JP2010266697A - String vibration detection sensor and pickup device for electronic musical instruments using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a string vibration detection sensor and a pickup device for electronic musical instruments using the same, which can regenerate a signal waveform which faithfully reflects a position of a metal string accompanied by vibration. <P>SOLUTION: The vibration detection sensor includes: the metal string 11; a magnet 16 which is spaced apart from the metal string 11 at a fixed distance; a magnetoresistive element 170, which is arranged between the metal string 11 and the magnet 16, for converting change of a direction of a magnetic flux between the magnet 16 and the metal string 11 accompanied by the vibration of the metal string 11, to an electric signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a string vibration detection sensor and a pickup device for an electric musical instrument using the same, and more particularly, to a string vibration detection sensor that extracts a vibration of a metal string by converting it into an electric signal and an electric musical instrument pickup device using the same.

  In an electric musical instrument such as an electric guitar, a pickup device using a string vibration detection sensor that converts vibration of a metal string into an electric signal is attached to the body portion. In such an electric musical instrument pickup device, conventionally, a permanent magnet is disposed between the lower ends of the yokes facing each other at a predetermined interval, and the magnetoresistor is positioned between the upper ends of the yokes so as to face the metal strings. By sandwiching the circuit board on which the effect element is arranged and vibrating the metal string, the distance between the upper end of the yoke and the metal string is changed, and the magnetic flux flowing through the magnetic circuit by the permanent magnet is changed. An element that is converted into an electric signal by a magnetoresistive element and taken out has been proposed (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 6-130961

  However, in the electric musical instrument pickup device using the conventional string vibration detection sensor described above, a configuration in which a change in magnetic flux density (that is, a change in the magnitude of the magnetic flux) due to the vibration of the metal string is detected by a magnetoresistive element. Therefore, there is a problem that the position of the vibrating metal string cannot be accurately grasped, and a signal waveform that accurately reflects the position of the metal string cannot be reproduced.

  The present invention has been made in view of such problems, and a string vibration detection sensor capable of reproducing a signal waveform faithfully reflecting the position of a metal string accompanying vibration, and a pickup for an electric musical instrument using the same. An object is to provide an apparatus.

  The string vibration detection sensor of the present invention includes a metal string, a magnet member disposed at a certain distance from the metal string, and disposed between the metal string and the magnet member, and the vibration of the metal string. And a magnetoresistive effect element for converting a change in the direction of magnetic flux between the magnet member and the metal string into an electric signal.

  According to the above string vibration detection sensor, since the change in the direction of the magnetic flux from the magnet member is converted into an electric signal by the magnetoresistive effect element, the change in accordance with the direction of the magnetic flux that changes in conjunction with the position of the metal string. Therefore, it is possible to reproduce a signal waveform that faithfully reflects the position of the metal string accompanying vibration.

  In the string vibration detection sensor, the magnet member has magnetic poles at both ends in a direction orthogonal to the extending direction of the metal string, and the magnetoresistive element is disposed in the vicinity of one magnetic pole of the magnet member. It is preferable. In this case, the magnet member has magnetic poles at both ends of the magnet member in the direction orthogonal to the extending direction of the metal string, and the magnetoresistive element is disposed in the vicinity of one of the magnetic poles (for example, N pole). Thus, it is possible to reliably pass the magnetic flux from the magnetoresistive effect element, and to output an electric signal corresponding to the direction of the magnetic flux changing in conjunction with the position of the metal string with higher accuracy.

  The string vibration detection sensor preferably includes a magnetic member extending from the other magnetic pole of the magnet member to the vicinity of the position of the metal string spaced from the detection region by the magnetoresistive effect element. In this case, since the magnetic flux reaching the metal string from one magnetic pole side of the magnet member can be guided to the magnetic pole on the other side of the magnet member, the passage path of the magnetic flux can be stabilized and the magnetic sensor can be more accurately detected. It is possible to improve the detection accuracy of the change in the direction of the magnetic flux in

  The pickup device for an electric musical instrument of the present invention uses any one of the above string vibration sensors. According to this electric musical instrument pickup device, it is possible to obtain the effects obtained by any of the above string vibration sensors.

