Respiration sensor

Abstract

Provided is a respiration sensor comprising: a strain detection sensor having disposed therein a plurality of ribbon tapes formed of a first fabric into which carbon nanotube (CNT) yarns are woven or knitted; a second fabric to which the strain detection sensor is attached; a ring-shaped band formed of fibers or a nonwoven fabric to which the second fabric is attached; and a conversion unit for converting fluctuation in the length of the strain detection sensor into an electrical signal.

Description

Respiration Sensor

[0001] The present disclosure relates to a respiration sensor.

[0002] Rapid Response Systems (RRS), which respond to sudden changes in health conditions both inside and outside the hospital, and Rapid Response Teams (RRT), the medical teams that carry out RRS activities, are becoming increasingly important. Although RRS is eligible for health insurance point additions, in general hospital beds other than intensive care units (ICUs) within hospitals, biochemical tests take time to perform, even though they use chemical tests such as blood oxygen levels and sepsis progression as indicators. Furthermore, predicting sudden changes in symptoms is difficult, and emergency response measures are often implemented after the fact. Therefore, RRS is almost always triggered when a patient is in a sudden critical condition or in cardiac arrest (Non-Patent Document 1: Tsuji, T., et al., Acute Med Surg, 10:e870, DOI: 10.1002 / ams2.870 (2023)). Furthermore, although telemetry measurement technology for electrocardiograms, body temperature, and electroencephalograms using the latest electronic devices has become more sophisticated due to the advancement of sensors and improvements in computer and communication technologies, RRS requires a system of human monitoring and judgment. As a result, cases of cardiac arrest leading to death occur at night or on holidays with significantly higher frequency than during the day or on weekdays (Non-Patent Document 2).

[0003] Previous research has reported that an increase in respiratory rate precedes cardiac arrest (Non-Patent Document 2: Sugita Manabu, et al., Panel Discussion PD22-7 at the 51st Annual Meeting of the Japanese Society of Intensive Care Medicine (Sapporo, March 15, 2024)). According to this report, the upper threshold for lesions due to an increase in respiratory rate appears approximately 12 hours earlier than the threshold for a dangerous blood oxygen concentration. Therefore, it has been found that emergency survival rates can be dramatically improved if respiratory rate can be monitored accurately and continuously via wireless telemetry.

[0004] Traditionally, patient respiratory activity monitoring both inside and outside of hospitals has been performed by nurses or by caregivers at home, but it is difficult to accurately capture changes in a patient's respiratory activity through visual observation. Therefore, various methods have been devised to develop respiratory activity monitoring technologies. In 2020, Vanegas et al. published a comprehensive review of respiratory activity monitoring technologies, covering papers published up to 2019 (Non-Patent Document 3: Vanegus, E., et al., Sensing Systems for Respiration Monitoring: A Technical Systematic Review, Sensors, 20, 5446; doi:10.3390 / s20185446 (2020)).

[0005] Non-Patent Document 3 provides a detailed overview of respiratory motion measurement methods. Non-Patent Document 3 covers methods for measuring respiratory airflow, including differential gas flow meters, turbine gas flow meters, hot-wire anemometers, photoelectric sensors, and optical fiber sensors. Respiratory sound is measured using a microphone, but this is considered to have low accuracy. Non-Patent Document 3 also covers thermistors, thermocouples, collector elements, infrared sensors, and cameras (thermography) as methods for measuring air temperature changes due to exhalation. However, these methods are not suitable for measurements in general environments due to disturbances caused by fans and other factors. Non-Patent Document 3 also covers capacitive elements, nanocrystals, impedance sensors, and optical fibers as methods for measuring changes in air humidity, but these methods are affected by external disturbances such as natural wind and fans. Non-Patent Document 3 also covers chest and abdominal motion sensors, including various strain sensors, transthoracic impedance sensors, motion detection accelerometers and gyroscopes, and cameras (image processing).

