JP2009042152A - Magnetic detection probe and method of manufacturing the magnetic detection probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic detection probe in which a part providing a magnetic detection element is compact, and to provide a method of manufacturing the magnetic detection probe. <P>SOLUTION: The magnetic detection probe includes surface-mounting of the magnetic detection element 3 on a substrate 2; in addition, enhancing rigidity by jointing a reinforcing part 5 to the substrate 2; and preventing falling-off, or the like, of the magnetic detection element 3 by forming an element protection part 4 on the circumference of the magnetic detection element 3. By using such a constitution, the width and the thickness of an edge side, providing the magnetic detection element 3, can be made more compact than those of the conventional types. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic detection probe used in a magnetic measurement device that detects and measures magnetism, and a method of manufacturing the magnetic detection probe.

For measurement of magnetism, for example, a magnetic detection probe including a magnetic detection element such as a Hall element is used (for example, Patent Document 1). In actual measurement, this magnetic detection probe is connected to a magnetic measurement device, and a magnetic detection element such as a Hall element arranged near the tip of the magnetic detection probe is placed close to a magnet or the like as a measurement object. Do. Therefore, if the tip of the magnetic detection probe is further reduced in size, magnetic measurement can be performed in a narrower position. Further, when performing measurement on the inner peripheral side of the curved surface, if the tip of the magnetic detection probe is further miniaturized, measurement can be performed closer to the measurement object, and measurement accuracy can be improved. For this reason, miniaturization of the magnetic detection probe is required.
JP 2006-2558592 A

  However, with the structure of the Hall probe (magnetic detection probe) described in Patent Document 1, it is difficult to further reduce the size. For example, in the hole probe described in Patent Document 1, in the configuration in which a hole is formed in the substrate and the Hall element is disposed therein, the width of the substrate is set to ensure the strength of the substrate in the portion where the hole is opened. Could not narrow. Moreover, since all the Hall probes described in Patent Document 1 perform the electrical connection between the substrate and the Hall element by wire bonding, this connection portion is thick.

  An object of the present invention is to provide a magnetic detection probe having a small magnetic detection element and a method for manufacturing the magnetic detection probe.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 is a magnetic detection probe (1) comprising a substrate (2) and a magnetic detection element (3) surface-mounted on the substrate.
According to a second aspect of the present invention, in the magnetic detection probe according to the first aspect of the present invention, the magnetic detection probe includes an element protection portion (4) formed to cover at least a part of the magnetic detection element (3). Magnetic detection probe (1).
A third aspect of the present invention is the magnetic detection probe according to the first or second aspect, wherein the magnetic detection element (3) of the substrate (2) is a surface (2a) on the surface-mounted side. The magnetic detection probe (1) further comprises a reinforcing portion (5) that is bonded to a portion where the magnetic detection element is not surface-mounted and reinforces the strength of the substrate.
According to a fourth aspect of the present invention, in the magnetic detection probe according to the third aspect, the total thickness of the portion where the reinforcing portion (5) is provided is the total thickness of the portion where the magnetic detection element (3) is provided. A magnetic detection probe (1) characterized by being substantially equal to the thickness.

According to a fifth aspect of the present invention, the step of surface mounting the magnetic detection element (3) on the substrate (2) and the element protection part (4) are formed so as to cover at least a part of the magnetic detection element mounted on the surface. A magnetic detection probe (1).
The invention of claim 6 is the method of manufacturing a magnetic detection probe according to claim 5, wherein the surface of the substrate (2) on which the magnetic detection element (3) is surface-mounted (2a), And the part where the magnetic detection element is not surface-mounted, or the surface (2a) on the side to be surface-mounted and the part where the magnetic detection element is not surface-mounted, It has a step which joins the reinforcement part (5) which reinforces the intensity | strength of a board | substrate, It is a manufacturing method of a magnetic detection probe provided with.

