Current sensor head and current sensor device

Abstract

The purpose of the present invention is to provide a current sensor head and a current sensor device which are capable of detecting a current flowing in a conductor without supplying electric power to a magnetic sensor element. The current sensor head comprises: a conductor; a magnetic sensor element that outputs return light which is obtained by rotating the plane of polarization of incident light in accordance with a magnetic field generated by a current flowing through the conductor; a fixing member that fixes the positional relation between the conductor and the magnetic sensor element; and a light guide member that guides the incident light to the magnetic sensor element and that guides the return light from the magnetic sensor element. The current sensor device comprises the current sensor device.

Description

Current Sensor Head and Current Sensor Device

[0001] The present invention relates to a current sensor head and a current sensor device.

[0002] Various techniques for detecting the current flowing through a conductor by detecting the magnetic field generated around the conductor when a current flows through the conductor are known. For example, Patent Document 1 describes a current sensor having a current conductor capable of shunting the current flowing through a conductor disposed on a substrate, a magnetic sensor element for detecting the magnetic field generated when a current flows through the current conductor, and a magnetic shield disposed so as to sandwich the current conductor and the magnetic sensor element. The current sensor described in Patent Document 1 can reduce noise caused by conductors and magnetic bodies disposed around the current sensor by having a magnetic shield that sandwiches the current conductor and the magnetic sensor element.

[0003] Japanese Patent Application Laid-Open No. 2003-329749

[0004] In the current sensor described in Patent Document 1, since a plurality of lead frames are arranged to supply an input voltage to the magnetic sensor element and extract the output voltage of the magnetic sensor element, noise is generated due to fluctuations in the input voltage and the output voltage. In the current sensor described in Patent Document 1, noise is generated due to fluctuations in the input voltage and the output voltage applied to the plurality of lead frames arranged in proximity to the magnetic sensor element, so there is a risk that the accuracy of detecting the magnetic field and current will decrease.

[0005] The present disclosure addresses such problems and aims to provide a current sensor head capable of detecting the current flowing through a conductor without supplying power to the magnetic sensor element.

[0006] The current sensor head according to the present disclosure includes a conductor, a magnetic sensor element that emits return light whose plane of polarization of incident light is rotated according to the magnetic field generated by the current flowing through the conductor, a fixing member that fixes the positional relationship between the conductor and the magnetic sensor element, and a light guiding member that guides the incident light to the magnetic sensor element and guides the return light from the magnetic sensor element.

[0007] Furthermore, in the current sensor head according to the present invention, it is preferable that the conductor has a pair of power supply pads to which current is supplied, and a connecting portion that connects the pair of power supply pads.

[0008] Furthermore, in the current sensor head according to this disclosure, the connection portion preferably has a circular cross-section and includes a detection portion positioned in close proximity to the magnetic sensor element, and a pair of current paths connecting a pair of power supply pads and the detection portion.

[0009] Furthermore, in the current sensor head according to this disclosure, it is preferable that each of the pair of power supply pads has a rectangular planar shape, and each of the pair of current paths has a truncated square pyramidal shape.

[0010] Furthermore, the current sensor head according to this disclosure preferably further comprises a pair of magnetic shielding members disposed between the detection unit and each of the pair of current paths to block the magnetic field.

[0011] Furthermore, in the current sensor head according to this disclosure, the fixing member is preferably a sealing material that is filled between a pair of power supply pads and seals the magnetic sensor element.

[0012] Furthermore, in the current sensor head according to the present disclosure, it is preferable that the conductor has a detection portion positioned in close proximity to the magnetic sensor element, and a pair of legs extending from each end of the detection portion in the direction opposite to the magnetic sensor element.

[0013] The current sensor device according to this disclosure includes a light-emitting unit that emits incident light, a current sensor head that emits reflected light corresponding to the magnetic field generated by the flow of current when incident light is incident on it, a detection signal generating unit that receives the reflected light and outputs a detection signal corresponding to the magnetic field, and an optical path unit that receives incident light from the light-emitting unit and emits the incident light to the current sensor head, and receives reflected light from the current sensor head and emits the reflected light to the detection signal generating unit, wherein the current sensor head includes a conductor, a magnetic sensor element that emits reflected light whose polarization plane of the incident light is rotated according to the magnetic field generated by the current flowing through the conductor, a fixing member that fixes the positional relationship between the conductor and the magnetic sensor element, and a light-guiding member that guides the incident light to the magnetic sensor element and guides the reflected light from the magnetic sensor element.

