JP2013000540A - Pulse wave detector, and pulse wave detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such the problems that a large number of components are used and a lot of time is needed for processing each of information obtained from a plurality of light receiving elements, since the plurality of light receiving elements and light emitting elements are provided and they are arranged near the artery with a high probability in a pulse wave detector.SOLUTION: The pulse wave detector includes one light receiving element and the plurality of light emitting elements having prescribed positional relation with one another. Thus, since one of the light emitting elements is arranged near the artery with the high probability and detection accuracy does not decline no matter from which light emitting element the light is detected by the light receiving element, there is provided the pulse wave detector which is capable of accurately detecting pulse waves, has the small number of components, consumes little power, and processes the information in a short time.

Description

  The present invention relates to a pulse wave detection device using light.

  In general, in a medical facility such as a hospital, when measuring biological information without damaging the patient's body, by measuring the light passing through the living body and passing through the living body with a light receiving element, Means for measuring biological information such as pulse rate and oxygen saturation is used. In recent years, interest in health has increased, and products that can generally use these biometric devices developed for medical use are commercially available. The device that detects the pulse wave and the pulse rate irradiates the living body to be measured with visible light or infrared light, detects a change in blood flow in the blood vessel with a light receiving element, performs calculation processing, and calculates the pulse wave and pulse rate. calculate. Details are as follows. Blood is drained from the heart at a constant rhythm according to the heartbeat, and the arteries are beating. Since hemoglobin contained in arterial blood has a light absorption characteristic different from that of other human tissues with respect to the wavelength of light, pulse waves can be measured by measuring and processing the pulsation change of arterial blood using that characteristic. And the pulse rate is calculated. In the pulse wave detection device using these lights, the most suitable measurement place is the fingertip abdomen. This portion has a high density of capillaries, and in medical use, products detected from the fingertips are common.

On the other hand, when a general person records the pulse wave and pulse rate during exercise and uses it to improve the exercise method, for example, if it is attached to the tip of the fingertip during running, it will interfere with running, so the device will be like a wristwatch and wrist There are also products that detect from the arm. However, because biological parts such as wrists and arms have a lower capillary density than fingertips and a wide range of measurement parts, an accurate pulse wave shows how the measurement device can be attached to the vicinity of an artery or a part with a high capillary density. Become a detection requirement.
Accordingly, an invention has been made to solve the problem by arranging a plurality of light emitting elements and light receiving elements in a wide range. As an example, the inventions described in Patent Documents 1 and 2 use a detection device including a plurality of sensors each composed of a light emitting element and a light receiving element, and are attached to a living body to be measured. Located directly above or near. Since the pulse component is easier to detect as it is closer to the artery, the optimal single light receiving element is selected and identified from the pulse wave signals detected by each sensor, and the pulse rate is calculated by processing the pulse wave signal. Yes.

JP 59-131327 A Japanese Patent Laid-Open No. 7-299043

In the conventional pulse detecting device, when the living body measurement place is wide, such as a forehead, a temple, a wrist, etc., in order to obtain more accurate pulse wave information, the number of sensors is arranged so as to be as close to the artery as possible. As the number of sensors increases, the processing time also increases. Furthermore, since the power consumption increases in proportion to the number of sensors, there is a problem that the operation time is adversely affected particularly in the case of a battery built-in device.
In view of the above problems, an object of the present invention is to provide a pulse wave detection device and a pulse wave detection system in which the number of necessary parts is reduced even in a wide detection location.

  In order to achieve the above object, the present invention provides a pulse wave detection device for detecting a pulse wave generated by a living body, comprising: a light receiving element that receives and detects light passing through the living body; A plurality of light emitting elements that are arranged at equal intervals in the same circle and that generate light that irradiates the living body, and a pulse wave signal that detects a pulse wave signal by photoelectrically converting the light detected by the light receiving element It has a detection part.

Further, the present invention is a pulse wave detection system having a pulse wave detection device for detecting a pulse wave generated by a living body and a display unit for displaying information,
The pulse wave detection device includes a light receiving element that receives and detects light passing through the living body, and light that is arranged at equal intervals in the same circle centered on the light receiving element and that irradiates the living body A plurality of light emitting elements that generate light, a pulse wave signal detecting unit that photoelectrically converts light detected by the light receiving element to detect a pulse wave signal, and a pulse rate based on the pulse wave signal detected by the pulse wave signal detecting unit A calculation unit that calculates and calculates biometric information including the communication unit that transmits the biometric information obtained by the calculation unit to a device provided outside,
The display unit displays the biological information received from the communication unit of the pulse wave detection device.

