JP7186419B2 - Magnetic body detection device - Google Patents

Description

The present invention relates to a magnetic substance detection device for detecting a magnetic substance contained in a moving verification object.

Generally, it is known to form a predetermined pattern on a verifiable object such as bills and securities using a magnetic material. For example, a predetermined pattern is printed on the verification object using magnetic ink. Also, a belt-like pattern is drawn into the verification object. During the distribution process, the pattern of the magnetic material is detected, and the authenticity of the magnetic material is determined by comparing the detected pattern with a normal pattern.

A magnetic body detection device suitable for the above application is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-200010. This magnetic body detection device includes a detector that detects a change in a bias magnetic field caused by a magnetic body passing through a predetermined transport path and outputs a voltage waveform corresponding to the detected change in the bias magnetic field.

Here, when the magnetic substance of the verification object is made of a hard magnetic substance, the magnetic substance may be magnetized during the distribution process of the verification object, and the magnetized state may be maintained. In this case, the magnetization state differs for each object to be verified, and the pattern of the magnetic material (output voltage waveform) detected by the detector is different from the normal pattern. Therefore, the magnetic material detection device of Patent Document 1 includes not only the above-described detector but also a magnetizer for preliminarily correcting the magnetization state of the magnetic material of the object to be verified to a predetermined state.

JP 2014-190734 A

The magnetizer of Patent Document 1 is arranged in front of the detector. That is, the magnetizer and the detector are constructed separately and are spaced apart in the conveying direction of the verification object. Therefore, there is a tendency for the size of the magnetic body detection device as a whole (especially the size in the moving direction of the object to be verified) to become relatively large. Moreover, since the magnetizer and the detector are configured separately, the number of parts is large.

SUMMARY OF THE INVENTION The present invention has been made to address the above problem, and an object of the present invention is to provide a compact magnetic body detection device with a reduced number of parts. In addition, in the description of each constituent element of the present invention below, in order to facilitate understanding of the present invention, the symbols corresponding to the embodiments are described in parentheses, but each constituent element of the present invention is It should not be construed as being limited to the configurations of the corresponding portions indicated by the reference numerals in the embodiment.

In order to achieve the above object, a feature of the present invention is to detect a magnetic material (MS) contained in a verification object (OB) moving in a first direction (back and forth direction) along a predetermined transport path (L). A magnetic body detection device (1, 1A) for a magnetic material detection device (1, 1A) for and a first magnet which is magnetized in a direction orthogonal to the second direction and whose one magnetic pole surface is arranged to face the conveying path , and a position spaced apart in the first direction when viewed from the first magnet. A second magnet extending in the second direction at and magnetized in the opposite direction to the first magnet, and having a magnetic pole opposite to the magnetic pole of one magnetic pole surface of the first magnet a second magnet (M2) having a magnetic pole surface facing the conveying path and cooperating with the first magnet to form a magnetic field in a predetermined space between the first magnet and the first magnet; a substrate (22) arranged in a magnetic force line path of the magnetic field formed in a predetermined space between the second magnet and a substrate (22) inclined at a predetermined angle with respect to the second direction on the surface of the substrate (22); a magnetoresistive element (23 , 24, 23-1, 23-2, 24-1, 24-2), wherein the first magnet and the second magnet are formed in cooperation with each other. A bias magnetic field having a strength smaller than the saturation magnetic field of the magnetoresistive effect element and directed to the magnetoresistive effect element in a direction perpendicular to the second direction in the surface of the substrate. (H1x, H2x) is given, and the magnetic body of the verification object is formed by the cooperation of the first magnet and the second magnet in a predetermined area near the first magnet. The magnetic sensor circuit is arranged in the space between the first magnet and the second magnet so as to be magnetized to a predetermined state under the influence of the magnetic pole face of the first magnet and the verification The magnetic body detection device is characterized in that the distance from the object conveying path is set smaller than the distance between the magnetic pole surface of the second magnet and the conveying path.

In this case, the distance between the conveying path and the second magnet is preferably set so that the magnetization state of the magnetic material of the verification object does not change within a predetermined area near the second magnet.

Further, in this case, a third magnet extending in the second direction at a position spaced apart in the opposite direction from the first magnet when viewed from the second magnet, intersecting the first direction, and magnetized in a direction orthogonal to the second direction, one of the magnetic pole surfaces is arranged to face the conveying path, and cooperates with the first magnet and the second magnet to cooperate with the second magnet. Further comprising a third magnet that forms a magnetic field in a predetermined space between the first magnet and the second magnet and that forms a magnetic field in a predetermined space between the first magnet and the second magnet, wherein the first to third magnets A magnetic field cooperatively formed between the first magnet and the second magnet produces a bias magnetic field having a strength smaller than the saturation magnetic field of the magnetoresistive element, and the bias magnetic field is applied to the magnetoresistive element. A bias magnetic field directed in a direction orthogonal to the second direction within the surface of the substrate is applied, and the magnetic material of the verification object is aligned with the first magnet within a predetermined region in the vicinity of the first magnet. It is magnetized in a predetermined state under the influence of the magnetic field formed between it and the second magnet. The magnetic sensor circuit is arranged in the space between the first magnet and the second magnet so as to be magnetized in a predetermined state under the influence of the magnetic field formed between the magnet and the third magnet. Further, the distance between the magnetic pole surface of the first magnet and the transportation path and the distance between the magnetic pole surface of the third magnet and the transportation path are set to the distances between the magnetic pole surface of the second magnet and the transportation path. It should be set smaller than the distance .

In this case, the magnetization direction of the first magnet and the magnetization direction of the third magnet may be the same.

It should be noted that the second magnet in the present invention includes an object that takes on the properties of a magnet under the influence of a magnetic field.

When the object to be verified passes through the transport path, when the magnetic material of the object to be verified approaches the magnetoresistive effect element, the bias magnetic field changes under the influence of the magnetic material of the object to be verified. This changes the electrical resistance value of the magnetoresistive element. The authenticity of the verification object can be determined based on the change in the electric resistance value.

In the present invention, the distance between the magnetic pole surface of the first magnet and the transport path is set smaller than the distance between the magnetic pole surface of the second magnet and the transport path. As a result, when the object to be verified passes through the transport path, the magnetization state of the magnetic material of the object to be verified is corrected to a predetermined state by the first magnet before it approaches the magnetoresistive effect element. That is, even if the hard magnetism of the verification object is magnetized in a state different from the predetermined state during the distribution process of the verification object, the magnetization state of the magnetic material of the verification object is corrected in advance. By correcting the magnetization state of the magnetic material of the object to be verified in this way, if it is a true object to be verified, the change in the bias magnetic field will match the change in the predetermined reference. The changes also correspond to changes in the predetermined criteria. Therefore, according to the present invention, the authenticity of the verification object can be determined with high accuracy. In addition, in the magnetic body detection device according to the present invention, since the magnetization state of the magnetic body of the verification object is corrected using the first magnet that forms the bias magnetic field, a magnetizer like the conventional magnetic body detection device is separately provided. No need to set. Therefore, according to the present invention, the number of parts can be reduced. Also, the magnetic body detection device can be miniaturized.

Also, the first magnet and the second magnet are formed in an elongated shape and extend parallel to each other in the second direction. Therefore, the magnetic lines of force generated by the first magnet and the second magnet are elliptical in the plane perpendicular to the second direction, and the shapes of the first and second magnets, particularly the shape of the magnetic pole faces, have some errors. However, the direction of the lines of magnetic force is stable, and the lines of magnetic force passing through the magnetoresistive element always have a constant direction. As a result, the bias magnetic field applied to the magnetoresistive element in the direction orthogonal to the second direction in the plane of the substrate is stabilized, and the change in the electrical resistance value of the magnetoresistive element due to the movement of the magnetic body is stabilized. It is possible to detect magnetic bodies with high accuracy. Further, by adjusting the distance and posture between the first magnet and the second magnet, the shape of the passage of the magnetic lines of force can be changed in various ways, which simplifies the setting of the bias magnetic field for the magnetoresistive effect element.

Another feature of the present invention is that the magnetoresistive element has a first magnetoresistive element and a second magnetoresistive element facing each other at the same position in the second direction within the surface of the substrate , In the magnetic body detection device, the magnetic field is set and the magnetic sensor circuit is arranged such that the bias magnetic field for the first magnetoresistive element and the second magnetoresistive element are directed in opposite directions.

According to this, the bias magnetic field applied in the direction orthogonal to the extending direction of the first magnetoresistive element and the second magnetoresistive element in the plane of the substrate is almost opposite in direction and has the same magnitude, and the magnetic body The change in the electrical resistance value of the first magnetoresistive element and the second magnetoresistive element due to the movement in the first direction can be changed substantially symmetrically in the positive and negative directions, and the first magnetoresistive element and the second magnetoresistive element change in electrical resistance can be easily utilized.

Another feature of the present invention is that the first magnetoresistive element (23) and the second magnetoresistive element (24) are connected in series, and a predetermined voltage is applied to both ends of the first magnetoresistive element and the second magnetoresistive element. It is provided with an electric circuit (31) for taking out the voltage at the connection point of the resistive element.

According to this, since the first magnetoresistive element and the second magnetoresistive element are half-bridge connected, a large output voltage can be obtained.

