JP2007107971A - Magnetic sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the bidirectional strength change of an external magnetic field by a simple configuration. <P>SOLUTION: A magnetic sensor device 1 comprises a linear Barkhausen element 6 that has a plurality of magnetic material layers so that the coercive force of a center section 6a becomes larger than that of an outer-periphery section 6b, and generates the inversion of magnetization at the outer-periphery section 6b by applying a magnetic field that is inverted alternately along the longitudinal direction; a coil 7 wound along the longitudinal direction outside the outer-periphery section 6b in the Barkhausen element 6; and a light output circuit 12 that is corrected across the coil 7 and outputs two kinds of light signals according to the polarity of a pulse voltage generated across the coil 7 by the inversion of magnetization. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic sensor device using magnetization reversal in the large Barkhausen effect.

As a technique relating to an element capable of generating magnetization reversal utilizing the large Barkhausen effect (hereinafter referred to as “Barkhausen element”), there is a magnetic sensor described in Patent Document 1 below. In this magnetic sensor, a cap having a high magnetic permeability is attached to the tip of a composite magnetic wire, which is a Barkhausen element, and an LED is connected between both ends of a coil wound around the outer periphery of the composite magnetic wire. An optical fiber is optically connected to. This magnetic sensor detects a change in an external magnetic field with a pulse voltage, converts this pulse voltage into an optical signal, and outputs it to the outside. The following cited document 2 also discloses a sensor device having a similar configuration.
Japanese Patent Laid-Open No. 9-43326 JP-A-5-264686

  However, in the sensor device as described above, a change in one direction of the external magnetic field can be detected and output as an optical signal, but a change in the intensity of the external magnetic field in both directions cannot be detected. When applying to a meter, a speedometer, a flow meter, etc., in order to ensure accuracy, the configuration of the external magnet has been complicated.

  In addition, by preparing multiple Barkhausen elements, it is possible to output the intensity changes in both directions of the external magnetic field separately, but in this case, the overall device configuration becomes complicated and the characteristics of the Barkhausen element There is a problem that a difference in detection sensitivity occurs due to variations.

  Therefore, the present invention has been made in view of such problems, and an object of the present invention is to provide a magnetic sensor device capable of detecting intensity changes in both directions of an external magnetic field with a simple configuration.

  In order to solve the above-described problems, the magnetic sensor device of the present invention has a plurality of magnetic layers so that the coercive force at the center is larger than the coercive force at the outer periphery, and alternately reverses along the longitudinal direction. A linear Barkhausen element that causes magnetization reversal at the outer periphery by applying a magnetic field, a coil wound along the longitudinal direction outside the outer periphery of the Barkhausen element, and connected to both ends of the coil And an optical output circuit that outputs two types of optical signals in accordance with the polarity of the pulse voltage generated between both ends of the coil due to magnetization reversal.

  According to such a magnetic sensor device, when a magnetic field that is alternately inverted is applied to the Barkhausen element, magnetization reversal occurs along the longitudinal direction of the Barkhausen element, and both ends of the coil wound around the Barkhausen element. A pulse voltage is generated. At this time, since two types of optical signals corresponding to the polarity of the pulse voltage are output from the optical output circuit connected to both ends of the coil, the intensity change in both directions of the external magnetic field can be achieved without adding a Barkhausen element. Can be detected.

  The light output circuit is connected between the first terminal and the second terminal of the coil, and emits light in response to the generation of the pulse voltage having the first polarity, and the first terminal. A second light emitting element that is connected in the opposite direction to the first light emitting element between the first terminal and the second terminal and that emits light in response to generation of a pulse voltage having a second polarity opposite to the first polarity; It is preferable to have. In this case, by outputting two types of optical signals having different wavelengths, luminances, and the like in the two light emitting elements according to the polarity of the pulse voltage, it is possible to easily detect intensity changes in both directions of the external magnetic field.