  According to the present invention, since the change in the direction of the magnetic flux from the magnet member is converted into an electric signal by the magnetoresistive effect element, the electric signal corresponding to the direction of the magnetic flux that changes in conjunction with the position of the metal string. Therefore, it is possible to reproduce a signal waveform that faithfully reflects the position of the metal string accompanying vibration.

It is a perspective view which shows the external appearance of the pick-up apparatus for electric musical instruments which concerns on Embodiment 1 of this invention. FIG. 2 is a perspective view of a state where a decorative sheet and a part of a case are removed from the electric musical instrument pickup device shown in FIG. 1. FIG. 3 is an exploded perspective view of the electric musical instrument pickup device shown in FIG. 2. 2 is a front view of the periphery of a magnetic sensor included in the electric musical instrument pickup device according to Embodiment 1. FIG. It is a figure for demonstrating the structure of the magnetoresistive effect element of the magnetic sensor which the pick-up apparatus for electric musical instruments which concerns on Embodiment 1 has. It is a figure for demonstrating the relationship between the vibration of a metal string and the electrical signal in the magnetic sensor which the pick-up apparatus for electric musical instruments which concerns on Embodiment 1 has. It is a perspective view which shows the external appearance of the pick-up apparatus for electric musical instruments which concerns on Embodiment 2 of this invention. It is a perspective view of the state which removed the case from the pickup device for electric musical instruments shown in FIG. FIG. 6 is a side sectional view of a periphery of a magnetic sensor included in an electric musical instrument pickup device according to a second embodiment. FIG. 6 is a perspective view of the periphery of a magnetic sensor included in an electric musical instrument pickup device according to Embodiment 2. It is a figure for demonstrating the relationship between the vibration of a metal string and the electrical signal in the magnetic sensor which the pick-up apparatus for electric musical instruments which concerns on Embodiment 2 has.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, a case where the string vibration detection sensor according to the present embodiment is applied to a pickup device for an electric musical instrument (hereinafter referred to as “pickup device”) will be described, but the present invention is not limited to this. The present invention can be applied to any device that detects vibration of a metal string. In the following, a case where the pickup device using the string vibration detection sensor according to the present embodiment is applied to an electric guitar will be described, but the present invention is not limited to this, and a metal string other than the electric guitar is used. It is possible to apply to an electric musical instrument (for example, an electric base, etc.).

(Embodiment 1)
FIG. 1 is a perspective view showing an appearance of a pickup device 10 according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the pickup device 10 shown in FIG. 1 with a decorative sheet and a part of the case removed. FIG. 3 is an exploded perspective view of the pickup device 10 shown in FIG. In FIG. 3, for convenience of explanation, a metal string 11 stretched between a body portion (not shown) and a neck portion of the electric guitar is omitted. In the following, the metal string 11 side in FIG. 1 is referred to as the upper side of the pickup device 10, and the body part side (not shown) is referred to as the lower side of the pickup device 10.

  The pickup device 10 according to the first embodiment is mounted at a predetermined position on the body portion so as to face a metal string 11 stretched between a body portion (not shown) and a neck portion of the electric guitar. As shown in FIG. 1, the pickup device 10 is attached to a case 12 for fixing a circuit board 15 and a magnet 16 to be described later, a fixing member 13 for fixing the case 12 to the body portion of the electric guitar, and an upper surface of the case 12. And a decorative sheet 14 to be formed. The case 12 is composed of, for example, first and second cases 12a and 12b which are formed of an insulating resin material and combined to accommodate a circuit board or the like. The first and second cases 12a and 12b are integrated by accommodating the protruding portions 12c and 12d of the side end portions of the first and second cases 12a and 12b in the opening 13a of the fixing member 13. Fixed to the body part of the electric guitar. The decorative sheet 14 is affixed to the recesses 12e and 12f formed on the upper surface of the case 12, and marks are provided at positions corresponding to the six metal strings 11 on the upper surface.

