JP2007232616A - Magnetic sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor in which noise of external disturbance is inhibited from intruding into the magnetoresistive element. <P>SOLUTION: The magnetic sensor 1 composed of the magnetoresistive element 25 formed on the rigid substrate 10, the surface of which is covered with the insulation resin layer 40, the conductive adhesion material layer 81, metallic layer 82 and resin protection layer 83, wherein the metallic layer 82 is adhered fixedly with the holder 6 through the conductive adhesion material layer 81, therefore the metal layer 82 is electrically connected with the holder 6 through the conductive adhesion material layer 81, and functions as a conductive layer for radio wave shielding. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic sensor device having a magnetoresistive element in a holder.

When detecting the position of a movable member in a machine tool or the like, for example, a method is adopted in which a magnetic scale is fixed to the movable member side and the position of the magnetic scale is detected by a magnetic sensor device. In a magnetic sensor device used for such an application, a magnetoresistive element is configured by a magnetoresistive pattern formed on a rigid substrate, and the rigid substrate has a magnetoresistive element positioned in an opening formed on the sensor surface of the holder. It arrange | positions in a holder so that it may do (for example, refer patent document 1).
JP 2005-249774 A

  However, the configuration disclosed in Patent Document 1 has a problem in that disturbance noise easily intrudes and detection accuracy is low because there is no electrical shielding with respect to the magnetoresistive element.

  In view of the above problems, an object of the present invention is to provide a magnetic sensor device that prevents disturbance noise from entering a magnetoresistive element.

  In order to solve the above problems, in the present invention, in a magnetic sensor device having a magnetoresistive element and a holder for holding the magnetoresistive element so that the magnetoresistive element is positioned in a sensor surface facing the magnetic scale. The holder has conductivity, and at least a region where the magnetoresistive element is located is covered with a radio wave shielding conductive layer, and the radio wave shield conductive layer is electrically connected to the holder. It is characterized by.

  In the present invention, the region where the magnetoresistive element is located is covered with the radio wave shielding conductive layer, and this radio wave shield conductive layer is electrically connected to the holder having conductivity, so that it will enter the magnetoresistive element. The disturbance noise is emitted to the holder through the radio wave shielding conductive layer. Therefore, according to the present invention, information from the magnetic scale can be detected without being affected by disturbance noise, and thus the detection accuracy is high.

  In the present invention, the radio wave shielding conductive layer is a nonmagnetic metal layer bonded and fixed to the sensor surface with a conductive adhesive layer, and the metal layer is interposed between the holder and the holder through the conductive adhesive layer. It is possible to adopt a configuration that is electrically connected to the. In the present invention, “adhesion” also means “adhesion”.

  In the present invention, the outer surface of the metal layer is preferably covered with a resin protective layer. If comprised in this way, it can prevent that the outer surface of a metal layer contacts with a movable member, and is damaged.

  In the present invention, the magnetoresistive element is composed of a magnetoresistive pattern formed on the main surface of a single rigid substrate, and the rigid substrate is oriented such that the magnetoresistive element faces the magnetic scale side. The configuration held by the holder can be employed.

  In this case, it is preferable that the surface of the magnetoresistive element is covered with an insulating resin layer.

  In the present invention, a first terminal portion and a second terminal portion are formed on the principal surface of the rigid substrate at each of one end and the other end sandwiching the magnetoresistive element therebetween, and the rigidity A first flexible substrate is connected to the one end of the substrate, a second flexible substrate is connected to the other end, and the insulating resin layer is formed of the first flexible substrate. And the second flexible substrate. With this configuration, since both sides of the region where the magnetoresistive element is formed in the rigid substrate have substantially the same configuration, the first flexible substrate and the second flexible substrate are connected to the rigid substrate. It is possible to prevent the magnetoresistive element from being tilted only by determining the posture of the rigid substrate with reference to the position where it is applied.

  In the present invention, the magnetoresistive element may be configured by a magnetoresistive pattern formed on each facing surface of the first rigid substrate and the second rigid substrate arranged to face each other.

  In the magnetic sensor device of the present invention, the magnetoresistive element is covered with a radio wave shield conductive layer, and the radio wave shield conductive layer is electrically connected to a conductive holder. For this reason, disturbance noise that tries to enter the magnetoresistive element is emitted to the holder via the radio wave shielding conductive layer. Therefore, according to the present invention, information from the magnetic scale can be detected without being affected by disturbance noise, and thus the detection accuracy is high.

  A magnetic sensor device to which the present invention is applied will be described with reference to the drawings.

