JP2000116611A - Pulse sensor - Google Patents

Abstract

(57) [Problem] To provide a pulse sensor capable of surely measuring a pulse of an object to be measured during exercise and measuring a pulse continuously for a long time. A pulse sensor (1) reflects irradiation light emitted from a light emitting diode (20) in a planar manner with a convex mirror (16) and reflects the irradiation light spread in a plane toward a light emitting surface (140) with a concave mirror (126). are doing. The irradiation light is scattered by the light scattering agent 40 on the way. When the irradiation light is spread and scattered in this manner, the object to be measured can be irradiated with a uniform amount of irradiation light in a planar shape from the light emitting surface 140, and therefore,
The reflected light reflected from the object to be measured and emitted from the irradiation surface irradiated with the irradiation light also has a planar and uniform light amount.
Therefore, even if the light receiving point for receiving the reflected light is shifted, the amount of the reflected light to be received does not change, so that the pulse of the object under exercise in which the light receiving point shifts sharply can be accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse sensor for detecting a pulse of an object to be measured.

[0002]

2. Description of the Related Art Conventionally, there is a pulse detecting device which detects a pulse of a measurement object by utilizing the property of hemoglobin contained in red blood cells to absorb light. This pulse detection device, when irradiating the measurement object with irradiation light, the amount of light reflected inside the measurement object body, when the blood flow of the blood flowing through the measurement object body is large, that is, the pulse This is a device that attempts to detect a pulse from the manner in which the amount of light changes, since it decreases when the light is striking and increases when the blood flow rate is low, that is, when a pulse is not struck. Therefore, the pulse detection device usually receives light reflected by the body to be measured among the light emitted from the light emitting unit that emits irradiation light to be irradiated to the object to be measured and the light emitted from the light emitting unit, A pulse sensor comprising light receiving means for converting the received light into an electric signal corresponding to the amount of received light, and a pulse calculator for calculating a pulse from the electric signal inputted from the pulse sensor are provided.

As shown in FIG. 5, a pulse sensor 200 used in such a pulse detecting device includes a light emitting element 210 such as a light emitting diode, a light receiving element 220 such as a photodiode, and a storage hole for storing these elements. And a sensor main body 230 formed in a flat plate shape having two openings on one plane.

[0004]

By the way, the pulse of the measured object during exercise is important information for knowing the exercise ability and physical condition of the measured object. However, the illustrated pulse sensor 20
The pulse detection device using No. 0 could not detect a pulse because the body surface of the measured object causes body movement such as muscle contraction, extension, and torsion.

[0005] This is because the above-mentioned reflected light is emitted from the light emitting element 21.
Since the light has a non-uniform amount of light that decreases as the distance from 0 increases, when detecting such a pulse by receiving such non-uniform reflected light, the light receiving point at which the light receiving element 220 receives the reflected light is slightly shifted. In the electric signal reflecting the difference in the light amount due to the difference in blood flow (hereinafter referred to as “pulse light amount difference”), the difference in the light amount due to the shift of the light receiving point (hereinafter, “displacement light amount difference”) Is superimposed.

In other words, in a situation where the measured object moves and the light receiving points are repeatedly shifted, such as when the measured object is moving, the pulse light intensity is superimposed on the electric signal by superimposing a plurality of deviation light amount differences on the electric signal. This is because the difference was canceled out and the pulse could not be calculated from the electric signal.

Here, an experimental result of measuring a pulse of a measured body in which a body motion has occurred by using a pulse detecting device provided with the pulse sensor 200 will be described. FIG.
FIG. 6A is an explanatory view showing a state in which a pulse sensor is attached to a wrist of a measurement object (here, “person”), and FIG. 6B is a diagram showing a state in which a pulse sensor is attached during exercise of a person. It is a graph of an electric signal. However, the upper graph shows an amplified electric signal directly output from the pulse sensor 200, and the lower graph shows gain control processing and pulse values other than the pulse value so that the pulse can be easily calculated by the pulse calculator. Frequency cut processing (0.5H with band pass filter)
z) or an electrical signal that has been subjected to a process of cutting a frequency signal of 4 Hz or more. In each graph, the sign of the electric signal is reversed.