Another feature of the present invention is that the magnetoresistive effect element further comprises: a third magnetoresistive element and a fourth magnetoresistive element provided at positions spaced apart in the second direction when viewed and opposed to each other at the same position in the second direction within the surface of the substrate , the substrate a third magnetoresistive element (23-2) and a fourth magnetoresistive element (24-2) whose electrical resistance changes with respect to a change in the magnetic field in the direction perpendicular to the second direction in the surface of the
The bias magnetic field for the third magneto-resistive element and the fourth magneto-resistive element are configured to be in opposite directions, and further, the terminal of the first magneto-resistive element on the side of the third magneto-resistive element and the fourth magneto-resistive element. The terminal of the resistance element on the side of the second magnetoresistance element is connected, and the terminal of the second magnetoresistance element on the side of the fourth magnetoresistance element and the terminal of the third magnetoresistance element on the side of the first magnetoresistance element are connected. connecting, connecting the terminal of the first magnetoresistance element opposite to the third magnetoresistance element and the terminal of the second magnetoresistance element opposite to the fourth magnetoresistance element, and connecting the third magnetoresistance The terminal of the element opposite to the first magnetoresistance element and the terminal of the fourth magnetoresistance element opposite to the second magnetoresistance element are connected, and the first magnetoresistance element and the second magnetoresistance element are connected. A predetermined voltage is applied between the connection point and the connection point between the third magnetoresistive element and the fourth magnetoresistive element, and the voltage at the connection point between the first magnetoresistive element and the fourth magnetoresistive element and a magnetic body detection device comprising an electric circuit (32) for extracting a differential voltage between the voltage at the connection point of the second magnetoresistive element and the third magnetoresistive element.

According to this, since the first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element and the fourth magnetoresistive element are connected in a full bridge, the output voltage is doubled compared to the case of the half bridge connection. be able to. Further, the electric circuit outputs the difference voltage between the voltage at the connection point of the first magnetoresistive element and the fourth magnetoresistive element and the voltage at the connection point of the second magnetoresistive element and the third magnetoresistive element, Noise in the bias magnetic field that causes changes in the electrical resistance values of the first and third magnetic low-resistance elements and the bias magnetic field that causes changes in the electrical resistance values of the second and fourth magnetic low-resistance elements is included, resistance value changes caused by these noises cancel each other out, and the S/N ratio of the output voltage is improved.

Another feature of the present invention is that the magnetoresistive effect element further comprises: a third magnetoresistive element and a fourth magnetoresistive element provided at positions spaced apart in the second direction when viewed and opposed to each other at the same position in the second direction within the surface of the substrate , the substrate a third magnetoresistive element (23-2) and a fourth magnetoresistive element (24-2) whose electrical resistance changes with respect to a change in the magnetic field in the direction perpendicular to the second direction in the surface of the The bias magnetic fields for the third magnetoresistive element and the fourth magnetoresistive element are configured to be in opposite directions, and the terminal of the first magnetoresistive element opposite to the third magnetoresistive element and the terminal of the first magnetoresistive element opposite to the third magnetoresistive element are connected to the terminal of the first magnetoresistive element opposite to the third magnetoresistive element. The terminals of the two magnetoresistive elements opposite to the fourth magnetoresistive element are connected, and the terminal of the third magnetoresistive element opposite to the first magnetoresistive element and the second magnetoresistive element of the fourth magnetoresistive element are connected. connecting the terminal opposite to the resistance element, connecting the terminal of the first magnetoresistance element on the side of the third magnetoresistance element and the terminal of the fourth magnetoresistance element on the side of the second magnetoresistance element, and The terminal of the second magnetoresistive element on the side of the fourth magnetoresistive element and the terminal of the third magnetoresistive element on the side of the first magnetoresistive element are connected, and the connection between the first magnetoresistive element and the fourth magnetoresistive element A predetermined voltage is applied between the connection point and the connection point between the second magnetoresistive element and the third magnetoresistive element, and the voltage at the connection point between the first magnetoresistive element and the second magnetoresistive element and a magnetic substance detection device comprising an electric circuit (32) for extracting a voltage difference between the voltage at the connection point of the third magnetoresistive element and the fourth magnetoresistive element.

Also by this, the first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element and the fourth magnetoresistive element are connected in a full bridge, so that the output voltage can be doubled compared to the case of the half bridge connection. can be done. Also in this case, the electric circuit outputs the difference voltage between the voltage at the connection point of the first magnetoresistive element and the second magnetoresistive element and the voltage at the connection point of the third magnetoresistive element and the fourth magnetoresistive element. By doing so, a bias magnetic field that causes changes in the electrical resistance values of the first magnetoresistive element and the third magnetic low resistance element and a bias magnetic field that causes changes in the electrical resistance values of the second magnetoresistive element and the fourth magnetic low resistance element. and contain noise, the resistance value changes caused by these noises cancel each other out, and the S/N ratio of the output voltage is improved.

Further, the present invention can be implemented as an invention of a magnetic substance detection method for detecting a magnetic substance contained in a moving detection object.

1 is a perspective view of a magnetic body detection device according to an embodiment of the present invention; FIG. It is a cross-sectional view perpendicular to the horizontal direction of the magnetic body detection device. FIG. 2 is an exploded perspective view of the magnetic body detection device as seen obliquely from the front; It is the exploded perspective view which looked at the magnetic body detection apparatus from diagonally back. 1 is a perspective view of a magnetic sensor circuit; FIG. FIG. 3 is a layout diagram showing an example of the layout of magnetoresistive elements; FIG. 4 is a layout diagram showing another example of the layout of magnetoresistive elements; FIG. 10 is a layout diagram showing still another example of the layout of magnetoresistive measures; FIG. 4 is a schematic diagram showing a magnetic field formed by magnets and a magnetic line of force vector in a conveying path; FIG. 4 is a side view showing an example of a bias magnetic field; FIG. 11 is a side view showing another example of a bias magnetic field; 4 is a graph showing change characteristics of an electric resistance value with respect to a magnetic field strength of a magnetoresistive element; FIG. 10 is a characteristic diagram showing changes in the magnetic vector and magnetic field of the hard magnetic body portion and changes in the electrical resistance value of the magnetoresistive element when the hard magnetic body portion moves forward; FIG. 10 is a characteristic diagram showing changes in the magnetic vector and magnetic field of the hard magnetic body portion and changes in the electrical resistance value of the magnetoresistive element when the soft magnetic body portion moves forward; FIG. 10 is a characteristic diagram showing changes in the magnetic vector and magnetic field of the hard magnetic body portion and changes in the electrical resistance value of the magnetoresistive element when the hard magnetic body portion moves rearward; It is an electric circuit diagram on a flexible printed circuit board. FIG. 2 is an electric circuit diagram showing an example of arrangement and connection of magnetoresistive elements connected in full bridge connection; FIG. 5 is an electric circuit diagram showing another example of arrangement and connection of magnetoresistive elements connected in full bridge connection; FIG. 2 is an electrical circuit diagram of a magnetic sensor circuit using a single magnetoresistive element; FIG. 4 is a schematic diagram of a magnetic field according to a variant of the invention; FIG. 17 is a characteristic diagram showing changes in the magnetic vector and the magnetic field of the hard magnetic body portion and changes in the electrical resistance value of the magnetoresistance element when the hard magnetic body portion moves forward according to the modification of FIG. 16 ; FIG. 17 is a characteristic diagram showing changes in the magnetic vector and the magnetic field of the hard magnetic body portion and changes in the electrical resistance value of the magnetoresistance element when the hard magnetic body portion moves forward according to the modification of FIG. 16 ;

A magnetic body detection device 1 according to an embodiment of the present invention will be described with reference to the drawings. First, the outline of the magnetic body detection device 1 will be described. As shown in FIGS. 1 and 2, the magnetic body detection device 1 moves the verification object OB linearly along the transport path L to determine the authenticity of the verification object OB. ). The verification object OB is, for example, banknotes, securities, etc., and the verification object OB includes the magnetic material MS. In the following description, the moving direction of the verification object OB is called the front-rear direction, and the thickness direction of the verification object OB is called the vertical direction. A direction perpendicular to the front-rear direction and perpendicular to the up-down direction is called a left-right direction. The magnetic body detection device 1 is arranged below the transport path L of the verification object OB, and utilizes changes in the magnetic field (bias magnetic field) due to the movement of the magnetic body MS included in the verification object OB to detect the magnetic body MS. The presence or absence (or array pattern) is detected. In the following description, the direction in which the verification object OB is transported from one end (entrance) of the transport path L to the other end (exit) is forward, and the opposite direction is backward. Although not shown, the verification object OB is conveyed in the front-rear direction using a conveyor plate, rollers, or the like.

Next, the configuration of the magnetic body detection device 1 will be described. As shown in FIGS. 2 to 4, the magnetic body detection device 1 includes a case 11, magnets M1, M2 and M3, a magnet fixing member 12 and a cover 13, and a plurality (for example 10) of magnetic sensor circuits MC.

The case 11 accommodates magnets M1, M2, M3, a magnet fixing member 12, etc., which will be described later. The case 11 is a groove-shaped (or box-shaped) member extending in the left-right direction. The upper surface of the case 11 is open. The case 11 is integrally formed of a magnetic material (for example, stainless steel exhibiting soft magnetism). In addition, a plurality of (10) slit-shaped through holes TH ₁₁ are arranged at equal intervals in the left-right direction on the bottom surface of the case 11 . The through hole _TH11 extends in the left-right direction.

The magnets M1, M2, M3 are composed of permanent magnets (for example, ferrite magnets, bond magnets, etc.). The magnets M1, M2, M3 are each extended in the left-right direction. A cross section perpendicular to the horizontal direction of the magnets M1 and M3 presents a substantially rectangular shape. The cross-sectional shapes of the magnets M1 and M3 are substantially the same. A cross section perpendicular to the left-right direction of the magnet M2 presents a substantially rectangular shape. The vertical dimension of the magnet M2 is smaller than the vertical dimension of the magnets M1 and M3. Magnets M1, M2 and M3 are magnetized in the vertical direction. However, the magnetization direction of the magnet M2 is opposite to the magnetization directions of the magnets M1 and M3. In this embodiment, the upper surfaces of the magnets M1 and M3 are N poles and the lower surfaces thereof are S poles, whereas the upper surface of the magnet M2 is an S pole and the lower surface is an N pole.