  Further, the optical output circuit is connected in series between the first terminal and the second terminal of the coil, and rectifies the current generated by the pulse voltage from the first terminal toward the second terminal. And the second rectifying element and the third and fourth rectifying elements connected in series between the first terminal and the second terminal and rectifying current from the second terminal toward the first terminal. A load resistor connected in series with the first and second rectifying elements or the third and fourth rectifying elements, between the first rectifying element and the second rectifying element, and a third rectifying element It is also preferable to have a light emitting element connected in series between the element and the fourth rectifying element. With such an optical output circuit, a pulse voltage is generated from the first terminal of the coil toward the second terminal and a case where the pulse voltage is generated from the second terminal toward the first terminal. The load resistance connected to the light emitting element can be changed, and an optical signal having two types of luminance corresponding to the polarity of the pulse voltage can be output by one light emitting element. As a result, it is possible to easily detect intensity changes in two directions of the external magnetic field.

  It is also preferable to further include a magnetic field generating circuit that applies a magnetic field until the saturation state is reached with respect to the Barkhausen element by external control. In this way, the detection function of the magnetic sensor device can be easily suspended.

  Furthermore, it is preferable that a magnetic shield is provided on the outer periphery of the central portion in the longitudinal direction of the Barkhausen element. By adopting such a configuration, it is possible to prevent an extra magnetic field from being applied to the Barkhausen element and to improve detection sensitivity.

  It is also preferable to further include a magnetic bypass unit that bypasses the magnetic field from the outside toward the central portion in the longitudinal direction of the Barkhausen element. In general, when an external magnetic field is applied to the central part of the Barkhausen element, the element is always placed in a strong magnetic field, so that the magnetization reversal characteristics tend to vary. By adopting a configuration that bypasses the magnetic field from the outside toward the center of the Barkhausen element, the magnetic field applied unnecessarily is weakened, and variations in magnetization reversal characteristics are effectively reduced.

  It is also preferable to further include a magnetic derivative provided between the vicinity of one end of the Barkhausen element and the vicinity of the other end. In this way, the magnetic derivative is interposed between the magnetic field applying means such as an external magnet and the Barkhausen element, so that the degree of freedom of the device configuration is expanded.

  According to the magnetic sensor device of the present invention, it is possible to detect an intensity change in both directions of an external magnetic field with a simple configuration.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a magnetic sensor device according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]
The magnetic sensor device 1 according to the first embodiment of the present invention is a device for detecting a change in magnetic flux of an external magnetic field, and is applied as a tachometer, a speedometer, a flow meter, a position detector, or the like. As shown in FIG. 1, the magnetic sensor device 1 includes a sensor unit 2 that generates a pulse voltage according to a change in an external magnetic field, and light that generates and outputs an optical signal according to the pulse voltage output from the sensor unit 2. A signal generation unit 3 and a temporary stop unit (magnetic field generation circuit) 4 that temporarily stops the function of the sensor unit 2 are arranged in a housing 5 having a light shielding property.

  The sensor unit 2 is formed by winding a coil 7 around the outer periphery 6 b of the linear Barkhausen element 6. The Barkhausen element 6 has a two-layer structure including a central portion (magnetic layer) 6a and an outer peripheral portion (magnetic layer) 6b having different coercive forces, and the coercive force of the central portion 6a is that of the outer peripheral portion 6b. It is larger than the magnetic force. As such a Barkhausen element, for example, an iron, cobalt, vanadium alloy (Bicalloy alloy) wire subjected to twisting or cladding is used. The coil 7 is wound along the longitudinal direction (left and right direction in FIG. 1) of the Barkhausen element 6 around the central axis of the Barkhausen element 6, and both ends 7 a and 7 b are circuit boards of the optical signal generating unit 3. 8 is connected.

  The optical signal generation unit 3 includes a light emitting diode (light emitting element) 9 connected on the circuit board 8, and light emitted from the light emitting diode 9 is placed on the optical axis of the light emitting diode 9 at the end of the housing 5. A light guide unit 10 that guides signals to the outside is provided through the housing 5. An optical fiber 11 is further connected to the outer end of the light guide 10. A light output circuit 12 including the light emitting diode 9 is formed on the circuit board 8 on which the light emitting diode 9 is mounted.