  According to the present invention, it is possible to provide a pulse wave detection device and a pulse wave detection system that reduce the number of necessary components even if the detection location is wide. Furthermore, there is an effect that the power consumption of the apparatus can be reduced according to the embodiment.

It is a front view of the pulse wave detection device in an embodiment. It is sectional drawing of the pulse-wave detection apparatus in embodiment. It is a block diagram which shows the structure of the pulse-wave detection apparatus in embodiment. It is a 1st figure explaining the pulse wave detection method in an embodiment. It is a 2nd figure explaining the pulse wave detection method in an embodiment. It is a 1st sketch of the biological measurement system in an embodiment. It is a 2nd sketch of the biological measurement system in embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A and 1B are diagrams showing a pulse wave detection device according to an embodiment, FIG. 1A is a front view (a view seen from a light receiving surface), and FIG. 1B is a cross-sectional view. Here, the case where the number of light emitting elements is 102A to 102D is described, but the number is not limited to four. Hereinafter, a description common to a plurality of light-emitting elements is referred to as a light-emitting element 102. The light emitting element 102 is arranged at an optimum distance 103 from the light receiving element 101 to the wavelength and light intensity of the light emitting element 102. When the light wavelength and light intensity change, the biological transmittance of the human tissue also changes. Therefore, the optimum distance 103 is set according to the wavelength of the selected light emitting element 102. That is, when a plurality of light emitting elements 102 are arranged, they are arranged on the same circle having a radius of 103 around the light receiving element 101. With respect to the distance between the light emitting elements 102, if the angle formed by the line connecting the light receiving elements 102 to the adjacent light receiving elements 101 is α, the angle α can be derived from the following equation.
α = 360 / n (n: total number of light emitting elements for pulse wave detection)
The wavelengths of the plurality of light emitting elements 102 are preferably used in a unified manner. This is because the biological transmittance varies depending on the wavelength as described above. When different wavelengths are used in combination, the depth at which the transmitted light reaches the living tissue varies depending on the difference in biological transmittance. In other words, the light detected by the light receiving element 101 is a portion having a different depth in the living body, which causes a problem of obtaining information on different living body parts. Therefore, for the pulse wave signal of one wavelength, the pulse wave signal of the other wavelength is biological information at a different depth and becomes noise, so it is necessary to select the same wavelength. In general, light having a wavelength in the vicinity of 400 to 600 nm where the extinction coefficient of oxyhemoglobin and deoxyhemoglobin in the blood is high, or in the vicinity of 800 to 1000 nm where the biological transmittance is high is suitable.

The positional relationship between the light emitting element 102 and the living body 106 to be measured is arranged so as to optically oppose and contact the measurement site of the living body 106 in the normal direction. When the light emitting element 102 and the living body 106 are optically separated from each other, the light is reflected from the surface of the living body and received by the light receiving element 101 together with the transmitted light including the pulse wave component that has passed through the inside of the living body. This is because of noise. Specifically, an LED (Light Emitting Diode) or the like is used as the light emitting element 102.
As the light receiving element 101, an element having as high a light receiving sensitivity as possible with respect to the wavelength of the light emitting element 102 is selected. The light receiving surface is arranged to face the measurement target. Specifically, a phototransistor, a photodiode, or the like is used as the light receiving element 101.

There is a base material 105 or a structural member 105 such as an electronic substrate to which the light receiving element 101 and the light emitting element 102 are attached, and there is an apparatus main body 104 in which these are incorporated. The apparatus main body 104 is provided with openings for the light receiving element 101 and the light emitting element 102, and a cover 107 made of a material that transmits light is attached thereto. The cover 107 may be optically selected and controlled using an optical filter.
A partition 108 is installed between the light emitting element 102 and the light receiving element 101 in order to prevent direct light from the light emitting element from entering. Specifically, it may be surrounded by a structural part like the partition 108 in FIG. 1, or may be partitioned by a tape having a light shielding effect.

  The apparatus main body 104 may be directly attached to the living body 106 using an adhesive. Specifically, a single-sided adhesive tape, a double-sided adhesive tape, etc. are used. The single-sided adhesive tape is affixed and fixed to a portion other than the light receiving surface of the apparatus main body 104, and is also affixed and fixed to the living body 106 to be measured. If the tape itself uses a stretchable base material or pressure-sensitive adhesive, even when body movement occurs, the movement is absorbed, so that the influence of body movement noise can be suppressed. The size of the tape is such that it covers the apparatus main body 104 so that ambient light does not enter the light receiving unit 101, and it is effective to use a material and color that have a light shielding effect.