The magnet fixing member 12 is made of synthetic resin and formed integrally. The magnet fixing member 12 is a member that keeps the magnets M1, M2, and M3 in this order parallel to each other with a predetermined distance in the front-rear direction. The magnet fixing member 12 is a groove-shaped member extending in the left-right direction. The outer dimensions of the magnet fixing member 12 are substantially the same as the inner dimensions of the case 11 . The magnet fixing member 12 has grooves G1, G2 and G3 that accommodate the magnets M1, M2 and M3, respectively. The grooves G1, G2, and G3 extend in the left-right direction. The groove portion G2 is provided between the groove portion G1 and the groove portion G3. The grooves G1 and G3 are opened upward, and the groove G2 is opened downward.

The groove portion G1 is composed of a side wall portion 121, a bottom wall portion 122 and a side wall portion 123. As shown in FIG. The groove portion G2 is composed of a side wall portion 123, a bottom wall portion 124 and a side wall portion 125. As shown in FIG. Moreover, the groove portion G3 is composed of a side wall portion 125 , a bottom wall portion 126 and a side wall portion 127 . The side wall portions 121, 123, 125, 127 are plate-like portions perpendicular to the front-rear direction. On the other hand, the bottom wall portions 122, 124, 126 are plate-shaped portions perpendicular to the vertical direction. The bottom wall portions 122 and 126 are positioned at the same height, and the bottom wall portion 124 is positioned higher than the bottom wall portions 122 and 124 .

The side wall portion 121 extends upward from the rear end of the bottom wall portion 122 . The upper end surface of the side wall portion 121 is positioned higher than the bottom wall portion 124 . The side wall portion 123 extends upward from the front end of the bottom wall portion 122 and is connected to the rear end of the bottom wall portion 124 . The side wall portion 127 extends upward from the front end of the bottom wall portion 126 . The upper end surface of the side wall portion 127 is at the same height as the upper end surface of the side wall portion 121 . The side wall portion 125 extends upward from the rear end of the bottom wall portion 126 and is connected to the front end of the bottom wall portion 124 . The wall thickness of the side wall portion 123 and the side wall portion 125 is set larger than the wall thickness of the side wall portion 121 and the side wall portion 127 . A plurality of slit-shaped through-holes _TH12 penetrating from the upper surface to the lower surface of the side wall portion 123 are arranged in the left-right direction. These through holes TH ₁₂ correspond to the through holes TH ₁₁ of the case 11 . With the magnet fixing member 12 housed in the case 11, each through hole _TH12 communicates with each through hole _TH11 .

The magnet M1 and the magnet M3 are housed in the groove G1 and the groove G3, respectively, and the magnet fixing member 12 is housed in the case 11 .

The cover 13 is a lid member that is attached to the case 11 and covers the upper end of the case 11 . The cover 13 is a groove-shaped (or box-shaped) member extending in the left-right direction. The lower surface of the cover 13 is open. The cover 13 is made of a highly rigid and elastic non-magnetic material.

The case 11 and the cover 13 have the same length in the left-right direction. The lengths of the magnets M1, M2, M3 and the magnet fixing member 12 in the left-right direction are slightly shorter than the lengths of the case 11 and the cover 13 in the left-right direction.

Next, the configuration of the magnetic sensor circuit MC will be described. The magnetic sensor circuit MC includes a substrate supporting member 21, a substrate 22, ferromagnetic thin film magnetoresistive elements 23 and 24, and a flexible printed circuit board 25, as shown in FIG. The substrate support member 21 is made of synthetic resin and formed integrally. The board support member 21 extends in the left-right direction. The cross-sectional shape of the substrate support member 21 perpendicular to the left-right direction is substantially hexagonal. That is, the substrate support member 21 has a lower surface 211 , a rear surface 212 , an inclined surface 213 , an upper surface 214 , an inclined surface 215 and a front surface 216 , and a right side 217 and a left side 218 . The lower surface 211 is perpendicular to the up-down direction. The rear surface 212 extends upward from the rear end of the lower surface 211 . The slope 213 obliquely extends forward and upward from the upper end of the rear surface 212 . The upper surface 214 extends forward from the tip (front and upper end) of the slope 213 . The slope 215 extends obliquely forward and downward from the front end of the upper surface 214 . The front surface 216 extends downward from the tip (front and lower end) of the slope 215 and is connected to the front end of the lower surface 211 . The right side surface 217 and the left side surface 218 are formed in a planar shape perpendicular to the left-right direction. The length of the substrate support member 21 in the left-right direction is 1/10 of the length of the magnet fixing member 12 in the left-right direction.

The substrate 22 is a plate-like member made of a non-magnetic material. The substrate 22 is formed to have the same size as the inclined surface 213 of the substrate support member 21 . The back surface of the substrate 22 is fixed to the slope 213 of the substrate support member 21 . The ferromagnetic thin-film magnetoresistive elements 23 and 24 are magnetoresistive elements (for example, AMR elements) formed on the upper surface of the substrate 22 by sputtering or the like using a ferromagnetic material magnetoresistive material. In the following description, the ferromagnetic thin film magnetoresistive elements 23 and 24 are simply referred to as magnetoresistive elements 23 and 24 for simplification. The magnetoresistive elements 23 and 24 have linear portions that extend linearly in the horizontal direction. These linear portions face each other. The electrical resistance values of the magnetoresistive elements 23 and 24 change according to the strength of the magnetic field (magnetic force) in the direction orthogonal to the horizontal direction within the surface of the substrate 22 . As the magnetoresistive elements 23 and 24, an anisotropic magnetoresistive (AMR) element, a giant magnetoresistive (GMR) element, a tunnel magnetoresistive (TMR) element, or the like can be employed.

In the above description, the magnetoresistive elements 23 and 24 have linear portions extending substantially in the left-right direction. The linear portions of the elements 23 and 24 are inclined by a predetermined angle with respect to the horizontal direction within the surface (plane) of the substrate 22 . This predetermined angle is, for example, within the range of 1° to 65°.

This point will be specifically described. As shown in FIG. 6A, the magnetoresistive elements 23 and 24 have, for example, two split linear portions 23a, 23b, 24a, and 24b obtained by splitting a linear portion extending substantially in the left-right direction. The portions 23 a , 23 b , 24 a , 24 b are inclined with respect to the horizontal direction within the surface of the substrate 22 . In the present embodiment, the right ends of the dividing line portions 23a and 23b are raised, and the right ends of the dividing line portions 24a and 24b are lowered. However, it is assumed that the dividing line portions 23a and 23b are inclined in the same direction and the dividing line portions 24a and 24b are inclined in the same direction. One ends of the dividing line portions 23a and 24a are connected to terminals 27a and 27b provided on the substrate 22 via conductors 26a and 26b, respectively. The other end of the dividing line portion 23a is connected to one end of the dividing line portion 23b via a conductor 26d, the other end of the dividing line portion 24a is connected to one end of the dividing line portion 24b via a conductor 26e, The other ends of the dividing line portions 23b and 24b are connected via a conductor 26f. That is, the magneto-resistive element 23 composed of the dividing line portions 23a and 23b and the magneto-resistive element 24 composed of the dividing line portions 24a and 24b are connected in series. A connection point between the magnetoresistive elements 23 and 24, that is, a connection point between the dividing line portions 23b and 24b is connected to a terminal 27c through a conductor 26c. The conductors 26a to 26f are formed on the surface of the substrate 22 by sputtering a conductive material (non-magnetic material). The terminals 27a and 27b are terminals for applying a voltage (+Vb, GND) between the magnetoresistive elements 23 and 24 connected in series, and the terminal 27c outputs the potential between the magnetoresistive elements 23 and 24 as the output voltage Vout It is a terminal for taking out.

In this embodiment, each of the linear portions of the magnetoresistive elements 23 and 24 is divided into two, but may be divided into three or more. However, also in this case, the plurality of dividing linear portions obtained by dividing the linear portion of the magnetoresistive element 23 and the plurality of dividing linear portions obtained by dividing the linear portion of the magnetoresistive element 24 are inclined in the same direction. do. Further, as shown in FIG. 6B, without dividing the linear portions of the magnetoresistive elements 23 and 24, each linear portion inclined with respect to the horizontal direction is formed on the surface of the substrate 22. good too. In this case, one ends of the linear portions of the magnetoresistive elements 23 and 24 are respectively connected to terminals 27a and 27b provided on the substrate 22 through conductors 26a and 26b similar to the above case. The other ends of the linear portions of the magnetoresistive elements 23 and 24 are connected by a conductor 26f to connect the magnetoresistive elements 23 and 24 in series. 22 is connected to a terminal 27c.

Furthermore, as shown in FIG. 6C, the magnetoresistive elements 23 and 24 may be configured to have two linear portions by folding back the extension portions extending in the left-right direction. In this case, the magnetoresistive element 23 is composed of a pair of linear portions 23A and 23B, the linear portion 23A is composed of dividing linear portions 23a and 23b similar to the above case, and the dividing linear portion 23B is composed of a dividing linear portion 23c. , 23d. The parting line portions 23c and 23d are provided on the upper surface of the substrate 22 so as to face the parting line portions 23a and 23b and parallel to the parting line portions 23a and 23b in a direction orthogonal to the horizontal direction. The magnetoresistive element 24 is composed of a pair of linear portions 24A and 24B. The linear portion 24A is composed of dividing linear portions 24a and 24b similar to those described above, and the dividing linear portion 24B is composed of dividing linear portions 24c and 24d. consists of The parting line portions 24c and 24d are provided on the upper surface of the substrate 22 so as to face the parting line portions 24a and 24b and parallel to the parting line portions 24a and 24b in a direction perpendicular to the horizontal direction.

The other end of the dividing linear portion 23c is connected to one end of the dividing linear portion 23d via a conductor 26g, and the other ends of the dividing linear portions 23b and 23d are connected via a conductor 26h to form a dividing linear portion. 23a, 23b and parting linear portions 23c, 23d are folded back and connected in series. The other end of the dividing line portion 24c is connected to one end of the dividing line portion 24d through a conductor 26i, and the other ends of the dividing line portions 24b and 24d are connected through conductors 26j to form the dividing line portion. 24a, 24b and parting linear portions 24c, 24d are folded back and connected in series. In this case, one end of each of the dividing line portion 23a of the magnetoresistive element 23 and the dividing line portion 24a of the magnetoresistive element 24 is connected to a terminal provided on the substrate 22 through the same conductors 26a and 26b as in the above case. 27a and 27b, respectively. One ends of the dividing line portion 23c of the magnetoresistive element 23 and the dividing line portion 24c of the magnetoresistive element 24 are connected by a conductor 26k to connect the magnetoresistive elements 23 and 24 in series. The connection point is connected to a terminal 27c provided on the substrate 22 via a conductor 26c.