  As shown in FIG. 2 which is a circuit diagram of the optical output circuit 12, one terminal 7a of the coil 7 wound around the Barkhausen element 6 is connected to an anode of a diode (rectifier element) 13a via a resistance element 14. The anode of the light emitting diode 9 is connected to the cathode of the diode 13a. Furthermore, the anode of the diode (rectifier element) 13b is connected to the cathode of the light emitting diode 9, and the other terminal 7b of the coil 7 is connected to the cathode of the diode 13b. That is, the light output circuit 12 has a configuration in which the resistor element 14, the diode 13a, the light emitting diode 9, and the diode 13b are connected in series in this order between the terminals 7a and 7b of the coil. These diodes 13a and 13b have a role of rectifying the current generated by the pulse voltage in the coil 7 from the terminal 7b toward the terminal 7a in the coil 7.

  Furthermore, the anode of the light emitting diode 9 is connected to the cathode of a diode (rectifier element) 13c, the anode of the diode 13c is connected to the terminal 7b, and the cathode of the light emitting diode 9 is connected to the diode (rectifier element) 13d. The anode is connected, and the cathode of the diode 13d is connected to the terminal 7a. In other words, the optical output circuit 12 has a configuration in which the diode 13c, the light emitting diode 9, and the diode 13d are connected in series in this order between the two terminals 7b and 7a of the coil. Has a role of rectifying the current generated by the pulse voltage in the coil 7 from the terminal 7a toward the terminal 7b.

  Here, by inserting the resistance element 14 in the closed circuit including the diodes 13a and 13b, the load resistance is made larger than that in the closed circuit including the diodes 13c and 13d, and the light is emitted from the light emitting diode 9 depending on the polarity of the pulse voltage. The brightness of the optical signal is changed into two types. Note that a resistive element having a resistance value different from that of the resistive element 14 may be connected in series on the closed circuit including the diodes 13c and 13d.

  Returning to FIG. 1, an electromagnet composed of an iron core portion 15 and a coil 16 is provided as a temporary stop portion 4 at a position adjacent to the sensor portion 2 inside the housing 5. The iron core portion 15 is disposed along an extension of the central axis of the Barkhausen element 6 so that one end surface thereof faces the end surface of the Barkhausen element 6, and the coil 16 is disposed outside the outer peripheral surface of the iron core portion 15. It is wound. Both terminals 17 of the coil 16 are led to the outside of the housing 5, and the magnetic field intensity generated by the temporary stop unit 4 is controlled by supplying a driving current for driving the electromagnet from the outside via the terminal 17. Is done.

  A rotating body 18 having a rotating shaft 18 a parallel to the central axis of the Barkhausen element 6 is arranged in parallel to the sensor unit 2 outside the housing 5 of the magnetic sensor device 1 having such a configuration. A rod-shaped permanent magnet 19 is provided on the outer peripheral portion of the rotating body 18 in parallel with the rotation axis.

  According to the magnetic sensor device 1 described above, the magnetic field in the longitudinal direction of the Barkhausen element 6 that is alternately inverted is applied to the end of the Barkhausen element 6 by the rotating body 18 installed outside the housing 5. As a result, magnetization reversal occurs along the longitudinal direction of the outer peripheral portion 6 b of the Barkhausen element 6, and a pulse voltage is generated between both terminals 7 a and 7 b of the coil 7 wound around the Barkhausen element 6. It has also been clarified by the present inventors that the polarity of this pulse voltage is reversed depending on the direction of change of the magnetic field applied to the Barkhausen element 6. At this time, in the light output circuit 12, the load of the light emitting diode 9 is different depending on whether the pulse voltage in the coil 7 is generated in the direction from the terminal 7a to the terminal 7b of the coil 7 or in the direction from the terminal 7b to the terminal 7a. Since the resistance can be changed, an optical signal having two types of luminance corresponding to the positive and negative of the pulse voltage is output from one light emitting element. Therefore, it is possible to easily detect the intensity change in both directions of the external magnetic field without adding the Barkhausen element 6, and at the same time, it is possible to autonomously transmit the detection result to a remote place via the optical fiber.

