached to the elastic belt 51. Thereafter, the connection terminal 52 a of the flexible substrate 52 is exposed to the outside through the terminal hole 51 d of the elastic belt 51. With the above attachment, the pulse wave measuring apparatus 1 shown in FIG. 2 is completed.

  The diameter of the fastening hole 51 c of the elastic belt 51 is larger than the outer diameter of the attaching portion 34 a of the belt fastening member 34, and the height of the attaching portion 34 a of the belt fastening member 34 is larger than the thickness of the elastic belt 51. For this reason, even when the elastic belt 51 changes in shape when the wrist is worn (for example, torsion or the like), each body surface of the container (11, 21, 31, 41) is fixed with sufficient clearance for each gap. The side that comes into contact with the body tends to adhere to the body surface.

  As described above, each container of the pulse wave measuring device 1 of the present invention is independently juxtaposed (fixed) to the elastic belt 51, so that there are thousands of differences due to differences in physique, age, sex, etc. The LED and PD can be attached in close contact with the surface of the wrist of a subject having another complicated shape.

  In addition, if each container is attached to the approximate position of the wrist artery, an LED / PD pair showing an ideal pulse waveform output is automatically selected and the pulse wave of the subject's wrist artery is measured. An accurate pulse wave can be measured without being aware of the precise attachment position to the wrist artery.

  Since the selection process is executed, for example, periodically, the wrist pulse wave can be accurately measured even when the subject is exercising and the wearing position of the pulse wave measuring device is shifted.

  Since the pulse wave measuring apparatus 1 of the present invention can accurately measure the pulse wave of the wrist artery of a subject with the minimum necessary LEDs and PDs, the apparatus can be miniaturized. Moreover, it is easy to wear on the subject's wrist and is convenient. In addition, the manufacturing cost and the manufacturing process can be reduced, and a decrease in solder reliability due to an increase in the number of elements can be prevented.

  In the above-described embodiment, four containers are arranged side by side, but various other modified examples can be adopted in the pulse wave measuring device of the present invention. For example, at least two containers for storing LEDs and PDs, that is, the containers 21 and 31 may be provided in parallel with the elastic belt 51. Moreover, a container may be arranged in parallel on both sides or one side of the containers 21 and 31, and LED and PD, or LED or PD may be stored in the storage chamber of the container. Even in this case, as shown in FIG. 4, it is preferable that the LEDs and the PD are respectively stored in a checkered pattern in the storage chambers of the containers provided side by side.

DESCRIPTION OF SYMBOLS 1 ... Pulse wave measuring device, 11, 21, 31, 41 ... Container, 11e, 21e, 31e, 41e ... LED, 11p, 21p, 31p, 41p ... PD, 11a, 21a, 31a ... Transparent cover, 32 ... Storage member 32a, 32b ... storage chamber, 32c ... partition wall, 33 ... reinforcing member, 34 ... belt fastening member, 34a ... mounting portion, 34b ... screw hole, 35 ... first screw, 36 ... second screw, 37 ... fixing member, 37a ... Screw hole, 51 ... Elastic belt, 51a, 51b ... Mounting hole, 51c ... Fastening hole, 51d ... Terminal hole, 52 ... Flexible substrate, 52a ... Connection terminal, 61 ... LED / PD unit, 62 ... Output data processing 63, unit control unit, 63a, memory, 63b, selection unit, W, wrist of the subject.

Claims (3)

A light emitting element for irradiating light to the wrist artery of the subject, a light receiving element for receiving reflected light of the irradiation light to the wrist artery, and driving control of the light emitting element to change the output voltage value of the light receiving element In the pulse wave measuring device having an elastic belt for mounting the control unit for measuring the pulse wave of the wrist artery of the subject to the wrist of the subject,
The light-emitting element and the light-receiving element are each housed in a storage chamber formed by partitioning into a vertically long container having a long side in the wrist axis direction of the subject that is arranged in parallel with the elastic belt,
The controller stores in advance a pulse waveform information as a reference in a memory, sequentially drives the plurality of light emitting elements, and changes in voltage values output from the plurality of light receiving elements that receive reflected light of the irradiation light; A pair consisting of one of the light emitting elements and one of the light receiving elements is selected based on the pulse waveform information stored in the memory, and the wrist artery of the subject is selected by the selected light emitting elements and light receiving elements. A pulse wave measuring device for measuring a pulse wave.   The containers are juxtaposed on both sides or one side of the two juxtaposed containers, and the light emitting element and the light receiving element, or the light emitting element or the light receiving element are accommodated in a storage chamber of the container. The pulse wave measuring device according to claim 1.   The pulse wave measuring device according to claim 2, wherein the light emitting element and the light receiving element are each stored in a checkered pattern in a storage chamber of the container provided side by side.

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