According to the present invention, the following effects can be obtained.
(1) Since the magnetic detection probe includes a magnetic detection element mounted on the surface of a substrate, a wire for wire bonding and a land for wire connection on the substrate are not required, and the magnetic detection element is provided. The thickness and width can be reduced.
Further, when wire bonding is used, the wire protrudes toward the detection surface side of the magnetic detection element. Therefore, the protrusion size of the wire is such that the detection surface of the magnetic detection element approaches the object to be measured. could not. However, in the present invention, since no wire is used, the detection surface of the magnetic detection element can be arranged closer to the surface of the magnetic detection probe. Therefore, at the time of measurement, the detection surface of the magnetic detection element can be brought close to the object to be measured.

(2) Since the element protection portion is formed so as to cover at least a part of the magnetic detection element, it is possible to prevent the magnetic detection element from falling off and to provide a highly reliable magnetic detection probe.

(3) Since there is a reinforcing portion that is bonded to a portion of the substrate on which the magnetic detection element is surface-mounted and is not surface-mounted and reinforces the strength of the substrate, the reinforcing portion Thus, the overall rigidity can be ensured. Therefore, a thin substrate can be used for the surface mounting portion of the magnetic detection element. For example, a flexible printed wiring board can be used, and a small magnetic detection probe can be obtained.
(4) Since the total thickness of the portion provided with the reinforcing portion is substantially equal to the total thickness of the portion provided with the magnetic detection element, the total thickness of the portion provided with the reinforcing portion is not increased. The entire thickness of the detection probe can be reduced.

(5) According to a method of manufacturing a magnetic detection probe comprising the steps of surface mounting a magnetic detection element on a substrate and forming an element protection portion so as to cover at least a part of the surface mounted magnetic detection element. In addition, a wire for wire bonding and a land for wire connection on the substrate are not required, and the magnetic detection element can be prevented from falling off, and a small and highly reliable magnetic detection probe can be manufactured.

(6) The surface of the substrate on which the magnetic detection element is surface-mounted, and the portion on which the magnetic detection element is not surface-mounted, or the surface to be surface-mounted, and According to the method of manufacturing a magnetic detection probe having the step of joining a reinforcing portion that reinforces the strength of the substrate to a portion on which the magnetic detection element is not to be surface-mounted, a magnetic device that secures overall rigidity by the reinforcing portion. A detection probe can be manufactured. Therefore, a thin substrate can be used for the portion where the magnetic detection element is surface-mounted, and a small magnetic detection probe can be manufactured.

  The purpose of providing a magnetic detection probe having a small magnetic detection element and a method for manufacturing the magnetic detection probe is to make the structure complicated by improving the connection form of the magnetic detection element and the substrate. Realized without.

(Embodiment)
FIG. 1 is a diagram showing an embodiment of a magnetic detection probe.
FIG. 2 is an enlarged view showing the vicinity of the tip of the magnetic detection probe. FIG. 2A is a view seen from the detection surface side, and FIG. 2B is a cross-sectional view taken along arrows A1-A2 shown in FIG. Hereinafter, the upper side of FIG. 2B is referred to as the detection surface side, and the lower side of FIG. 2B is referred to as the back surface side.
In addition, each figure shown below including FIG. 1 is the figure typically shown, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.
In the following description, specific numerical values, shapes, materials, and the like are shown and described, but these can be changed as appropriate.
The magnetic detection probe 1 according to the present embodiment includes a substrate 2, a magnetic detection element 3, an element protection unit 4, a reinforcement unit 5, a solder unit 6, a lead wire 7, and a covering unit 8.

The substrate 2 is a flexible printed wiring board having a rectangular shape when viewed from the detection surface side, a wiring pattern is formed on the surface 2a on the detection surface side, a coverlay is not formed, and a part of the wiring pattern is exposed. Portions 2c and 2d are formed (see FIG. 3). The substrate 2 includes a land portion 2c (see FIG. 3A) on the front end side (side on which the magnetic detection element 3 is provided) of the substrate 2 and a land portion 2d on the other end side (hereinafter, rear end side). Is formed. In the present embodiment, no wiring pattern is formed on the back surface 2b.
The substrate 2 of the present embodiment has a thickness t1 = 0.1 mm and a width B = 0.6 mm.