In this experiment, the pulse sensor 200 was brought into close contact with the back of the wrist of a person, and the pulse sensor 200 was
As shown in (a), the light receiving element 220 and the light emitting element 210
Vibration was performed in the direction of arrow Y, assuming that there was body movement in the arrangement direction (direction of arrow Y in the figure). Then
As shown in FIG. 6 (b), the electric signal output from the pulse sensor shows only the difference in the amount of light of the vibration that vibrates in accordance with the rhythm of the vibration of the pulse sensor 200, and the difference in the amount of light of the pulse can be read at all. Did not.

Accordingly, an object of the present invention is to provide a pulse sensor capable of reliably measuring a pulse of a body to be measured during exercise.

[0010]

According to a first aspect of the present invention, there is provided a light emitting means for emitting irradiation light which can be absorbed by blood, and the irradiation light emitted by the light emitting means. Forming a light emitting surface for emitting light, and a light guiding means for guiding the irradiation light to the light emitting surface; and a light guiding unit disposed at a center of the light emitting surface and being incident from a light emitting direction on the light emitting surface. Light-receiving means for receiving reflected light, wherein the light emission surface is opposed to the object to be measured, and the light-emitting means emits light, whereby a change in blood flow based on the pulse of the object to be measured is reflected. In a pulse sensor that receives reflected light by the light receiving unit and outputs an electric signal according to the amount of light received by the light receiving unit, the light guide unit diffusely reflects the irradiation light from the light emitting unit in a planar shape. A convex mirror, irradiation light reflected by the convex mirror, It has a concave mirror that reflects in a plane toward the light emitting surface, and scattering means that is disposed between the concave mirror and the light emitting surface and scatters the irradiation light reflected by the concave mirror. .

The pulse sensor according to the first aspect of the present invention uses a convex mirror among the convex mirror, concave mirror and scattering means provided in the light guide means, and spreads the irradiation light emitted from the light emitting means in a plane toward the concave mirror. And then using a concave mirror,
The illuminating light spread in a plane is reflected toward the light emitting surface in a planar manner, and further, using a scattering means, the illuminating light that is reflected by the concave mirror and spread in a plane toward the light emitting direction is scattered to emit light. Released from the surface to the outside.

In the pulse sensor according to the first aspect of the present invention, first, the irradiation light emitted from the light emitting means is spread in a plane using a convex mirror and a concave mirror, guided to a light emitting surface, and further scattered using a scattering means. As a result, when the light is emitted directly from the light-emitting means to the outside, the non-uniform irradiation light that is biased toward the center can be emitted to the outside as planar light with a uniform light amount. Further, since the irradiation light emitted from the light emitting means is guided to the light emitting surface by being reflected by the convex mirror and the concave mirror, the irradiation light can be efficiently emitted to the outside.

As a result, when the pulse sensor according to claim 1 is mounted on the object to be measured so that the light emitting surface faces the object to be measured, and the light emitting means emits light, the pulse sensor is attached to the irradiation surface facing the light emitting surface. Is irradiated with a uniform amount of irradiation light spread in a plane, so that the reflected light reflected inside the body of the object to be measured becomes a light with a uniform light amount spread in a plane and is emitted from the irradiation surface to the outside. It is done. Although the reflected light is attenuated to some extent by the scattering means, the irradiation light emitted by the light emitting means is guided to the light emitting surface with high efficiency. It is released from.

Therefore, when the pulse sensor according to the first aspect is used, a uniform amount of reflected light that can be received by the light receiving means can be received from any part of the irradiation surface, and the reflected light is received by body movement. Even if the light receiving point shifts, it is possible to always receive a uniform amount of reflected light and output an electric signal reflecting only the pulse. Therefore, if the pulse detecting device provided with the pulse sensor according to claim 1 is used,
Even if the body to be measured moves, an electric signal reflecting only the pulse can be output, so that the pulse of the person who is exercising can be reliably detected.

The light emitting means is preferably a light emitting diode or another element which consumes less power. This is because the pulse can be measured continuously for a long time even if a battery or the like is used as the power source of the light emitting means. Further, as the light receiving means, it is preferable to use a photodiode or any other element capable of converting an electric signal reflecting the amount of received light. Further, as the scattering means, a light milky white substance such as silicon or polyethylene is preferable.

By the way, in order to measure the pulse by using the blood flow of the artery of the wrist, when the pulse sensor according to the above-mentioned claim 1 is installed on the wrist and the pulse is measured, as in the invention according to the second aspect Preferably, a pulse sensor is used in which the light emitting unit irradiates visible light that is split into red light as the irradiation light, and the light receiving unit receives the visible light that is split into red light as the reflected light. .