Here, the reason why the extending directions of the magnetoresistive elements 23 and 24 (linear portions of the magnetoresistive elements 23 and 24) are inclined by a predetermined angle with respect to the horizontal direction within the surface (plane) of the substrate 22 will be explained. back. In order to stably change the magnetic field resistance of the magnetoresistive elements 23 and 24, that is, the ferromagnetic thin film magnetoresistive element made of AMR, the magnetic force is unidirectionally directed in the longitudinal direction of the magnetoresistive elements 23 and 24, that is, in the direction of the easy axis of magnetization. should be given. In other words, when the magnetoresistive elements 23 and 24 are extended in the horizontal direction, the lines of magnetic force (bias magnetic field) by the magnets M1, M2 and M3 are basically perpendicular to the extension direction of the magnetoresistive elements 23 and 24, and the magnetoresistive elements 23 and 24 extend in the horizontal direction. No magnetic force is generated in the resistance elements 23 and 24, and the operations of the magnetoresistive elements 23 and 24 are unstable. Therefore, in this embodiment, the extending direction of the magnetoresistive elements 23 and 24 is inclined by a predetermined angle with respect to the horizontal direction on the surface of the substrate 22, thereby stabilizing the operation of the magnetoresistive elements 23 and 24. . This point also applies to the various modifications (FIGS. 6B and 6C) of the magnetoresistive elements 23 and 24 described above.

Flexible printed circuit board 25 is an elongated printed circuit board. The flexible printed board 25 has flexibility. Electrical wiring is applied to the flexible printed circuit board 25, and an electrical circuit including a bridge circuit of the magnetoresistive elements 23 and 24 is configured. This electric circuit applies a DC voltage Vb to the terminals 27a of the substrates 22, grounds the terminals 27b, and connects the terminals 27c to the amplifier 31 (see FIG. 13). As a result, a DC voltage Vb is applied between the magnetoresistive elements 23 and 24 connected in series, and an output voltage Vout at the connection point of the magnetoresistive elements 23 and 24 is output via the amplifier 31 . Note that these circuits may be provided in a circuit device connected to the flexible printed circuit board 25 instead of the flexible printed circuit board 25 .

A plurality of (ten in this embodiment) magnetic sensor circuits MC configured as described above are arranged in the horizontal direction and fixed to the magnet fixing member 12 (see FIGS. 3 and 4). Specifically, the lower surface 211 of the substrate support member 21 of each magnetic sensor circuit MC is fixed to the upper surface of the bottom wall portion 124 . The lower end of each flexible printed circuit board 25 is inserted through the through hole TH ₁₂ of the magnet fixing member 12 and the through hole TH ₁₁ of the case 11 . Finally, the cover 13 is put on the upper part of the case 11 and fixed.

In the magnetic body detection device 1 configured as described above, the upper magnetic pole surfaces of the magnets M1, M2, and M3 face the transport path L, respectively. However, the upper magnetic pole faces (N pole) of the magnets M1 and M3 are at substantially the same height, and the upper magnetic pole face (S pole) of the magnet M2 is positioned lower than the upper surfaces of the magnets M1 and M3. be. That is, the distance between the upper magnetic pole surfaces of the magnets M1 and M3 and the transport path L is set smaller than the distance between the upper magnetic pole surface of the magnet M2 and the transport path L. Magnets M 1 , M 2 , M 3 cooperate to form a magnetic field that extends around the periphery of case 11 and cover 13 .

Next, the arrangement relationship between the magnets M1, M2, M3 and the magnetic sensor circuit MC will be described in detail. The magnetic lines of force of the magnetic field, which are the magnetic lines of force directed from the magnet M1 to the magnet M2 and the magnetic lines of force directed from the magnet M3 to the magnet M2, are in a plane perpendicular to the left-right direction in the absence of the verification object OB (magnetic body MS): It presents a curve as shown in FIG. 7(A). The paths of these magnetic lines of force intersect the transport path L of the verification object OB. Also, the magnetic resistance elements 23 and 24 of the substrate 22 are positioned in the middle of the path of the lines of magnetic force from the magnet M1 to the magnet M2. In a plane perpendicular to the horizontal direction, a component H1x of the magnetic force line (magnetic force line vector H1) passing through the magnetoresistive element 23 and parallel to the surface of the substrate 22 and a magnetic force line (magnetic force line vector H1) passing through the magnetoresistive element 24 H2) and the component H2x parallel to the surface of the substrate 22 are oriented in the opposite direction and have the same size. 22 (that is, the inclination angle of the slope 213)) is set.

For example, as shown in FIG. 8A, in a plane perpendicular to the horizontal direction, a point on a straight line connecting the magnetoresistive elements 23 and 24 and between the magnetoresistive elements 23 and 24 The magnetic lines of force at the central position Po (where the distances between the magnetoresistive element 23 and the magnetoresistive element 24 are equal) are perpendicular to the surface of the substrate 22, and the direction of the magnetic force line vector H1 and the direction of the magnetic force line vector H2 are aligned with each other at the central position. The magnets M1, M2, M3 and the magnetic sensor circuit MC are arranged so as to be tilted inward substantially symmetrically with respect to the magnetic force line (magnetic force line vector Ho) passing through Po. That is, the magnetic force line vectors H1 and H2 are inclined in the opposite direction (inward) when viewed from the magnetic force line vector Ho within a plane perpendicular to the left-right direction. Since the distance between the magnetoresistive elements 23 and 24 is small, the magnitudes of the magnetic force line vectors H1 and H2 are almost equal.

In this case, if the magnetic line of force vectors H1 and H2 are divided into components H1x and H2x parallel to the surface of the substrate 22 and components H1y and H2y perpendicular to the surface of the substrate 22, the components H1x and H2x are opposite to each other (inward) and their magnitudes are are approximately equal. The components H1y and H2y have the same direction and approximately the same magnitude.

On the other hand, for example, as shown in FIG. 8B, the direction of the magnetic force line vector H1 and the direction of the magnetic force line vector H2 are tilted outward substantially symmetrically with respect to the magnetic force line (magnetic force line vector Ho) passing through the central position Po. , the magnets M1, M2, M3 and the magnetic sensor circuit MC may be arranged. In this case, the components H1x and H2x are set in mutually opposite directions (outside), and at the same time, their magnitudes are set substantially equal.

An example in which the bias magnetic field is set as shown in FIG. 8A will be described below, but even if the bias magnetic field is set as shown in FIG. 8B, the same effects described later can be obtained.

Here, the change characteristic of the electric resistance value with respect to the magnetic field of the ferromagnetic thin film magnetoresistive element (anisotropic magnetoresistive element) constituting the magnetoresistive elements 23 and 24 will be described. As shown in FIG. 9, the electric resistance value between both ends of the ferromagnetic thin film magnetoresistive element in the extension direction is in the direction substantially orthogonal to the extension direction of the ferromagnetic thin film magnetoresistive element in the plane where the thin film exists. is maximum when the magnetic field strength of is "0". The electrical resistance value decreases as the absolute value of the magnetic field strength increases, and when the magnetic field strength reaches the saturation magnetic field, the electrical resistance value becomes substantially constant. That is, in this embodiment, the electrical resistance values of the magnetoresistive elements 23 and 24 are maximized when the components H1x and H2x are "0". Also, as the components H1x and H2x increase, the electrical resistance gradually decreases and the strength of the magnetic field further increases. When the components H1x and H2x reach the saturation magnetic field, the electrical resistance becomes substantially constant.

Therefore, the magnets M1, M2, and M3 move the magnetoresistive elements 23 and 24 so that the electrical resistance values of the magnetoresistive elements 23 and 24 change maximally without saturating when the verification object OB (magnetic body MS) passes. A bias magnetic field is preferably applied to 23,24. Therefore, in the absence of the verification object OB (magnetic material MS), the electrical resistance values of the magnetoresistive elements 23 and 24 differ from the maximum resistance value of the magnetoresistive elements 23 and 24 due to changes in the magnetic field and the electrical resistance value at the saturation magnetic field. The components H1x and H2x are set as the bias magnetic field such that the average value (median value) of . In this case, as described above, in the absence of the verification object OB (magnetic material MS), the components H1x and H2x are in opposite directions and have approximately the same magnitude. Therefore, as shown in FIG. The magnetic forces of the magnets M1, M2 and M3 and the distances between the magnets M1, M2 and M3 and the magnetic sensor circuit MC are set so that the components H1x and H2x become the bias magnetic fields +Hb and -Hb. In FIG. 9, the electrical resistance values of the magnetoresistive elements 23 and 24 in the state where the bias magnetic field +Hb and -Hb are applied to the magnetoresistive elements 23 and 24 as components H1x and H2x are shown as the reference resistance value Rb. . This reference resistance value Rb is approximately equal to the average value of the maximum resistance value of the magnetoresistive elements 23 and 24 due to the change in the magnetic field and the electric resistance value at the saturation magnetic field.

In the state where the bias magnetic field +Hb is applied to the magnetoresistive element 23 in this manner, the electrical resistance value of the magnetoresistive element 23 increases with the bias magnetic field +Hb as the center of the absolute value |H1x| of the component H1x (decrease in the positive direction corresponding to the lower left direction in FIG. 8A). It gradually increases from Rb. The electrical resistance value of the magnetoresistive element 24 gradually increases from the reference resistance value Rb around the bias magnetic field −Hb as the absolute value |H2x| of the component H2x increases (increases in the negative direction corresponding to the upper right direction in FIG. 8A). , and gradually increases from the reference resistance value Rb as the absolute value |H2x| of the component H2x decreases (decreases in the negative direction corresponding to the upper right direction in FIG. 8A). As will be described later, in this embodiment, the component H1x of the magnetic field passing through the magnetoresistive element 23 becomes negative or The component H2x never becomes positive.