  The double-sided adhesive tape is placed on one side of the light receiving surface of the apparatus main body 104 so that the optical performance of the light receiving element 101 and the light emitting element 102 is not affected, and the other surface is attached to the living body 106 to be measured. Attached. Since the double-sided pressure-sensitive adhesive tape only has to be bonded between the light receiving surface and the living body 106, restrictions on attaching to the living body 106 are eased compared to the case where a single-sided adhesive tape is used. Moreover, since the tape itself cannot be directly seen, it is excellent from the viewpoint of design. If a material having high light transmittance is selected as the material of the double-sided adhesive tape and is applied to the entire surface of the light receiving surface, it can be applied without worrying about the positions of the light receiving element 101 and the light emitting element 102, and workability is improved. Further, since the adhesive tape itself becomes a light guide plate and optically connects between the living body 106 and the light receiving element 101, light including a pulse wave can be received without loss as compared with the case where there is nothing.

As a method of fixing the apparatus main body 104 to the living body 106, there is also a method of fixing by attaching a belt-like restraining tool. Specifically, belts, hook-and-loop fasteners, and the like. When attaching to the living body 106 with a belt, the apparatus main body 104 is provided with a guide for mounting the belt, fixed to the guide, and attached to the living body 106 to be measured. Since the belt can be wrapped around a living body like a wristwatch and fixed with a fastener at an arbitrary position, it is easy to handle and has an excellent appearance. Similarly to the belt, the surface fastener is provided with a guide for passing the surface fastener around the apparatus main body 104, wound around the living body 106 to be measured, and fixed to an arbitrary length by coupling the surface fasteners. Since the hook-and-loop fastener does not require a belt-like fastener, the structure is simple and inexpensive.
In addition, if an elastic body is used for both the belt and the hook and loop fastener, it follows the movement of the living body, so that the pulse wave can be measured even if body movement occurs.

FIG. 2 shows the configuration of the apparatus main body 104, and includes an interface unit 201, a filter unit 202, a gain adjustment unit 203, a control unit 204, a battery 205, a calculation unit 206, a storage unit 207, a communication unit 208, and a pulse wave signal detection. Part 209.
The light emitted from the light emitting element 102 is photoelectrically converted by the light receiving element 101 through the living body. Noise and direct current components are removed from the photoelectrically converted electrical signal by the filter unit 202 and amplified by the gain adjustment unit 203. The pulse wave signal detection unit 209 processes the electrical signal in time series to obtain a pulse wave signal, which is stored in the storage unit 207, or wired or wirelessly via the communication unit 208 (both not shown). Send). It is also possible to give the calculation unit 206 a frequency analysis function and generate from the pulse wave signal to biological information such as the pulse rate in the apparatus main body 104.

  3A and 3B are diagrams for explaining the details of the detection method of the present invention. FIG. 3A is a simplified configuration diagram for explanation, and FIG. 3B is a diagram schematically showing a measurement target and a detection device. In FIG. 3A, if the wavelengths and light intensities of the light emitting elements 102A to 102D are the same, the distance 103 between the light emitting elements 102A to 102D and the light receiving element 101 is equal, and the logical detection range 301 is determined. Can be detected. From the above formula, the positional relationship of the light emitting elements 102A to 102D is α = 360/4 = 90 degrees if there are four. In this way, even if there is only one light receiving element 101, light generated by any light emitting element can be detected under the same conditions, and the problem that the detection accuracy decreases can be solved.

  As shown in FIG. 3B, it is assumed that there is a blood vessel 306 to be measured and there are portions 307 and 308 suitable for measurement. In the present invention, when the portions 307 suitable for measurement are distributed on a straight line connecting the light emitting element 102A and the light receiving element 101, they can be detected without any problem as in the prior art. Even if it is off the straight line connecting the light emitting element and the light receiving element as in the portion 308 suitable for measurement, the light intensity can be compensated for by the transmitted scattered light of the light emitting elements 102C and 102D. Detection is possible within a circle having a radius 103 (detection range 301). Since the light receiving element 101 can be realized by one, a plurality of light receiving elements can be arranged as in the prior art, and the process of selecting and processing the optimum signal from all the light receiving element signals can be saved, and the processing means can be simplified. . In order to make up for the detection range 301 in the prior art, at least as many light receiving elements 101 as light emitting elements are required. Even if there are a plurality of light emitting elements 102, low power consumption can be easily realized by an efficient method such as pulse control. However, since the light receiving element 101 always requires power, in the present invention using one light receiving element. Therefore, power consumption can be reduced as compared with the prior art.

