Wearable sensing device

Abstract

To enable more suitable sensing without having an influence of a magnetic field on a human body.SOLUTION: A wearable sensing device includes a reader circuit including a reader coil incorporated in clothing using a conductive thread and a power source that supplies alternation voltage to the reader coil, and senses the impedance change of at least one first sensor coil disposed between wound wires of the reader coil. The reader coil is configured as a meander coil obtained by performing winding in one winding direction and winding in the other winding direction with respect to a winding axis alternately at predetermined intervals. The reader circuit includes a plurality of capacitors disposed at equal intervals electrically in at least a part of positions where the winding direction of the reader coil is changed. A reference circuit that forms a balanced bridge circuit with the reader circuit and having impedance matching with the reader circuit is provided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wearable sensing device, and more particularly to a wearable sensing device having a reader coil incorporated into clothing using conductive yarns.

Background Art

[0002] Conventionally, as this type of technology, a sensing system has been proposed that includes a plurality of sensor modules fixed to a human body, a plurality of antenna modules attached to clothing so as to face the plurality of sensor modules, and a controller (see, for example, Patent Document 1). In this sensing system, the plurality of sensor modules have a sensor chip and a coil antenna, and the plurality of antenna modules have a coil antenna and a switch. Then, the controller turns on the switch of a specific antenna module to supply power to the sensor chip of the sensor module that can communicate through the coil antenna of the antenna module and the coil antenna of the sensor module, and receives its output signal.

[0003] Also, there has been proposed one having a resonance structure formed of a conductive fiber or a conductive medium on a non-conductive base fabric (see, for example, Patent Document 2). In this technology, the incident electromagnetic wave is changed by resonating with the incident electromagnetic wave, and the degree of change with respect to the electromagnetic wave is changed by deformation according to the physical quantity. Thereby, it is said that a wearable sensor device made only of fibers can be realized without significantly impairing the aesthetics and appearance of the clothing.

[0004] Furthermore, there has been proposed a conductive fiber in which another type of conductive yarn is wound around an aluminum foil conductive fiber obtained by round-twisting an organic fiber as a core (see, for example, Patent Document 3). In this conductive fiber, disconnection due to cracking and peeling of the aluminum foil is prevented, and it is made flexible and bendable.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Patent No. 6653819 [Patent Document 2] Japanese Patent Publication No. 2019-148599 [Patent Document 3] Japanese Patent Publication No. 2016-061006 [Overview of the project] [Problems that the invention aims to solve]

[0006] Conventionally, this type of technology involves placing sensors on clothing or the human body for purposes such as health management and behavior recognition. In the system described in Patent Document 1 above, the sensor module is attached to the human body and the antenna module is attached to the clothing. If the positions of the sensor module and the antenna module are misaligned, the coupling degree of the coil antenna decreases, which can result in problems with power supply and reception of sensor output signals. Furthermore, if the magnetic field generated on the winding axis of the coil antenna penetrates the human body, the effect of the magnetic field on the human body must also be considered.

[0007] The primary objective of the wearable sensing device of the present invention is to achieve better sensing without affecting the human body with magnetic fields. [Means for solving the problem]

[0008] The wearable sensing device of the present invention employs the following means to achieve the above-mentioned main objective.

[0009] The wearable sensing device of the present invention A wearable sensing device comprising a leader circuit having a leader coil incorporated into clothing using conductive thread and a power supply that supplies an alternating voltage to the leader coil, which senses impedance changes of at least one first sensor coil arranged between the windings of the leader coil, The leader coil is configured as a meander coil obtained by alternately winding in one direction and winding in another direction with respect to the winding axis at a predetermined interval. The leader circuit has a plurality of capacitors electrically arranged at equal intervals at least a portion of the position where the winding direction of the leader coil is changed, Furthermore, The leader circuit, together with the leader circuit, forms a balanced bridge circuit and includes a reference circuit whose impedance is matched to the leader circuit. It is characterized by the following:

