JP6917852B2 - Biological information measurement device and pulse oximeter - Google Patents

Description

The present invention relates to a device for measuring biological information and a pulse oximeter.

A pulse oximeter is a medical device capable of non-invasively measuring _{arterial oxygen saturation (hereinafter, simply referred to as SpO 2} or oxygen saturation), which represents the ratio of oxygenated hemoglobin to total hemoglobin in arterial blood (for example, patent). Refer to Documents 1 and 2).

The pulse oximeter is configured to attach a probe to a measurement site such as a finger, toe, or earlobe. The probe is provided with a light emitting element such as a light emitting diode and a photodetector such as a photodiode. Then, red light and infrared light are irradiated from the light emitting element toward the measurement site, and the light transmitted through the measurement site or reflected from the measurement site is detected by the photodetector. The pulse oximeter calculates the oxygen saturation using the detection signal of the transmitted light or the reflected light obtained by the photodetector. Specifically, the fluctuation of the photodetection level synchronized with the pulse of arterial blood is compared between the case of red light and the case of infrared light, and the oxygen saturation is calculated from the ratio. The pulse oximeter displays the calculated arterial blood oxygen saturation on the display unit.

Japanese Unexamined Patent Publication No. 2001-78990 JP 2015-107152

By the way, in a pulse oximeter, a light emitting element such as a light emitting diode may cause burns to a finger, a toe, an earlobe, or the like, which is a measurement site. One of the causes of this burn is that the heat generated by the light emitting element itself is transmitted to the measurement site by heat conduction. In addition, one of the causes of burns is that the measurement site generates heat due to the synchrotron radiation from the light emitting element.

Further, in the pulse oximeter, the current consumption of the light emitting element occupies a large proportion of the current consumption of the entire pulse oximeter. Therefore, the current consumption of the battery-powered light emitting element has a great influence on the battery operating time of the entire pulse oximeter.

The present invention has been made in consideration of the above points, and provides a biometric information measuring device and a pulse oximeter in which a subject is not burned and current consumption is reduced.

One aspect of the biometric information measuring device of the present invention is
An external light intake unit that captures external light into the measurement site,
A first photodetector that detects the red light of the external light that has passed through the measurement site, and
A second photodetector that detects the infrared light of the external light that has passed through the measurement site, and
To be equipped.

One aspect of the pulse oximeter of the present invention is
The device for measuring biological information and
A signal processing unit that obtains arterial blood oxygen saturation based on the detection results of the first and second photodetectors, and
To be equipped.

According to the present invention, it is possible to measure biological information such as oxygen saturation that does not require a light emitting element, and as a result, the subject is not burned by the light emitting element and the current consumption is reduced. Become.

The figure which shows the whole structure of the pulse oximeter which concerns on embodiment Cross-sectional view of the probe portion seen from the side surface direction of the finger when the probe is attached to the finger. Cross-sectional view of the probe portion seen from the fingertip direction with the probe attached to the finger

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an overall configuration of a pulse oximeter according to the present embodiment. The pulse oximeter 10 has a probe unit 100 and a main body unit 200. The probe portion 100 and the main body portion 200 are connected via a cable 300. The probe portion 100 can be attached to the finger of the subject, and the main body 200 can be attached to the vicinity of the wrist of the subject using a wristband (not shown).

The main body 200 is a signal processing unit 203 (FIG. 2) and a display unit 201 that perform measurement processing of oxygen saturation using the detection signal of transmitted light input from the photodetectors 104 and 105 (FIG. 2) of the probe unit 100. It also has an operation unit 202 and the like.

2 and 3 are cross-sectional views for explaining the configuration of the probe portion 100 of the present embodiment. FIG. 2 is a cross-sectional view of the probe portion 100 viewed from the side surface direction of the finger when the probe portion 100 is attached to the finger, and FIG. 3 is a cross-sectional view of the probe portion 100 viewed from the fingertip direction when the probe portion 100 is attached to the finger. It is a cross-sectional view of.

The probe portion 100 has a case 101, and the case 101 has a shape that wraps a fingertip so that light does not enter the inside as much as possible.

An external light intake hole 102 is formed in the case 101 at a position facing the oxygen saturation measurement site. In the case of the examples of FIGS. 2 and 3, the external light intake hole 102 is formed at a position facing the claw.

A collimator lens 103 is provided at a position corresponding to the external light intake hole 102, so that the external light that has entered the case 101 from the external light intake hole 102 is made into parallel light by the collimator lens and then measured. It shines in. Further, a condensing lens may be provided in addition to the collimator lens 103 to condense external light and allow it to enter the measurement site. However, the optical system such as the collimator lens 103 may be omitted if necessary and sufficient oxygen saturation can be measured without them.

Further, photo detectors 104 and 105 are provided in the case 101. The photo detectors 104 and 105 are provided at positions in the case 101 on the side opposite to the external light intake hole 102 with the measurement portion interposed therebetween. Photodetectors 104 and 105 are, for example, photodiodes. The photodetectors 104 and 105 are arranged at positions where the probe portion 100 comes into contact with the pad of the finger of the subject when the probe portion 100 is attached to the finger.

The photodetector 104 is configured to detect red light (for example, wavelength 660 [nm]) contained in the external light transmitted through the measurement site. On the other hand, the photo detector 105 is configured to detect infrared light (for example, a wavelength of 940 [nm]) contained in the external light transmitted through the measurement site.

The signal processing unit 203 is provided in the main body unit 200 (FIG. 1), and the red light detection result and the infrared light detection result are input from the photodetectors 104 and 105, and the red light and the infrared light are combined. The oxygen saturation is calculated based on the ratio. In addition, in FIG. 2, it was shown that one line came out from each of the photo detectors 104 and 105, but in reality, a plurality of conducting wires including plus and minus lines came out from each of the photo detectors 104 and 105. There is.