[0014] The current sensor head according to this disclosure can detect current flowing through a conductor without supplying power to a magnetic sensor element.

[0015] This is a block diagram of a current sensor device according to an embodiment. (a) is a perspective view of the current sensor head shown in Figure 1, (b) is a perspective view of the current sensor head shown in (a), and (c) is a cross-sectional view along the line A-A shown in (b). This is a perspective view of the first power supply pad, the second power supply pad and the connection part shown in Figure 2(b). This is a perspective view of the current sensor head according to the first modified example. This is a perspective view of the current sensor head according to the second modified example.

[0016] The current sensor head and current sensor device according to the present invention will be described below with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the invention described in the claims and its equivalents.

[0017] (Configuration and function of the current sensor device according to the embodiment) Figure 1 is a block diagram showing the current sensor device according to the embodiment.

[0018] The current sensor device 1 includes a light-emitting unit 10, a circulator 20, a first optical element 30, an optical path unit 40, a current sensor head 50, and a detection signal generation unit 60. The optical path between the light-emitting unit 10, the circulator 20, the first optical element 30, the optical path unit 40, the current sensor head 50, and the detection signal generation unit 60 is formed by an optical fiber 15, which is a PANDA (Polarization-maintaining AND Absorption-reducing) fiber. In one example, the outer diameter of the optical fiber 15 is 125 μm. However, the optical path between the first optical element 30, the optical path unit 40, the current sensor head 50, and the detection signal generation unit 60 may be formed by polarization-maintaining optical fibers other than PANDA fibers, such as bow-tie fibers and elliptical jacket fibers.

[0019] The light-emitting unit 10 includes a light-emitting element 11, an isolator 12, and a polarizer 13. The light-emitting element 11 is, for example, a semiconductor laser or a light-emitting diode. Specifically, a Fabry-Perot laser, a superluminescent diode, etc., can be preferably used as the light-emitting element 11.

[0020] The isolator 12 protects the light-emitting element 11 by allowing light incident from the light-emitting element 11 to pass through to the circulator 20 side, while preventing light incident from the circulator 20 from passing through to the light-emitting element 11 side. The isolator 12 is, for example, a polarization-dependent optical isolator, or it may be a polarization-independent optical isolator.

[0021] The polarizer 13 is an optical element that converts the light emitted by the light-emitting element 11 into linearly polarized light, and its type is not particularly limited. The first linearly polarized light obtained by the polarizer 13 is incident on the first optical element 30 via the circulator 20.

[0022] The circulator 20 is an optical splitter that transmits the first linearly polarized light emitted from the light-emitting unit 10 to the first optical element 30, and splits the second linearly polarized light emitted from the first optical element 30 to the detection signal generation unit 60. The circulator 20 is formed, for example, by a Faraday rotor, a half-wave plate, a polarizing beam splitter, and a reflective mirror.

[0023] The first optical element 30 is, for example, a half-wave plate positioned such that its azimuth angle is 22.5 degrees with respect to the polarization plane of the first linearly polarized light incident from the circulator 20. The first optical element 30 rotates the polarization plane of the first linearly polarized light incident from the circulator 20 by 45 degrees and emits the first linearly polarized light into the optical path section 40. The first linearly polarized light whose polarization plane has been rotated by 45 degrees in the first optical element 30 has a first linearly polarized light CW1 which is P-polarized and a second linearly polarized light CCW1 which is S-polarized and orthogonal to the first linearly polarized light CW1.

[0024] Furthermore, the first optical element 30 rotates the polarization plane of the second linearly polarized light, which is incident linearly polarized light from the optical path section 40, by 45 degrees and emits it to the circulator 20.

[0025] The optical path section 40 includes a first beam splitter 41, a second beam splitter 42, a first optical path 43, a second optical path 44, and a second optical element 45.