  The magnetic detection element 3 is a magnetoelectric conversion element that converts a magnetic quantity into an electric quantity. In this embodiment, a gallium arsenide type Hall element is used. The shape of the magnetic detection element 3 when viewed from the detection surface side is a substantially square with a width C = 0.3 mm on one side, and the thickness t2 = 0.1 mm. The magnetic detection element 3 is surface-mounted on the surface 2 a near the tip of the substrate 2. A solder portion 6 is formed between the substrate 2 and the magnetic detection element 3, and a land portion 2c (see FIG. 3A) of the substrate 2 and an electrode (not shown) of the magnetic detection element 3 are connected. ing. The thickness of the solder part 6 is t3 = 0.1 mm. Therefore, the thickness of the entire portion where the magnetic detection element 3 is mounted is approximately 0.3 mm.

  The element protection unit 4 is a resin portion formed so as to cover the periphery of the magnetic detection element 3. Here, covering refers to a state in which the element protection unit 4 is formed so as to be in contact with any part of the appearance of the magnetic detection element 3, and does not indicate a form in which the whole is covered. In the present embodiment, the element protection unit 4 is provided so as not to cover the surface on the detection surface side of the magnetic detection element 3, and the surface on the detection surface side of the element protection unit 4 is the detection surface of the magnetic detection element 3. It is substantially flush with the side surface. The element protection unit 4 is formed by applying and curing an epoxy resin or the like, for example. By providing the element protection unit 4, the magnetic detection element 3 mounted on the surface of the substrate 2 is prevented from falling off the substrate 2, and the reliability of the magnetic detection probe 1 is improved.

  The reinforcing portion 5 is joined to a portion of the substrate 2 on the surface 2a that is the surface on which the magnetic detection element 3 is mounted, and where the magnetic detection element 3 and the element protection portion 4 are not formed. The reinforcing portion 5 is provided so as not to cover the land portion 2 d formed on the rear end side of the substrate 2. In the present embodiment, the reinforcing portion 5 is formed by joining nonmagnetic plate members having a width of 0.6 mm and a thickness of 0.15 mm using a double-sided tape (not shown) having a thickness of 0.05 mm. Therefore, the thickness of the portion provided with the reinforcing portion 5 is substantially equal to the thickness of the portion provided with the magnetic detection element 3. By providing the reinforcing portion 5, the rigidity of the magnetic detection probe 1 becomes higher than that of the substrate 2 alone, and the position of the magnetic detection element 3 does not become unstable during measurement, and stable measurement can be performed.

One end of the lead wire 7 is soldered to a land portion 2d formed on the rear end side of the substrate 2, and the other end is connected to a connector (not shown). In the present embodiment, four lead wires 7 are provided.
The coating portion 8 is a coating formed by thermally shrinking a heat-shrinkable tube. In this embodiment, a tube made of an electron beam cross-linked soft polyolefin resin is used. The covering portion 8 covers from the position near the rear end of the substrate 2 to the position where the lead wire 7 is connected to a connector (not shown) from the position covering the reinforcing portion 5.

Next, the manufacturing method of the magnetic detection probe 1 of this embodiment is demonstrated.
FIG. 3 is a diagram showing a method for manufacturing a magnetic detection probe. FIG. 3 shows an enlarged view of the distal end side of the magnetic detection probe.
First, the substrate 2 is manufactured (FIG. 3A). Four land portions 2 c are formed on the front end side of the surface 2 a of the substrate 2. The land portion 2 c is provided at a position corresponding to an electrode (not shown) of the magnetic detection element 3. A wiring portion 2e covered with a cover lay is formed from the four land portions 2c toward the rear end side, and is connected to the four land portions 2d at the rear end.

