Interference suppression device for vital sign measurement

Abstract

This prevents and suppresses radio interference, enabling accurate measurement of heart rate and other parameters using radar. [Solution] When measuring vital signs including the heart rate of a person P by irradiating them with radio waves, the system includes an antenna 2 that can be placed on the surrounding objects, including the bed B on which the person P is lying down, and which receives the irradiated radio waves; a rectifier circuit 3 that forms a rectenna with the antenna 2 and converts the radio waves received by the antenna 2 into electrical energy; and a secondary battery 4 that stores the electrical energy converted by the rectifier circuit 3.

Description

Technical Field

[0005]

[0001] The present invention relates to an interference suppression device for vital measurement for suppressing radio wave interference when non - contact measurement of a person's heart rate and respiratory rate is performed using a radio wave sensor such as a radar.

Background Art

[0002] For example, as a technique for non - contact measurement of the heart rate of a patient hospitalized in a hospital, etc., a device using radio waves / electromagnetic waves (microwave or millimeter - wave radar) with a short wavelength has been developed (see, for example, Patent Document 1). This device irradiates radio waves to a patient, receives the reflected waves from the patient, filters them with at least one frequency component included in the heartbeat signal, and performs calculations related to the heartbeat from the signal waveform obtained by the filtering.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when measuring the heart rate etc. using a radio wave sensor such as a radar, radio waves are also irradiated to surrounding objects such as the bed on which the patient is lying, and radio wave interference may occur due to the reflected waves from those surrounding objects. And when such radio wave interference occurs, noise increases, the S / N ratio deteriorates, and the measurement accuracy of the heart rate etc. decreases.

[0005] Therefore, an object of the present invention is to provide an interference suppression device for vital measurement that can prevent / suppress radio wave interference and enable proper measurement of the heart rate etc.

Means for Solving the Problems

[0006] To solve the above problems, the invention described in claim 1 is an interference suppression device for vital sign measurement, characterized in that, when measuring vital signs including the heart rate of a person to be measured by irradiating the person to be measured with radio waves, the device comprises an antenna that can be disposed on a surrounding object including a bed on which the person to be measured lies and receives the irradiated radio waves, and a rectifier means that forms a rectenna (an antenna that converts electromagnetic waves into direct current) with the antenna and converts the radio waves received by the antenna into electrical energy.

[0007] The invention described in claim 2 is characterized in that, in the interference suppression device for vital sign measurement described in claim 1, it comprises an energy storage means for storing the electrical energy converted by the rectifier means. [Effects of the Invention]

[0008] According to the invention described in claim 1, when measuring a person's heart rate, etc., using a radio wave sensor such as a radar, even if radio waves are irradiated onto surrounding objects such as a bed, those radio waves are received by the antenna. As a result, reflected waves from sources other than the person being measured are reduced, and radio wave interference caused by reflected waves from surrounding objects is prevented and suppressed, making it possible to accurately measure heart rate, etc.

[0009] Furthermore, the radio waves received by the antenna are converted into electrical energy by a rectification mechanism. This prevents the radio waves from being wasted as heat and allows them to be effectively utilized as electrical energy. Moreover, by utilizing radio waves as electrical energy, it becomes possible to contribute to power saving and the reduction of carbon dioxide emissions.

[0010] According to the invention described in claim 2, since the electrical energy converted by the rectifier means is stored in the energy storage means, it becomes possible to effectively and flexibly utilize the electrical energy from radio waves (for any purpose at any time). [Brief explanation of the drawing]

[0011] [Figure 1]This figure shows the vital sign measurement interference suppression device according to an embodiment of this invention applied to a bed. [Figure 2] Figure 1 is a schematic block diagram showing the interference suppression device for vital sign measurement. [Figure 3] This figure shows the vital sign measurement interference suppression device according to an embodiment of this invention applied to a curtain. [Modes for carrying out the invention]

[0012] The present invention will be described below based on the illustrated embodiments.

[0013] Figure 1 shows the vital sign measurement interference suppression device 1 according to an embodiment of this invention applied to bed B, and Figure 2 is a schematic block diagram showing the vital sign measurement interference suppression device 1. This vital sign measurement interference suppression device 1 is a device for preventing and suppressing radio wave interference when measuring vital signs, including the heart rate of a person being measured by irradiating the person being measured P with radio waves. In this embodiment, the person being measured P is a patient hospitalized in a hospital, and a radar-type vital sign measurement device L is placed around bed B where the person being measured P is lying down. This device irradiates the person being measured P with short-wavelength radio waves (millimeter-wave radar) and measures the heart rate and respiratory rate based on the reflected waves from the person being measured P.

[0014] The vital sign measurement interference suppression device 1 mainly comprises an antenna 2, a rectifier circuit (rectifier means) 3, and a secondary battery (energy storage means) 4.

[0015] Antenna 2 is an antenna that can be installed on an object surrounding the person being measured P and receives radio waves emitted from the radar-type vital sign measuring device L. Here, an object is an object placed around the person being measured P that may be emitted from (reached by) radio waves from the radar-type vital sign measuring device L. In this embodiment, the case of a sheet on the bed B on which the person being measured P lies will be described.