[0006] The most commonly used respiratory motion measurement method is the detection of chest or abdominal motion. Although chest or abdominal motion detection is desirable as a method for detecting the peak of complex respiratory motion, which is not necessarily deep, as the peak of lung expansion can be shallow, a method for accurately converting this respiratory motion into an electrical signal has yet to be developed. Non-Patent Document 3 reports that conventional strain gauges and mechanical expansion / contraction sensors (e.g., rotary load cells) have an ambiguous detection of the respiratory motion peak. While solutions such as synchronizing with a metronome to identify the peak have been proposed, such methods are considered unsuitable for measurements outside of specific laboratory conditions, since even movements such as standing up from a stationary position can cause the synchronized calibration standard to shift. Therefore, Non-Patent Document 3 argues that a sensor system that satisfies all of the following requirements has yet to be developed: long-term continuous measurement, comfortable wearing, and unaffected by sweating, water, or everyday physical movements such as walking and sitting and standing.

[0007] In particular, existing sensors for detecting chest or abdominal movement essentially require direct attachment to bare skin to improve sensitivity. Solutions to the numerous problems caused by direct attachment to bare skin are needed. Furthermore, conventional sensors essentially detect strain at a single point. Since they measure muscle bending and stretching movements other than chest or abdominal expansion that accompany breathing without distinguishing them from breathing, noise processing in the measurement data becomes cumbersome. Complicated noise processing in the measurement data makes it impossible to use simple software and requires large power supplies, communication devices, and computers. The need for large power supplies, communication devices, and computers makes it difficult to measure breathing while maintaining a natural lifestyle.

[0008] Although every respiratory motion detection technology readily conceivable to those skilled in the art is available, no respiratory sensor has yet emerged that meets the needs of medical professionals, particularly those in the respiratory respiratory response (RRS) and respiratory response (RRT) fields. Technologies related to sensors for detecting chest or abdominal motion are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 3-56410, 5-115461, and 2001-17409. Japanese Patent Application Laid-Open Nos. 3-56410, 5-115461, and 2001-17409 disclose sensors equipped with a strain sensor, resistor, and capacitor attached to a belt. However, these sensors primarily consist of strain gauges that detect changes in electrical resistance or field capacitance at a single point using solid semiconductors or rubber-like materials, and because they do not conform to the soft body, they are unable to accurately detect respiratory motion. Particularly in medical settings, there are no products that selectively detect chest or abdominal respiratory motion.

[0009] The present disclosure has been made in consideration of the above points, and aims to provide a breathing sensor that, compared to conventional breathing sensors, has a simpler configuration yet can detect the breathing state of a wearer with high accuracy and does not cause discomfort to the wearer.

[0010] A respiratory sensor according to a first aspect of the present disclosure comprises a strain detection sensor in which a plurality of ribbon tapes made of a first fabric woven or knitted with carbon nanotube (CNT) yarn are arranged, a second fabric to which the strain detection sensor is attached, a ring-shaped band made of fiber or nonwoven fabric to which the second fabric is attached, and a conversion unit that converts fluctuations in the length of the strain detection sensor into an electrical signal.

[0011] A respiratory sensor according to a second aspect of the present disclosure is a respiratory sensor according to the second aspect, wherein the strain detection sensor is oriented approximately perpendicular to the body axis of a human or animal when the band is wrapped around the chest or abdomen of the human or animal.

[0012] A respiratory sensor according to a third aspect of the present disclosure is the respiratory sensor according to the first or second aspect, wherein the ribbon tapes are arranged substantially parallel to each other.

[0013] A respiratory sensor according to a fourth aspect of the present disclosure is the respiratory sensor according to the first or second aspect, wherein the CNT yarn is woven or knitted into the first fabric in a wave-like shape that includes extension portions that extend along the short direction of the ribbon tape and are arranged approximately parallel to each other at intervals along the long direction of the ribbon tape, and fold-back portions that connect adjacent extension portions by folding back in the short direction.

[0014] A respiratory sensor according to a fifth aspect of the present disclosure is the respiratory sensor according to the first or second aspect, wherein the ribbon tape has a width of 10 mm or less.

[0015] A respiratory sensor according to a sixth aspect of the present disclosure is the respiratory sensor according to the first or second aspect, wherein the conversion unit electrically outputs the one-dimensional expansion and contraction and three-dimensional deformation of the strain detection sensor as a change in electrical resistance or impedance.

