JP2010203792A - Electric apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric apparatus wherein a detector is reduced in size by making components common in use. <P>SOLUTION: The detector includes an annular signal electrode 10, a reference electrode 20, and a current transformer 31, and measures a current flowing in a finger of a user put in the internal space of the ring of the current transformer in the axial direction through the current transformer. The reference electrode surrounds the current transformer, and functions also as a shield for protecting the current transformer from external noise. However, the reference electrode is so constituted as to have an approximately U-shaped cross section vertical to the circumferential direction, and a gap 23. By the presence of this gap, any current which flows in the axial direction of the current transformer is not generated in a K-domain surrounded by the internal surface of the ring of the current transformer, and no current is measured by the current transformer when the finger fitted to the detector is separated from the other body region. On the other hand, a current which flows in the axial direction of the current transformer is generated in the K-domain, and a large current value is measured when a finger fitted to the detector is in contact with the other body region. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrical device that measures a current flowing through a conductor.

  Conventionally, while an electric signal is input to a user's body from a transmitter attached to the user's body, an electrode for contacting or approaching the user's body is provided on the receiver side, and the transmitter is attached When the user touches or approaches the electrode, the electrical signal transmitted from the transmitter propagating through the user's body is input to the receiver side through the electrode, and the user is sent to the electrode. A system that detects a contact operation and performs various processes is known.

  Specifically, a transmission signal including ID information is input to the user's body from a transmitter worn on the user's arm, and is received by electrostatic coupling when the user brings a finger close to the receiving electrode provided around the gate. A system in which a receiver authenticates a user and opens and closes a gate based on a transmission signal from the transmitter propagating to a side electrode is known (see Patent Document 1).

As a human body communication method, a method for realizing communication by inputting a weak radio wave to the user's body and a method for realizing communication by inputting a weak current to the user's body are known.
In addition, as a measuring instrument for measuring the current flowing through the conductor, a current transformer in which a coil is wound around an annular core is provided, and when the conductor is arranged at the center of the current transformer, the current flowing through the conductor There is known a measuring instrument that measures the current flowing in the axial direction of a current transformer in a conductor by using the fact that a voltage is generated at both ends of a coil by electromagnetic induction due to the magnetic field generated (see Patent Document 2). .

  Further, as this type of measuring instrument, there is known a measuring instrument in which the periphery of a current transformer is covered with a shield in order to suppress the influence of external noise. In addition, a technique using an electrode as a shield for an internal circuit is also conventionally known (see Patent Document 1).

Japanese Patent Laid-Open No. 10-229357 JP 7-325109 A

  By the way, in the above-described conventional human body communication technology, the transmitter is attached to the user's body, and the electric signal output from the transmitter is detected on the receiver side which is an external device, so that the electrodes provided in the receiver The user's contact movement is detected, but if the user's contact movement is only detected, the user's contact with the conductor can be used to change the propagation path of the current flowing through the user's body. It is possible to detect a user's contact operation with a single device for body wearing.

  And the present inventors are developing the new detection apparatus using this thought. Specifically, a pair of electrodes are brought into contact with the target object, an electric signal is applied between the pair of electrodes, and a current flowing through the target object in a region outside the region P surrounded by the pair of electrodes. We are developing a detection device that detects whether or not the target object has a closed ring shape by measuring.

  FIG. 9 is a diagram illustrating the principle. As shown in FIG. 6A, when the target object has an open ring shape, current flows only in the region P surrounded by the pair of electrodes. However, as shown in FIG. When the object has a closed ring shape, current flows also in the external region of the region P. Therefore, in the external region of the region P (for example, the point Z shown in FIG. 5B), the object is measured by the measuring instrument. By measuring the current flowing through the body, it is possible to detect whether or not the target object has a closed ring shape.

  Note that the above-described target object is particularly assumed to be the user's body, and if this technology is applied, it is possible to detect an operation in which the user touches or separates both hands or two fingers. is there.