(overall structure)
FIG. 1 is an explanatory diagram of an encoder using a magnetic sensor device to which the present invention is applied. 2A, 2 </ b> B, and 2 </ b> C are a bottom view of the magnetic sensor device shown in FIG. 1, a vertical cross-sectional view of the main part, and a cross-sectional view showing the periphery of the magnetoresistive element in an enlarged manner.

  As shown in FIG. 1, when the magnetic sensor device 1 according to the present embodiment is used for a magnetic linear encoder, it is fixed to a movable member (not shown) with respect to the bottom surface (sensor surface) of the magnetic sensor device 1. The magnetic scales 3 are opposed to each other. On the magnetic scale 3, for example, N poles and S poles are alternately arranged along the longitudinal direction (moving direction). Therefore, if the output signal from the magnetic sensor device 1 when the movable member moves in the longitudinal direction of the magnetic scale 3 together with the magnetic scale 3 is detected, the position and moving speed of the movable member can be detected.

  The magnetic sensor device 1 includes a holder 6 made of a substantially rectangular parallelepiped aluminum die-cast product, a rectangular cover 68 covering the opening of the holder 6, and a cable 7 extending from the holder 6. A cable insertion hole 69 is formed on the side surface of the holder 6, and the cable 7 is drawn from the cable insertion hole 69.

  2A, 2B, and 2C, the holder 6 has a sensor surface 60 that is a flat surface that protrudes from the bottom surface of the holder 6 through a step on the bottom surface facing the magnetic scale 3. Is formed. An opening 65 is formed in the sensor surface 60, and the magnetoresistive element 25 formed on the rigid substrate 10 such as a silicon substrate or a ceramic grace substrate is disposed in the opening 65.

(Configuration of rigid substrate and flexible substrate)
3A, 3B, and 3C are a plan view showing a state in which a flexible substrate is connected to a rigid substrate, a longitudinal sectional view thereof, and a magnetic sensor device to which the present invention is applied, and It is sectional drawing which shows the state which formed the resin protective layer in the rigid board | substrate.

  2B, 3C, 3A, and 3B, the magnetic sensor device 1 according to the present embodiment is formed with a magnetoresistive pattern on the main surface formed of one surface of the rigid substrate 10. A magnetoresistive element 25 is formed. Here, the magnetoresistive element 25 is formed in a substantially central region of the rigid substrate 10 in the scanning direction (longitudinal direction of the magnetic scale 3 shown in FIG. 1). The main surface of the rigid substrate 10 includes a plurality of terminals to which one end of the magnetoresistive pattern is connected at one end 11 of both ends sandwiching the magnetoresistive element 25 from both sides in the scanning direction. A first terminal portion 21 is formed, and a second terminal portion 22 having a plurality of terminals connected to the other end of the magnetoresistive pattern is formed at the other end portion 12. The magnetoresistive pattern is made of a magnetic film such as ferromagnetic NiFe formed on the main surface of the rigid substrate 10 by a semiconductor process, and constitutes a Wheatstone bridge or the like. The terminal is made of a conductive film formed simultaneously with the magnetoresistive pattern.

  The first flexible substrate 31 is connected to the one end portion 11 of the rigid substrate 10 configured as described above, and the first flexible substrate 31 is formed on the base film 36. The end portion of the conductive pattern 37 (signal line) is connected to the first terminal portion 21 by a method such as solder bonding, alloy bonding, or bonding using an anisotropic conductive film. Further, in the rigid substrate 10, a second flexible substrate 32 is connected to the other side end 12, and a conductive pattern 37 (signal) formed on the base film 36 in the second flexible substrate 32. The end of the line is connected to the second terminal portion 22 by a method such as solder bonding, alloy bonding, or bonding using an anisotropic conductive film. Here, of the conductive patterns 37 formed on the base film 36 in the first flexible substrate 31 and the second flexible substrate 32, the first terminal portion 21 and the second terminal portion 22 are joined. The portion to be plated is subjected to Sn—Cu plating or the like.

  In this embodiment, the first flexible substrate 31 and the second flexible substrate 32 are configured by a part of one flexible substrate 30 as shown in FIG. That is, the flexible substrate 30 includes a rectangular portion 33 that is connected to the cable 7 shown in FIG. 1 and a pair of U-shaped extending portions 34 that extend from the lower end edge of the rectangular portion 33 to the left and right sides. , 35, and the first flexible substrate 31 is formed by one of the extended portions 34, 35, and the second flexible portion 31 is formed by the other extended portion 35. A conductive substrate 32 is configured. Therefore, the thickness of the base film 36 and the thickness of the conductive pattern 37 are the same between the first flexible substrate 31 and the second flexible substrate 32. In addition, the flexible substrate 30 is symmetrical, and the first flexible substrate 31 and the second flexible substrate 32 have the same planar shape.