Next, the operation of the magnetic body detection device 1 according to the embodiment configured as described above will be described. In addition, the magnetic body MS is elongated in the left-right direction in the verification object OB. Also, the magnetic body MS includes a plurality of hard magnetic body parts MS1 and a plurality of soft magnetic body parts MS2. The hard magnetic body part MS1 and the soft magnetic body part MS2 are each formed in a linear shape extending in the left-right direction. It is assumed that the hard magnetic body part MS1 and the soft magnetic body part MS2 are arranged in a predetermined order in the front-rear direction to form a predetermined pattern.

First, as shown in FIG. 10, the electrical resistance of the magnetoresistive elements 23 and 24 when the verification object OB is moved forward (that is, from the rear end (entrance side) to the front end (exit side) of the transport path L) Explain the value change.

The hard magnetic body part MS1 included in the object to be verified OB is magnetized under the influence of the lines of magnetic force when passing through the transport path L. FIG. Here, in a state where the magnetic body MS does not exist in the transport path L, among the magnetic force lines of the magnetic field formed by the magnets M1, M2, and M3, the direction and magnitude (magnetic force line vector) of the magnetic force line that intersects the transport path L is As shown in FIG. 7B, it differs depending on the position. For example, in the area near the magnet M1, the magnetic line of force vector rotates clockwise as it goes forward. Therefore, the magnetization direction (magnetic vector) of the hard magnetic body portion MS1 changes to rotate clockwise in FIG. 10A as it goes forward from the position P1 near the magnet M1. Hereinafter, the direction of the forward magnetic vector is assumed to be "0°", and the angle of the vector obtained by rotating the vector in the counterclockwise direction is represented by a positive value. Further, the direction of the forward magnetic vector is assumed to be "0°", and the angle of the vector obtained by rotating the vector in the clockwise direction is represented by a negative value.

The direction of the magnetic vector of the hard magnetic body portion MS1 will be specifically described below. In this embodiment, when the hard magnetic body part MS1 is at the position P1, the direction of the magnetic vector of the hard magnetic body part MS1 is approximately "45°". When the hard magnetic body part MS1 moves further forward and is located at the position A1 directly above the magnetoresistive elements 23 and 24, the direction of the magnetic vector of the hard magnetic body part MS1 is approximately "-45°". Further, when the hard magnetic body part MS1 is at the position A2 directly above the magnet M2, the direction of the magnetic vector is "-80°" to "-90°". As shown in FIG. 7B, the magnetic line of force vector gradually increases from the vicinity of the position A2 toward the front. Instead, it moves further forward while remaining approximately constant. Then, the hard magnetic body portion MS1 is re-magnetized at a position P2 near the magnet M3. The direction of the magnetic vector is approximately "135°".

When the hard magnetic body part MS1 passes over the magnetoresistive elements 23 and 24 while changing the direction of its magnetic vector as shown in FIG. As a result, the components H1x and H2x change, and the electrical resistance values of the magnetoresistive elements 23 and 24 change.

In a state where the hard magnetic body part MS1 is sufficiently separated from the magnetoresistive elements 23 and 24, the lines of magnetic force passing through the magnetoresistive elements 23 and 24 are not affected by the magnetic body MS. Therefore, the components H1x and H2x of the magnetic line vectors H1 and H2 in the magnetoresistive elements 23 and 24 are maintained at the bias magnetic fields +Hb and -Hb, and the electrical resistance values between both ends of the magnetoresistive elements 23 and 24 are both the reference resistance values kept at Rb. When the magnetic body MS approaches the magnetoresistive elements 23 and 24, the magnetic field passing through the magnetoresistive elements 23 and 24 begins to be affected by the hard magnetic body portion MS1, and the components of the magnetic line vectors H1 and H2 in the magnetoresistive elements 23 and 24 As H1x and H2x change, the electrical resistance values between both ends of the magnetoresistive elements 23 and 24 change, respectively. A change in the electrical resistance value will be specifically described below.

As shown in FIG. 10B, as the hard magnetic body part MS1 moves from the position P1 to the position A1, the lines of magnetic force are gradually drawn upward under the influence of the hard magnetic body part MS1. As a result, the component H1x of the magnetic line vector H1 passing through the magnetoresistive element 23 becomes larger than the bias magnetic field Hb, and the electrical resistance value of the magnetoresistive element 23 becomes smaller than the reference resistance value Rb. That is, as shown by the solid line graph in FIG. 10D, the electrical resistance value of the magnetoresistive element 23 gradually decreases and becomes the minimum value at position A1. Then, as the hard magnetic body portion MS1 moves further forward from the position A1, the electrical resistance value of the magnetoresistive element 23 gradually increases and returns to the reference resistance value Rb.

As the hard magnetic body part MS1 moves further forward, the lines of magnetic force are gradually pushed downward under the influence of the hard magnetic body part MS1, as shown in FIG. 10(C). As a result, the component H1x of the magnetic line vector H1 passing through the magnetoresistive element 23 becomes smaller than the bias magnetic field Hb, and the electrical resistance value of the magnetoresistive element 23 becomes greater than the reference resistance value Rb. That is, as shown by the solid line graph in FIG. 10(D), the electrical resistance value of the magnetoresistive element 23 gradually increases and reaches the maximum value at position A2. Then, as the hard magnetic body part MS1 moves further forward, the electric resistance value gradually decreases, and when the influence of the hard magnetic body part MS1 on the magnetic lines of force disappears, the component H1x returns to the bias magnetic field +Hb, and the magnetoresistive element The electrical resistance value of 23 returns to the reference resistance value Rb.

Next, changes in the electrical resistance value of the magnetoresistive element 24 will be described. The magnetic force line vector H2 is in a symmetrical relationship with the magnetic force line vector H1 with the magnetic force line vector Ho as the center, and the component H2x of the magnetic force line vector H2 is set to have the positive and negative directions opposite to those of the component H1x and to form the bias magnetic field -Hb. there is Therefore, depending on the position of the hard magnetic body portion MS1, the electrical resistance value of the magneto-resistive element 24 changes from the change in the electrical resistance value of the magneto-resistive element 23 (the solid line graph in FIG. 10(D)) to the reference resistance value Rb. 10(D), which is reversed by . Strictly speaking, the solid line graph and broken line graph in FIG. can be ignored.

On the other hand, as the soft magnetic body part MS2 included in the verification object OB moves forward, the direction of the magnetic vector of the soft magnetic body part MS2 changes successively under the influence of the magnetic lines of force. In other words, the soft magnetic body part MS2 always attracts the lines of magnetic force. When the soft magnetic body part MS2 passes above the magnetoresistive elements 23 and 24, the magnetic force line vectors H1 and H2 are affected by the soft magnetic body part MS2, and the components H1x and H2x change to change the magnetic resistance. The electrical resistance values of the elements 23 and 24 change.

Specifically, as shown in FIG. 11A, when the soft magnetic body part MS2 passes over the magnetoresistive element 23, the lines of magnetic force are attracted upward under the influence of the soft magnetic body part MS2. As a result, the component H1x of the magnetic line vector H1 passing through the magneto-resistive element 23 becomes larger than the bias magnetic field Hb, and the electrical resistance value of the magneto-resistive element 23 becomes the reference resistance value as shown by the solid line graph in FIG. smaller than Rb. As the soft magnetic body portion MS2 moves from the position P1 to the position A1, the electrical resistance value of the magnetoresistive element 23 gradually decreases and reaches the minimum value at the position A1. As the soft magnetic body part MS2 moves further forward from the position A1, the electrical resistance value of the magnetoresistive element 23 gradually increases and returns to the reference resistance value Rb. Unlike the hard magnetic body part MS1, in the case of the soft magnetic body part MS2, there is no region where the lines of magnetic force are pushed down from the reference state. Therefore, in this case, the electrical resistance value of the magnetoresistive element 23 does not exceed the reference resistance value Rb.

Further, the electric resistance value of the magnetoresistive element 24 due to the forward movement of the soft magnetic body part MS2 is the change in the electric resistance value of the magnetoresistive element 23 due to the forward movement of the soft magnetic body part MS2 (Fig. 11(B) 11(B), which is obtained by inverting the solid line graph in FIG. 11(B) with respect to the reference resistance value Rb.

Next, changes in the electrical resistance values of the magnetoresistive elements 23 and 24 when the verification object OB is moved backward (that is, from the front end (exit side) to the rear end (entrance side) of the transport path L) will be described. .

First, changes in the electrical resistance values of the magnetoresistive elements 23 and 24 due to passage through the hard magnetic material portion MS1 will be described. The hard magnetic body part MS1 included in the object to be verified OB is magnetized under the influence of the lines of magnetic force when passing through the transport path L. FIG. As shown in FIG. 7B, the magnetic line of force vector rotates counterclockwise from the vicinity of the magnet M3 toward the rear. Therefore, the magnetization direction (magnetic vector) of the hard magnetic body portion MS1 changes so as to rotate counterclockwise in FIG.

Specifically, in this embodiment, when the hard magnetic body portion MS1 is at the position P2, the direction of the magnetic vector of the hard magnetic body portion MS1 is approximately "135°". When the hard magnetic body part MS1 moves further rearward and is near the position A2, the direction of the magnetic vector of the hard magnetic body part MS1 is "-100°" to "-90°". As shown in FIG. 7B, the magnetic line of force vector gradually increases toward the rear from the vicinity of position A2, but since the magnetization characteristics of the hard magnetic material portion MS1 have hysteresis, the magnetic vector does not change. Instead, it moves further backward while being kept substantially constant. Then, the hard magnetic material portion MS1 is re-magnetized at the position P1. The direction of the magnetic vector is approximately "45°".