[0016] A breathing sensor according to a seventh aspect of the present disclosure is the breathing sensor according to the first or second aspect, wherein the longitudinal direction of the ribbon tape and the stretch direction of the second fabric are substantially the same direction.

[0017] A respiratory sensor according to an eighth aspect of the present disclosure is the respiratory sensor according to the first or second aspect, wherein the fibers other than the CNT yarn in the strain detection sensor are made of an elastomer and a non-elastomer.

[0018] A respiration sensor according to a ninth aspect of the present disclosure is the respiration sensor according to the first or second aspect, wherein in the strain detection sensor, the fibers other than the CNT yarn are synthetic fibers.

[0019] According to the present disclosure, it is possible to provide a breathing sensor that has a simpler configuration than conventional breathing sensors yet can detect the breathing state of a wearer with high accuracy and does not cause discomfort to the wearer.

[0020] 1 is a diagram showing the appearance of a respiratory sensor according to an embodiment of the disclosed technology; FIG. 2 is a diagram showing the appearance of a base to which a ribbon tape is attached; FIG. 3 is a diagram showing an enlarged view of the ribbon tape; FIG. 4 is a diagram showing an example of a graph of respiratory movements measured by a subject wearing a respiratory sensor according to an embodiment of the present invention in a seated position; FIG. 5 is a diagram showing an example of a graph of respiratory movements measured by a subject wearing a respiratory sensor according to an embodiment of the present invention in a seated position; FIG. 6 is a graph comparing the progress up to cardiac arrest using the number of breaths of a subject measured by a respiratory sensor according to an embodiment of the present invention and other biomarkers.

[0021] Before describing the embodiments of the present disclosure, the circumstances that led the present inventor to the embodiments of the present disclosure will be described.

[0022] According to literature by experts on respiratory movement measurement (Non-Patent Documents 1, 2, 3), respiratory movement measurement is an essential measurement item for intensive care and emergency or critical care, and although numerous technologies have been proposed, no practical product technology has yet emerged for use in medical settings. The reasons for this can be summarized as follows:

[0023] Wearing devices to measure changes in breath, temperature, or humidity in the air is not only burdensome for the subject due to their large size and weight, but also makes it difficult to accurately measure changes in gas flow rate, temperature, or humidity. Optical fiber, camera, or radio wave motion capture devices are highly sensitive, but require the subject's body to be restrained or measurements to be taken in a specific location, making them unsuitable for long-term measurements in natural conditions.

[0024] Measurement of abdominal or thoracic respiratory movement using strain gauges including load cells is inflexible because the measurement sensor is a solid body for single-point measurement. Furthermore, measurements using strain gauges require a belt-like attachment that is attached tightly to the subject's skin to avoid interference from muscle movements other than respiratory movement or unevenness in clothing.

[0025] Therefore, measurements using strain gauges ultimately place an increased burden on the subject, due to the effects of sweating (wetness can cause the textile band to loosen and polarize), discomfort from having a solid, i.e., plate-like, object in close contact with bare skin, the onset of skin eczema, and the bulkiness of the device due to the insulating coating used to protect against water. A balance-type method has also been disclosed (Japanese Patent Laid-Open Publication No. 5-115461), but slippage occurs through clothing, so the device must be in close contact with the subject's skin.

[0026] Furthermore, non-contact respiratory movement measurement using a camera or radio wave measurement is only suitable for measurements in specific environments where an observation device is present, and is not suitable for measurements in ordinary living environments. For this reason, problems have been pointed out, such as measurement being impossible even in a general hospital bed due to patient position or radio wave interference with other monitors (Non-Patent Document 3).

[0027] Existing belt-type respiratory movement sensors worn by the subject mainly use a semiconductor solid-state strain gauge that measures at a single point. Rotary mechanical gauge sensors have also been proposed as an exception, but the measurement device is large and therefore not very practical. The present inventors therefore conducted extensive research into the problems with belt-type sensors that have not yet been put to practical use, and have devised a respiratory sensor, as described below, that has a simpler configuration than conventional respiratory sensors, yet can detect the wearer's respiratory state with high accuracy and does not cause discomfort to the wearer.