  4A and 4B are sketches of the biological measurement system according to the embodiment, and show an example of a measurement system when a belt is used as a fixing method for the apparatus main body 104 of the present invention. 4A is a view seen from the light receiving surface of the apparatus main body 104, and FIG. 4B is an overall view of the measurement system including the rear view of FIG. 4A. The measuring instrument main body 401 including the apparatus main body 104 includes a guide 402 for attaching a belt, and the belt 403 is attached thereto. The belt 403 is provided with a fastener 404, and the belt can be wound around and fixed to the living body 106 to be measured. The measurement device main body 401 includes a display unit 405, which can display information obtained by the calculation unit 206 and call and display information stored in the storage unit 207. The measurement device main body 401 is provided with an operation unit 406, and can perform measurement start, measurement stop, information input, display switching, data transmission / reception, and the like.

  An external information processing device 407 is prepared separately from the measurement device main body 401. Information obtained by the arithmetic unit 206 of the apparatus main body 104 and information stored in the storage unit 207 are wirelessly transmitted and received by the external information processing apparatus 407. The external information processing apparatus 407 has a function of analyzing biological information in detail based on information from the apparatus main body 104, and performs, for example, estimation of fatigue, comparison with past data, calculation of exercise intensity, etc. Along with the biological information from the main body 104, the information is displayed on the display unit 408 of the external information processing apparatus 407. The external information processing apparatus 407 is provided with an operation unit 409, and starts receiving from the apparatus main body 104, stops receiving, starts recording, stops recording, detailed analysis of biological information, information input, display switching, data transmission / reception, etc. Can be implemented.

The external information processing apparatus 407 is effective as a means for the person himself / herself to confirm the biological information in real time when the measurement apparatus main body 401 is fixed to a biological part that cannot be confirmed by the person himself / herself, such as an arm or a head. Or, when performing full-scale exercise training, it is also effective when the instructor constantly monitors the external information processing device 407 and gives appropriate advice to the training operator.
4A and 4B are examples of a measurement system using the apparatus main body 104 of the present invention, and the measurement system to which the present invention is applied is not limited to this. In other embodiments, examples in which additions and changes of constituent elements are added to the disclosed examples can be considered, but all fall within the scope of the present invention.

  101: light receiving element, 102: light emitting element, 104: apparatus main body, 105: base material, 106: living body, 107: cover, 201: interface unit, 202: filter unit, 203: gain adjusting unit, 204: control unit, 205 : Battery, 206: calculation unit, 207: storage unit, 208: communication unit, 209: pulse wave signal detection unit, 301: detection range, 306: blood vessel to be measured, 307 to 308: measurement site, 401: device main body Including measuring instrument, 402: guide, 403: belt, 404: fastener, 405: display unit, 406: operation unit, 407: external information processing device, 408: display unit, 409: operation unit.

Claims (9)

A pulse wave detection device for detecting a pulse wave generated by a living body,
One light receiving element that receives and detects light through the living body;
A plurality of light-emitting elements that are arranged at equal intervals in the same circle centered on the light-receiving element and that generate light for irradiating the living body;
A pulse wave detection apparatus comprising: a pulse wave signal detection unit that photoelectrically converts light detected by the light receiving element to detect a pulse wave signal.   2. The pulse wave detection device according to claim 1, further comprising a calculation unit that calculates and obtains biological information including a pulse rate based on the pulse wave signal detected by the pulse wave signal detection unit. .   The pulse wave detection apparatus according to claim 2, further comprising a storage unit that stores biological information obtained by the calculation unit.   The pulse wave detection device according to claim 2, further comprising a display unit that displays biological information obtained by the calculation unit.   The pulse wave detection device according to claim 2, further comprising a communication unit that transmits biological information obtained by the calculation unit to an information processing device provided outside. A pulse wave detection system having a pulse wave detection device for detecting a pulse wave generated by a living body and a display unit for displaying information,
The pulse wave detector is
One light receiving element that receives and detects light through the living body;
A plurality of light-emitting elements that are arranged at equal intervals in the same circle centered on the light-receiving element and that generate light for irradiating the living body;
A pulse wave signal detector that photoelectrically converts light detected by the light receiving element to detect a pulse wave signal;
A calculation unit for calculating biological information including a pulse rate based on the pulse wave signal detected by the pulse wave signal detection unit;
A communication unit that transmits biometric information obtained by the calculation unit to a device provided outside;
The display unit
The biological information received from the communication part of the said pulse wave detection apparatus is displayed. The pulse wave detection system characterized by the above-mentioned.   7. The pulse wave detection system according to claim 6, wherein the communication unit of the pulse wave detection device performs wireless communication with the display unit.   2. The pulse wave detection device according to claim 1, wherein the pulse wave detection device includes a band-shaped restraining tool and is fixed to the living body.   The pulse wave detection device according to claim 1, wherein the pulse wave detection device includes an adhesive and is fixed to the living body.

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