When the hard magnetic body part MS1 passes over the magnetoresistive elements 23 and 24 while changing the direction of its magnetic vector as shown in FIG. As a result, the components H1x and H2x change, and the electrical resistance values of the magnetoresistive elements 23 and 24 change.

Specifically, as shown in FIGS. 12(B) and 12(C), as the hard magnetic body part MS1 goes from above the magnet M2 toward the rear, the magnetic lines of force are affected by the hard magnetic body part MS1. It receives and is gradually drawn upwards. As a result, the component H1x of the magnetic line vector H1 passing through the magnetoresistive element 23 becomes larger than the bias magnetic field Hb, and the electrical resistance value of the magnetoresistive element 23 increases to the reference resistance value Rb as shown by the solid line graph in FIG. 12(D). become smaller. That is, the electrical resistance value of the magnetoresistive element 23 gradually decreases and becomes the minimum value at position A1. Then, as the hard magnetic body portion MS1 moves further rearward from the position A1, the electrical resistance value of the magnetoresistive element 23 gradually increases and returns to the reference resistance value Rb.

Next, the change in the electrical resistance value of the magnetoresistive element 24 due to passage through the hard magnetic material portion MS1 will be described. Also in this case, depending on the position of the hard magnetic body portion MS1, the electrical resistance value of the magnetoresistive element 24 changes from the change in the electrical resistance value of the magnetoresistive element 23 (the solid line graph in FIG. 12(D)) to the reference resistance value Rb It changes like the dashed line graph in FIG. 12(D), which is inverted with respect to Also in this case, strictly speaking, the solid line graph and broken line graph in FIG. Since it is minute, the deviation can be ignored.

Next, changes in the electrical resistance values of the magnetoresistive elements 23 and 24 due to passage through the soft magnetic body portion MS2 will be described. As described above, the soft magnetic body part MS2 always attracts magnetic lines of force. Therefore, changes in the electrical resistance values of the magnetoresistive elements 23 and 24 are the same as those in FIG. 11(B).

In this way, by moving the verification object OB having the magnetic material MS along the transport path L, the electrical resistance values of the magnetoresistive elements 23 and 24 are changed to the values shown in FIGS. D) changes as shown. On the other hand, the magnetoresistive elements 23 and 24 are connected in series, and a DC voltage (+Vb, GND) is applied to both ends thereof, as shown in the electric circuit diagram of FIG. Then, the potential at the connection point of the magnetoresistive elements 23 and 24 is output through the amplifier 31 as the output voltage Vout. Therefore, the output voltage Vout corresponds to the difference in change in the electrical resistance values of the magnetoresistive elements 23 and 24 (the difference between the solid line graph and the broken line graph in FIGS. 10(D), 11(B), and 12(D)). voltage. As a result, the output voltage Vout is obtained by doubling the change in the electrical resistance value of the magnetoresistive element 23 (or the magnetoresistive element 24). In the above description, only one magnetic sensor composed of the magnetoresistive elements 23 and 24 has been described. The output is the same.

As described above, in the magnetic substance detection device 1, the distance between the magnetic pole surfaces of the magnets M1 and M3 arranged at the entrance and the exit of the transportation path L and the transportation path L is the distance between the magnetic pole surface of the magnet M2 and the transportation path. It is set smaller than the distance with L. As a result, when the verification object OB passes through the transport path L, the magnetization state of the hard magnetic body portion MS1 is corrected to a predetermined state by the magnet M1 or the magnet M3 before the magnetic body MS approaches the magnetic sensor circuit MC. be done. That is, even if the hard magnetic body MS1 is magnetized in a state different from the predetermined state during the distribution process of the verification object OB, before the hard magnetic body MS1 is detected by the magnetic sensor circuit MC, the hard magnetic body The magnetization state of body MS1 is corrected. By correcting the magnetization state of the hard magnetic body part MS1 in this manner, the waveform of the output voltage Vout of the magnetic body detection device 1 becomes the same as the normal waveform if the verification object OB is true. Therefore, according to the magnetic body detection device 1, the authenticity of the verification object OB can be determined with high accuracy. Further, in the magnetic body detection device 1, the magnet M1 and the magnet M3 among the magnets M1, M2, and M3 forming the bias magnetic fields +Hb and -Hb applied to the magnetic sensor circuit MC are used to correct the hard magnetic body portion MS1. Therefore, there is no need to separately provide a magnetizer unlike the conventional magnetic body detection device. Therefore, according to this embodiment, the number of parts of the magnetic body detection device 1 can be reduced. Moreover, the magnetic body detection device 1 can be miniaturized.

Further, the detected waveform when the hard magnetic body part MS1 is moved forward (see FIG. 10D) and the detected waveform when the soft magnetic body part MS2 is moved forward (see FIG. 11B). can be different from Further, the detected waveform when the hard magnetic body part MS1 is moved forward (see FIG. 10D) and the detected waveform when the hard magnetic body part MS1 is moved backward (see FIG. 12D). can be different from Therefore, according to the magnetic substance detection device 1, based on the difference in the detected waveforms, the authenticity of the verification object OB can be determined with high accuracy. For example, not only the comparison between the verification waveform pattern and the normal pattern when the object to be verified OB is moved forward, but also the comparison between the verification waveform pattern and the normal pattern when the object to be verified OB is moved backward. Also, the authenticity of the object to be verified OB can be determined with higher accuracy.

Further, in the magnetic body detection device 1, the three magnets M1, M2, and M3 extending in the left-right direction are arranged at predetermined intervals in the front-rear direction. As a result, magnetic lines of force between the magnets M1, M2, and M3 are generated in a curved shape within a plane perpendicular to the left-right direction. Even if there are some errors in the shape of the magnets M1, M2, and M3, especially in the shape of the magnetic pole faces, the direction of the magnetic lines of force is stable, and the magnetic lines of force passing through the magnetoresistive elements 23 and 24 are always in the same direction. . As a result, the bias magnetic fields +Hb and -Hb applied to the magnetoresistive elements 23 and 24 are stabilized, and changes in the electrical resistance values of the magnetoresistive elements 23 and 24 due to movement of the magnetic body MS can be stabilized. It becomes possible to detect the body MS with high accuracy. Further, by adjusting the distance and arrangement direction (magnetization direction) of the magnets M1, M2 and M3, the shape of the trajectory of the lines of magnetic force can be changed variously, and the bias magnetic fields +Hb and -Hb for the magnetoresistive elements 23 and 24 can be changed. It is easy to set the orientation and size of

Further, in the above embodiment, the extending direction of the magnetoresistive elements 23 and 24 or the parting line portions 23a to 23d and 24a to 24d of the magnetoresistive elements 23 and 24 is set to be slightly different from the horizontal direction on the surface of the substrate 22. Placed at an angle. As a result, in the magnetic resistance elements 23 and 24 or the dividing line portions 23a to 23d and 24a to 24d of the magnetic resistance elements 23 and 24, magnetic flux lines are generated in a certain direction along the extension direction of the magnetic resistance elements 23 and 24. Changes in the resistance of the resistance elements 23 and 24 can be stabilized. As a result, it is possible to improve the detection accuracy of the magnetic material MS by the magnetic material detection device.

In the above embodiment, the case 11 is made of a magnetic material (stainless steel, which is a soft magnetic material) and covers the lower sides of the magnetic resistance elements 23 and 24 of the magnets M1, M2 and M3. As a result, the distribution of the lines of magnetic force on the side of the magnetoresistive elements 23 and 24 by the magnets M1, M2 and M3 can be stabilized without being affected by the external magnetic field. can be enhanced.

Further, in the above embodiment, the bias magnetic fields (component H1x and component H2x) applied to the magnetoresistive elements 23 and 24 are set to have substantially opposite directions and the same magnitude. As a result, the change in the electrical resistance values of the magnetoresistive elements 23 and 24 due to the movement of the magnetic body MS in the front-rear direction can be changed substantially symmetrically in the positive and negative directions. Change can be made accessible. Since the magnetoresistive elements 23 and 24 constituting one magnetic sensor circuit MC are half-bridge-connected to take out the output voltage Vout, the change in the output voltage Vout is less than that in the case of using one magnetoresistive element. can be increased.

In the above embodiment, as described above, the magnetoresistive elements 23 and 24 forming one magnetic sensor circuit MC are half-bridge connected to take out the output voltage Vout. However, instead of this, one magnetic sensor circuit MC is composed of four magnetoresistive elements 23-1, 23-2, 24-1, 24-2, and these magnetoresistive elements 23-1, 23- 2, 24-1 and 24-2 may be connected in a full bridge to take out the output voltage Vout. In this case, magnetoresistive elements 23-1, 23-2, 24-1 and 24-2 are provided on the surface of one substrate 22, as shown in FIG. 14(A). The magnetoresistive elements 23-1 and 24-1 are formed in the same manner as the magnetoresistive elements 23 and 24, and the conductors on the substrate are the same as those of the magnetoresistive elements 23 and 24 described above. As for the terminals, the terminals 27a-1, 27b-1 and 27c-1 correspond to the terminals 27a, 27b and 27c, respectively. The magnetoresistive elements 23-2, 24-2, the terminals 27a-2, 27b-2, 27c-2 and the conductors connecting them are the magnetoresistive elements 23-1, 24-1, the terminals 27a-1, 27b. -1, 27c-1 and the conductors connecting them, and arranged symmetrically in the horizontal direction. That is, the magneto-resistive elements 23-2 and 24-2 are arranged on the surface of the substrate 22 at positions extending in the lateral direction from the magneto-resistive elements 23-1 and 24-1, respectively. and are arranged facing each other. The magnetoresistive elements 23-1, 24-1, the terminals 27a-1, 27b-1, 27c-1 and the conductors connecting them, the magnetoresistive elements 23-2, 24-2, the terminals 27a-2, 27b -2, 27c-2 and conductors connecting them may be provided on independent substrates 22, respectively.