According to the pulse sensor of the second aspect,
The reason for irradiating visible light (hereinafter referred to as "red light") that is split into red light as irradiation light from the irradiation means and receiving red light as reflected light received by the light receiving means is as follows. by. In the following, the reason will be described by comparing visible light (hereinafter referred to as “blue light”), which is separated into blue light with a shorter wavelength than red light, and infrared light with a longer wavelength, with red light. .

First, infrared rays have the property of being more easily transmitted through the object to be measured than red light. In other words, when infrared light is used as irradiation light and reflected light, infrared light emitted from the irradiation means penetrates the measured object and is emitted to the outside, while infrared light emitted from outside (hereinafter referred to as “disturbance”) is emitted. Since it easily penetrates the measured object and is easily received by the light receiving means, the electric signal reflecting the light amount of the light received by the light receiving means hardly reflects the change in the light amount of the reflected light, and on the other hand, reflects the influence of disturbance. This is because it was difficult to detect a pulse from this electric signal.

Second, red light has the property of reaching the artery of the subject to a certain depth and being reflected as compared with blue light, as compared with blue light. In other words, when the blue light is irradiated as the irradiation light and the reflected light, the blue light is reflected near the body surface before reaching the artery, so the change in the amount of the reflected light is not much reflected in the electric signal. This is because it was difficult to detect the pulse from the electric signal.

Therefore, if red light is used as the irradiation light as in the pulse sensor according to the second aspect, the reflected light reflecting the blood flow rate of the artery on the wrist can be received by the light receiving means without being affected by disturbance. You can do it. The red light preferably has a wavelength of 620 nm to 700 nm, but is not limited thereto.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Here, FIG. 1A is a cross-sectional view of the pulse sensor of the present embodiment, FIG. 1B is a surface view of the pulse sensor, and FIG. FIG. 9 is an explanatory diagram for explaining a state of detecting a pulse of the measured object.

A pulse detecting device that detects the pulse of a subject by utilizing the property of hemoglobin contained in red blood cells to absorb light, irradiates the subject with light as shown in FIG. A pulse sensor 1 for receiving reflected light from a measurement object and converting the reflected light into an electric signal corresponding to the amount of reflected light;
And a pulse calculator 60 for calculating the pulse of the object to be measured based on the electric signal input from. This pulse detection device
When light is applied to the measured object, the reflected light is absorbed according to the blood flow rate of the blood flowing through the body of the measured object, and the amount of light increases or decreases. The reflected light is received, and the pulse calculator 60 calculates the pulse of the measured object from the electric signal obtained by converting the reflected light according to the light amount.

The pulse detecting device provided with the pulse sensor 1 of the present embodiment measures the pulse sensor 1 to measure the pulse of the measured object, especially during exercise.
The pulse calculator 60 is fixed around the waist with a belt or the like (not shown).
In addition, this pulse detection device has a built-in battery in the pulse calculator 60 as a power source for detecting the pulse of the object to be measured during exercise.

The processing for calculating the pulse from the electric signal by the pulse calculator 60 is not the gist of the present embodiment, and therefore the detailed description is omitted. Hereinafter, the pulse sensor 1 of the present embodiment will be described in detail. As shown in FIG. 1, a pulse sensor 1 of the present embodiment includes a pulse sensor main body 10 formed in a hollow, thick, substantially disk-shaped shape, and a pulse sensor A light-emitting diode 20 that emits irradiation light to irradiate the object, and a photodiode 30 that receives light reflected by the object to be measured.

The pulse sensor main body 10 includes a bottom portion 124 having a substantially semicircular cross section, and a bottomed cylindrical portion 12 formed in a cylindrical shape, and an opening 12 of the bottomed cylindrical portion 12.
2, a flexible, thin-film resin plate 14 made of vinyl chloride, which is attached along the opening surface of the opening 122, and a bottomed cylindrical portion 12 in the center of the resin plate 14. A hemispherical convex mirror 16 is provided upright toward the bottom 124. A reflective material is attached to the inside of the bottom 124 of the bottomed cylindrical portion 12, and the light reflected by the convex mirror 16 is directed toward the opening surface. It is formed in a concave mirror shape so as to reflect light. Hereinafter, the portion inside the bottom portion 124 to which the reflective material is attached is referred to as a “concave mirror 126”. still,
The reason why the flexible material is used as the resin plate 14 is that when the pulse sensor 1 is attached to the object to be measured, the resin plate 14 is brought into close contact with the skin to prevent external light from entering.