  However, when the detection device is configured as a device for body wearing, if the device is too large, it is not convenient for the user. On the other hand, in current measurement, since it is necessary to measure the weak current flowing through the user's body, when using the current transformer as a measuring instrument, a shield is provided around the current transformer to improve detection accuracy. Therefore, this is the cause of the increase in the size of the apparatus.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a technique capable of downsizing the detection device.

  An electrical device of the present invention made to achieve the above object includes an annular element in which a coil is wound around an annular core, and the annular object in the measurement target object accommodated in a space surrounded by the annular element. A measuring instrument that measures the current flowing in the axial direction of the element and outputs the measurement result is provided. This measuring instrument measures the current flowing in the axial direction of the annular element in the measurement target object, using as an index the voltage generated at both ends of the coil due to the magnetic flux change in the annular core.

  In addition, the electrical device of the present invention is provided with an annular shield that surrounds the annular element in order to suppress current measurement errors in the measuring instrument due to noise. In addition, a signal electrode for applying a signal is provided at a position away from the shield in the axial direction of the shield.

  The electrical apparatus further includes an application circuit, and the application circuit is electrically connected to the signal electrode and the shield, and the shield is used as the reference electrode, and the measurement target object positioned between the reference electrode and the signal electrode is used. An AC signal is applied to the part. The shield is in contact with the measurement target object on the inner side of the ring, and the signal electrode is disposed so as to contact the measurement target object extending in the axial direction of the shield.

  In addition, the shield has a ring-opening shape with a gap in the cross section perpendicular to the circumferential direction. In other words, the shield is electrically connected to the first path located on the signal electrode side among the paths along the above-mentioned ring opening that connects the connection point between the application circuit and the shield and the contact point between the object to be measured and the shield. The second path that is continuous and located on the opposite side of the first path is configured to be electrically discontinuous with a gap.

The annular element is arranged inside the ring opening and surrounded by the shield in a cross section perpendicular to the circumferential direction.
As described above, the electrical apparatus of the present invention is for detecting whether or not the measurement target object is a closed ring. When the measurement object is open, there is only one route through which the electrical signal applied from the signal electrode propagates to the reference electrode (FIG. 9A). On the other hand, when the object to be measured is a closed ring, a route in which the electrical signal propagates directly to the adjacent reference electrode (hereinafter referred to as “direct route”), and the electrical signal goes around the closed ring to the reference electrode. There are two types of routes (hereinafter referred to as “detour routes”) that propagate (FIG. 9B).

  Therefore, by utilizing such a phenomenon, an annular element is arranged outside the region P of the measurement target object surrounded between the reference electrode and the signal electrode, and the current flowing through the detour route is measured. It is possible to detect whether the measurement target object has a closed ring shape.

  However, if the electric device is configured such that the annular element, the reference electrode, and the signal electrode are arranged in order with respect to the measurement target object, the electric device becomes large. Furthermore, for noise countermeasures, the annular element is preferably surrounded by a shield. However, an electrical device is configured so that the annular element is surrounded by the shield while the annular element, the reference electrode, and the signal electrode are sequentially arranged. If this is configured, the electric equipment is further increased in size.

Therefore, in the present invention, the shield and the reference electrode are used in common to reduce the size of the electric device.
However, simply using the shield as a reference electrode causes the following problems. For the purpose of noise suppression, the shield is preferably configured so that the cross section perpendicular to the circumferential direction is a closed ring shape so as to completely surround the annular element (see FIG. 10).

  However, when the shield has such a closed ring shape, as shown in FIGS. 10A and 10B, the measurement target object is applied from the signal electrode regardless of whether it is a closed ring shape or an open ring shape. The electric signal propagates through the shield 103 around the annular element 101 so as to wrap around the annular element 101.

  That is, whether the measurement target object is a closed ring shape or an open ring shape, a current passing through the inner region of the ring of the annular element 101 in the axial direction is generated, and the current value obtained through the annular element 101 is There arises a problem that the difference according to the state of the measurement target object disappears. FIG. 10A is a diagram showing a propagation mode of an electric signal when the measurement target object has an open ring shape, and FIG. 10B shows an electric current when the measurement target object has a ring-closed shape. It is the figure which showed the propagation mode of the signal.