  As shown in FIGS. 2 and 3, a circuit board 15 is disposed inside the case 12 at a position sandwiched between the first and second cases 12a and 12b. The circuit board 15 has a generally rectangular flat plate shape, and six openings 151 are formed at predetermined positions corresponding to the six metal strings 11 (see FIG. 3). These openings 151 have a rectangular shape in which the longitudinal direction is arranged in the vertical direction, and the magnet holding pieces 121 provided on the inner wall portion of the second case 12b are inserted therethrough so that the tip ends thereof are slightly exposed. It has become a thing. A magnet 16 having a generally cylindrical shape is sandwiched between the tip portions of these magnet holding pieces 121, and the circumferential surface of the magnet 16 is slightly exposed from the opening 151 (see FIG. 2). In this case, the magnet 16 is in a state where its center is arranged at the center of the circuit board 15. In the pickup device 10 according to Embodiment 1, the magnet 16 has its upper end magnetized to the N pole and its lower end magnetized to the S pole.

  A mounting region 152 in which the magnetic sensor 17 is mounted is provided above the opening 151 in the circuit board 15. The magnetic sensor 17 is mounted in the mounting region 152 and is disposed opposite to the upper end of the magnet 16 disposed in the opening 151, and detects a change in the direction of magnetic flux generated between the magnet 16 and the metal string 11. Is. A mounting region 153 in which the amplifier IC 18 is mounted is provided on the side of the opening 151. The amplification IC 18 is mounted in the mounting area 153 and amplifies an electric signal from the magnetic sensor 17. Further, on the left side of the leftmost opening 151 shown in FIG. 3, there is a mounting region 154 on which an output terminal member 19 having an external terminal 191 that outputs an electrical signal from the magnetic sensor 17 to the outside is mounted. Is provided. The output terminal member 19 is mounted on the mounting region 154 and configured to output an electric signal amplified by the amplifier IC 18 to the control unit of the electric guitar.

  FIG. 4 is a front view of the periphery of the magnetic sensor 17 mounted on the circuit board 15. As shown in FIG. 4, the magnetic sensor 17 is mounted on the upper side of the magnet 16 disposed in the opening 151 of the circuit board 15, and the metal string 11 is spaced apart by a certain distance on the upper side. Is arranged. Therefore, when the upper end and the lower end of the magnet 16 are magnetized to the N pole and the S pole, respectively, the magnetic flux from the magnet 16 is directed from the upper end of the magnet 16 to the metal string 11, and the lower end of the magnet 16. It is comprised so that it may return to a part. In this case, the magnetic flux from the magnet 16 passes through the magnetic sensor 17. In this case, when the metal string 11 vibrates, the direction of the magnetic flux from the magnet 16 (the angle of the magnetic field) changes according to the position of the metal string 11 as shown for convenience on the magnetic sensor 17 in FIG. The magnetic sensor 17 detects a change in the direction of the magnetic flux. In particular, in the pickup device 10 according to the first embodiment, the metal string 11 that vibrates in a direction (left-right direction shown in FIG. 4) perpendicular to the arrangement direction of the magnetic poles of the magnet 16 (up-down direction shown in FIG. 4). The change of the direction of the corresponding magnetic flux is detected effectively.

  Here, the configuration of the magnetic sensor 17 of the pickup device 10 according to the first embodiment will be described. The magnetic sensor 17 is configured by a bridge circuit in which four magnetoresistive elements 170 that convert changes in the direction of magnetic flux into electric signals are combined. FIG. 5 is a view for explaining the configuration of the magnetoresistive effect element 170 of the magnetic sensor 17. As shown in FIG. 5, the magnetoresistive effect element 170 that outputs an electric signal in response to magnetism has a basic structure, such as an exchange bias layer (antiferromagnetic material layer) 171 and a fixed layer (pinned magnetic layer) 172. And a nonmagnetic layer 173 and a free layer (free magnetic layer) 174 are laminated on the circuit board 15 and are a kind of GMR (Giant Magneto Resistance) element using a giant magnetoresistance effect. It is configured as a resistance effect element.

In order for the magnetoresistive effect element 170 to exhibit the giant magnetoresistive effect (GMR), for example, the exchange bias layer 171 is an α-Fe ₂ O ₃ layer, the fixed layer 172 is a NiFe layer, the nonmagnetic layer 173 is a Cu layer, free The layer 174 is formed of a NiFe layer, but is not limited to these, and may be any material that exhibits a giant magnetoresistive effect (GMR). Further, the magnetoresistive effect element 170 is not limited to the one having the above laminated structure as long as it exhibits a giant magnetoresistive effect (GMR).