[0026] The first beam splitter 41 emits the first linearly polarized light CW1 into the first optical path 43 and the second linearly polarized light CCW1 into the second optical path 44. The first beam splitter 41 also receives the third linearly polarized light CW2 from the second optical path 44 and the fourth linearly polarized light CCW2 from the first optical path 43. The third linearly polarized light CW2 and the fourth linearly polarized light CCW2 are mutually orthogonal polarization components of the second linearly polarized light emitted to the first optical element 30.

[0027] The second beam splitter 42 receives the first linearly polarized light CW1 from the first optical path 43 and the second linearly polarized light CCW1 from the second optical path 44. The second beam splitter 42 also emits the third linearly polarized light CW2 to the second optical path 44 and the fourth linearly polarized light CCW2 to the first optical path 43.

[0028] The first beam splitter 41 and the second beam splitter 42 separate the incident light into a P-polarized component and an S-polarized component, and then combine the P-polarized component and the S-polarized component and emit them. The first beam splitter 41 and the second beam splitter 42 are, for example, prism-type beam splitters, but may also be planar beam splitters or wedge-type beam splitters.

[0029] The first optical path 43 leads the first linearly polarized light CW1 introduced from the first beam splitter 41 to the second beam splitter 42, and also leads the fourth linearly polarized light CCW2 introduced from the second beam splitter 42 to the first beam splitter 41. The second optical path 44 leads the second linearly polarized light CCW1 introduced from the first beam splitter 41 to the second beam splitter 42, and also leads the third linearly polarized light CW2 introduced from the second beam splitter 42 to the first beam splitter 41.

[0030] The first optical path 43 is a PANDA fiber with one end optically connected to the first beam splitter 41 and the other end optically connected to the second beam splitter 42. The second optical path 44 is a PANDA fiber with one end optically connected to the first beam splitter 41 and the other end optically connected to the second beam splitter 42. The first optical path 43 and the second optical path 44 may be polarization-maintaining fibers such as bowtie fibers and elliptical jacket fibers. A second optical element 45 is arranged in the second optical path 44.

[0031] The second optical element 45 includes a first (1 / 4) wave plate 46, a second (1 / 4) wave plate 47, and a 45-degree Faraday rotator 48.

[0032] The first (1 / 4) wave plate 46 is a 1 / 4 wave plate whose optical axis is tilted at 45 degrees with respect to the slow axis and fast axis of the PANDA fiber that forms the second optical path 44. The first (1 / 4) wave plate 46 converts linearly polarized light into circularly polarized light and also converts circularly polarized light into linearly polarized light.

[0033] The second (1 / 4) wave plate 47 is a 1 / 4 wave plate positioned with its optical axis tilted at -45 degrees with respect to the slow axis and fast axis of the PANDA fiber that forms the second optical path 44. The second (1 / 4) wave plate 47 converts circularly polarized light from the 45-degree Faraday rotator 48 into linearly polarized light, and also converts linearly polarized light into circularly polarized light.

[0034] The 45-degree Faraday rotator 48 is a Faraday rotator that changes the rotation angle of circularly polarized light incident from the first (1 / 4) wave plate 46 and the second (1 / 4) wave plate 47, respectively.

[0035] The 45-degree Faraday rotor 48 changes the rotation angle of the circularly polarized light incident on the first (1 / 4) wave plate 46 such that the rotation angle of the second linearly polarized light CCW1 emitted from the second (1 / 4) wave plate 47 is shifted by 45 degrees from the rotation angle of the second linearly polarized light CCW1, which is the linearly polarized light incident on the first (1 / 4) wave plate 46. The 45-degree Faraday rotor 48 also changes the rotation angle of the circularly polarized light such that the rotation angle of the third linearly polarized light CW2 emitted from the first (1 / 4) wave plate 46 is shifted by -45 degrees from the rotation angle of the third linearly polarized light CW2 incident on the second (1 / 4) wave plate 47.

[0036] The current sensor head 50 is positioned at the tip of the optical fiber 15 and is optically connected to the second beam splitter 42 via the optical fiber 15. The current sensor head 50 is a current sensor head that detects magnetic fields generated by currents flowing through wiring patterns and flat conductors such as busbars formed on a circuit board. The current sensor head 50 receives linearly polarized light emitted from the light-emitting unit 10 as incident light, and also emits reflected light whose plane of polarization has been rotated according to the applied magnetic field when the incident light is incident via the optical fiber 15.