In this case, the initial purpose of detecting whether or not the measurement target object has a closed ring shape cannot be achieved.
For this reason, in the present invention, the cross section perpendicular to the circumferential direction of the shield is formed into the above-described ring-opening shape, thereby preventing the electric signal applied from the signal electrode from propagating through the shield so as to enclose the annular element. is doing. That is, as long as the electric signal applied from the signal electrode does not propagate to the reference electrode by the detour route, no current passing through the inner region of the ring of the annular element in the axial direction is generated. Occurrence is prevented.

  Therefore, according to the present invention, it is possible to reduce the size of an electric device for detecting whether or not a measurement target object is a closed ring while maintaining good detection accuracy. In order to increase current measurement accuracy, it is preferable to prevent current flowing in the axial direction in the shield as much as possible when the object to be measured has an open ring shape. Therefore, the connection point between the application circuit and the shield is preferably provided at the end of the shield on the signal electrode side.

  By the way, in order to protect the annular element from noise, as described above, it is ideal that the section perpendicular to the circumferential direction of the shield is closed and the periphery of the annular element is completely surrounded by the shield. However, in order to avoid the above-mentioned problem, such a shield configuration cannot be adopted.

  In view of this, the shield may be configured such that, in a cross section perpendicular to the circumferential direction, both ends of the ring opening are overlapped in a state having the gap and a state shifted in the radial direction of the ring opening. Item 2). If the shield is configured in this way, the annular element can be surrounded by the shield so that it cannot be seen from the outside. Therefore, noise (radio waves) that fly linearly enters the gap and reaches the annular element. In addition, adverse effects on the annular element can be suppressed. Therefore, if the shield has such a configuration, it is possible to configure an electric device that is resistant to noise.

  Further, the shield may be configured to have a wavy gap in the circumferential direction (claim 3). The gap may be provided straight instead of the wavy shape in the circumferential direction.However, if the gap is provided in this manner, a straight wide opening is formed in the circumferential direction. The possibility of reaching the annular element through the gap is increased. On the other hand, if the gap is wave-shaped, it is possible to prevent the formation of a straight and wide opening in the circumferential direction, and reduce the possibility that noise flying from the outside will reach the annular element through the gap. Can do.

  In addition, examples of the measurement target object include a user's body, and the above-described electrical device is an electrical device attached to the user's body, and measures the current output as a measurement result from the measuring instrument. Based on the value, it can be configured to include a detecting unit that detects that another body part of the user is in contact with the body part of the user located in a direction farther from the signal electrode than the contact part with the shield. .

  Specifically, the detection means detects the contact when the measured current value obtained from the measuring instrument exceeds a reference value, and detects the contact portion when the measured current value obtained from the measuring instrument falls below the reference value. It can be set as the structure which detects separation.

  By using this electric device, for example, it is possible to detect an operation of bringing the fingertip of the right hand with the electric device attached to the arm into contact with the left hand. That is, when the fingertip of the right hand with an electrical device attached to the arm is brought into contact with the left hand, a closed ring conductor path is formed by the right arm, the left arm, and the trunk, and this contact part is separated In this case, the closed annular conductor path disappears, and the measured value of the current measured through the annular element changes greatly. Therefore, according to this electric device, the contact / separation operation of the user body can be detected.

It is explanatory drawing which showed the basic composition and the operation principle of the detection apparatus 1. 2 is a block diagram illustrating an electrical configuration of the detection apparatus 1. FIG. 2 is a cross-sectional view perpendicular to the circumferential direction of the detection device 1. FIG. It is a figure showing the propagation mode of an electric signal when an electric signal is impressed from signal electrode. It is the flowchart which showed the content of the process which the control part 60 performs. It is a figure regarding the detection apparatus 2 of a 2nd Example. It is a figure showing the side surface composition of reference electrode 80 when gap 83 is made into a wave in the peripheral direction. It is a figure regarding the detection apparatus 3 of a 3rd Example. It is the figure which showed the principle which detects whether a target object is a closed ring shape. It is a figure which shows the propagation aspect of an electric signal when an element is completely enclosed by a shield.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an explanatory diagram showing the basic configuration and operation principle of the detection device 1 of the present embodiment. As shown to Fig.1 (a), the detection apparatus 1 of a present Example is mounted | worn with a user's finger | toe, and is made into the ring shape.