  The fixed layer 172 of the magnetoresistive effect element 170 shown in FIG. 5 is magnetized by the exchange bias layer 171, and the magnetization direction is fixed (pinned) in a specific direction by the exchange bias layer 171. The magnetization direction of the free layer 174 with respect to the magnetization direction of the fixed layer 172 changes depending on the direction of the external magnetic field. Terminal layers 175 are bonded to both ends of the magnetoresistive effect element 170. The change in the electric resistance value between the two terminal layers 175 is output as an electric signal by changing the magnetization direction of the free layer 174 depending on the direction of the external magnetic field with respect to the fixed magnetization direction of the fixed layer 172. It is supposed to be.

  FIG. 6 is a diagram for explaining the relationship between the vibration of the metal string 11 and the electrical signal in the bridge circuit to which the magnetoresistive effect element 170 of the pickup device 10 according to the first embodiment is connected. In FIG. 6, while the output voltage is shown on the vertical axis, the magnetic field generated from the magnet 16 to the metal string 11 on the horizontal axis and passing over the magnetic sensor 17 (hereinafter referred to as “magnetic field angle” as appropriate). "). In the magnetic field angle shown in FIG. 6, the state in which the metal string 11 is not vibrating is 180 °. In the pickup device 10 according to the first embodiment, a change in the magnetic field angle corresponding to the vibration of the metal string 11 is detected, and more specifically, the change in the magnetic field angle is converted into an electric signal by the magnetoresistive effect element 170. It is supposed to be.

  In order to simplify the description, an electrical signal output limited to vibration in the range of 1 mm in the metal string 11 will be described. As shown in FIG. 6, in the pickup device 10 according to the first embodiment, the magnetic field angle from the magnet 16 with respect to 1 mm of vibration of the metal string 11 is in the range of about 175 ° to about 185 ° (the range of about 10 °). ) To change. In this case, the electrical signal (voltage signal) output from the magnetic sensor 17 varies in the range of about 25 mV to about −25 mV (about 50 mV). In this case, the magnetic field angle from the magnet 16 changes in conjunction with the position of the metal string 11, and the electric signal changes accordingly.

  Thus, in the pickup device 10 as the string vibration detection sensor according to the first embodiment, the magnetic sensor 17 having the magnetoresistive effect element 170 converts the change in the direction of magnetic flux (magnetic field angle) from the magnet 16 into an electrical signal. As a result, an electric signal corresponding to the direction of magnetic flux (magnetic field angle) that changes in conjunction with the position of the metal string 11 can be output, so the position of the metal string 11 associated with vibration is faithfully reflected. It is possible to reproduce the signal waveform.

  Further, in the pickup device 10 as the string vibration detection sensor according to the first embodiment, the magnetic sensor 17 has one magnetic pole (here, the magnetic sensor 17 has magnetic poles at both ends of the magnet 16 in a direction orthogonal to the extending direction of the metal string 11. In this case, the magnetic flux from the magnet 16 can be surely passed over the magnetic sensor 17, and the magnetic field angle that changes in conjunction with the position of the metal string 11 can be obtained with higher accuracy. A corresponding electrical signal can be output.

(Embodiment 2)
In the pickup device 10 according to the first embodiment, the magnetic sensor 17 is disposed in the vicinity of the upper side of the magnet 16, and the metal string 11 is stretched at a position separated by a certain distance above the magnetic sensor 17. Thus, the magnetic flux from the magnet 16 is configured to return from the upper end portion of the magnet 16 to the metal string 11 and then return to the lower end portion of the magnet 16. The pickup device 20 according to the second embodiment is different from the pickup device 10 according to the first embodiment in that a magnetic member that configures a path through which the magnetic flux that has reached the metal string 11 returns to the lower end of the magnet 16 is provided. Hereinafter, the configuration of the pickup device 20 according to the second embodiment will be described focusing on differences from the first embodiment.