[0028] An example of an embodiment of the present disclosure will be described below with reference to the drawings. The same reference numerals are used throughout the drawings to designate identical or equivalent components and parts. The dimensional proportions of the drawings are exaggerated for illustrative purposes and may differ from the actual proportions.

[0029] 1 is a diagram showing the appearance of a respiratory sensor 10 according to an embodiment of the present disclosure. The respiratory sensor 10 is a sensor that measures the respiration of a human or animal. As shown in FIG. 1, the respiratory sensor 10 includes a base 11 made of a stretchable fabric, a protective tape 12, a wireless communication amplifier 13, and a belt 14.

[0030] The base 11 is made of a stretchable fabric and serves as a base for attaching the ribbon tape described below. The base 11 stretches only in the longitudinal direction, i.e., the left-right direction. The protective tape 12 is used to fix the initial position of the respiratory sensor 10 when it is attached. The wireless communication amplifier 13 is an amplifier for wirelessly transmitting signals measured by the sensor to an external device. The wireless communication amplifier 13 is capable of wirelessly transmitting and receiving signals with general-purpose electronic devices such as personal computers via, for example, Bluetooth (registered trademark) or Wi-Fi (registered trademark). The wireless communication amplifier 13 may include internally a detection circuit for detecting changes in the impedance of the ribbon tape described below as an analog signal, an AD converter for converting the detected analog signal to a digital signal, a memory for storing the measured signal, a wireless module for wirelessly transmitting the signal stored in the memory to an external device, and a control circuit for controlling its operation. Furthermore, the wireless communication amplifier 13 is preferably driven by 3V to 3.7V, has a sampling rate of 50Hz to 4000Hz, and weighs less than 30 grams.

[0031] The belt 14 is a single band to be wrapped around the chest or abdomen of the subject whose respiratory condition is to be measured, and is long enough to wrap around the chest or abdomen of the human body. The belt 14 may be stretchable or non-stretchable, but is preferably made of woven or knitted fabric with low stretchability, and the base 11 is attached to the belt 14 with a hook-and-loop fastener. The length of the belt 14 to be worn is adjusted with hook-and-loop fasteners 15 provided on both ends of the belt 14. In consideration of hygienic use, particularly in hospitals, the belt 14 is preferably made of a detachable and replaceable material such as nonwoven fabric so as to be disposable.

[0032] FIG. 2 is a diagram showing the appearance of the base 11 to which ribbon tapes are attached. As shown in FIG. 2, two ribbon tapes 21a and 21b are attached to the base 11 as strain sensors so that they are approximately parallel, preferably vertically parallel. The ribbon tapes 21a and 21b are made of, for example, elastic polyurethane warp yarns and polyester weft fibers. Carbon nanotube (CNT) yarns are woven or knitted into the ribbon tapes 21a and 21b in a wavy pattern. The ribbon tapes 21a and 21b are provided with connection terminals 22 at both ends of the ribbon tapes 21a and 21b in the longitudinal direction. CNT yarns are provided at one end of the ribbon tapes 21a and 21b to connect the ribbon tapes 21a and 21b (see the dashed line in the figure).

[0033] In this embodiment, the ribbon tapes 21 a and 21 b each have a length of 50 mm and a width of 10 mm or less, preferably 8 mm or less, and more preferably 5 mm or less. The longitudinal direction of the ribbon tapes 21 a and 21 b and the stretch direction of the base 11 are substantially the same direction.

[0034] FIG. 3 is an enlarged view of the ribbon tape 21a. CNT yarns 31 are knitted or woven into the ribbon tape 21a. The CNT yarns 31 extend along the short direction of the ribbon tape 21a and are woven or knitted into the ribbon tape 21a in a wave-like shape including extensions 41 that are spaced apart and arranged substantially parallel along the long direction of the ribbon tape 21a, and folded-back portions 42 that connect adjacent extensions by folding back in the short direction. The CNT yarns 31 are knitted or woven continuously into the ribbon tape 21a. The fibers of the ribbon tape 21a other than the CNT yarns 31 are preferably made of an insulating fiber material, and in this case, they may be made of an elastomer and a non-elastomer, or may be made of synthetic fibers. The elastomer may be selected from the group consisting of, for example, PET (polyethylene terephthalate), nylon (PA, polyamide), PP (polypropylene), TPU (thermoplastic polyurethane), polystyrene (GPPS), etc. Synthetic fibers may be used, for example, polyester, nylon, acrylic, etc.