On the flexible printed circuit board 25, the terminals 27a-1, 27b-1, 27c-1 and the terminals 27a-2, 27b-2, 27c-2 are electrically connected as follows. A DC voltage Vb is applied to the terminal 27c-1, and the terminal 27c-2 is grounded (GND). The terminal 27a-1 and the terminal 27b-2 are connected, and the connection point is connected to the non-inverting input of the amplifier 32. FIG. The terminal 27b-1 and the terminal 27a-2 are connected, and the connection point is connected to the inverting input of the amplifier 32. FIG. As a result, the magnetoresistive elements 23-1 and 24-2 are connected in series, and the voltage Vb-GND is applied to both ends thereof, and the voltage at the connection point of the magnetoresistive elements 23-1 and 24-2 is amplified. 32 non-inverting inputs. The magnetoresistive elements 24-1 and 23-2 are connected in series, and a voltage Vb-GND is applied to both ends of the magnetoresistive elements 24-1 and 23-2. to the inverting input of The amplifier 32 outputs the differential voltage between the non-inverting input and the inverting input as the output voltage Vout.

Such a connection constitutes a full-bridge circuit. As the magnetic body MS moves, the electrical resistance values of the magnetoresistive elements 23-1 and 24-2 change in opposite directions, and the magnetoresistive element 23-2 , 24-1 change positively and negatively, and the voltage at the connection point between the magnetoresistive elements 23-1 and 24-2 and the connection point between the magnetoresistive elements 24-1 and 23-2 The voltage at the point also changes in opposite directions. Since the voltages at the two connection points are supplied to the non-inverting input and the inverting input of the amplifier 31 and the amplifier 31 outputs the voltage difference between the two connection points, the voltage at the two connection points is substantially equal to the voltage at the two connection points. An output voltage Vout obtained by adding and synthesizing the changes is output. As a result, it is possible to obtain an output voltage Vout that is twice as high as in the case of the half-bridge connection described above.

Further, when the amplifier 32 outputs the voltage difference between the two connection points, the component H1x that causes changes in the electrical resistance values of the magnetoresistive elements 23-1 and 23-2 and the voltage difference between the magnetoresistive elements 24-1 and 24-2. Even if noise is included in each of the components H2x that cause changes in the electrical resistance value, the resistance value changes caused by these noises cancel each other out, improving the S/N ratio of the output voltage Vout.

Further, instead of the full bridge connection shown in FIG. 14(A), the magnetoresistive elements 23-1, 23-2, 24-1, 24-2 and the amplifier 32 are connected in a full bridge as shown in FIG. 14(B). may That is, a DC voltage Vb is applied to the terminals 27b-1 and 27a-2, and the terminals 27a-1 and 27b-2 are grounded (GND). The terminal 27c-1 is connected to the inverting input of the amplifier 32, and the terminal 27c-2 is connected to the non-inverting input of the amplifier 32. FIG. As a result, the magnetoresistive elements 24-1 and 23-1 are connected in series, and the voltage Vb-GND is applied to both ends thereof, and the voltage at the connection point of the magnetoresistive elements 24-1 and 23-1 is amplified. 32 inverting inputs. The magnetoresistive elements 23-2 and 24-2 are connected in series, and a voltage Vb-GND is applied to both ends of the magnetoresistive elements 23-1 and 24-2. to the non-inverting input of The amplifier 32 outputs the differential voltage between the non-inverting input and the inverting input as the output voltage Vout.

Such a connection also constitutes a full bridge circuit. , 23-1 change positively and negatively. The voltage at the point also changes in opposite directions. Since the voltages of the two connection points are supplied to the non-inverting input and the inverting input of the amplifier 31 and the amplifier 31 outputs the voltage difference between the two connection points, An output voltage Vout obtained by adding and synthesizing the voltage changes at the connection points is output, and an output voltage Vout twice as large as that in the above-described half-bridge connection can be obtained as in the case described above.

Also in this case, the amplifier 32 outputs the voltage difference between the two connection points, and the component H1x and the magnetoresistive elements 24-1 and 24-1, which cause changes in the electrical resistance values of the magnetoresistive elements 23-1 and 23-2. Even if noise is included in each of the components H2x that cause a change in the electrical resistance value of 24-2, these noises cancel each other out, improving the S/N ratio of the output voltage Vout.

Furthermore, one magnetic sensor does not have to be configured with a plurality of magnetoresistive elements 23, 24 (or 23-1, 23-2, 24-1, 24-2), and is configured with only one magnetoresistive element. You may do so. In this case, as shown in FIG. 15, only the magnetoresistive element 23 is provided on the upper surface of the substrate 22, and the DC voltage +Vb is applied to the terminal 27c. The magnetoresistive element 23, conductors and terminals 27a and 27c are constructed in the same manner as in the above embodiment. Then, the terminal 27a is connected to one end of the fixed resistor 33 provided on the flexible printed circuit board 25, and the other end of the fixed resistor 33 is grounded (GND). Then, the connection point between the magnetoresistive element 23 and the fixed resistor 33 is input to the amplifier 31 and the output voltage Vout is taken out from the amplifier 31 .

Even with this configuration, it is possible to extract the output voltage Vout that changes according to the change in the electrical resistance value of the magnetoresistive element 23 accompanying the movement of the magnetic body MS. It is possible to detect However, the output voltage Vout in this case is about half that in the above embodiment.

14A, 14B, and 15, which are modifications of the above embodiment, and the magnetoresistive elements 23, 24, 23-1, 23-2, 24-1, and 24-2 shown in FIGS. 6A and 6B. As described above, it may be divided so as to have three or more linear portions, or each may be composed of a single linear portion. Further, as described with reference to FIG. 6C, two or more lines are formed by folding back portions in which the magnetoresistive elements 23, 24, 23-1, 23-2, 24-1, and 24-2 are extended in the horizontal direction. It may be configured to have a shaped portion.

Further, as shown in FIG. 16, a magnetic body detection device 1A may be provided in which the magnetization direction of the magnet M3 is set in the direction opposite to that of the magnetic body detection device 1. FIG. The configuration of the magnetic body detection device 1A is the same as that of the magnetic body detection device 1 except for the magnetization direction of the magnet M3.

Next, the operation of the magnetic body detection device 1A will be described. First, as shown in FIG. 17, the electrical resistance of the magnetoresistive elements 23 and 24 when the verification object OB is moved forward (that is, from the rear end (entrance side) to the front end (exit side) of the transport path L) Explain the value change.

In the magnetic body detection device 1A, various parameters (magnetic force and arrangement of the magnets M1, M2, M3, etc.) are adjusted so that the direction of the magnetic vector of the hard magnetic body part MS1 is as follows (see FIG. 17A). is set. When the hard magnetic body part MS1 is at the position P1, the direction of the magnetic vector of the hard magnetic body part MS1 is approximately "45°". When the hard magnetic body part MS1 moves further forward and is at positions A1 and A2, the direction of the magnetic vector of the hard magnetic body part MS1 is substantially "0°". Then, when the hard magnetic body part MS1 is at the position P2, the direction of the magnetic vector of the hard magnetic body part MS1 is approximately "-45°".

When the hard magnetic body part MS1 passes over the magnetoresistive elements 23 and 24 while changing the direction of its magnetic vector as described above, the magnetic force line vectors H1 and H2 are affected by the hard magnetic body part MS1, The components H1x and H2x change, and the electrical resistance values of the magnetoresistive elements 23 and 24 change.

Specifically, as shown in FIG. 17B, as the hard magnetic body part MS1 moves from the position P1 to the position A1, the lines of magnetic force are gradually drawn upward under the influence of the hard magnetic body part MS1. be done. As a result, the component H1x of the magnetic line vector H1 passing through the magnetoresistive element 23 becomes larger than the bias magnetic field Hb, and the electrical resistance value of the magnetoresistive element 23 becomes smaller than the reference resistance value Rb. That is, as shown by the solid line graph in FIG. 17(D), the electrical resistance value of the magnetoresistive element 23 gradually decreases and reaches the minimum value at position A1. Then, as the hard magnetic body portion MS1 moves further forward from the position A1, the electrical resistance value of the magnetoresistive element 23 gradually increases and returns to the reference resistance value Rb.

As the hard magnetic body part MS1 moves further forward, the lines of magnetic force are gradually pushed downward under the influence of the hard magnetic body part MS1, as shown in FIG. 17(C). As a result, the component H1x of the magnetic line vector H1 passing through the magnetoresistive element 23 becomes smaller than the bias magnetic field Hb, and the electrical resistance value of the magnetoresistive element 23 becomes greater than the reference resistance value Rb. That is, as shown by the solid line graph in FIG. 17(D), the electrical resistance value of the magnetoresistive element 23 gradually increases and reaches the maximum value at position A2. Then, as the hard magnetic body part MS1 moves further forward, the electric resistance value gradually decreases, and when the influence of the hard magnetic body part MS1 on the magnetic lines of force disappears, the component H1x returns to the bias magnetic field +Hb, and the magnetoresistive element The electrical resistance value of 23 returns to the reference resistance value Rb.

The electrical resistance value of the magnetoresistive element 24 is the dashed line in FIG. It changes like a graph.

On the other hand, as described above, the soft magnetic body part MS2 always attracts magnetic lines of force. Therefore, changes in the electrical resistance values of the magnetoresistive elements 23 and 24 are the same as those in FIG. 11(B).

Next, changes in the electrical resistance values of the magnetoresistive elements 23 and 24 when the verification object OB is moved backward (that is, from the front end (exit side) to the rear end (entrance side) of the transport path L) will be described. .