  The detection device 1 includes a signal electrode 10 and a reference electrode 20 that are a pair of electrodes for applying an electrical signal to the user's body, and a current sensor 30 for current measurement. When a finger (hereinafter referred to as a detection device wearing finger) comes into contact with another body part, a closed ring-shaped conductor path is formed in the user's body. Detect contact / separation to body parts.

  As shown in the left diagram of FIG. 1B, even when an electric signal is applied from the signal electrode 10 when a closed ring conductor path is not formed on the user's body, the electric signal is And the body part corresponding to the region P surrounded by the reference electrode 20 is only propagated.

  On the other hand, when a closed ring-shaped conductor path is formed in the user's body due to contact between the detection device wearing finger and another body part, as shown in the right diagram of FIG. A detour route that propagates from the signal electrode 10 to the reference electrode 20 around the closed annular conductor path is generated.

  The detection device 1 according to the present embodiment detects the current by measuring the current flowing through the body of the user corresponding to the detour route outside the area P surrounded by the signal electrode 10 and the reference electrode 20 by the current sensor 30. Detects contact / separation of the device wearing finger to other body parts.

  FIG. 2 is a block diagram illustrating an electrical configuration of the detection apparatus 1. The detection apparatus 1 according to the present embodiment includes the signal electrode 10, the reference electrode 20, and the current sensor 30 described above, and an application circuit 40 that applies an electrical signal (alternating current signal) between the signal electrode 10 and the reference electrode 20; Based on the wireless transmitter 50 for wireless communication with the external device 70 and the current measurement value output from the current sensor 30, contact / separation of the detection device wearing finger to other body parts is detected, and the detection result is obtained. And a control unit 60 that transmits to the external device 70 through the wireless transmission unit 50.

  The external device 70 receives the status signal representing the detection result transmitted from the detection device 1 wirelessly, and executes processing based on the detection result. For example, according to a detection result, the process which displays the moving image which opens and closes a character's finger | toe in virtual space through a display is performed. With such an operation of the external device 70, the detection device 1 functions as an input interface to the external device 70.

  Then, the detailed structure of each part which comprises the detection apparatus 1 is demonstrated. First, the signal electrode 10 provided in the detection device 1 of the present embodiment is configured as an annular electrode. A user's finger is inserted into the space surrounded by the signal electrode 10 (the inner space of the ring) when the detector 1 is worn. The signal electrode 10 is provided in the detection device 1 so as to come into contact with the user's finger on the inner surface 11 of the ring with the user's finger inserted.

  The current sensor 30 includes an annular current transformer 31 formed by winding a coil 31b around an annular core 31a, and a signal processing circuit 35 connected to both ends of the coil 31b included in the current transformer 31. . Like the signal electrode 10, the user's finger is inserted into the space (inner ring space) surrounded by the current transformer 31 when the detection device 1 is worn.

  That is, the current sensor 30 is surrounded by the current transformer 31 by utilizing the fact that a voltage is generated at both ends of the coil 31b due to electromagnetic induction by acting on the magnetic field generated by the current flowing in the axial direction in the central portion of the current transformer 31. The current flowing in the axial direction of the current transformer 31 is measured with the user's finger housed in the space.

  The signal processing circuit 35 is connected to both ends of the coil 31b of the current transformer 31, amplifies a difference between signals input from both ends of the coil 31b, and outputs a differential amplification circuit 35a. And a rectifier 35b that rectifies the output signal (AC signal) of the circuit 35a and converts it into a DC signal, and outputs the output signal from the rectifier 35b as a current measurement value.

  In this way, the effective value of the voltage generated at both ends of the coil 31b of the current transformer 31 is converted from the current sensor 30 into a measured value (effective value) of the current flowing in the axial direction in the space surrounded by the current transformer 31. Is output.