[0037] The detection signal generation unit 60 includes a third beam splitter 61, a first photodetector 62, a second photodetector 63, and a signal processing circuit 65, and receives the second linearly polarized light split by the circulator 20. The detection signal generation unit 60 separates the second linearly polarized light into an S-polarized component and a P-polarized component, receives the S-polarized component and the P-polarized component, converts them into electrical signals, and performs differential amplification to output a detection signal Ed corresponding to the magnetic field applied to the current sensor head 50. The third beam splitter 61 is a polarizing beam splitter (PBS) such as a prism type, planar type, wedge substrate type, or optical waveguide type, and separates the second linearly polarized light split by the circulator 20 into an S-polarized component 66 and a P-polarized component 67.

[0038] Each of the first light-receiving element 62 and the second light-receiving element 63 is, for example, a PIN photodiode. The first light-receiving element 62 receives the S-polarization component 66, and the second light-receiving element 63 receives the P-polarization component 67. Each of the first light-receiving element 62 and the second light-receiving element 63 photoelectrically converts the received light and outputs an electric signal corresponding to the amount of the received light. The signal processing circuit 65 outputs a detection signal Ed corresponding to the magnetic field applied to the current sensor head 50 by differentially amplifying the electric signal indicating the S-polarization component and the electric signal indicating the P-polarization component.

[0039] (Configuration and Function of Current Sensor Head According to Embodiment) FIG. 2(a) is a perspective view of the current sensor head 50, FIG. 2(b) is a perspective view of the current sensor head 50, and FIG. 2(c) is a cross-sectional view taken along the line A-A shown in FIG. 2(b).

[0040] The current sensor head 50 includes a head fiber 51, a magnetic sensor element 52, a first power supply pad 53, a second power supply pad 54, a connection portion 55, and a sealing member 56. The current sensor head 50 detects a magnetic field H generated by a current I supplied through the first power supply pad 53 and the second power supply pad 54.

[0041] The head fiber 51 is a PANDA fiber similar to the optical fiber 15 and is fusion-connected to the optical fiber 15. The head fiber 51 is a light guide member that guides incident light incident from the optical fiber 15 to the magnetic sensor element 52 and guides return light emitted from the magnetic sensor element 52 to the optical fiber 15.

[0042] The magnetic sensor element 52 includes a quarter-wave plate, a Faraday rotator, and a mirror element, and at least a part thereof is disposed in a magnetic field H generated by a current I supplied to the connection portion 55. The quarter-wave plate is disposed such that its optical axis is inclined at 45 degrees with respect to the slow axis and the fast axis of the head fiber 51, which is a PANDA fiber. The quarter-wave plate converts incident light incident from the head fiber 51 as linearly polarized light into circularly polarized light and outputs it to the Faraday rotator, and converts return light incident from the Faraday rotator as circularly polarized light into linearly polarized light and outputs it to the head fiber 51.

[0043] The Faraday rotor is a granular film having a dielectric and magnetic nanoparticles of nano order dispersed in the dielectric in a state of being stably phase-separated from the dielectric, and is disposed on the end face of a quarter-wave plate. Note that the Faraday rotor may be a magnetic thin film other than the granular film. For example, the Faraday rotor may be a rare-earth iron garnet thin film formed of a single crystal having a garnet-type crystal structure represented by a composition formula of R Ｘ Y ３－Ｘ Fe ５ O １２ where R is a rare metal (Rare Earth Metal) and an element that can be substituted with Y.

[0044] The mirror element is formed on the Faraday rotor and reflects the light transmitted through the Faraday rotor toward the Faraday rotor. As the mirror element, for example, a silver (Ag) film, a gold (Au) film, an aluminum (Al) film, a dielectric multilayer mirror, or the like can be used.

[0045] FIG. 3 is a perspective view of the first power supply pad 53, the second power supply pad 54, and the connection portion 55.