[0010] In the wearable sensing device of the present invention, the leader coil is configured as a meander coil obtained by alternately winding in one direction and winding in another direction with a predetermined interval around the winding axis. At the winding axis of the leader coil, the magnetic field from winding in one direction and the magnetic field from winding in another direction cancel each other out, so no magnetic field is generated. Therefore, it is possible to suppress the effect of the magnetic field from the leader coil on the human body. Furthermore, in the wearable sensing device of the present invention, the leader circuit has a plurality of capacitors electrically arranged at equal intervals at least a portion of the position where the winding direction of the leader coil is changed. In order to sensitively sense the impedance change of the first sensor coil, it is conceivable to increase the inductance of the leader coil and increase the frequency, but if the number of turns of the leader coil is increased and the inductance is increased, the coil functions like a capacitor, so it becomes necessary to lower the frequency. On the other hand, if a plurality of capacitors are appropriately distributed around the coil, a high frequency can be achieved even if the inductance of the coil is increased. In this way, by attaching multiple capacitors to the leader coil, the number of turns in the leader coil can be increased to increase its inductance, and it can function at high frequencies, thereby improving the sensitivity of the sensing. Furthermore, the wearable sensing device of the present invention has a balanced bridge circuit configured together with the leader circuit, and is equipped with a reference circuit whose impedance is matched to the leader circuit. As a result, sensing can be performed with high sensitivity. As a result, sensing can be performed more effectively without affecting the human body with magnetic fields.

[0011] In the wearable sensing device of the present invention, the reference circuit may have the same second coil as the leader coil, the same number of second capacitors as the plurality of capacitors, and the same second power supply as the power supply, and may be configured as the same circuit as the leader circuit. This allows for better impedance matching and more sensitive sensing.

[0012] Furthermore, in the wearable sensing device of the present invention, the reference circuit may be configured as a circuit having a second coil configured as a meander coil with a different number of turns than the leader coil, a plurality of second capacitors identical to the plurality of capacitors but in a different number, and a second power supply with a different voltage than the power supply, and configured in the same connection state as the leader circuit. In this way, the size of the leader coil and the second coil can be made different.

[0013] In a wearable sensing device of the present invention, in which the reference circuit comprises a second coil, a plurality of second capacitors, and a second power supply, the device may further include at least one second sensor coil disposed between the windings of the second coil of the reference circuit, and the reference circuit may function as a leader circuit and the leader circuit may function as a reference circuit to sense the impedance change of the at least one second sensor coil disposed between the windings of the second coil. That is, the impedance change of the first sensor coil is sensed by the leader circuit and the impedance change of the second sensor coil is sensed by the reference circuit. This makes it possible to place a sensor coil not only between the windings of the leader coil in the leader circuit, but also between the windings of the second coil in the reference circuit.

[0014] In a wearable sensing device of the present invention in which a reference circuit functions as a reader circuit, the reader coil may be arranged from one end of the tubular portion of the garment toward the center, and the second coil may be arranged from the other end of the circumferential portion of the garment toward the center. For example, when the reference circuit is arranged in a shirt with the same configuration as the reader circuit, one of the reader coil and the second coil may be arranged in the upper half of the torso portion of the shirt, and the other of the reader coil and the second coil may be arranged in the lower half of the torso portion of the shirt. Alternatively, when the second coil of the reference circuit is arranged in a shirt with half the number of turns of the leader coil of the reader circuit, the second coil may be arranged from the top 1 / 3 of the torso portion of the shirt, and the reader coil may be arranged from the top 1 / 3 to the bottom of the torso portion of the shirt, or conversely, the reader coil may be arranged from the top 2 / 3 of the torso portion of the shirt, and the second coil may be arranged from the top 2 / 3 to the bottom of the torso portion of the shirt.

[0015] Furthermore, in a wearable sensing device of the present invention in which the reference circuit functions as a reader circuit, the reader coil may be located in one of a pair of tubular parts of the garment, and the second coil may be located in the other of the pair of tubular parts of the garment. For example, when the reference circuit is arranged in a shirt with the same configuration as the reader circuit, one of the reader coil and the second coil may be placed in the right sleeve, and the other of the reader coil and the second coil may be placed in the left sleeve. When arranged in trousers, one of the reader coil and the second coil may be placed in the right crotch area, and the other of the reader coil and the second coil may be placed in the left crotch area.