  In addition, the reference electrode 20 is configured as an annular electrode like the signal electrode 10. Even in the space surrounded by the reference electrode 20 (the inner space of the ring), the user's finger is inserted when the detection device 1 is worn. That is, the reference electrode 20 is provided in the detection device 1 so as to come into contact with the user's finger on the inner surface 21 side of the ring with the user's finger inserted.

  By the way, the reference electrode 20 is configured so that a cross section perpendicular to the circumferential direction has a ring-opening shape having a gap 23. In other words, the reference electrode 20 is configured such that a cross section perpendicular to the circumferential direction is substantially U-shaped.

  That is, the reference electrode 20 has a configuration in which a region sandwiched between two cylindrical members 20a and 20b is closed at one cylindrical member end in a state where two cylindrical members 20a and 20b having different diameters are overlapped. The inner surface of the small-diameter cylindrical member 20a is configured to come into contact with the user's finger in a state where the detection device 1 is mounted on the user's finger.

  And in the detection apparatus 1 of a present Example, the current transformer 31 is accommodated in the area | region pinched | interposed into these two cylindrical members 20a and 20b. With this configuration, the reference electrode 20 surrounds the current transformer 31 and functions as a shield for protecting the current transformer 31 from external noise (radio waves).

  The current transformer 31 is housed in a space sandwiched between the two cylindrical members 20a and 20b of the reference electrode 20 so that the central axis of the current transformer 31 and the central axis of the reference electrode 20 coincide with each other. Yes.

  In addition, the inner diameter R1 of the signal electrode 10 and the inner diameter R2 of the reference electrode 20 are set to be the same, and the signal electrode 10 and the reference electrode 20 are spaced apart by a predetermined interval in the axial direction so that the central axes thereof coincide with each other. Has been placed. With this configuration, the detection device 1 is configured to have a finger mounting hole 1a through which the signal electrode 10 and the reference electrode 20 communicate.

  FIG. 3 specifically shows the arrangement of the signal electrode 10, the reference electrode 20, and the current transformer 31 conceptually represented in FIG. 2 in a cross-sectional view perpendicular to the circumferential direction of the detection device 1. It is. However, the detailed configuration of the current transformer 31 is not shown in FIG.

  As shown in FIG. 3, an insulating material INS is filled between the signal electrode 10, the reference electrode 20, and the current transformer 31, and the signal electrode 10, the reference electrode 20, and the current transformer 31 are filled with the insulating material INS. Each is fixed at a predetermined position in the detection apparatus 1.

  Next, a propagation mode of the electric signal when the electric signal is applied from the signal electrode 10 to the user's body will be described with reference to FIG. FIG. 4A is a diagram illustrating a propagation mode of an electric signal in a state in which the detection device wearing finger is separated from another body part, and FIG. It is the figure which showed the propagation aspect of the electrical signal in the state in which the body part contacted and the closed ring-shaped conductor path was formed in the user's body.

  In this embodiment, the connection point E between the application circuit 40 and the reference electrode 20 is provided at the end of the reference electrode 20 on the signal electrode 10 side. The reference electrode 20 is a path along the ring opening that connects the contact point F, which is the contact point between the user's body and the reference electrode 20 and is farthest from the signal electrode 10, and the connection point E. 1, the first path J1 located on the signal electrode 10 side (more specifically, the first path J1 located on the signal electrode 10 side with respect to the straight line passing through the points E and F) is made electrically continuous. The second path J2 located on the opposite side of the first path has a gap 23 and is electrically discontinuous.

  Therefore, in a state where the detection device wearing finger and the other body part are separated from each other, the electrical signal applied from the signal electrode 10 is the user's body and the reference electrode 20 as shown by a one-dot chain line in FIG. Is propagated from the contact point G closest to the signal electrode 10 to the reference electrode 20 and flows to the connection point E, and a current that wraps around the current transformer 31 is generated. do not do. That is, no current that propagates through the inner space of the ring of the current transformer 31 is generated.