[0035] The CNT yarn 31 has a CNT diameter of 2 to 10 nm or less, and more preferably 2 to 5 nm. The CNT yarn 31 according to this embodiment is preferably a homogeneous CNT yarn spun from CNTs of uniform length and diameter that do not contain metal impurities. CNTs are inorganic artificial nanomaterials, and their physicochemical properties make them promising as new technology platform materials. CNTs, which are fibrous substances with lengths of tens to hundreds of μm, do not contain metal impurities, and have uniform lengths and diameters, can be made into homogeneous yarns with lengths of approximately 1 km or more. Furthermore, homogeneous CNT yarns spun from CNTs have properties such as high water resistance and extremely low chemical reactivity. 10 ５ If a homogeneous CNT yarn with conductivity of 0.5 S / m or more, high flexibility, and mechanical strength is used, it will become a material that can be handled in the same way as silk thread or synthetic fiber. The thickness of the CNT yarn 31 is desirably set to provide flexibility for bending deformation and to prevent breakage, and may be appropriately selected within the range of 20 dtex to 1000 dtex. The specific gravity of the CNT yarn 31 is 0.02 g / cm ３ In this case, the thickness of the CNT yarn 31 may be appropriately selected within the range of 10 μm to 1 mm.

[0036] Respiration is measured by the respiration sensor 10 by measuring, as impedance changes, changes in the electrical resistance and capacitance of the CNT yarns 31, which are the conductors of the ribbon tapes 21a and 21b. Movement of the chest or abdomen caused by breathing causes the surfaces of the ribbon tapes 21a and 21b to expand and contract, changing the spacing between the CNT yarns 31 woven or knitted into the ribbon tapes 21a and 21b. As the spacing between the CNT yarns 31 changes, the impedance of the ribbon tapes 21a and 21b changes, and the strain or stretch applied to the ribbon tapes 21a and 21b is measured as an electrical signal.

[0037] If only one ribbon tape woven or knitted with CNT yarn is used for the respiratory sensor 10, it is not possible to determine whether the signal output by the respiratory sensor 10 is a signal caused by the subject's breathing or a signal caused by the subject's twisting motion.

[0038] In contrast, the respiratory sensor 10 according to the present embodiment uses multiple ribbon tapes 21a, 21b, making it possible to determine whether the signal output by the respiratory sensor 10 is a signal caused by the subject's breathing or a signal caused by the subject's body twisting. When multiple ribbon tapes 21a, 21b are used, there is a significant difference in the electrical output of the ribbon tapes 21a, 21b in the case of body twisting, but the electrical output is approximately the same in the case of breathing. In other words, the respiratory sensor 10 according to the present embodiment can selectively observe the electrical signal waveform caused by chest or abdominal movement due to breathing, even when the subject's body is twisted.

[0039] The ribbon tapes 21a, 21b into which the CNT yarn 31 is woven or knitted can detect changes in impedance, which is the sum of the capacitance and electrical resistance of the CNT yarn 31, with very little power. Therefore, a small detection device can be used to detect the signal, and because the signal is an electrical output, existing general-purpose signal detection and analysis software can be used to analyze the signal. Therefore, the respiratory sensor 10 equipped with the ribbon tapes 21a, 21b does not require dedicated analysis software and is therefore versatile.