[0016] Furthermore, in the wearable sensing device of the present invention in which the reference circuit functions as a reader circuit, the reader coil is formed to be folded back in a half turn, is disposed on the front side of the tubular portion of the clothing, and the second coil is formed to be folded back in a half turn and may be disposed on the rear side of the tubular portion of the clothing. For example, when the reference circuit is arranged on a shirt with the same configuration as the reader circuit, one of the reader coil and the second coil may be arranged on the front body of the shirt, and the other of the reader coil and the second coil may be arranged on the back body of the shirt.

[0017] Also, in the wearable sensing device of the present invention in which the reference circuit functions as a reader circuit, the reader coil is formed to be folded back in a half turn and is disposed on one of the half circumferential surfaces when the tubular portion of the clothing is divided by a plane including the central axis, the second coil is formed to be folded back in a half turn and may be disposed on the other half circumferential surface that is paired with the one side surface of the tubular portion of the clothing. For example, when the reference circuit is arranged on a shirt with the same configuration as the reader circuit, one of the reader coil and the second coil may be arranged on the right half circumferential surface of the body of the shirt, and the other of the reader coil and the second coil may be arranged on the left half circumferential surface of the body of the shirt.

Brief Description of the Drawings

[0018] [Figure 1] It is a configuration diagram showing an outline of the configuration of the wearable sensing device 20 of the embodiment. [Figure 2] It is an explanatory diagram showing a sensing state when the sensor coils S1 to S5 are arranged in the wearable sensing device 20 of the embodiment. [Figure 3] It is an explanatory diagram showing a magnetic coupling state between the reader coil RC and the sensor coil S. [Figure 4] It is an explanatory diagram showing a change in the resonance frequency when the impedance of the sensor coil S changes. [Figure 5] It is an explanatory diagram showing a magnetic coupling state between the reader coil RC and the sensor coils S1 to S5. [Figure 6] It is an explanatory diagram showing the resonance frequencies of the sensor coils S1 to S5. [Figure 7] It is an explanatory diagram explaining the case where capacitor dispersion arrangement is applied to the reader coil RC. [Figure 8] It is a circuit diagram showing the wearable sensing device 20 of the embodiment as a balanced bridge circuit. [Figure 9] It is an explanatory diagram showing the impedance error between coils with respect to the change in frequency when using a semiconductor chip as a reference circuit and when using the same circuit (embodiment) as the reader circuit. [Figure 10] It is an explanatory diagram showing the sensitivity with respect to different resonance frequencies when using a semiconductor chip as a reference circuit and when using the same circuit (embodiment) as the reader circuit. [Figure 11] It is an explanatory diagram showing ΔZin with respect to the resonance frequency when the sensor coils S1 to S5 are arranged and sensed in the wearable sensing device 20 of the embodiment. [Figure 12] It is a configuration diagram showing the outline of the configuration of the wearable sensing device 120 of the modification example. [Figure 13] It is a configuration diagram showing the outline of the configuration of the wearable sensing device 220 of the modification example. [Figure 14] It is a configuration diagram showing the outline of the configuration of the wearable sensing device 320 of the modification example.

Mode for Carrying Out the Invention

[0019] Next, a mode for carrying out the present invention will be described. FIG. 1 is a configuration diagram showing the outline of the configuration of the wearable sensing device 20 of the embodiment. The wearable sensing device 20 of the embodiment includes, as shown in the figure, a first reader circuit 30, a second reader circuit 40, an operational amplifier Am, and a PC 50.

[0020] The first leader circuit 30 consists of a first leader coil 32 woven into the torso 24 of the shirt 22 as clothing, a plurality of first capacitors 34 distributed around the leader coil 32, and a first power supply V1 with an alternating voltage.