  Therefore, in a state where the detection device wearing finger and the other body part are separated from each other, the magnetic flux along the annular core 31a of the current transformer 31 is not substantially generated. As a result, the current sensor 30 hardly measures the current. Become.

  On the other hand, in a state in which the detection device wearing finger is in contact with another body part, as shown by a thick solid line in FIG. 4B, a signal is transmitted via a contact point C between the detection device wearing finger and the other body part. Since a propagation path (detour route) of an electric signal propagating from the electrode 10 to the reference electrode 20 is generated, a current flowing in the axial direction of the current transformer 31 is generated in the region K surrounded by the inner surface of the ring of the current transformer 31. By forming the magnetic flux along the annular core 31a, as a result, in the current sensor 30, a much larger current is measured than in the state where the detection device wearing finger and the other body part are separated from each other.

  Therefore, in the present embodiment, contact / separation between the detection apparatus wearing finger and another body part is detected based on the current measurement value output from the current sensor 30 while the reference electrode 20 has a shielding function. It can be done.

  The control unit 60 according to the present embodiment detects contact / separation between the detection device wearing finger and another body part based on the current measurement value output from the current sensor 30 that measures the current generated in this way. The status signal representing the detection result is transmitted to the external device 70 through the wireless transmission unit 50.

  Specifically, as shown in FIG. 5, the control unit 60 determines whether or not the current measurement value exceeds a predetermined threshold value (S110), and the current measurement value exceeds the predetermined threshold value. If it is (Yes in S110), a status signal indicating finger contact is transmitted to the external device 70 through the wireless transmission unit 50 (S120), and if the current measurement value is equal to or less than a predetermined threshold value, wireless The process of transmitting a status signal indicating finger separation to the external device 70 through the transmission unit 50 (S130) is repeatedly executed. Accordingly, the control unit 60 sequentially transmits the status signal indicating the detection result to the external device 70.

  The configuration of the detection device 1 of the present embodiment has been described above. In this embodiment, the reference electrode 20 functions as a shield that protects the current transformer 31 by arranging the reference electrode 20 around the current transformer 31. Therefore, it is not necessary to provide a separate shield independently from the reference electrode 20, and the detection device 1 can be downsized.

  Further, in this embodiment, the cross section perpendicular to the circumferential direction of the reference electrode 20 is formed in an open shape so that the electric signal applied from the signal electrode 10 is transmitted through the reference electrode 20 and encloses the current transformer 31. I tried to prevent it from propagating. Therefore, even when the reference electrode 20 has a function as a shield, the contact / separation between the detection device wearing finger and another body part can be satisfactorily detected from the current measurement value obtained through the current transformer 31. Can do.

[Second Example]
Then, the detection apparatus 2 of 2nd Example is demonstrated. However, in the detection apparatus 2 of the second embodiment, the shape of the reference electrode 80 is different from that of the reference electrode 20 of the first embodiment, and other configurations are the same as those of the first embodiment. Accordingly, only the configuration of the reference electrode 80 will be described below.

  6A is a diagram showing a cross section perpendicular to the circumferential direction of the reference electrode 80 included in the detection device 2 of the second embodiment, and FIG. 6B shows a side surface of the reference electrode 80. FIG. FIG. 6C is a cross-sectional view perpendicular to the circumferential direction of the detection device 2. However, the detailed configuration of the current transformer 31 is not shown in FIG.

  As shown in FIG. 6 (a), the reference electrode 80 provided in the detection device 2 of the second embodiment has a structure in which two cylindrical members 80a and 80b having different diameters are overlapped with each other. The region sandwiched between the two is closed at the end of the cylindrical member on one side, thereby having a closed portion 80c.

  The reference electrode 80 has an end opposite to the end of the large-diameter cylindrical member 80b where the blocking portion 80c is formed, along a plane perpendicular to the axial direction of the cylindrical member 80b. The end of the small-diameter cylindrical member 80a, which has a flange 80f extending in the central direction, is opposite to the end of the cylindrical member 80a in the axial direction. Is configured to have a flange shape having a flange portion 80e extending in a direction approaching the cylindrical member 80b along a vertical surface.