[0040] By using ribbon tapes 21a, 21b woven or knitted with CNT yarn 31 as the strain sensors, it is possible to measure strain in a line perpendicular to the human body's spine (horizontal direction) and convert it into an electrical signal, rather than measuring the amount of strain at a specific point. By wrapping the belt 14 around the abdomen or chest of the human body and arranging the ribbon tapes 21a, 21b along the stretch direction of the belt 14, measurements are taken on a surface with a length in the horizontal direction of the abdomen or chest, allowing the respiratory sensor 10 to selectively detect abdominal or thoracic expansion associated with breathing. Therefore, the respiratory sensor 10 is less susceptible to the effects of folds or wrinkles in clothing, making it possible to accurately measure breathing even through clothing.

[0041] The respiratory sensor 10 according to this embodiment has multiple ribbon tapes 21a, 21b arranged approximately parallel to one another, so that it can measure the respiratory movement of the subject even through the subject's clothing, such as a dress shirt, white coat, pajamas, thin wool clothing, etc., even if the clothing is wrinkled or overlapped. Note that it is desirable to wear the respiratory sensor 10 according to this embodiment over underwear such as a T-shirt to make it less noticeable in daily life and to prevent the subject from accidentally touching the respiratory sensor 10.

[0042] 4 to 6 are diagrams showing example graphs of breathing movements measured while a subject wearing the breathing sensor 10 according to this embodiment is in a seated position. In the graphs of FIGS. 4 to 6, the horizontal axis represents time, and the vertical axis represents the strength of the signal transmitted from the breathing sensor 10. The graph shown in FIG. 4 is a graph showing normal breathing while in a seated position, FIG. 5 is a graph showing deep breathing while in a seated position, and FIG. 6 is a graph showing rapid breathing while in a seated position. As shown in FIGS. 4 to 6, the breathing sensor 10 according to this embodiment is capable of identifying clear peaks of each breath not only in normal breathing but also in the complex waveforms of deep breathing and rapid breathing.

[0043] FIG. 7 is a graph comparing the subject's respiratory rate measured by the respiratory sensor 10 according to the present embodiment with other biomarkers over the course of cardiac arrest. FIG. 7 shows changes in blood oxygen concentration (SpO2), arterial blood carbon dioxide partial pressure (PaCO2), respiratory rate (RR), and minute ventilation (VE; V is indicated by a dot). In the graph of FIG. 7, the subject experiences a fatal event (e.g., sepsis, congestive heart failure, or pulmonary embolism) at time t1. At time t2, the subject's blood oxygen concentration and respiratory rate begin to change. At time t3, approximately 12 hours after time t2, the first blood oxygen concentration warning (blood oxygen concentration dropped to 85 percent) occurs. From time t2 to t3, it can be seen that the subject is mistakenly believed to be in good health.

[0044] In this way, when a change in the respiratory rate is detected by the respiratory sensor 10, preventive measures can be taken before the subject falls into an emergency, which can lead to saving the subject's life.

[0045] The respiratory sensor 10 of this embodiment aims to achieve a higher survival rate by detecting accurate changes in respiratory rate well before cardiac arrest using software that receives signals from the respiratory sensor 10 and remotely notifies the RRT via a computer, enabling the activation of RRS. RRS is already covered by insurance, and standard protocols (implementation guidelines) for earlier and more reliable prediction of RRS activation are needed. The respiratory sensor 10 of this embodiment enables accurate telemetry of changes in respiratory movement, both inside and outside a hospital, without causing discomfort to the subject, enabling remote computer-based daily monitoring of patients with illnesses both in and outside a hospital. As a result, the respiratory sensor 10 of this embodiment reduces the burden on medical professionals and enables preventive measures to be taken on subjects before an emergency occurs, potentially saving many lives.

[0046] Although the embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person skilled in the art of the present disclosure can conceive of various modifications or alterations within the scope of the technical idea described in the claims, and it is understood that these modifications or alterations also naturally fall within the technical scope of the present disclosure.

[0047] Furthermore, the effects described in the above embodiments are explanatory or exemplary and are not limited to those described in the above embodiments. In other words, the technology according to the present disclosure may achieve other effects that are obvious to a person skilled in the art of the present disclosure from the description in the above embodiments, in addition to or instead of the effects described in the above embodiments.