  FIG. 7 is a perspective view showing an appearance of the pickup device 20 according to Embodiment 2 of the present invention. FIG. 8 is a perspective view of the pickup device 20 shown in FIG. 7 with a part of the case removed. 9 and 10 are a side sectional view and a perspective view, respectively, around the magnetic sensor 17 included in the pickup device 20 according to the second embodiment. In addition, in the pickup apparatus 20 according to the second embodiment shown in FIGS. 7 to 10, the same reference numerals are given to the configurations common to the pickup apparatus 10 according to the first embodiment, and the description thereof is omitted. To do. In the following, the metal string 11 side in FIG. 7 is referred to as the upper side of the pickup device 20, and the body part side (not shown) is referred to as the lower side of the pickup device 20.

  As shown in FIGS. 7 and 8, the pickup device 20 according to the second embodiment is different from the pickup device 10 according to the first embodiment in the configuration of the case 21 that forms the outer shape of the device. Whereas the case 12 of the pickup device 10 according to the first embodiment is combined in the extending direction of the metal string 11, the case 21 of the pickup device 20 according to the second embodiment is combined in the vertical direction of the pickup device 20. It has a configuration. The case 21 includes a first case 21a that is fixed to the body portion of the electric guitar and a second case 21b that is overlaid on the first case 21a. The first case 21b is located inside the second case 21b. A space for accommodating the circuit board 15 and the magnet 16 is provided in a state of being overlaid on 21a. 8 shows a state in which the second case 21b is removed from the pickup device 20 shown in FIG.

  As shown in FIG. 8, the circuit board 15 is disposed inside the second case 21b so as to be orthogonal to the first case 21a. A rectangular opening 151 in which the magnet 16 is disposed is provided at a predetermined position of the circuit board 15. The magnet 16 is sandwiched between an upper end portion of the opening 151 and a magnetic member 23 described later, and the peripheral surface of the magnet 16 is slightly exposed from the opening 151 (see FIG. 9). . In the pickup device 20 according to the second embodiment, the magnet 16 has its upper end magnetized to the N pole and its lower end magnetized to the S pole, as in the pickup device 10 according to the first embodiment. Yes. A magnetic sensor 17 is mounted on the upper side of each opening 151, and an amplification IC 18 is mounted on the lower side of the predetermined opening 151. The configurations of the magnetic sensor 17 and the amplification IC 18 are the same as those of the pickup device 10 according to the first embodiment.

  On the upper surface of the first case 21a, a pair of support pieces 22a and 22b are erected at positions corresponding to the respective openings 151. These support pieces 22 a and 22 b have a strip shape and are provided in the vicinity of the edge of the first case 21 a so as to face the surface of the circuit board 15. On the upper end portions of these support pieces 22a and 22b, the magnetic member 23 in a state where one end portion is inserted through the opening 151 is placed. The magnetic member 23 generally has an L-shape, one end of which is placed on the upper end portion of the support piece 22a, the bent portion 23a is placed on the upper end portion of the support piece 22b, and the other end is made of metal. It is in a state of extending to the vicinity of the string 11. The other end of the metal string 11 is configured to extend to the vicinity of the position of the metal string 11 separated from the detection region by the magnetic sensor 17 (magnetoresistance effect element 170). The magnet 16 is placed in the vicinity of one end of the magnetic member 23 inserted through the opening 151 as described above, and is sandwiched between the upper end of the opening 151.

  Here, a passage path of magnetic flux generated from the magnet 16 in the pickup device 20 according to the second embodiment will be described. FIG. 9 is a sectional side view of the periphery of the magnetic sensor included in the electric musical instrument pickup device according to the second embodiment. In FIG. 9, the second case 21b is omitted as in FIG. As described above, in the pickup device 20 according to the second embodiment, the upper end portion of the magnet 16 is magnetized to the N pole and the lower end portion is magnetized to the S pole. The generated magnetic flux travels toward the metal string 11, passes through the metal string 11, extends to the vicinity of the metal string 11, passes through the magnetic member 23, and returns to the lower end of the magnet 16. When the metal string 11 vibrates, the direction of the magnetic flux from the magnet 16 (the angle of the magnetic field) changes according to the position of the metal string 11 as shown in FIG. The magnetic sensor 17 detects a change in the direction of the magnetic flux. In particular, in the pickup device 20 according to the second embodiment, similarly to the pickup device 10 according to the first embodiment, the magnetic flux corresponding to the metal string 11 that vibrates in a direction orthogonal to the arrangement direction of the magnetic poles of the magnet 16. Effectively detect changes in the direction of.