  In the flexible substrate 30, a plurality of small semicircular cutouts 39 are formed at both end edges located in the width direction of the pair of extending portions 34 and 35, and the cutouts 39 are formed. The flexible substrate and the rigid substrate 10 are shown in FIGS. 2A and 2B in a state where the bent portion is folded as a valley fold portion (indicated by a one-dot chain line) and a mountain fold portion (indicated by a two-dot chain line). As described above, the rigid substrate 10 is disposed on the bottom surface of the holder 6 with the main surface of the rigid substrate 10 facing outward (downward).

  In the magnetic sensor device 1 configured as described above, the surface of the magnetoresistive element 25 is covered with the insulating resin layer 40, the conductive adhesive layer 81, the nonmagnetic metal layer 82, and the resin protective layer 83, and the metal The layer 82 is bonded and fixed to the holder 6 via the conductive adhesive layer 81. Accordingly, the metal layer 82 is electrically connected to the holder 6 through the conductive adhesive layer 81, and the metal layer 82 functions as a radio wave shielding conductive layer that covers the surface of the magnetoresistive element 25.

  Here, the resin protective layer 83, the metal layer 82, and the conductive adhesive material layer 81 are laminated on both surfaces of the metal layer 82 made of aluminum foil, copper foil, or the like. The film 80 is bonded and fixed to the holder 6 through the conductive adhesive layer 81. Further, the resin protective layer 83, the metal layer 82, and the conductive adhesive layer 81 are formed on the surface of the resin protective layer 83 made of a film substrate such as PET, the metal layer 82 made of an aluminum film or a copper film, and the conductive layer. A film 80 in which a conductive pressure-sensitive adhesive layer 81 is laminated is bonded and fixed to the holder 6 via a conductive pressure-sensitive adhesive layer 81. The conductive adhesive layer 81 is made by dispersing carbon particles, aluminum particles, silver particles, copper particles, etc. in various adhesive materials. The thickness of the film 80 is about 50 μm and is extremely thin. Therefore, the gap between the magnetoresistive element 25 and the magnetic scale 3 can be reduced to 300 μm or less. The resin protective layer 83 is better from the viewpoint of protecting the metal layer 82, but the resin protective layer 83 may be omitted depending on the type of metal constituting the metal layer 82 and the usage pattern. .

  A method of manufacturing the magnetic sensor device 1 having such a configuration will be described with reference to FIGS. 2 (A), (B), (C) and FIGS. 3 (A), (B), (C). The configuration of the magnetic sensor device 1 will be further described in detail.

  In this embodiment, first, after forming the magnetoresistive element 25, the first terminal portion 21, and the second terminal portion 22 on the main surface of the rigid substrate 10 by a semiconductor process, one end portion of the rigid substrate 10 is formed. 11 is connected to the first flexible substrate 31, and the second flexible substrate 32 is connected to the other end 12 of the rigid substrate 10.

  Next, between the main surface of the rigid substrate 10 and the first flexible substrate 31 and between the main surface of the rigid substrate 10 and the second flexible substrate 32, the flexible substrate 30. Since the gaps 38a and 38b are generated due to the portion where the conductive pattern is not formed and the portion where the terminal is not formed in the rigid substrate 10, the gap 38a and 38b are made of epoxy resin or the like. The sealing resin 41 is filled. When an anisotropic conductive film is used for joining the first flexible substrate 31 and the second flexible substrate 32 to the rigid substrate 10, the resin portion can fill the gap. Therefore, it is not necessary to separately fill the gap with resin.

  Next, after bending the flexible substrate 30 along a valley fold portion indicated by a one-dot chain line and a mountain fold portion indicated by a two-dot chain line in FIG. 3A, the main surface of the rigid substrate 10 is set to the outside (downward). Then, the flexible substrate 30 and the rigid substrate 10 are arranged at the bottom in the holder 6. At that time, in the first flexible substrate 31 and the second flexible substrate 32, the back surface side 361 of the portion of the base film 36 connected to the rigid substrate 10 matches the sensor surface 60 of the holder 6. In addition, the rigid substrate 10, the first flexible substrate 31, and the second flexible substrate 32 are fixed in the holder 6.