[0021] The first leader coil 32 is woven with conductive thread from the center of the body portion 24 to the upper side, with the center of the body portion 24 as the winding axis, and is configured as a meander coil obtained by alternately winding in one direction (e.g., clockwise) and another direction (e.g., counterclockwise) at predetermined intervals. Multiple first capacitors 34 are arranged at electrically equal intervals at positions where the winding direction of the first leader coil 32 is changed (folding positions on the left side in the figure). One terminal of the first leader coil 32 is connected to one terminal of the first power supply V1, and the other terminal is connected to the inverting input terminal of the operational amplifier Am. The other terminal of the first power supply V1 is grounded.

[0022] The second leader circuit 40 includes a second leader coil 42 identical to the first leader coil 32 and woven into the lower part of the body 24 from the center, multiple second capacitors 42 identical to the multiple first capacitors 34 distributed around the first leader coil 32 and similarly distributed around the second leader coil 42, and a second power supply V2 identical to the first power supply V1 but in the opposite phase. One terminal of the second leader coil 42 is connected to one terminal of the second power supply V2, and the other terminal is connected to the inverting input terminal of the operational amplifier Am. The other terminal of the second power supply V2 is grounded.

[0023] The operational amplifier Am, together with the resistor Ramp attached to the negative feedback circuit, forms a well-known inverting amplifier circuit, with its non-inverting input terminal grounded. The output terminal of operational amplifier Am is input to PC50.

[0024] The PC50 is configured as a well-known microcomputer centered around a CPU, and in addition to the CPU, it also includes ROM, RAM, input / output ports, and other components.

[0025] Figure 2 is an explanatory diagram showing the sensing behavior when sensor coils S1 to S5 are arranged in the wearable sensing device 20 of the embodiment. Sensor coils S1 to S5 are configured as coils with appropriately different inductances and capacitances so that their resonant frequencies do not overlap, and are connected to a sensor unit (not shown). When current is passed through the first leader coil 32 and the second leader coil 42 as shown by the arrows in the figure, a magnetic field is generated around each coil 32 and 42 as shown to the right of each coil. In the central axis direction of the torso 24 of the shirt 22, the magnetic fields cancel each other out because each coil 32 and 42 is configured as a meander coil. Therefore, the effect of the magnetic field on the human body is suppressed when the shirt 22 is worn. On the other hand, the magnetic fields reinforce each other between adjacent windings of each leader coil 32 and 42, but since this is only on the surface of the clothing, the effect of the magnetic field on the human body is small. When sensor coils S1 to S5 are arranged between the windings such that their winding axes are perpendicular to the winding axes of each leader coil 32 and 42, the magnetic field generated between the windings of each sensor coil 32 and 42 penetrates each sensor coil S1 to S5, creating a magnetic coupling between each leader coil 32 and 42 and each sensor coil S1 to S5. The sensor portion of the sensor coils S1 to S5 is configured as a sensing device, such as a pressure-sensitive element or a temperature-sensitive element, and changes its impedance in response to changes in physical state quantities such as pressure, temperature, and strain. Therefore, the sensor coils S1 to S5 change their resonant frequency in response to physical state quantities. In the wearable sensing device 20 of this embodiment, the frequencies of the first power supply V1 and the second power supply V2 are changed to detect the resonant frequencies of the sensor coils S1 to S5, and changes in the physical state quantities of the sensors are detected as changes in the resonant frequency.