  Further, a magnetic current is applied to the Barkhausen element 6 by supplying a drive current large enough to magnetically saturate the Barkhausen element 6 from the outside via the terminal 17 of the temporary stop unit 4. The detection function of the device can be easily suspended. In particular, in this case, since the temporary stop function can be realized without adding a new element to the light output circuit 12, the reliability of the magnetic sensor device 1 is not impaired.

  Further, in the optical signal generation unit 3 of the magnetic sensor device 1, an electromotive force of 26.7 mV is obtained per turn of the coil 7, and an electromotive force of about 80 V is obtained from the coil 7 having 3000 turns. It has a sufficient electromotive force to drive the diode 9. As described above, since the light emitting diode 9 is directly driven by the pulse voltage generated by the Barkhausen element 6 and the coil 7, a control circuit and a power supply circuit for driving the light emitting element are not required, and the magnetic sensor device 1 It is possible to reduce the size and prevent malfunction due to noise generated from the control circuit, the power supply circuit, and the like.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 3 is a perspective view of the magnetic sensor device 21 according to the second embodiment of the present invention, and FIG. 4 is a circuit configuration diagram of the light output circuit 32 of FIG. The magnetic sensor device 21 according to the present embodiment is different from that of the first embodiment in the configuration of the light emitting diode 29 in the optical signal generation unit 23 and the circuit configuration of the optical output circuit 32.

  That is, as shown in FIG. 4, the light output circuit 32 formed on the circuit board 28 has a configuration in which two LEDs 29a and 29b having different emission colors are connected to the terminals 7a and 7b of the coil 7, and the LED 29a Is connected between the terminal 7a and the terminal 7b, and a pulse voltage generated in the optical output circuit 32 by the coil 7 is generated between the terminal 7a and the terminal 7b with a polarity (first polarity) in which the terminal 7a is positive. The LED 29b is connected in the opposite direction to the LED 29a between the terminal 7a and the terminal 7b, and the pulse voltage generated in the light output circuit 32 by the coil 7 is between the terminal 7a and the terminal 7b. When light is generated with a positive polarity (second polarity), light is emitted. More specifically, the anode of LED 29a is connected to terminal 7a of coil 7, the cathode of LED 29a is connected to terminal 7b of coil 7, and the anode of LED 29b is connected to terminal 7b of coil 7, and LED 29b Is connected to the terminal 7 a of the coil 7. With such a configuration, either the LED 29a or the LED 29b emits light with a different emission color according to the polarity of the pulse voltage generated between the both terminals 7a and 7b of the coil 7. The light emitting diode 29 is configured to include these LEDs 29a and 29b, synthesizes the light generated from the LEDs 29a and 29b, and emits them as optical signals to the outside. Note that LEDs having different emission luminance characteristics may be used as the LEDs 29a and 29b.

  The circuit configuration of the light output circuit 32 can take various modifications. For example, as shown in FIG. 5, the anode of the LED 29a is connected to the terminal 7a, the anode of the LED 29b is connected to the terminal 7b, and the cathodes of the LED 29a and the LED 29b are connected to each other. The element 30a, 30b may be connected. Even in such a circuit configuration, the LED 29a emits light when the pulse voltage is generated with the first polarity, and the LED 29b emits light when it is generated with the second polarity.

  According to such a magnetic sensor device 21, two types of optical signals having different wavelengths, luminances, and the like in the two LEDs 29 a and 29 b are output according to the polarity of the pulse voltage between the terminals 7 a and 7 b of the coil 7. The intensity change in both directions of the external magnetic field can be easily detected on the optical signal receiving side. Further, without preparing a plurality of optical fibers, the intensity change in both directions of the external magnetic field can be transmitted to a remote place as two types of optical signals.