  Next, as shown in FIG. 3C, a resin such as an epoxy resin is provided in a region sandwiched between the first flexible substrate 31 and the second flexible substrate 32 on the main surface of the rigid substrate 10. After being filled, the resin is cured and an insulating resin layer 40 covering the magnetoresistive element 25 is formed as shown by a dotted line rising to the right in FIG. At that time, in the opening 65 of the holder 6, the gaps between the first flexible substrate 31 and the second flexible substrate 32 and the opening 65 may be filled with resin. Through the above steps, the fixing of the rigid substrate 10 to the holder 6 is completed in the magnetic sensor device 1.

  Next, as shown in FIG. 2C, a film 80 in which a resin protective layer 83, a metal layer 82, and a conductive adhesive material layer 81 are formed in this order is used, and the conductive adhesive material layer 81 is applied to the sensor surface 60. Aim for it.

  Thus, in this embodiment, the surface of the magnetoresistive element 25 is covered with the insulating resin layer 40, the conductive adhesive material layer 81, the metal layer 82, and the resin protective layer 83, and the metal layer 82 is made of the conductive adhesive material. It is bonded and fixed to the holder 6 through the layer 81. Therefore, the metal layer 82 is electrically connected to the holder 6 through the conductive adhesive layer 81. Through the above steps, in the magnetic sensor device 1, the surface of the magnetoresistive element 25 can be covered with the radio wave shielding conductive layer made of the metal layer 82.

(Main effects of this form)
As described above, in the magnetic sensor device 1 of the present embodiment, at least the region where the magnetoresistive element 25 is located is covered with the nonmagnetic metal layer 82 (radio wave shielding conductive layer) on the sensor surface 60. 82 is electrically connected to the holder 6 having conductivity. For this reason, disturbance noise that tries to enter the magnetoresistive element 25 is emitted to the holder 6 through the metal layer 82. Therefore, since disturbance noise does not reach the magnetoresistive element 25, information from the magnetic scale 3 can be detected without being affected by the disturbance noise, and detection accuracy is high.

  Further, in this embodiment, the first terminal portion 21 and the second terminal portion 22 are formed on each of the one end portion 11 and the other end portion 22 of the rigid substrate 10, and the one end portion of the rigid substrate 10 is formed. 11 is connected to the first flexible substrate 31 and the other end 22 is connected to the second flexible substrate 32. For this reason, since both sides of the magnetoresistive element 25 have substantially the same configuration, the base film 36 of the first flexible substrate 31 and the second flexible substrate 32 that are connected to the rigid substrate 10 is used. The magnetoresistive element 25 can be arranged in parallel to the sensor surface 60 only by determining the posture of the rigid substrate 10 so that the back surface side 361 coincides with the sensor surface 60 of the holder 6. Therefore, when the bottom surface of the holder 6 is arranged opposite to the magnetic scale 3, the magnetoresistive element 25 and the magnetic scale 3 can be arranged in parallel and close to each other, so that the sensitivity can be improved.

  Here, the magnetic sensor device 1 according to this embodiment includes an encoder that detects a position of a magnetic field in a certain direction by detecting a change in strength in a certain direction and a type that detects the direction of a rotating magnetic field with a magnetic field sensitivity that is substantially equal to or higher than saturation sensitivity. It can be applied to any of the encoders. However, an encoder that detects the direction of the rotating magnetic field requires a magnetic field sensitivity that is substantially equal to or higher than the saturation sensitivity. Therefore, it is necessary to increase the detection sensitivity by narrowing the interval between the magnetic scale 3 and the sensor surface 60 of the magnetic sensor device 1. Therefore, the magnetic sensor device 1 of this embodiment is suitable for configuring an encoder of a type that detects the direction of the rotating magnetic field.

  In this embodiment, since the surface of the magnetoresistive element 25 is covered with the insulating resin layer 40 applied between the first flexible substrate 31 and the second flexible substrate 32, the moisture resistance of the magnetoresistive element 25 is reduced. Performance can be improved.

  Further, in this embodiment, the sealing resin is formed in the gap 38 a between the main surface of the rigid substrate 10 and the first flexible substrate 31 and the gap 38 b between the main surface of the rigid substrate 10 and the second flexible substrate 32. Since 41 is filled, the adhesive strength between the rigid substrate 10 and the flexible substrate 30 can be improved, and the terminal portions 21 and 22 formed on the rigid substrate 10 are protected from moisture and the like. Can do.