[0026] Next, the sensing in the wearable sensing device 20 of the embodiment will be described. The wearable sensing device 20 of the embodiment functions as passive inductive telemetry. Figure 3 is an explanatory diagram showing the magnetic coupling state between the leader coil RC and the sensor coil S, and Figure 4 is an explanatory diagram showing the change in the resonant frequency when the impedance of the sensor coil S changes. Figure 5 is an explanatory diagram showing the magnetic coupling state between the leader coil RC and the sensor coils S1 to S5, and Figure 6 is an explanatory diagram showing the resonant frequencies of the sensor coils S1 to S5. As shown in Figure 3, when an alternating voltage is applied to the leader coil RC to generate a magnetic field in the leader coil RC, that magnetic field penetrates the sensor coil S, and a magnetic coupling occurs between the leader coil RC and the sensor coil S. By sequentially changing the frequency of the alternating voltage applied to the leader coil RC, the resonant frequency of the sensor coil S can be detected. When the impedance of the sensor part connected to the sensor coil S is changed, as shown in Figure 4, the detected resonant frequency of the sensor coil S changes from f0 to f0'. In this way, by applying an alternating voltage to the leader coil RC, it is possible to detect the impedance change of the sensor portion of the sensor coil S, which is magnetically coupled to the leader coil RC. Therefore, no power supply is required for the sensor coil S. Now, if multiple sensor coils S1 to S5 are used, each with appropriately different inductances and capacitances so that their resonant frequency ranges do not overlap, then, as shown in Figures 5 and 6, a single leader coil RC can detect the impedance changes of the sensor portions of multiple sensor coils S1 to S5 as changes in resonant frequency. In the example in Figure 2, the first leader coil 32 detects the impedance changes of the sensor portions of sensor coils S1 to S3, and the second leader coil 42 detects the impedance changes of the sensor portions of sensor coils S4 and S5.

[0027] Sensing sensitivity improves as the distance between the leader coil and the sensor coil decreases, as the inductance of the leader coil increases, and as the frequency of the alternating voltage applied to the leader coil increases. As shown in Figure 2, the distance between each leader coil 32, 42 and each sensor coil S1 to S5 cannot be changed, so it is preferable to increase the inductance of each leader coil 32, 42 and increase the frequency of the alternating voltage applied to each leader coil 32, 42. Generally, increasing the number of turns to increase the inductance causes the leader coil to function as a capacitor, necessitating a decrease in the frequency of the alternating voltage. As shown in Figure 7, if multiple capacitors C1 to C3 are distributed to a certain extent around the leader coil RC, the leader coil RC functions as a coil with high inductance even at high frequencies. In the wearable sensing device 20 of this embodiment, as shown in Figures 1 and 2, multiple capacitors 34 and 44 are arranged at electrically equal intervals at the positions where the winding direction of each leader coil 32 and 42 is changed (the folding position on the left side in the figures). This makes each leader coil 32 and 42 a coil with a large inductance that functions even at high frequencies, thereby improving the sensing sensitivity.

[0028] In the wearable sensing device 20 of this embodiment, a balanced bridge circuit is used to improve sensing sensitivity. Figure 8 is a circuit diagram showing the wearable sensing device 20 of this embodiment as a balanced bridge circuit. Considering the output Vout of the operational amplifier Am when the impedance Zin of the second leader circuit 40 changes, with the first leader circuit 30 being a reference circuit with constant impedance Zref, the output Vout can be calculated by the following equation (1), where Vin is the power supply voltage. In equation (1), ΔZ is Zin - Zref.

[0029]

number

[0030] Now, assuming that Zin in the standard state is equal to Zref and ΔZin is the deviation of Zin from the standard state, then ΔZ = ΔZin. The change in the magnetic coupling state between the sensor coil S and the second leader coil 42 due to the impedance change of the sensor coil S, that is, the change in the resonant frequency, appears as ΔZin, which is amplified by the operational amplifier Am and output as output Vout. Here, we consider the sensitivity of ΔZ in two cases: Case 1, where Zin in the standard state is 100Ω and Zref is 99Ω, and Case 2, where Zin in the standard state is 100Ω and Zref is 90Ω. When ΔZin is 1Ω, in Case 1, it is a change of 1Ω relative to 1Ω (Zin-Zref in the standard state), so the change ratio (change amount / (Zin-Zref in the standard state)) is 1 / 1 = 1. On the other hand, in Example 2, the change is 1Ω relative to 10Ω (Zin-Zref under standard conditions), so the change ratio is 1 / 10 = 0.1, which is 1 / 10 of that in Example 1. Since the change ratio is intended to represent sensing sensitivity, the smaller the difference between Zin and Zref, the better the sensitivity. For this reason, by using a reference circuit with impedance matching applied to the reader circuit, the sensing sensitivity can be improved. In the wearable sensing device 20 of the embodiment, impedance matching between the reader circuit and the reference circuit is achieved by making the first reader circuit 30 and the second reader circuit 40 the same configuration. Furthermore, if we consider the output Vout of the operational amplifier Am when the impedance Zref of the first reader circuit 30 changes, with the second reader circuit 40 being a reference circuit with constant impedance Zin, the output Vout becomes equation (1) with Zin and Zref swapped, which is the same as when the first reader circuit 30 is considered as a reference circuit. In other words, in the wearable sensing device 20 of this embodiment, when the impedance change of sensor coils S1 to S3 is detected by the first reader coil 32 of the first reader circuit 30, the second reader circuit 40 functions as a reference circuit, and conversely, when the impedance change of sensor coils S4 and S5 is detected by the second reader coil 42 of the second reader circuit 40, the first reader circuit 30 functions as a reference circuit.