  In addition, this invention is not limited to embodiment mentioned above. For example, in the magnetic sensor devices 1 and 21, a magnetic shield member may be provided on the outer periphery of the central portion in the longitudinal direction of the Barkhausen element 6. FIG. 6 is a perspective view of a magnetic sensor device 41 which is a modification of the first embodiment of the present invention. As shown in the figure, the outside of the coil 7 wound around the central portion of the Barkhausen element 6 is covered with a magnetic shield member 42 made of a material having a low magnetic impedance such as iron or cobalt alloy. Due to the presence of such a magnetic shield member 42, for example, when a bar-shaped magnet is rotated around a rotation axis perpendicular to the central axis of the Barkhausen element 6, a strong magnetic field is generated at the center of the Barkhausen element 6. It can prevent being applied. It is known that when the Barkhausen element 6 is always placed in a strong magnetic field, the magnetization reversal characteristics vary, and the output pulse voltage varies by 20 to 30%. By providing the magnetic shield member 42, such fluctuations in the pulse voltage can be effectively reduced, so that the detection sensitivity of the magnetic sensor device can be improved.

  Further, a magnetic derivative made of iron, nickel alloy, iron alloy or the like may be provided between both end portions of the Barkhausen element 6 and a magnetic field generating portion such as a permanent magnet outside the housing 5. By providing such a magnetic derivative, a free magnetic path that does not depend on the positional relationship between the Barkhausen element 6 and the magnetic field generation unit can be formed. Even in this case, since the magnetic derivative follows the change of the external magnetic field at a high speed, the sensitivity of the entire magnetic sensor device can be maintained without affecting the magnetization reversal in the Barkhausen element 6. 7 to 9 show modifications of the magnetic sensor device including the magnetic derivative. In FIGS. 8 and 9, the components other than the sensor unit 2 and the magnetic derivative in the magnetic sensor device are not shown.

  In the magnetic sensor device 61 shown in FIG. 7, in the vicinity of both ends of the Barkhausen element 6, a pair of rectangular parallelepiped magnetic derivatives 62 a and 62 b are inserted into one end of the Barkhausen element 6. The other end side is located in the vicinity of the N pole or S pole of the permanent magnet 19 fixed to the outer peripheral portion of the rotating body 18. Thus, by providing a magnetic derivative between the vicinity of one end of the Barkhausen element 6 and the vicinity of the other end, the sensitivity of the entire magnetic sensor device can be improved.

  FIG. 8 shows the structure of a magnetic derivative in a magnetic sensor device for detecting reciprocating motion in a cylinder or the like in an engine. In the magnetic sensor device 81 shown in the figure, a pair of rod-shaped permanent magnets 82a and 82b whose magnetic poles are directed in different directions are provided so as to be parallel to the central axis of the Barkhausen element 6, and Barkhausen. A magnetic derivative 83 is provided between one end of the element 6 and one end of the permanent magnets 82a and 82b. Further, between the other end portions of the permanent magnets 82a and 82b and the other end portion of the Barkhausen element 6, a piston ring that reciprocates between the permanent magnets 82a and 82b in accordance with the reciprocating movement of the cylinder is integrated. A magnetic derivative 84 is provided. Between the magnetic derivative 84 and the other end of the Barkhausen element 6, a magnetic derivative 85 is further provided that magnetically induces between the Barkhausen element 6 and the magnetic derivative 84 when the magnetic derivative 84 reciprocates. According to such a magnetic sensor device 81, the position of a reciprocating part in an engine or the like can be easily detected, and the device can be downsized and simplified when performing timing control such as engine ignition and exhaust. It becomes easy.