  Due to the flanges 80e and 80f, the gap 83 of the reference electrode 80 of this embodiment is narrower in the radial direction than the gap 23 of the first embodiment, as shown in FIG. 6B. Is formed.

  In the detection device 2, the current transformer 31 is accommodated in the internal space surrounded by the cylindrical members 80 a and 80 b, the closed portion 80 c, and the flange portions 80 e and 80 f in the reference electrode 80. 31 is protected from external noise by the reference electrode 80.

  In the detection device 2 configured in this way, the radial width of the gap 83 is narrower than the radial width of the gap 23 in the first embodiment, so that external noise enters from the gap 83 and the current transformer 31. It is possible to suppress the deterioration of the accuracy of the current measurement using the method as compared with the first embodiment. Therefore, according to the present embodiment, contact / separation between the detection device wearing finger and another body part can be detected with high accuracy.

In this embodiment, the example in which the gap 83 is provided straight in the circumferential direction has been described above. However, it is more preferable that the gap 83 is provided in a wave shape in the circumferential direction.
FIG. 7A is a diagram illustrating a side configuration of the reference electrode 80 when the gap 83 is provided in a wave shape (specifically, zigzag shape). The wavy gap 83 can be realized by adjusting the lengths of the flange portions 80e and 80f.

  When the straight gap 83 is provided in the circumferential direction (see FIG. 6B), the opening width L0 of the gap 83 that is linearly opened in the circumferential direction increases. As shown in FIG. 7B, the opening width L1 of the gap 83 opened linearly in the circumferential direction is shortened.

  Therefore, when the gap 83 is wave-shaped, external noise is less likely to propagate to the current transformer 31 side through the gap 83 than when the gap 83 is provided straight in the circumferential direction, and the current transformer 31 can be strongly protected from external noise. it can.

[Third embodiment]
Next, the detection device 3 of the third embodiment will be described. However, in the detection device 3 of the third embodiment, the shape of the reference electrode 90 is different from that of the reference electrode 20 of the first embodiment, and other configurations are the same as those of the first embodiment. Accordingly, only the configuration of the reference electrode 90 will be described below.

  FIG. 8A is a diagram showing a cross-sectional shape perpendicular to the circumferential direction of the reference electrode 90 included in the detection device 3 of the third embodiment, and FIG. It is a vertical sectional view. However, the detailed configuration of the current transformer 31 is not shown in FIG.

  As shown in FIG. 8 (a), the reference electrode 90 provided in the detection device 3 of the third embodiment is a state in which two cylindrical members 90a and 90b having different diameters are overlapped with each other. The region sandwiched between the two is closed at the end of the cylindrical member on one side, thereby having a closed portion 90c.

  Of the two cylindrical members 90a and 90b, the axial length Db of the large-diameter cylindrical member 90b is set to a value smaller than the axial length Da of the small-diameter cylindrical member 90a. In other words, the large-diameter cylindrical member 90b is shorter in the axial direction than the small-diameter cylindrical member 90a.

The cylindrical members 90a and 90b are overlapped with the end portion on the side having the closing portion 90c being aligned.
In addition, the end of the large-diameter cylindrical member 90b opposite to the end where the blocking portion 90c is formed extends in the central direction along a plane perpendicular to the axial direction of the cylindrical member 90b. It has a bowl shape having a portion 90f. The flange portion 90f is provided so as to approach the cylindrical member 90a as long as it does not contact the small-diameter cylindrical member 90a.

  On the other hand, the end of the small-diameter cylindrical member 90a opposite to the end where the blocking portion 90c is formed extends in the large-diameter direction along a plane perpendicular to the axial direction of the cylindrical member 90a. It has a hook shape having a hook portion 90e.

Specifically, the flange portion 90e extends in the large-diameter direction so as to cover the gap SP formed between the flange portion 90f and the cylindrical member 90a from the outside.
That is, the reference electrode 90 of the present embodiment is configured to have a ring-opening shape having a gap 93 in a cross section perpendicular to the circumferential direction, but the flanges 90e, 90b constituting both ends of the ring-opening. 90f is superposed in a state shifted in the radial direction of the ring opening.