Considering the accuracy of measurement, it is preferable to prevent light from obliquely from entering the photodetectors 104 and 105 as much as possible. Therefore, the size of the external light intake hole 102 is preferably as small as possible as long as the amount of light can be secured. That is, the size of the external light intake hole 102 is preferably the minimum size that can secure the amount of light.

Further, the subject may be able to manually change the size of the external light intake hole 102. For example, a shutter mechanism that can be opened and closed may be provided so that the subject can manually change the size of the external light intake hole 102. In this way, the size of the external light intake hole 102 can be changed so that good oxygen saturation can be measured, for example, according to the measurement result of oxygen saturation.

As described above, the pulse oximeter 10 of the present embodiment uses the external light outside the case 101 such as sunlight and illumination light, takes in the external light inside the probe unit 100, and converts the external light transmitted through the measurement site into the external light. Since the oxygen saturation is calculated by detecting the contained red light component and infrared light component, it is possible to measure the oxygen saturation without the need for a light emitting element.

As described above, according to the present embodiment, the external light intake hole 102 that takes in external light into the measurement site, the first photodetector 104 that detects the red light of the external light that has passed through the measurement site, and the like. A signal processing unit 203 that obtains arterial oxygen saturation based on the detection results of the second photodetector 105 that detects the infrared light of the external light transmitted through the measurement site and the first and second photodetectors 104 and 105. And, so that the measurement of oxygen saturation that does not require a light emitting element can be realized, and as a result, the current consumption can be reduced and the probe configuration can be simplified without being damaged by the light emitting element. become.

The above-described embodiments are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from its gist or its main features.

In the above-described embodiment, the case where the external light intake hole 102 is formed in the case 101 has been described, but the present invention is not limited to this, and the point is that the red light required for measuring the oxygen saturation of the external light is required. Any structure may be used as long as it can capture the light and the infrared light into the measurement site, and a film that transmits these lights may be provided instead of the external light intake hole 102.

Further, in addition to the configuration of the above-described embodiment, an auxiliary light emitting element (for example, LED) for irradiating the measurement site may be provided. Then, when a sufficient amount of light for measurement cannot be taken in from the external light intake hole 102, if the auxiliary light emitting element is turned on, the environment in which it can be used is expanded while suppressing burns and current consumption. become able to. For example, an LED that emits light containing both wavelengths of red light and infrared light is provided in the vicinity of the external light intake hole 102, and when the amount of external light is insufficient for measurement, the LED is made to emit light, and this light is emitted. May be refracted using a prism or the like and incident on the measurement site.

Further, in the above-described embodiment, the pulse oximeter 10 of the type in which the probe portion 100 is attached to the finger has been described as an example, but the present invention is of the type in which the probe portion is attached to a measurement site such as a toe or an earlobe. The same applies to pulse oximeters. Furthermore, the present invention is widely applicable as a biometric information measuring device that measures biometric information using red light and infrared light transmitted through a measurement site.

Further, in the above-described embodiment, a separate pulse oximeter in which the probe portion 100 and the main body portion 200 are separated has been described as an example, but the present invention is not limited to this, and the integrated pulse oximeter is used. It can also be applied.

Further, in the above-described embodiment, the case where the detection signal obtained by the probe unit 100 is output to the signal processing unit 203 of the pulse oximeter 10 has been described, but the detection signal obtained by the probe unit 100 is used as other biological information. It may be output to a processing device. That is, the probe unit 100 of the above-described embodiment can be applied to other than the pulse oximeter. For example, the detection signal obtained by the probe unit 100 may be output to a biometric information processing device that measures a photoelectric pulse wave. Practically, since the probe unit 100 has an output unit such as a cable or a connector that outputs the detection results of the photodetectors 104 and 105, the probe unit 100 is connected to an external biometric information processing device via the output unit. In this way, the probe unit 100 can be widely used as a device for measuring biological information.

The present invention can obtain the effect that the subject is not burned and the current consumption is reduced, and is suitable for, for example, a portable pulse oximeter.

10 Pulse oximeter 100 Probe part 101 Case 102 External light intake hole 103 Collimator lens 104, 105 Photodetector 200 Main body part 203 Signal processing part

Claims (5)

An external light intake unit that captures external light into the measurement site,
A first photodetector that detects the red light of the external light that has passed through the measurement site, and
A second photodetector that detects the infrared light of the external light that has passed through the measurement site, and
Equipped with
The external light intake portion is an external light intake hole formed in the case of the probe attached to the measurement site.
The first and second photodetectors are provided at positions in the case of the probe on the side opposite to the external light intake hole with the measurement site in between.
The external light intake unit has a lens that converts the external light incident from the external light intake hole into parallel light.
A device for measuring biological information. An external light intake unit that captures external light into the measurement site,
A first photodetector that detects the red light of the external light that has passed through the measurement site, and
A second photodetector that detects the infrared light of the external light that has passed through the measurement site, and
Equipped with
The external light intake portion is an external light intake hole formed in the case of the probe attached to the measurement site.
The first and second photodetectors are provided at positions in the case of the probe on the side opposite to the external light intake hole with the measurement site in between.
The size of the intake hole can be changed by the user.
A device for measuring biological information. Further, it has an auxiliary light emitting element that irradiates the measurement site.
The device for measuring biological information according to claim 1 or 2. An output unit for outputting the detection results of the first and second photo detectors is further provided.
The device for measuring biological information according to any one of claims 1 to 3. The device for measuring biological information according to any one of claims 1 to 4,
A signal processing unit that obtains arterial blood oxygen saturation based on the detection results of the first and second photodetectors, and
A pulse oximeter equipped with.

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