[0031] It is possible to use a semiconductor chip (LCR circuit) as a reference circuit in which the impedance Zref is the same as Zin under standard conditions. However, when using a semiconductor chip, the sensor coil exhibits good sensitivity for some frequencies that resonate, but the sensitivity may be low at other frequencies. Figure 9 is an explanatory diagram showing the impedance error between coils with respect to frequency changes when a semiconductor chip is used as the reference circuit and when the same circuit as the reader circuit (embodiment) is used. Figure 10 is an explanatory diagram showing the sensitivity to different resonant frequencies when a semiconductor chip is used as the reference circuit and when the same circuit as the reader circuit (embodiment) is used. In the figures, the solid line represents the embodiment, and the dashed line represents the case when a semiconductor chip is used. As shown in Figure 9, when a semiconductor chip is used, the impedance error between coils is small at frequencies in the central range of the figure, but at other frequencies the impedance error exceeds the threshold and becomes large. On the other hand, in the embodiment, the impedance error is below the threshold over a wide range of frequencies. As a result, as shown in Figure 10, when a semiconductor chip is used, good sensitivity is observed for sensor coils whose resonant frequency (f2) is in the central range of the figure, but sensitivity is low for sensor coils whose resonant frequencies (f1, f3) are other frequencies. On the other hand, in the embodiment, good sensitivity is observed for sensor coils whose resonant frequencies (f1 to f3) are over a wide range of frequencies. In the wearable sensing device 20 of the embodiment, the first reader circuit 30 and the second reader circuit 40 have the same configuration in order to achieve good sensing sensitivity over a wide range of frequencies.

[0032] Figure 11 is an explanatory diagram showing the ΔZin with respect to the resonant frequency when sensing is performed with sensor coils S1 to S5 arranged in the wearable sensing device 20 of the embodiment as shown in Figure 2. In the figure, f1 to f3 are the resonant frequencies of sensor coils S1 to S3, and f4 and f5 are the resonant frequencies of sensor coils S4 and S5. The reason why ΔZin for sensor coils S1 to S3, which are arranged between the windings of the first leader coil 32, appears on the positive side (upper side), and ΔZin for sensor coils S4 and S5, which are arranged between the windings of the second leader coil 42, appears on the negative side (lower side) is based on the fact that the first power supply V1 and the second power supply V2 are in opposite phase.