A light scattering agent 40 made of light opaque silicon is embedded in a closed space formed by the cylindrical portion 12 and the resin plate 14. Next, the light-emitting diode 20 emits visible light (hereinafter, referred to as “red light” as necessary) that is split into red light as irradiation light at 660 nm.
Is a light emitting element having a peak wavelength of, and is mounted on the mirror surface of the concave mirror 126 facing the top of the convex mirror 16.

The photodiode 30 receives the red light reflected by the measured object as reflected light, and converts the reflected light into an electric signal corresponding to the amount of light.
A light-receiving element having sensitivity to the visible light side with m as a light-receiving peak wavelength, which is attached to the center of the resin plate 14 below the convex mirror 16 so that the light-receiving surface is along the opening surface of the opening 122. .

Further, a power supply line a for supplying power to the light emitting diode 20 is wired in the bottom portion 124 of the bottomed cylindrical portion 12, and an electric signal is output to the outside on the inner surface of the resin plate 14. The power supply line b is connected to the power supply line b, and both power supply lines a and b are connected to the pulse calculator 60. When the pulse calculator 60 operates, the light emitting diode 20 is supplied with power through the power supply line a and emits light.

Hereinafter, the surface of the opening 122 excluding the light receiving surface for receiving the reflected light of the photodiode 30 and emitting the irradiation light to the outside is referred to as a light emitting surface 140. The pulse sensor 1 configured as described above converts the irradiation light emitted from the light emitting diode 20 into a light scattering agent 40 on the way.
First, while being scattered by passing through the inside, the light is reflected by the convex mirror 16 so as to spread in a plane toward the concave mirror 126,
Next, the irradiation light spread in a planar shape is reflected by the concave mirror 126 in a planar shape toward the light emitting surface 140 and emitted from the light emitting surface 140 to the outside.

Then, in the pulse sensor 1, first, the light emitting diode 20 using the convex mirror 16 and the concave mirror 126 is used.
Irradiation light emitted from the LED is spread in a plane and guided to the light emitting surface 140, and further scattered using the light scattering agent 40. Therefore, when the light is emitted directly from the light emitting diode 20 to the outside, the light is unevenly biased toward the center. Irradiation light can be emitted to the outside as planar light having a uniform light amount. Light emitting diode 2
Irradiation light emitted from the first and second mirrors 12 and 12
Since the light is reflected by the light 6 and guided to the light emitting surface 140, the irradiation light can be efficiently emitted to the outside without being blocked by the photodiode 30.

As a result, when the pulse sensor 1 is mounted on the measured object such that the light emitting surface 140 faces the measured object, and the light emitting diode 20 emits light, the light emitting surface 14 is
Since a uniform amount of irradiation light spread in a plane is applied to the irradiation surface facing 0, the reflected light reflected in the body of the measured object becomes a light having a uniform light amount spread in a plane. It is emitted from the irradiation surface to the outside. Although the reflected light is attenuated to some extent by the light scattering agent 40 on the way, the irradiation light emitted from the light emitting diode 20 is guided to the light emitting surface 140 with high efficiency. It is emitted from the irradiation surface with the amount of light.

Therefore, when the pulse sensor 1 is used, a uniform amount of reflected light that can be received by the photodiode 30 can be received from any part of the irradiation surface. Even if it is shifted, it is possible to always receive a uniform amount of reflected light and output an electric signal reflecting only the pulse.

Here, the pulse sensor 1 of the present embodiment was attached to the object to be measured, and the electric signal was measured by vibrating in the Y direction as shown in FIG. Will be described briefly. FIG. 3 is a graph showing the measurement results. However, the upper graph shows an amplified electric signal directly output from the pulse sensor 1, and the lower graph shows a graph other than the gain control process and the pulse value so that the pulse calculator 60 can easily calculate the pulse. (A process of cutting a frequency signal of 0.5 Hz or less by a band-pass filter or a frequency signal of 4 Hz or more) and the like. In each graph, the sign of the electric signal is reversed.

In the present measurement, the measurement was performed in a state where the pulse sensor 1 was attached and not vibrated (at rest) and in a state where it was vibrated (body movement). FIG. 3 shows the state of the electric signal measured at the time of rest and at the time of body movement. When the pulse sensor 1 according to the present embodiment is used, as can be seen from FIG. 3, not only at rest, but also at the time of body movement, a mountain representing the pulse clearly appears (arrow portion in the figure). It can be seen that detection can be performed reliably.