[0046] The first power supply pad 53, the second power supply pad 54, and the connection portion 55 are formed of a material that is a non-magnetic and conductive member such as copper (Cu) and aluminum, and are integrally formed. The first power supply pad 53, the second power supply pad 54, and the connection portion 55 are conductors through which a current I flows between the first power supply pad 53 and the second power supply pad 54. The first power supply pad 53 and the second power supply pad 54, which are a pair of power supply pads, have a rectangular planar shape and form a pair of end faces of the current sensor head 50.

[0047] The connection portion 55 has a first current path 57, a second current path 58, and a detection target portion 59. The first current path 57 and the second current path 58 have a frustum-of-a-square-pyramid shape, the lower base is in contact with the first power supply pad 53 and the second power supply pad 54, and the detection target portion 59 is disposed on the upper base. The first current path 57 and the second current path 58, which function as a pair of current paths, electrically connect each of the first power supply pad 53 and the second power supply pad 54, which are a pair of power supply pads, and the detection target portion 59.

[0048] The detected portion 59 has a cylindrical shape, with one end face connected to the upper bottom of the first current path 57 and the other end face connected to the upper bottom of the second current path 58. A magnetic sensor element 52 is positioned in the center of the side surface of the detected portion 59.

[0049] The detected portion 59 is undesirable to be long because its parasitic inductance increases with length. However, if the detected portion 59 is short, the magnetic sensor element 52 may be affected by the magnetic field generated by the current I flowing through the first current path 57 and the second current path 58 located at both ends, which could cause noise. The detected portion 59 is designed to have a length that minimizes the influence of the magnetic field generated by the current flowing through the first current path 57 and the second current path 58.

[0050] The sealing member 56, also called a mold resin, is made of a synthetic resin that is a non-magnetic material such as epoxy resin. The sealing member 56 is placed between the first power supply pad 53 and the second power supply pad 54 and seals the magnetic sensor element 52, the first current path 57, the second current path 58, and the detected part 59.

[0051] As the first power supply pad 53 and the second power supply pad 54 are electrically connected to wiring patterns and the like arranged on the printed circuit board, a current I flows between the first power supply pad 53 and the second power supply pad 54. The current I flowing between the first power supply pad 53 and the second power supply pad 54 is supplied to the detected unit 59 via the first current path 57 and the second current path 58. As the current I is supplied to the detected unit 59, a magnetic field H is generated around the detected unit 59. The detected unit 59 has a cylindrical shape, and the current I is supplied so that it flows through a circular cross-section, so the magnetic field H generated around the detected unit 59 is generated in a circular shape around the detected unit 59 according to Ampère's law. As a result of the magnetic field H being generated around the detected unit 59, the polarization planes of the incident and reflected light, which are circularly polarized light that passes through the Faraday rotor of the magnetic sensor element 52, rotate in accordance with the strength of the magnetic field H applied to the Faraday rotor. Since the magnetic field H applied to the Faraday rotor is proportional to the current I flowing through the detection unit 59, the current sensor device 1 can detect the current I flowing through the detection unit 59 from the detection signal Ed corresponding to the magnetic field H applied to the Faraday rotor.

[0052] (Effects of the current sensor head according to the embodiment) The magnetic sensor element 52 emits reflected light whose polarization plane of the incident light is rotated according to the magnetic field H generated by the current I flowing through the detection unit 59. Therefore, the current sensor head 50 can detect the current I flowing through the conductor without supplying power to the magnetic sensor element 52. Since the current sensor head 50 can detect the current I flowing through the conductor without supplying power to the magnetic sensor element 52, there is no risk that the accuracy of detecting the magnetic field and current will decrease due to the power supplied to the magnetic sensor element 52.

[0053] Since the positional relationship between the first power supply pad 53, the second power supply pad 54, and the connection part 55, which are conductors through which the current I flows, and the magnetic sensor element 52 is fixed, the current sensor head 50 can uniquely determine the relationship between the current I and the magnetic field H applied to the magnetic sensor element 52. Because the current sensor head 50 can uniquely determine the relationship between the current I and the magnetic field H, the calculation process for calculating the current I from the detection signal Ed is simplified, and design changes such as designing the yoke shape according to the shape of the object to be measured are unnecessary, thereby reducing the cost of detecting the current I.