[0033] In the wearable sensing device 20 of the embodiment described above, the first leader coil 32 and the second leader coil 42 are knitted into the torso portion 24 of the shirt 22 as mean coils using conductive thread, so that the effect of magnetic fields on the human body can be suppressed when the shirt 22 is worn. By arranging sensor coils S1 to S5 between the windings of the first leader coil 32 and the second leader coil 42, changes in the physical state quantities in the sensor portions of the sensor coils S1 to S5 can be detected. Furthermore, since the wearable sensing device 20 of the embodiment employs passive inductive telemetry, there is no need to power the sensor coils S1 to S5. This makes the sensor coils simple and lightweight. In addition, in the wearable sensing device 20 of the embodiment, by appropriately distributing multiple capacitors 34 and 44 around the first leader coil 32 and the second leader coil 42, sensing sensitivity can be improved. In addition, the wearable sensing device 20 of this embodiment uses a balanced bridge circuit for detection, which improves sensing sensitivity. In particular, by having the first reader circuit 30 and the second reader circuit 40 have the same configuration, and by having the second reader circuit 40 function as a reference circuit when detecting impedance changes of sensor coils S1 to S3 placed between the windings of the first reader coil 32, and by having the first reader circuit 30 function as a reference circuit when detecting impedance changes of sensor coils S4 and S5 placed between the windings of the second reader coil 42, sensing sensitivity can be improved and impedance changes of more sensor coils can be sensed simultaneously.

[0034] In the wearable sensing device 20 of this embodiment, the first leader coil 32 and the second leader coil 42 are configured as mean coils obtained by alternately winding the winding axis in one direction (e.g., clockwise) and one direction (e.g., counterclockwise). However, they may also be configured as mean coils obtained by alternately winding multiple turns in one direction and multiple turns in other directions. In this case, it is preferable to wind the multiple turns in the same direction closely together, configure the mean coil so that there is a certain distance between adjacent multiple turns in other directions, and place the sensor coil between adjacent multiple turns.

[0035] In the wearable sensing device 20 of the embodiment, the first leader coil 32 and the second leader coil 42 are meander coils with the same number of turns, but they may be meander coils with different numbers of turns as long as impedance matching is achieved. Figure 12 is a schematic diagram showing the configuration of a modified wearable sensing device 120. In the modified wearable sensing device 120, the first leader circuit 130 comprises a first leader coil 132 configured as a meander coil with a small number of turns and a small number of capacitors 134, and the second leader circuit 140 comprises a second leader coil 142 configured as a meander coil with a large number of turns and a large number of capacitors 144. To achieve impedance matching, the impedance of the second leader coil 142 should be multiplied by a so that it is equal to the impedance of the first leader coil 132, and the alternating voltage of the first power supply V1 should be multiplied by a so that it is equal to the alternating voltage of the second power supply V2. In this case, the output Vout of the operational amplifier Am can be determined by the following equation (2). In equation (2), Z1 is the impedance of the first leader coil 142, Z2 is the impedance of the second leader coil 142, and ΔZ is Z2 - Z1. In this way, the wearable sensing device 120 can be constructed using two meander coils with different winding counts.

[0036]

number

[0037] In the wearable sensing device 20 of this embodiment, the first leader coil 32 is woven into the upper half of the torso portion 24 of the shirt 22, and the second leader coil 42 is woven into the lower half of the torso portion 24. However, the first leader coil may be woven into one half-circumferential surface when the torso portion 24 of the shirt 22 is divided by a plane including the central axis, and the second leader coil may be woven into the other half-circumferential surface of the torso portion 24. For example, as shown in the modified wearable sensing device 220 of Figure 13, the first leader coil 232 may be woven into the front of the torso portion 24 of the shirt 22, and the second leader coil 242 may be woven into the back of the torso portion 24. In this case, the first leader coil 232 and the second leader coil 242 may be folded back after half a turn, and a plurality of capacitors 234, 244 may be placed at this folded portion. Alternatively, the first leader coil 232 may be woven into the right half of the body portion 24, and the second leader coil 242 may be woven into the left half of the body portion 24.

[0038] Furthermore, as shown in the modified wearable sensing device 320 in Figure 14, the first leader coil 332 may be woven into one of the pair of crotch sections of the trousers, and the second leader coil 342 may be woven into the other crotch section. Alternatively, although not shown, the first leader coil may be woven into one of the pair of sleeves of the shirt, and the second leader coil may be woven into the other sleeve of the shirt.

[0039] In the examples and modified wearable sensing devices 20, the first leader coils 32, 332 and the second leader coils 42, 342 are knitted into a shirt or trousers, but the first leader coils and the second leader coils may also be knitted into other clothing, such as a sweater, hat, or socks.