  FIG. 9 shows the configuration of the magnetic sensor device in the case where the central portion of the rod-shaped permanent magnet is the center of rotation. The magnetic sensor device 101 includes flat ring-shaped magnetic derivatives 103a and 103b that face each other, and the magnetic derivatives 103a and 103b have protrusions 106a and 106b that protrude outward in parallel to the surfaces of the magnetic derivatives 103a and 103b, respectively. The sensor part 2 is arranged between the protruding part 106a and the protruding part 106b so that both ends of the Barkhausen element 6 are close to the inner surfaces of the protruding parts 106a and 106b. The magnetic derivative 103a and the magnetic derivative 103b are supported with each other by joining a connecting member 107 made of a cylindrical non-magnetic material on the opposing surface. Between the magnetic derivative 103a and the magnetic derivative 103b, a rod-shaped permanent magnet 102 is positioned along a plane parallel to the magnetic derivatives 103a and 103b so that the center of gravity G is located on the central axis of the magnetic derivatives 103a and 103b. The permanent magnet 102 is rotatably supported along a plane parallel to the magnetic derivatives 103a and 103b with the center of gravity G sandwiched between the magnetic poles as the center of rotation. Furthermore, a plurality of magnetic derivatives 104 projecting toward the inner surface of the magnetic derivative 103b are attached to the magnetic derivative 103a, and a plurality of magnetic derivatives 105 projecting toward the inner surface of the magnetic derivative 103a are attached to the magnetic derivative 103b. It has been. The magnetic derivative 104 and the magnetic derivative 105 are alternately arranged along the outer edges of the magnetic derivatives 103a and 103b, and are arranged so as to face each other with the center of gravity G of the permanent magnet interposed therebetween. With this arrangement, the magnetic derivative 104 and the magnetic derivative 105 are simultaneously positioned in the vicinity of both magnetic poles of the permanent magnet 102 as the permanent magnet 102 rotates. According to the configuration of such a magnetic derivative, magnetic induction can be performed between both magnetic poles of the permanent magnet and both ends of the Barkhausen element according to the rotation of the permanent magnet 102, and during the rotation of the permanent magnet. The detection can be performed a plurality of times.

  A magnetic bypass section may be provided on the magnetic path between the central portion of the Barkhausen element 6 and a magnetic field generating section such as an external permanent magnet. As shown in FIG. 10, which is a modified example of the sensor unit 2 including the magnetic bypass unit, a rod-like permanent magnet 112 as a magnetic field generating unit extends along a plane including the Barkhausen element 6 with the center of rotation between both magnetic poles. It is rotatably supported. The sensor unit 2 is provided with a magnetic bypass unit 113 provided so as to surround both magnetic poles of the permanent magnet 112 when the sensor unit 2 is perpendicular to the central axis of the Barkhausen element 6. The magnetic bypass unit 113 bypasses the magnetic field generated from the permanent magnet 112 when the inclination angle of the permanent magnet 112 with respect to the central axis of the Barkhausen element 6 is equal to or larger than a predetermined angle, thereby applying a magnetic field to the Barkhausen element 6. It plays a role to weaken. In general, when the external magnet rotates along a plane including the Barkhausen element 6, the Barkhausen element 6 is always placed in a strong magnetic field, so that there is a tendency that variations in magnetization reversal characteristics are likely to occur. By providing such a magnetic bypass part 113, when the magnetic pole of the permanent magnet 112 moves away from both ends of the element 6 as it rotates, the magnetic field applied to the element is weakened, and variation in magnetization reversal characteristics is effectively achieved. Reduced.

  Further, the arrangement direction of the sensor unit 2 and the rotating body 18 as the magnetic field generation unit in the magnetic sensor devices 1 and 21 is not limited to a specific direction. For example, as illustrated in FIG. The central axis of the Barkhausen element 6 may be arranged so as to be parallel to the circuit board 8. In this case, the rotating shaft 18 a of the rotating body 18 is fixed so as to be parallel to the central axis of the Barkhausen element 6.