  FIG. 11 is a diagram for explaining the relationship between the vibration of the metal string 11 and the electrical signal in the bridge circuit to which the magnetoresistive effect element 170 of the pickup device 20 according to the second embodiment is connected. In FIG. 11, as in FIG. 6, the vertical axis indicates the output voltage, while the horizontal axis indicates the magnetic field generated from the magnet 16 to the metal string 11 and the magnetic field angle passing over the magnetic sensor 17. ing. Moreover, in the magnetic field angle shown in FIG. 11, the state where the metal string 11 is not oscillating is 180 °.

  In FIG. 11 as well, similarly to FIG. 6, an electrical signal output limited to 1 mm vibration of the metal string 11 will be described. As shown in FIG. 11, in the pickup device 20 according to the second embodiment, the magnetic field angle from the magnet 16 with respect to 1 mm of vibration of the metal string 11 is in the range of about 175 ° to about 185 ° (the range of about 10 °). ) To change. The electric signal (voltage signal) output from the magnetic sensor 17 varies in the range of about 25 mV to about −25 mV (about 50 mV). In this case, the magnetic field angle from the magnet 16 changes in conjunction with the position of the metal string 11, and the electric signal changes accordingly.

  As described above, also in the pickup device 20 as the string vibration detection sensor according to the second embodiment, the magnetic sensor 17 having the magnetoresistive effect element 170 converts the change in the direction of magnetic flux (magnetic field angle) from the magnet 16 into an electrical signal. As a result, an electric signal corresponding to the direction of magnetic flux (magnetic field angle) that changes in conjunction with the position of the metal string 11 can be output, so the position of the metal string 11 associated with vibration is faithfully reflected. It is possible to reproduce the signal waveform.

  In particular, in the pickup device 20 as the string vibration detection sensor according to the second embodiment, the magnetic member 23 that guides the magnetic flux reaching the metal string 11 from the upper end portion of the magnet 16 to the lower end portion of the magnet 16 is provided. Therefore, the passage path of the magnetic flux can be stabilized, and the detection accuracy of the change in the direction of the magnetic flux in the magnetic sensor 17 can be improved more accurately.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above embodiment, the case where the upper end portion of the magnet 16 is magnetized to the N pole while the lower end portion is magnetized to the S pole has been described. However, the configuration of the magnet 16 is limited to this. It can be changed as appropriate. The magnetic poles formed on the magnet 16 may be oppositely magnetized on the condition that a magnetic flux that can pass over the magnetic sensor 17 is generated.

10, 20 Pickup device for electric musical instruments (pickup device)
DESCRIPTION OF SYMBOLS 11 Metal string 12,21 Case 12a, 21a 1st case 12b, 21b 2nd case 12c, 12d Protrusion part 12e, 12f Recessed part 121 Magnet holding piece 13 Fixing member 13a Opening part 14 Cosmetic sheet 15 Circuit board 151 Opening part 152,153 154 Mounting area 16 Magnet 17 Magnetic sensor 170 Magnetoresistive element 171 Exchange bias layer (antiferromagnetic layer)
172 Fixed layer (pinned magnetic layer)
173 Nonmagnetic layer 174 Free layer (free magnetic layer)
175 Terminal layer 18 Amplifier IC
19 output terminal member 191 external terminal 22a, 22b support piece 23 magnetic member

Claims (4)

  A metal string, a magnet member disposed at a certain distance from the metal string, and the magnet member and the metal string that are disposed between the metal string and the magnet member and are caused by vibration of the metal string. And a magnetoresistive effect element that converts a change in the direction of the magnetic flux between the magnetic signal and the electric signal into a string vibration detection sensor.   The magnet member has magnetic poles at both ends in a direction perpendicular to the extending direction of the metal string, and the magnetoresistive element is disposed in the vicinity of one magnetic pole of the magnet member. Item 2. The string vibration detection sensor according to item 1.   3. The string vibration detection sensor according to claim 2, further comprising a magnetic member extending from the other magnetic pole of the magnet member to the vicinity of the position of the metal string separated from the detection region by the magnetoresistive effect element.   A pickup device for an electric musical instrument using the string vibration detection sensor according to any one of claims 1 to 3.

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