[0040] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, the first leader coil 32 and the second leader coil 42 correspond to "leader coils," the first power supply V1 and the second power supply V2 correspond to power supplies, the first leader circuit 30 and the second leader circuit correspond to "leader circuits," the sensor coils S1 to S5 correspond to "first sensor coils," and the multiple capacitors 34 and 44 correspond to "multiple capacitors." When the first leader circuit 30 corresponds to "leader circuit," the second leader circuit corresponds to "reference circuit," and when the second leader circuit 40 corresponds to "leader circuit," the first leader circuit corresponds to "reference circuit."

[0041] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0042] Although embodiments for carrying out the present invention have been described above, the present invention is not limited in any way to these embodiments, and it is of course possible to carry it out in various forms without departing from the spirit of the present invention. [Industrial applicability]

[0043] This invention can be used in industries such as the manufacturing of wearable sensing devices. [Explanation of symbols]

[0044] 20,120,220,320 Wearable sensing device, 22 Shirt, 24 Torso, 30,130 First leader circuit, 40,140 Second leader circuit, 32,132,232,332 First leader coil, 34,44,134,144,234,244 Multiple capacitors, 42,142,242,342 Second leader coil, 50 PC, Am op-amp, V1 First power supply, V2 Second power supply, Ramp resistor.

Claims

1. A wearable sensing device comprising a leader circuit having a leader coil incorporated into clothing using conductive thread and a power supply that supplies an alternating voltage to the leader coil, which senses the impedance change of at least one first sensor coil arranged between the windings of the leader coil, The leader coil is configured as a meander coil obtained by alternately winding in one direction and winding in another direction with respect to the winding axis at a predetermined interval. The leader circuit has a plurality of capacitors electrically arranged at equal intervals at least a portion of the position where the winding direction of the leader coil is changed, Furthermore, The leader circuit, together with the leader circuit, forms a balanced bridge circuit and includes a reference circuit whose impedance is matched to the leader circuit. A wearable sensing device characterized by the following:

2. A wearable sensing device according to claim 1, The reference circuit includes a second coil identical to the leader coil, a plurality of second capacitors identical to the plurality of capacitors, and a second power supply identical to the power supply, and is configured as the same circuit as the leader circuit. Wearable sensing device.

3. A wearable sensing device according to claim 1, The reference circuit comprises a second coil configured as a meander coil with a different number of turns than the leader coil, a plurality of second capacitors identical to the plurality of capacitors but in a different number, and a second power supply with a different voltage than the power supply, and is configured as a circuit with the same connection state as the leader circuit. Wearable sensing device.

4. A wearable sensing device according to claim 2 or 3, The reference circuit comprises at least one second sensor coil positioned between the windings of the second coil, The reference circuit is made to function as a reader circuit, and the reader circuit is made to function as a reference circuit to sense the impedance change of at least one second sensor coil placed between the windings of the second coil. Wearable sensing device.

5. A wearable sensing device according to claim 4, The leader coil is positioned from one end of the tubular portion of the garment toward the center, The second coil is positioned from the other end of the tubular portion of the garment toward the center, Wearable sensing device.

6. A wearable sensing device according to claim 4, The leader coil is positioned in one of the pair of tubular portions of the garment. The second coil is also positioned on the other side of the pair of tubular parts of the garment. Wearable sensing device.

7. A wearable sensing device according to claim 4, The leader coil is formed to be folded back halfway around and is positioned on the front side of the tubular portion of the garment. The second coil is formed to be folded back halfway and is positioned on the rear side of the tubular portion of the garment. Wearable sensing device.

8. A wearable sensing device according to claim 4, The leader coil is formed to be folded back in half, and is positioned on one half-circumferential surface when the tubular portion of the garment is divided by a plane including the central axis. The second coil is formed to be folded back in half and is positioned on the other half-circumferential side of the tubular portion of the garment, opposite to the one half-circumferential side. Wearable sensing device.

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