[0016] Furthermore, the function of antenna 2 is to receive irradiated radio waves and to form a rectenna with the rectifier circuit 3 described later; in other words, it can be any shape or configuration as long as it can form a device that converts radio waves into electrical (DC) energy. In this embodiment, the antenna elements are arranged and connected in a grid or mesh pattern, and the whole is made to be flexible and deformable. Also, antenna 2 may be attached to the bed sheet B afterwards (for example, by sewing it on), or antenna 2 may be integrated into the bed sheet B (for example, by sewing it in beforehand).

[0017] Incidentally, it is assumed that one radar-type vital sign measuring device L will measure the heart rate and other vital signs of one subject P. Therefore, for example, if multiple patients / subjects P are housed in one hospital room, and each subject P is measured by irradiating them with radio waves using the radar-type vital sign measuring device L to measure their heart rate and other vital signs, it is thought that a problem will arise in which adjacent radio waves interfere with each other, reducing the measurement accuracy. To address this, it is possible to prevent radio wave interference by limiting the radio wave irradiation range to only the area around one subject P and suppressing unnecessary (wide-area) radio wave emission.

[0018] The rectifier circuit 3 forms a rectenna with the antenna 2 and is a circuit / device that converts radio waves received by the antenna 2 into electrical (DC) energy. Here, any structure / circuit that can convert into electrical energy is acceptable, but for example, it is composed of a demodulation diode or a Schottky diode. In this embodiment, one rectifier circuit 3 is connected to the entire antenna 2, but a rectifier circuit may be provided for each antenna element. Such a rectifier circuit 3 is designed to be detachably attached to a structure surrounding the antenna 2, for example, to the frame of the bed B.

[0019] The secondary battery 4 is a component that stores the electrical energy converted by the rectifier circuit 3. That is, the rectifier circuit 3 is connected to the terminals of the secondary battery 4, and the secondary battery 4 is charged by the DC energy converted by the rectifier circuit 3. Such a secondary battery 4 is detachably attached to a structure around the rectifier circuit 3, for example, the frame of the bed B. Incidentally, a DC / DC converter may be provided between the rectifier circuit 3 and the secondary battery 4 as needed.

[0020] Also, by removing the secondary battery 4 from the rectifier circuit 3 and connecting a load that consumes DC energy to the terminals of the secondary battery 4, the secondary battery 4 discharges and the load operates. Here, the load may be anything, for example, a radar-type vital measurement device L, a nurse call facility, or the like.

[0021] Thus, according to this vital measurement interference suppression device 1, when measuring the heart rate etc. of the measured person P lying in the bed B using a radio wave sensor such as a radar, even if the sheet of the bed B is also irradiated with radio waves, the radio waves are received by the antenna 2. As a result, reflected waves from outside the measured person P are reduced, and it is possible to prevent / suppress the occurrence of radio wave interference caused by the reflected waves from the sheet of the bed B, and it becomes possible to appropriately measure the heart rate etc.

[0022] Moreover, the radio waves received by the antenna 2 are converted into electrical energy by the rectifier circuit 3. Therefore, it is possible to prevent the radio waves from becoming heat and the energy from being wasted, and to effectively use it as electrical energy. Furthermore, by using radio waves as electrical energy, it is possible to contribute to power saving and reduction of carbon dioxide emissions.

[0023] That is, if it is only necessary to prevent and suppress the reflected wave from the sheet of the bed B, the sheet of the bed B may be made of an electromagnetic wave absorbing cloth. However, in the electromagnetic wave absorbing cloth, the absorbed electromagnetic wave is only converted into heat, and the generated heat is wasted. On the other hand, in this vital measurement interference suppression device 1, the absorbed radio wave can be effectively utilized as electric energy.

[0024] Furthermore, since the electric energy converted by the rectifier circuit 3 is stored in the secondary battery 4, it is possible to effectively and flexibly (at any time and for anything) utilize the electric energy from radio waves.

[0025] The embodiments of this invention have been described above. However, the specific configuration is not limited to the above embodiments, and even if there are design changes or the like within the scope that does not depart from the gist of this invention, they are included in this invention. For example, in the above embodiment, the case where the vital measurement interference suppression device 1 is applied to the bed B has been described, but it is also applicable to other peripheral objects. For example, as shown in FIG. 3, it may be applied to the curtain C in the hospital ward. <00001​​​​​​​​​​​​​ 4. Secondary batteries (energy storage means) P Person to be measured L Radar-type vital sign measurement device B Bed (Surroundings) C. Curtain (surrounding object)

Claims

1. In a case where vital signs, including the heart rate of a person being measured, are measured by irradiating the person being measured with radio waves, an antenna that can be installed on the surrounding objects, including the bed on which the person being measured is lying down, and which receives the irradiated radio waves, The antenna and the rectenna are configured together, and the rectifier means converts the radio waves received by the antenna into electrical energy, An interference suppression device for vital sign measurement, characterized by comprising the following features.

2. The system includes an energy storage means for storing the electrical energy converted by the rectifier means. The interference suppression device for vital sign measurement according to feature 1.

Images