[0054] Furthermore, since the current sensor head 50 has a pair of power supply pads, a first power supply pad 53 and a second power supply pad 54, it is possible to detect the current flowing through a chip component having similar power supply pads before placing the chip component and to determine the electrical characteristics of the chip component.

[0055] Furthermore, since the current sensor head 50 detects a circular magnetic field H generated by the current I flowing through the detected part 59 which has a cylindrical cross-section, it is possible to further simplify the calculation process of determining the current I from the detection signal Ed.

[0056] Furthermore, since the current sensor head 50 has its detection unit 59 connected at both ends to the upper bases of the first current path 57 and the second current path 58, which have a truncated square pyramidal shape, the influence of the magnetic field generated by the current I flowing through the first current path 57 and the second current path 58 can be minimized.

[0057] Furthermore, in the current sensor head 50, the magnetic sensor element 52 is fixed by a sealing member 56 that seals the magnetic sensor element 52, so the sealing member 56 can have two functions as a sealing member and a fixing member.

[0058] (Modified current sensor head according to the embodiment) In the current sensor head 50, the detected part 59 is designed to have a length that minimizes the influence of the magnetic field generated by the current flowing through the first current path 57 and the second current path 58, thereby suppressing the influence of the magnetic field generated by the current flowing through the first current path 57 and the second current path 58. However, in the current sensor head 50 according to the embodiment, the influence of the magnetic field generated by the current flowing through the first current path 57 and the second current path 58 may be suppressed by arranging a magnetic shielding member between the first current path 57 and the second current path 58 and the magnetic sensor element 52.

[0059] Figure 4 is a perspective view of the current sensor head according to the first modified example. The current sensor head 50a functions as a current sensor head of the current sensor device 1, similar to the current sensor head 50.

[0060] The current sensor head 50a differs from the current sensor head 50 in that it has a pair of magnetic shielding members, a first magnetic shielding member 57a and a second magnetic shielding member 58a, which are positioned between the first current path 57 and the second current path 58 and the magnetic sensor element 52. The configuration and function of the components of the current sensor head 50a other than the first magnetic shielding member 57a and the second magnetic shielding member 58a are the same as those of the components of the current sensor head 50 which are given the same reference numerals, so a detailed explanation is omitted here.

[0061] The first magnetic shielding member 57a and the second magnetic shielding member 58a are flat plate-shaped members made of a magnetic material such as ferrite, and are a pair of magnetic shielding members arranged between the first current path 57 and the second current path 58 and the magnetic sensor element 52.

[0062] The current sensor head 50a can suppress the influence on the magnetic sensor element 52 by blocking the magnetic field generated by the current flowing through the first current path 57 and the second current path 58, by arranging the first magnetic shield member 57a and the second magnetic shield member 58a.

[0063] Furthermore, by arranging the first magnetic shielding member 57a and the second magnetic shielding member 58a in the current sensor head 50a, the length of the detected portion 59 can be made the shortest possible length for which the magnetic sensor element 52 can be placed. By making the length of the detected portion 59 of the current sensor head 50a the shortest possible length for which the magnetic sensor element 52 can be placed, parasitic inductance is minimized, and noise can be further suppressed.

[0064] Furthermore, although the current sensor head 50 has a shape similar to a chip component having a pair of power supply pads, the current sensor head according to this embodiment may have a shape other than that similar to a chip component.

[0065] Figure 5 is a perspective view of the current sensor head according to the second modified example. The current sensor head 70 functions as a current sensor head of the current sensor device 1, similar to the current sensor head 50.

[0066] The current sensor head 70 includes a head fiber 71, a magnetic sensor element 72, a base 73, and an adhesive member 74, and detects the magnetic field generated by the current supplied via the base 73.

[0067] The head fiber 71, like the head fiber 51, is a PANDA fiber and is fusion-spliced ​​to the optical fiber 15 of the current sensor device 1. The head fiber 71 guides the incident light entering from the optical fiber 15 to the magnetic sensor element 72 and also guides the reflected light emitted from the magnetic sensor element 72 back to the optical fiber 15.