[Other embodiments]
In the above embodiment, the magnetoresistive element 25 is configured by the magnetoresistive pattern formed on the main surface of the single rigid substrate 10, but as shown in FIGS. You may apply this invention to the magnetic sensor apparatus 1 with which the magnetoresistive element 25 was comprised by the magnetoresistive pattern formed in each opposing surface of the 1st rigid board | substrate 10a and the 2nd rigid board | substrate 10b. Also in this case, the first rigid substrate 10a and the second substrate 10b are held in the aluminum holder 6 in a state where the flexible substrates 31 and 32 are connected. In this state, the magnetoresistive element 25 is located in the opening 65 formed in the sensor surface 60 of the holder 6, and the magnetoresistive element 25 is composed of the insulating resin layer 40, the conductive adhesive material layer 81, and the nonmagnetic material. The metal layer 82 and the resin protective layer 83 are covered. Further, the metal layer 82 is bonded and fixed to the holder 6 via the conductive adhesive layer 81. Accordingly, the metal layer 82 is electrically connected to the holder 6 via the conductive adhesive layer 81, and the metal layer 82 functions as a radio wave shielding conductive layer that covers the surface of the magnetoresistive element 25. Also in this case, the resin protective layer 83, the metal layer 82, and the conductive adhesive material layer 81 are formed by laminating the resin protective layer 83 and the conductive adhesive material layer 81 on both surfaces of the metal layer 82 made of aluminum foil or the like. A film 80 or the like is bonded and fixed to the holder 6 via a conductive adhesive layer 81.

  In addition to the magnetic linear encoder shown in FIG. 1, the magnetic sensor device 1 according to the present embodiment is arranged such that the sensor surface faces a magnetic scale arranged on the outer peripheral surface or end surface of the rotating drum (movable member). It can be used as a magnetic rotary encoder.

It is explanatory drawing of the encoder using the magnetic sensor apparatus to which this invention is applied. (A), (B), (C) is the bottom view of the magnetic sensor apparatus shown in FIG. 1, the longitudinal cross-sectional view of the principal part, and sectional drawing which expands and shows the periphery of a magnetoresistive element. (A), (B), (C) is a plan view showing a state in which a flexible substrate is connected to a rigid substrate, a longitudinal sectional view thereof, and a rigid substrate in the magnetic sensor device to which the present invention is applied. It is sectional drawing which shows the state in which the resin layer was formed. (A), (B) is the longitudinal cross-sectional view of the principal part of another magnetic sensor apparatus to which this invention is applied, and sectional drawing which expands and shows the periphery of a magnetoresistive element.

Explanation of symbols

1 Magnetic Sensor Device 3 Magnetic Scale 6 Holder 10 Rigid Substrate 40 Insulating Resin Layer 41 Sealing Resin 60 Holder Sensor Surface 65 Opening 80 Film 81 Conductive Adhesive Layer (Conductive Adhesive Layer)
82 Metal layer (conductive layer for radio wave shield)
83 Resin protective layer

Claims (7)

In a magnetic sensor device having a magnetoresistive element and a holder for holding the magnetoresistive element so that the magnetoresistive element is positioned on a sensor surface facing the magnetic scale.
The holder has electrical conductivity;
The sensor surface is covered with a radio wave shielding conductive layer at least in a region where the magnetoresistive element is located,
The radio wave shielding conductive layer is electrically connected to the holder. In Claim 1, the radio wave shielding conductive layer is a nonmagnetic metal layer bonded and fixed to the sensor surface by a conductive adhesive layer,
The magnetic sensor device, wherein the metal layer is electrically connected to the holder through the conductive adhesive layer.   3. The magnetic sensor device according to claim 2, wherein an outer surface of the metal layer is covered with a resin protective layer. In any one of Claim 1 thru | or 3, the said magnetoresistive element is comprised by the magnetoresistive pattern formed in the main surface of one rigid board | substrate,
The rigid sensor is held by the holder in a posture in which the magnetoresistive element faces the magnetic scale side.   5. The magnetic sensor device according to claim 4, wherein a surface of the magnetoresistive element is covered with an insulating resin layer. In Claim 5, the main surface of the rigid substrate is formed with a first terminal portion and a second terminal portion on each of one end and the other end sandwiching the magnetoresistive element therebetween,
A first flexible substrate is connected to the one end of the rigid substrate, and a second flexible substrate is connected to the other end.
The magnetic sensor device, wherein the insulating resin layer is formed between the first flexible substrate and the second flexible substrate on the rigid substrate.   4. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is constituted by a magnetoresistive pattern formed on each opposing surface of the first rigid substrate and the second rigid substrate arranged to face each other. Magnetic sensor device.

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