It is a plane perspective view of the magnetic sensor apparatus which is 1st Embodiment of this invention. It is a circuit diagram of the optical output circuit formed on the circuit board of FIG. It is a plane perspective view of the magnetic sensor apparatus which is 2nd Embodiment of this invention. FIG. 4 is a circuit diagram of an optical output circuit formed on the circuit board of FIG. 3. FIG. 5 is a circuit diagram showing another connection form of the light output circuit of FIG. 4. It is a plane perspective view of the magnetic sensor apparatus which is a modification of this invention. It is a plane perspective view of the magnetic sensor apparatus which is a modification of this invention. It is a figure which shows schematic structure of the magnetic sensor apparatus which is a modification of this invention. (A) is a front view of the magnetic derivative in the modification of this invention, (b) is a side view of the magnetic derivative of (a). (A) is a side view which shows the structure containing the sensor part and magnetic bypass part in the modification of this invention, (b) is a top view of the sensor part and magnetic bypass part of (a). It is a plane perspective view of the magnetic sensor apparatus which is a modification of this invention.

Explanation of symbols

  1, 21, 41, 61, 81, 101 ... magnetic sensor device, 3, 23 ... optical signal generation unit, 4 ... temporary stop unit (magnetic field generation circuit), 6 ... Barkhausen element, 6 a ... central part (magnetic layer) ), 6b... Peripheral part (magnetic layer), 7... Coil, 7a, 7b... Terminal, 9, 29. Light emitting diode (light emitting element), 29a, 29b .. LED (light emitting element), 12, 32. , 13a, 13b, 13c, 13d ... Diode (rectifier element), 14 ... Resistance element, 19, 82a, 82b, 102, 112 ... Permanent magnet, 42 ... Magnetic shield member, 62a, 62b, 83, 84, 85, 103a , 103b, 104, 105 ... magnetic derivatives, 113 ... magnetic bypass section.

Claims (7)

It has a plurality of magnetic layers so that the coercive force of the central part is larger than the coercive force of the outer peripheral part, and a magnetic field that reverses alternately along the longitudinal direction is applied to cause magnetization reversal in the outer peripheral part. A linear Barkhausen element,
Outside the outer periphery of the Barkhausen element, a coil wound along the longitudinal direction;
An optical output circuit that is connected to both ends of the coil and outputs two types of optical signals according to the polarity of a pulse voltage generated between the ends of the coil due to the magnetization reversal;
A magnetic sensor device comprising: The optical output circuit is
A first light emitting element connected between the first terminal and the second terminal of the coil and emitting light in response to the generation of the pulse voltage of the first polarity;
The first light emitting element is connected in the opposite direction between the first terminal and the second terminal, and in response to the generation of the pulse voltage having a second polarity opposite to the first polarity. A second light emitting element that emits light,
The magnetic sensor device according to claim 1, comprising: The optical output circuit is
First and second connected in series between a first terminal and a second terminal of the coil, and rectifies current generated by the pulse voltage from the first terminal toward the second terminal. Rectifying elements of
A third and a fourth rectifying element connected in series between the first terminal and the second terminal and rectifying the current from the second terminal toward the first terminal;
A load resistor connected in series with the first and second rectifying elements, or the third and fourth rectifying elements;
A light emitting device connected in series between the first rectifying device and the second rectifying device and between the third rectifying device and the fourth rectifying device;
The magnetic sensor device according to claim 1, comprising:   The magnetic sensor device according to claim 1, further comprising a magnetic field generation circuit that applies a magnetic field to the Barkhausen element until a saturation state is reached by control from the outside.   The magnetic sensor device according to claim 1, wherein a magnetic shield is provided on an outer periphery of a central portion in a longitudinal direction of the Barkhausen element. A magnetic bypass part for bypassing the magnetic field from the outside toward the central part in the longitudinal direction of the Barkhausen element;
The magnetic sensor device according to claim 1, wherein the magnetic sensor device is a magnetic sensor device.   The magnetic sensor device according to claim 1, further comprising a magnetic derivative provided between the vicinity of one end of the Barkhausen element and the vicinity of the other end.

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