[0068] The magnetic sensor element 72, like the magnetic sensor element 52, has a quarter-wave plate, a Faraday rotor, and a mirror element, and at least a portion of it is positioned within the magnetic field generated by the current supplied to the base 73.

[0069] The base 73 is a conductor formed from a non-magnetic and conductive material such as copper and aluminum, and has a base portion 75, a first leg portion 76, and a second leg portion 77. The base portion 75 has a rectangular planar shape and is the detection portion on which the magnetic sensor element 72 is placed on its upper surface. The base portion 75 is positioned in close proximity to the magnetic sensor element 72, as the magnetic sensor element 72 is placed on its upper surface. The base portion 75 may also have a cylindrical shape. The base 73 may also be replaced with a metal plate jumper.

[0070] The first leg portion 76 and the second leg portion 77 have a trapezoidal columnar shape. The first leg portion 76 is positioned at one end of the base portion 75, and the second leg portion 77 is positioned at the other end of the base portion 75, extending from the lower surface opposite the upper surface of the base 73 on which the magnetic sensor element 72 is positioned, in the direction opposite to the upper surface. The bottom surfaces of the first leg portion 76 and the second leg portion 77 are supplied with current from the conductor to be measured, similar to the first power supply pad 53 and the second power supply pad 54.

[0071] The adhesive member 74 is an adhesive made of a synthetic resin that is a non-magnetic material, such as acrylic resin, and is used to bond the magnetic sensor element 72 to the upper surface of the base 75.

[0072] In the current sensor device 1, linearly polarized incident light is incident on the current sensor head 50 and linearly polarized reflected light is emitted. However, the current sensor head 50 may also be configured to incident circularly polarized light and emit circularly polarized reflected light.

[0073] Those skilled in the art will understand that various changes, substitutions, and modifications can be made without departing the scope of the present invention. For example, the embodiments and modifications described above may be combined as appropriate within the scope of the present invention.

Claims

A conductor and A magnetic sensor element that emits reflected light whose polarization plane is rotated according to the magnetic field generated by the current flowing through the conductor, A fixing member for fixing the positional relationship between the conductor and the magnetic sensor element, A light guide member that guides the incident light to the magnetic sensor element and guides the reflected light from the magnetic sensor element, A current sensor head characterized by having the following features. 　 The aforementioned conductor is A pair of power supply pads to which the aforementioned current is supplied, A connecting part that connects the pair of power supply pads, A current sensor head according to claim 1, having the following features. 　 The aforementioned connection part is A detection unit having a circular cross-section and positioned in close proximity to the magnetic sensor element, A pair of current paths connecting the pair of power supply pads and the detected unit, A current sensor head according to claim 2, having the following features. 　 Each of the pair of power supply pads has a rectangular planar shape, The current sensor head according to claim 3, wherein each of the pair of current paths has a truncated square pyramidal shape. 　 The current sensor head according to claim 3, further comprising a pair of magnetic shielding members disposed between the detected portion and each of the pair of current paths to block a magnetic field. 　 The current sensor head according to any one of claims 2 to 5, wherein the fixing member is a sealing material that is filled between the pair of power supply pads and seals the magnetic sensor element. 　 The aforementioned conductor is A detection unit is positioned in close proximity to the magnetic sensor element, The current sensor head according to claim 1, further comprising a pair of legs extending from each end of the detected portion in a direction opposite to the magnetic sensor element. 　 A light-emitting part that emits incident light, A current sensor head that emits reflected light corresponding to the magnetic field generated by the flow of current when incident light is incident upon it, A detection signal generation unit receives the reflected light and outputs a detection signal corresponding to the magnetic field, The optical path section includes an optical path section into which the incident light is incident from the light-emitting section and the incident light is emitted to the current sensor head, and into which the reflected light is incident from the current sensor head and the reflected light is emitted to the detection signal generation section. The current sensor head is A conductor and A magnetic sensor element that emits reflected light whose polarization plane is rotated according to the magnetic field generated by the current flowing through the conductor, A fixing member for fixing the positional relationship between the conductor and the magnetic sensor element, A light guide member that guides the incident light to the magnetic sensor element and guides the reflected light from the magnetic sensor element, A current sensor device characterized by having the following features.

Images