Next, the magnetic detection element 3 is surface-mounted on the surface 2a of the substrate 2 by soldering (in this embodiment, reflow soldering). Hereinafter, this process will be described.
When the substrate 2 is prepared, a solder paste (which will later become the solder portion 6) is printed and applied to the land portion 2c (FIG. 3B).
The magnetic detection element 3 is placed on the surface 2a of the substrate 2 with the solder paste interposed therebetween so that the solder paste printed on the land portion 2c and the electrode (not shown) of the magnetic detection element 3 correspond to each other. Thereafter, the substrate 2 is heated until the melting temperature of the solder paste is reached, the solder paste is melted, and the land portion 2c and an electrode (not shown) of the magnetic detection element 3 are soldered (FIG. 3C).

After the magnetic sensing element 3 is mounted on the surface 2a of the substrate 2, the reinforcing portion 5 is bonded onto the surface 2a of the substrate 2 (FIG. 3D). The reinforcing portion 5 is joined to the surface 2a of the substrate 2 by a double-sided tape, but an adhesive may be used.
After joining the reinforcing portion 5 to the substrate 2, an epoxy resin is applied around the magnetic detection element 3 and cured to form the element protection portion 4 (FIG. 3E).
Thereafter, the lead wire 7 is soldered to the land portion 2d, and the lead wire is connected to a connector (not shown). Further, the heat-shrinkable tube is covered over a necessary range and heated to form the covering portion 8 (see FIG. 1), thereby completing the manufacture of the magnetic detection probe 1.

The magnetic detection probe 1 according to the present embodiment achieves miniaturization of the tip by the above-described configuration and manufacturing method. In order to explain this effect, a comparative experiment was conducted.
As described above, the magnetic detection probe 1 of the present embodiment has a width of 0.6 mm and a thickness of 0.3 mm. For comparison, a conventional magnetic detection probe in which a magnetic detection element and a substrate are connected by wire bonding was prepared. The magnetic detection probe of this comparative example has a width of 1.5 mm and a thickness of 1.2 mm.
Using the magnetic detection probe 1 of this embodiment and the magnetic detection probe of the comparative example, the magnetic flux density was measured on the inner periphery of the annular magnet. The magnet to be measured is an 8-pole magnetized magnet having an inner diameter of 10 mm. Each magnetic detection probe is connected to a magnet analyzer MAD-300 (manufactured by DMT Co., Ltd.), and the detection surface at the tip of each magnetic detection probe is placed close to just before contacting the inner diameter of the magnet. The measurement was performed while rotating.

FIG. 4 is a graph showing the results of comparative experiments.
The measurement result L1 indicated by the solid line indicates the measurement result when the magnetic detection probe 1 of the present embodiment is used, and the measurement result L2 indicated by the broken line indicates the measurement result when the magnetic detection probe of the comparative example is used. Show.
In contrast to the case of the comparative example, in the case of the present embodiment, a higher magnetic flux density value is obtained, and the waveform change is finer. This is an effect obtained for the following two reasons.
(Reason 1)
Since the magnetic detection probe 1 of this embodiment is narrower than that of the comparative example, it can be closer to the inner wall of the magnet and can detect magnetic changes with higher accuracy.
(Reason 2)
In the magnetic detection probe 1 of the present embodiment, since the magnetic detection element 3 is surface-mounted, the detection surface of the magnetic detection element 3 is more magnetic than the comparative example in which the magnetic detection element is mounted by wire bonding. It is located near the surface of 1. Therefore, the detection surface of the magnetic detection element 3 can be closer to the inner wall of the magnet, and a magnetic change can be detected with higher accuracy.

Further, since the magnetic detection probe 1 of the present embodiment is thinner than that of the comparative example, it can be inserted into a thinner part or a thinner space in which a closed magnetic circuit is formed.
FIG. 5 is a diagram showing a usage example of the magnetic detection probe of the present embodiment.
In the example shown in FIG. 5, the magnetic detection probe 1 is inserted between the core 100 in which the closed magnetic circuit is formed and the magnet 200 and is measuring the magnetic flux of the narrow closed magnetic circuit.
As described above, by using the magnetic detection probe 1 of the present embodiment, the following measurement can be performed easily and accurately.
(1) Magnetic flux measurement in a narrow gap that could not be measured until now.
(2) Closed magnetic path magnetic flux measurement in very narrow gaps such as between magnet cores.
(3) Inner magnetic flux measurement of small-diameter magnets where measurement gaps are easy to create