  Although the detection device 3 of the third embodiment has been described above, in this embodiment, the current transformer 31 is prevented from being seen from the outside by overlapping the flange portions 90e and 90f, so that it jumps linearly. The possibility that incoming noise (radio waves) enters from the gap 93 and reaches the current transformer 31 to adversely affect the current transformer 31 can be reduced. Therefore, according to the present embodiment, it is possible to configure the detection device 3 that is resistant to noise and has high detection accuracy.

[Correspondence with Claims]
The correspondence relationship between the detection device described in “Claims” and the above-described embodiment is as follows. That is, the annular element described in “Claims” corresponds to the current transformer 31 of the above embodiment, and the measuring instrument corresponds to the signal processing circuit 35. The signal electrode described in “Claims” corresponds to the signal electrode 10 of the above embodiment, and the shield corresponds to the reference electrodes 20, 80, and 90. In addition, the application circuit corresponds to the application circuit 40 of the above-described embodiment, and the detection unit corresponds to processing executed by the control unit 60.

[Others]
As mentioned above, although the Example of this invention was described, this invention is not limited to the said Example, It can take a various aspect. For example, although the configuration of the ring-shaped detection devices 1 to 3 has been described in the above embodiment, the detection devices 1 to 3 may be formed in a bracelet shape. Thus, if the detection devices 1 to 3 are made into bracelet shapes and the detection devices 1 to 3 are attached to the user's arm, the hand on which the detection devices 1 to 3 are attached comes into contact with the opposite hand. This can be detected.

DESCRIPTION OF SYMBOLS 1-3 ... Detection apparatus, 10 ... Signal electrode, 20, 80, 90 ... Reference electrode, 20a, 20b, 80a, 80b, 90a, 90b ... Cylindrical member, 23, 83, 93 ... Gap, 30 ... Current sensor, 31 ... Current transformer, 31a ... annular core, 31b ... coil, 35 ... signal processing circuit, 35a ... differential amplifier circuit, 35b ... rectifier, 40 ... application circuit, 50 ... radio transmission part, 60 ... control part, 70 ... external device , 80c, 90c ... closed part, 80e, 80f, 90e, 90f ... buttocks

Claims (4)

An annular element in which a coil is wound around an annular core;
Using the voltage generated at both ends of the coil due to the magnetic flux change in the annular core as an index, the current flowing in the axial direction of the annular element is measured in the measurement object housed in the space surrounded by the annular element, A measuring instrument that outputs measurement results;
An annular shield surrounding the annular element, wherein the shield is in contact with the object to be measured inside the ring;
In the axial direction of the shield, a signal electrode for signal application that is provided at a position away from the shield and that contacts the measurement object extending in the axial direction of the shield;
An application circuit that is electrically connected to the signal electrode and the shield, and that uses the shield as a reference electrode and applies an AC signal to a portion of the measurement target object located between the reference electrode and the signal electrode; ,
With
The shield has a cross section perpendicular to the circumferential direction in an open ring shape having a gap, and connects the connection point between the application circuit and the shield and the contact point between the object to be measured and the shield. Of the paths along the ring opening, the first path located on the signal electrode side is electrically continuous, and the second path located on the opposite side of the first path is electrically connected with the gap. A discontinuous configuration,
The electrical device, wherein the annular element is disposed inside the ring opening and surrounded by the shield in a cross section perpendicular to a circumferential direction.   The shield is configured such that, in a cross section perpendicular to the circumferential direction, both ends of the ring opening are overlapped in a state having the gap and a state shifted in a radial direction of the ring opening. The electric device according to claim 1.   The electric device according to claim 1, wherein the shield is configured to have the wavy gap in the circumferential direction. An electrical device to be worn on the user's body as the measurement target object,
Based on the measurement value of the current output as the measurement result from the measuring instrument, the other body part of the user is in contact with the body part of the user located in a direction away from the signal electrode rather than the contact part with the shield. The electric device according to claim 1, further comprising: a detecting unit that detects that the operation has been performed.