[0048] The following supplementary notes are further disclosed in relation to the above embodiments. (Supplementary Note 1) A respiratory sensor comprising: a strain detection sensor in which a plurality of ribbon tapes made of a first fabric woven or knitted with carbon nanotube (CNT) yarn are arranged; a second fabric to which the strain detection sensors are attached; a ring-shaped band made of fiber or nonwoven fabric to which the second fabric is attached; and a conversion unit that converts fluctuations in the length of the strain detection sensors into an electrical signal. (Supplementary Note 2) The respiratory sensor according to Supplementary Note 1, wherein the strain detection sensors are arranged in a direction substantially perpendicular to the body axis of a human or animal when the band is wrapped around the chest or abdomen of the human or animal. (Supplementary Note 3) The respiratory sensor according to Supplementary Note 1 or 2, wherein the ribbon tapes are arranged substantially parallel to each other. (Supplementary Note 4) The respiratory sensor according to any one of Supplementary Notes 1 to 3, wherein the CNT yarn is woven or knitted into the first fabric in a wave-like shape including extensions extending along the short direction of the ribbon tape and arranged approximately parallel to each other at intervals along the long direction of the ribbon tape, and folded-back portions that connect adjacent extensions by folding back in the short direction. (Supplementary Note 5) The respiratory sensor according to any one of Supplementary Notes 1 to 4, wherein the ribbon tape has a width of 10 mm or less. (Supplementary Note 6) The respiratory sensor according to any one of Supplementary Notes 1 to 5, wherein the conversion unit electrically outputs one-dimensional expansion and contraction and three-dimensional deformation of the strain detection sensor as changes in electrical resistance or impedance. (Supplementary Note 7) The respiratory sensor according to any one of Supplementary Notes 1 to 6, wherein the longitudinal direction of the ribbon tape and the expansion and contraction direction of the second fabric are approximately the same direction. (Supplementary Note 8) The respiratory sensor according to any one of Supplementary Notes 1 to 7, wherein the fibers other than the CNT yarn in the strain detection sensor are made of an elastomer and a non-elastomer. (Supplementary Note 9) The respiratory sensor according to any one of Supplementary Notes 1 to 8, wherein the fibers other than the CNT yarn in the strain detection sensor are made of synthetic fibers.

[0049] The disclosure of Japanese Patent Application No. 2024-105543, filed on June 28, 2024, is incorporated herein by reference in its entirety.

Claims

1. A respiratory sensor comprising: a strain detection sensor in which a plurality of ribbon tapes made of a first fabric woven or knitted with carbon nanotube (CNT) yarn are arranged; a second fabric to which the strain detection sensor is attached; a ring-shaped band made of fiber or nonwoven fabric to which the second fabric is attached; and a conversion unit that converts fluctuations in the length of the strain detection sensor into an electrical signal.

2. The respiratory sensor according to claim 1, wherein the strain detection sensor is oriented approximately perpendicular to the body axis of the human or animal when the band is wrapped around the chest or abdomen of the human or animal.

3. The respiratory sensor according to claim 1 or 2, wherein the ribbon tapes are arranged substantially parallel to each other.

4. The respiratory sensor according to claim 1 or 2, wherein the CNT yarn is woven or knitted into the first fabric in a wave-like shape including extensions that extend along the short side of the ribbon tape and are arranged approximately parallel to each other at intervals along the long side of the ribbon tape, and fold-back portions that connect adjacent extensions by folding back in the short side.

5. The respiratory sensor according to claim 1 or 2, wherein the ribbon tape has a width of 10 mm or less.

6. The respiratory sensor according to claim 1 or 2, wherein the conversion unit electrically outputs the one-dimensional expansion and contraction and three-dimensional deformation of the strain detection sensor as a change in electrical resistance or impedance.

7. The respiratory sensor according to claim 1 or 2, wherein the longitudinal direction of the ribbon tape and the stretch direction of the second fabric are substantially the same direction.

8. The respiratory sensor according to claim 1 or 2, wherein the fibers other than the CNT yarn in the strain detection sensor are made of an elastomer and a non-elastomer.

9. The respiratory sensor according to claim 1 or 2, wherein the fibers other than the CNT yarn in the strain detection sensor are synthetic fibers.

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