As described above, by using the pulse detecting device provided with the pulse sensor 1 of the present embodiment, it is possible to output an electric signal in which only the pulse is reflected even if the body to be measured moves. Therefore, the pulse of the person who is exercising can be reliably detected. Further, in the present embodiment, since red light is used as the irradiation light, it is affected by disturbance such as infrared light,
In addition, since visible light (hereinafter referred to as “blue light”) that is dispersed in blue is not reflected near the body surface before reaching an artery, it can be applied to a deep part of the object to be measured, such as a wrist. Receives reflected light reflecting changes in blood flow in an artery,
The pulse can be reliably measured.

In this embodiment, the pulse sensor 1 uses the light emitting diode 20 for irradiating red light and the photodiode 30 for receiving red light in order to measure the pulse using the artery of the wrist. According to the place where you do
Blue light (Ideal for attaching to a finger etc. to measure pulse)
A light-emitting diode or photodiode that radiates or receives infrared light (ideal when measuring the pulse by attaching it to a wrist, finger, or earlobe with the object to be measured resting in a place with little disturbance light indoors) Since the pulse can be measured by the pulse sensor 1 provided, the light emitting means and the light receiving means of the present invention are not limited to the above embodiment.

In the present embodiment, the light scattering agent 40 is filled in the closed space surrounded by the bottomed cylindrical body 10 and the resin plate 14, but, for example, as shown in FIG. The light scattering agent 40 may be filled only in the space to be irradiated, and the irradiation light reflected by the concave mirror 126 may be merely scattered.

Further, a condenser lens may be provided on the light receiving surface of the photodiode 30. Further, in order to attach the pulse sensor 1, a tape may be used in addition to the belt 50, and the present invention is not limited to this embodiment. In the above embodiment, the light emitting diode 20 is used as the light emitting means of the present invention, the photodiode 30 is used as the light receiving means, and the bottomed cylindrical body 1 is used.
0, the convex mirror 16 and the concave mirror 126 correspond to light guiding means, and the light scattering agent 40 corresponds to scattering means.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view and a surface view of a pulse sensor of the present embodiment.

FIG. 2 is an explanatory diagram for explaining a state in which the pulse sensor of the present embodiment is attached to a wrist.

FIG. 3 is a graph of a pulse signal output from the pulse sensor of the present embodiment.

FIG. 4 is a cross-sectional view of the pulse sensor of the present embodiment.

FIG. 5 is a schematic explanatory diagram for explaining a conventional parallel-type sensor.

6A and 6B are an explanatory diagram for explaining a state where a pulse is measured by a conventional parallel sensor, and a graph of a pulse signal when a pulse of a person exercising is measured by the parallel sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pulse sensor, 10 ... Pulse sensor main body, 12 ... Bottomed cylindrical part, 14 ... Resin plate, 16 ... Convex mirror, 20 ... Light emitting diode, 30 ... Photodiode, 40 ... Light scattering agent, 50
... belt, 60 ... pulse calculator, 122 ... opening, 124
… Bottom, 126… Concave mirror

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yushito Sai 3-6-29 Nishiki, Naka-ku, Nagoya-shi, Aichi Inside Kowa Spinning Co., Ltd. No. 29 Kowa Corporation F term (reference) 4C017 AA10 AB02 AC28 FF05

Claims (2)

[Claims] 1. A light-emitting means for emitting irradiation light which can be absorbed by blood, and a light-emitting surface for emitting the irradiation light emitted by the light-emitting means is formed. Light guiding means for guiding the light emitting surface; and light receiving means disposed at the center of the light emitting surface for receiving reflected light incident from the light emitting direction on the light emitting surface. By causing the light emitting means to emit light in opposition to the measurement object, the reflected light reflecting the change in the blood flow rate based on the pulse of the measured object is received by the light receiving means, and the amount of light received by the light receiving means A pulse sensor that outputs an electric signal according to the following: the light guide means, a convex mirror that diffuses and reflects the irradiation light from the light emitting means in a planar shape, and the irradiation light reflected by the convex mirror to the light emitting surface. A concave mirror reflecting in a plane toward the surface, and the concave mirror Is disposed between the light emitting surface, the pulse sensor characterized by having a scattering means for scattering illumination light reflected by the concave mirror. 2. The pulse sensor according to claim 1, wherein the light emitting unit irradiates, as the irradiating light, visible light that is split into red light, and the light receiving unit emits the visible light that is split into red light. A pulse sensor which receives as reflected light.