In this case, as shown in FIG. 18A, when the hard magnetic body part MS1 is at the position P2, the direction of the magnetic vector of the hard magnetic body part MS1 is approximately "-45°". When the hard magnetic body part MS1 moves further rearward and is at positions A2 and A1, the direction of the magnetic vector of the hard magnetic body part MS1 is approximately "0°". Then, when the hard magnetic body part MS1 is at the position P1, the direction of the magnetic vector of the hard magnetic body part MS1 is approximately "45°". As shown in FIGS. 17A and 18A, in the magnetic material verification device 1A, the direction of the magnetic vector at each position when the hard magnetic part MS1 moves forward and the direction of the magnetic vector when moving backward The direction of the magnetic vector at each position is the same. Therefore, as shown in FIGS. 18B and 18C, when the hard magnetic body part MS1 moves backward, the magnetic lines of force exert the same influence as when the hard magnetic body part MS1 moves forward. receive. Therefore, as shown in FIGS. 18(D) and 17(D), the change in the electrical resistance values of the magnetoresistive elements 23 and 24 when the hard magnetic body portion MS1 moves backward is Same as when moving forward.

On the other hand, as described above, the soft magnetic body part MS2 always attracts magnetic lines of force. Therefore, changes in the electrical resistance values of the magnetoresistive elements 23 and 24 are the same as those in FIG. 11(B).

The effect equivalent to that of the magnetic substance detection device 1 can also be obtained by the magnetic substance detection device 1A. However, in this case, the detected waveform when the hard magnetic body part MS1 moves forward is the same as the detected waveform when it moves backward (see FIGS. 17(D) and 18(D)).

Furthermore, the various modifications described in the section on the magnetic material detection device 1 are also applied to the magnetic material detection device 1A according to this modification.

Although one embodiment of the present invention has been described above, the implementation of the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the object of the present invention.

For example, although the magnet M2 in the above embodiment is a permanent magnet, it may be a magnetic body that forms a magnetic field in cooperation with the magnets M1 and M3. Also, if there is no need to compare the detected waveform when the verification object OB is moved forward and the detected waveform when it is moved backward, the magnet M3 in the above embodiment may be omitted. In the above embodiment, the magnetization directions (vertical direction) of the magnets M1, M2, and M3 are perpendicular to the conveying direction (backward direction) of the verification object OB. You may incline with respect to the conveyance direction of verification object OB.

11... Case, M1, M2, M3... Magnet, 13... Cover, 21... Substrate support member, 22... Substrate, 23, 24, 23-1, 23-2, 24-1, 24-2... Magnetoresistive element ( Ferromagnetic thin film magnetoresistive element), 23A, 23B linear portions 23a to 23d, 24a to 24d dividing linear portions 25 flexible printed circuit board 31, 32 amplifier 33 fixed resistor L conveying path, MS... magnetic material, MS1... hard magnetic material part, MS2... soft magnetic material part, OB... object to be verified

Claims (8)

A magnetic body detection device for detecting a magnetic body contained in a verification object moving in a first direction along a predetermined transport path,
a first magnet extending in a second direction orthogonal to the first direction, the first magnet being magnetized in a direction that intersects the first direction and is orthogonal to the second direction;One of the magnetic pole faces is arranged to face the conveying patha first magnet;
extending in the second direction at a position spaced apart in the first direction when viewed from the first magnet,A second magnet magnetized in a direction opposite to that of the first magnet, wherein a magnetic pole surface opposite to the magnetic pole of one magnetic pole surface of the first magnet is arranged to face the conveying path,Cooperating with the first magnet,between the first magneta second magnet that forms a magnetic field in a predetermined space;
a substrate arranged in a magnetic force line path of the magnetic field formed in a predetermined space between the first magnet and the second magnet; andthe surface of the substrateis formed to have a linear portion extending in a direction inclined by a predetermined angle with respect to the second direction,the surface of the substratea magnetic sensor circuit having a magnetoresistive effect element whose electric resistance value changes with respect to a change in the magnetic field in the direction orthogonal to the second direction in the
By the magnetic field formed by the cooperation of the first magnet and the second magnet, a bias magnetic field having a strength smaller than the saturation magnetic field of the magnetoresistive element is applied to the magnetoresistive element. A bias magnetic field directed in a direction orthogonal to the second direction is applied within the surface of the substrate, and the magnetic material of the verification object is positioned within a predetermined region near the first magnet and the first magnet. The magnetic sensor circuit is arranged in the space between the first magnet and the second magnet so that the second magnet is magnetized in a predetermined state under the influence of the magnetic field formed in cooperation with the second magnet. Further, the distance between the magnetic pole surface of the first magnet and the conveying path of the verification object is set smaller than the distance between the magnetic pole surface of the second magnet and the conveying path. A magnetic body detection device characterized by: In the magnetic body detection device according to claim 1,
Magnetic substance detection, wherein the distance between the conveying path and the second magnet is set so that the magnetization state of the magnetic substance of the verification object does not change within a predetermined region near the second magnet. Device. In the magnetic body detection device according to claim 1 or 2,
A third magnet extending in the second direction at a position spaced apart in a direction opposite to the first magnet when viewed from the second magnet, crossing the first direction and in the second direction one of the magnetic pole faces is arranged to face the conveying path, cooperates with the first magnet and the second magnet, and forms a predetermined space between the second magnet and a third magnet that forms a magnetic field in a predetermined space between the first magnet and the second magnet,
A magnetic field formed between the first magnet and the second magnet by cooperation of the first to third magnets provides a bias magnetic field having a strength smaller than the saturation magnetic field of the magnetoresistive effect element. a bias magnetic field directed in a direction perpendicular to the second direction in the surface of the substrate is applied to the magnetoresistive element, and the verification is performed in a predetermined region near the first magnet. A magnetic body of an object is magnetized in a predetermined state under the influence of the magnetic field formed between the first magnet and the second magnet, and furthermore, in a predetermined region near the third magnet. The first magnet and the second magnet are arranged so that the magnetic material of the verification object is magnetized in a predetermined state under the influence of the magnetic field formed between the second magnet and the third magnet. The magnetic sensor circuit is arranged in the space between the second magnet and the distance between the magnetic pole surface of the first magnet and the conveying path, and the distance between the magnetic pole surface of the third magnet and the conveying path. , wherein the distance between the magnetic pole surface and the conveying path is set to be smaller than that of the magnetic material detecting device. In the magnetic body detection device according to claim 3,
A magnetic body detection device, wherein the magnetization direction of the first magnet and the magnetization direction of the third magnet are the same. In the magnetic body detection device according to any one of claims 1 to 4,
The magnetoresistive element has a first magnetoresistive element and a second magnetoresistive element facing each other at the same position in the second direction within the surface of the substrate ,
A magnetic body detection device, wherein the magnetic field is set and the magnetic sensor circuit is arranged so that the bias magnetic field for the first magnetoresistive element and the second magnetoresistive element are directed in opposite directions. The magnetic body detection device according to claim 5, further comprising:
Electricity in which the first magnetoresistive element and the second magnetoresistive element are connected in series and a predetermined voltage is applied to both ends thereof to take out the voltage at the connection point between the first magnetoresistive element and the second magnetoresistive element A magnetic body detection device comprising a circuit. In the magnetic body detection device according to claim 5,
The magnetoresistive effect elements are further provided within the surface of the substrate at positions spaced apart in the second direction when viewed from the first magnetoresistive element and the second magnetoresistive element. a third magneto-resistive element and a fourth magneto-resistive element facing each other at the same position in the second direction in the surface of the substrate , wherein the electric Having a third magnetoresistive element and a fourth magnetoresistive element whose resistance value changes,
The bias magnetic fields for the third magneto-resistive element and the fourth magneto-resistive element are arranged in opposite directions, and
The terminal of the first magnetoresistance element on the side of the third magnetoresistance element and the terminal of the fourth magnetoresistance element on the side of the second magnetoresistance element are connected, and the fourth magnetoresistance element of the second magnetoresistance element is connected. side terminal and the terminal of the third magnetoresistive element on the side of the first magnetoresistive element, and the terminal of the first magnetoresistive element opposite to the third magnetoresistive element and the terminal of the second magnetoresistive element A terminal opposite to the fourth magnetoresistive element is connected, and a terminal of the third magnetoresistive element opposite to the first magnetoresistive element and a terminal of the fourth magnetoresistive element opposite to the second magnetoresistive element side terminals are connected, and a predetermined voltage is applied between the connection point between the first magnetoresistive element and the second magnetoresistive element and the connection point between the third magnetoresistive element and the fourth magnetoresistive element. and an electric circuit for extracting a difference voltage between a voltage at a connection point between the first magnetoresistive element and the fourth magnetoresistive element and a voltage at a connection point between the second magnetoresistive element and the third magnetoresistive element. A magnetic body detection device characterized by: In the magnetic body detection device according to claim 5,
The magnetoresistive effect elements are further provided within the surface of the substrate at positions spaced apart in the second direction when viewed from the first magnetoresistive element and the second magnetoresistive element. a third magneto-resistive element and a fourth magneto-resistive element facing each other at the same position in the second direction in the surface of the substrate , wherein the electric Having a third magnetoresistive element and a fourth magnetoresistive element whose resistance value changes,
The bias magnetic fields for the third magneto-resistive element and the fourth magneto-resistive element are arranged in opposite directions, and
The terminal of the first magnetoresistive element opposite to the third magnetoresistive element and the terminal of the second magnetoresistive element opposite to the fourth magnetoresistive element are connected, and the third magnetoresistive element of the third magnetoresistive element is A terminal opposite to the first magnetoresistive element and a terminal of the fourth magnetoresistive element opposite to the second magnetoresistive element are connected, and a terminal of the first magnetoresistive element on the side of the third magnetoresistive element is connected to the terminal of the fourth magnetoresistive element. connecting a terminal of a fourth magnetoresistive element on the second magnetoresistive element side, and connecting a terminal of the second magnetoresistive element on the side of the fourth magnetoresistive element and the first magnetoresistive element of the third magnetoresistive element; side terminals are connected, and a predetermined voltage is applied between the connection point between the first magnetoresistive element and the fourth magnetoresistive element and the connection point between the second magnetoresistive element and the third magnetoresistive element. and an electric circuit for extracting a difference voltage between a voltage at a connection point between the first magnetoresistive element and the second magnetoresistive element and a voltage at a connection point between the third magnetoresistive element and the fourth magnetoresistive element. A magnetic body detection device characterized by:

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