According to this embodiment, since the magnetic detection element 3 is surface-mounted on the substrate 2, there is no portion protruding in the thickness direction of the wiring portion of wire bonding. Therefore, the thickness of the magnetic detection probe 1 of the present embodiment can be reduced as compared with the case of connecting by wire bonding.
Further, since no wire is used, the detection surface of the magnetic detection element can be arranged closer to the surface of the magnetic detection probe, and the detection surface of the magnetic detection element can be brought closer to the object to be measured during measurement.
Further, since the magnetic detection element 3 is surface-mounted on the substrate 2, it is not necessary to provide a wire bonding land around the magnetic detection element 3 on the substrate 2. Therefore, the width | variety of the board | substrate 2 can be narrowed and the width | variety of the magnetic detection probe 1 can be narrowed compared with the case where it connects by wire bonding as a result.

(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the scope of the present invention.
(1) In this embodiment, the example in which the element protection unit 4 is provided around the magnetic detection element 3 has been described. However, the present invention is not limited to this, and the tip of the magnetic detection probe is further provided without providing the element protection unit. The width may be narrowed.

(2) In this embodiment, although the example which provided the reinforcement part 5 was shown, not only this but the reinforcement part 5 does not need to be provided.
(3) In the present embodiment, as an example of the method of manufacturing the magnetic detection probe 1, the surface mounting of the magnetic detection element 3 is performed, and then the joining of the reinforcing portion 5 and the formation of the element protection portion 4 are performed in this order. However, the present invention is not limited to this. For example, the reinforcing portion 5 may be joined after the element protection portion 4 is formed.

(4) In the present embodiment, the magnetic detection element 3 is an example of a Hall element. However, the present invention is not limited to this. ) Other elements that sense magnetism such as elements may be used.

(5) In the present embodiment, the magnetic detection element 3 is provided with the element protection unit 4 around the surface, and the surface of the magnetic detection element 3 is exposed. The surface may be covered with the part 4, or the surface may be covered with a separately prepared protective tape or the like.
In addition, although this embodiment and modification can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited to the present embodiment described above.

It is a figure which shows embodiment of a magnetic detection probe. It is the figure which expanded and showed the front-end | tip vicinity of the magnetic detection probe. It is a figure which shows the manufacturing method of a magnetic detection probe. It is a graph which shows a comparative experiment result. It is the figure which showed the usage example of the magnetic detection probe of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic detection probe 2 Board | substrate 3 Magnetic detection element 4 Element protection part 5 Reinforcement part 6 Solder part 7 Lead wire 8 Covering part

Claims (6)

A substrate,
A magnetic sensing element surface-mounted on the substrate;
Magnetic detection probe comprising: The magnetic detection probe according to claim 1,
Having an element protection part formed so as to cover at least a part of the magnetic detection element;
Magnetic detection probe characterized by. The magnetic detection probe according to claim 1 or 2,
A reinforcing portion that is a surface of the substrate on which the magnetic detection element is surface-mounted and is bonded to a portion on which the magnetic detection element is not surface-mounted to reinforce the strength of the substrate;
Magnetic detection probe characterized by. The magnetic detection probe according to claim 3,
The total thickness of the portion provided with the reinforcing portion is substantially equal to the total thickness of the portion provided with the magnetic detection element;
Magnetic detection probe characterized by. Surface mounting a magnetic sensing element on a substrate;
Forming an element protection portion so as to cover at least part of the surface-mounted magnetic detection element;
A method of manufacturing a magnetic detection probe comprising: In the manufacturing method of the magnetic detection probe according to claim 5,
The surface of the substrate on which the magnetic detection element is surface-mounted, and the portion on which the magnetic detection element is not surface-mounted, or the surface to be surface-mounted, and Bonding a reinforcing portion for reinforcing the strength of the substrate to a portion where the magnetic detection element is not to be surface-mounted,
A method of manufacturing a magnetic detection probe comprising:

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