JPH102945A - Attaching structure of magnetic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the highly reliable attaching structure of a magnetic sensor, wherein the solder connection of the electrode part of the magnetic sensor and the land of a circuit board is performed securely. SOLUTION: This structure is constituted by connecting a magnetic sensor 10 having a magnetism sensing part 12 formed on an insulating chip substrate 11 and an electrode part 13 for solder junction connected to the magnetism sensing part 12 to a land 21 on a circuit board 20 by a solder 30. In this case, the magnetic sensor 10 is mounted so that a bottom surface 15 of the sensor 10 covers an edge part 21a of the land 21 in an overlapped pattern. Furthermore, the magnetic sensor 10 is held with a holder, and the positioning part provided in this holder and the board positioning part provided in the board 20 are engaged. Thus, the magnetic sensor 10 is mounted so that the bottom surface 15 of the magnetic sensor 10 securely covers edge part 21a of the land 21 in the overlapped pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor mounting structure which is disposed near a magnetic recording medium formed on a rotating body such as various motors and detects a rotating position and a rotating speed of the rotating body.

[0002]

2. Description of the Related Art For example, a rotary motor is disposed near a magnetic recording medium attached to a rotating body of a capstan motor used for a video tape recorder, an audio tape recorder, or the like, or other various motors, and the rotating position and rotating speed of the rotating body are determined. Magnetic sensors for detecting speed are known. FIG. 4 shows an example of such a magnetic sensor mounting structure. In FIG. 4, a wiring pattern of an appropriate shape is formed on a circuit board 20, and one end of the wiring pattern is a land 25 with a conductive portion exposed. Most of the area except the land 25 is covered with the insulating layer 22.

[0003] A magnetic sensor 60 such as a magnetoresistive element is mounted on the circuit board 20 by solder 30 so as to be substantially perpendicular to the circuit board 20. The magnetic sensor 60 is provided on the surface of an insulating substrate 61 such as glass.
It is formed by forming a magnetoresistive pattern made of Fe, Ni-Co, or the like. A part of the surface on which the magnetoresistive pattern is formed serves as a magnetic sensing portion 62, and electrode portions 63 and 63 'are formed on both lower surfaces of the magnetic sensor 60 in the figure. The electrodes 63 and 63 'are connected to the circuit board 2
The lands 25 are connected to the lands 25 by solder 30.

[0004] On the other hand, the magnetic sensing portion 62 of the magnetic sensor 60 is provided at an appropriate distance from the magnetic recording medium 40 provided on the rotating body.
And serves to replace a change in magnetic flux due to the rotation of the magnetic recording medium 40 with an electrical signal such as a resistance value change or a voltage change. The electric signal is transmitted to a predetermined processing circuit via the land 25 of the circuit board 20 and the wiring pattern, and the rotator is controlled based on the signal.

[0005]

In FIG. 4, a land 25 on a circuit board 20 is connected to an end face 60a of a magnetic sensor 60.
The magnetic sensing portion 62 of the magnetic sensor 60 is formed longer than the width in the thickness direction of the mounting surface on the circuit board 20.
Side and the rear side 64 thereof. The magnetic sensor 60 shown in FIG. 4 has electrode portions 63, 63 'on both lower surfaces, and each of the electrode portions 63, 63'.
Is joined to the land 25 by the solder 30.
The tension of the left and right solders 30 of the magnetic sensor 60 is almost evenly balanced.

However, as shown in FIGS. 5 and 6, the magnetic sensor 60 having the electrode portion 63 only on one surface side is connected to the circuit board 20.
In the case where the solder 30 is mounted, the solder 30 may be partially biased due to the influence of the tension of the solder 30 depending on the size and the mounting position of the lands 26 and 27. For example, as shown in FIG. 5, the magnetic sensor 60 is soldered to the land 26 formed to be longer than the width in the thickness direction of the magnetic sensor 60 so that the lands 26 are located on both sides of the magnetic sensor 60. Then, a tug-of-war phenomenon of the solder 30 occurs between the magnetic sensing part 62 side and the back surface 64 side with the magnetic sensor 60 interposed therebetween, and the solder 30 gathers on the back surface 64 side of the magnetic sensor 60, and the magnetic sensing part 62 side There is a possibility that a good connection state may not be secured in the electrode portion 63.

Further, as shown in FIG. 6, when the electrode portion 63 of the magnetic sensor 60 is soldered to the land 27 at a slight distance from the land 27, the solder 30 gathers on the land 27 side before the electrode portion 63 due to surface tension. Then, in the same manner as described above,
3 may not be able to secure a good connection.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. Solder connection between an electrode portion of a magnetic sensor and a land on a circuit board is reliably performed, and high reliability is achieved. An object of the present invention is to propose a mounting structure of a magnetic sensor.

[0009]

According to one aspect of the present invention, there is provided a magnetic sensing part formed on an insulating chip substrate and a solder joint connected to the magnetic sensing part. In a mounting structure of a magnetic sensor in which a magnetic sensor having an electrode portion for use is connected to a land formed on a circuit board by soldering, the magnetic sensor has a bottom surface at one end of the land. The electrode portion and the land are placed so as to cover each other and are connected to each other.

According to a second aspect of the present invention, the magnetic sensor is arranged such that the end of the land is located on the back side of the center line between the surface having the magnetic sensing portion and the back surface of the magnetic sensor. It is characterized by being placed on the land.

According to a third aspect of the present invention, the magnetic sensor is held by a holder having a positioning portion, and the positioning portion of the holder is engaged with the substrate positioning portion formed near the land. It is characterized by.

According to the mounting structure of the magnetic sensor having such a configuration, the solder connection between the electrode portion of the magnetic sensor and the land on the circuit board is reliably performed, and the reliability of the product can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic sensor mounting structure according to the present invention will be described below with reference to the drawings. 1A is a cross-sectional view showing a state immediately before the magnetic sensor is mounted on the circuit board, FIG. 1B is a cross-sectional view showing a state after the magnetic sensor is mounted, and FIG. FIG. In FIG. 1, a magnetic sensor 10
A Ni—Fe film or Ni
-A magnetoresistive thin film such as a Co film is formed in a predetermined pattern, a part of which is formed as a magnetic sensing part 12, and a part is an electrode part 13a, 13b, 13c for solder bonding. The three electrode portions 13a, 13b, and 13c are at substantially equal intervals, and reach the lower end of the chip substrate 11. The magnetic sensor 10 in the present embodiment is a magnetoresistive effect element. When this magnetic sensor 10 is used for detecting the rotation of a motor, three electrode portions 13a, 13b, 1
3c, the electrode 13a is used as an input terminal, the electrode 13b is used as an output terminal, and the electrode 13c is used as a ground terminal. A magnetic sensor having two output terminals and four electrode portions may be used.

The circuit board 20 to which the magnetic sensor 10 is attached is made of a resin material such as phenol or epoxy, or a metal substrate formed by coating an insulating material on a metal plate such as iron. A predetermined wiring pattern 22 is formed on the circuit board 20 by an etching method or the like, and an insulating layer 23 is formed on most of the wiring pattern 22, but a conductor is exposed on a portion of the connection land 21. doing.
The lands 21 are connected to the electrode portions 13a and 13 of the magnetic sensor 10.
The numbers corresponding to b and 13c are formed at substantially the same intervals.

As shown in FIG. 1A, a cream solder 30 is applied to the lands 21 of the circuit board 20 in advance. Then, as shown in FIG. 1B, the magnetic sensor 10 is mounted such that the bottom surface 15 covers the end 21 a of the land 21. That is, the magnetic sensor 10 is mounted such that the end 21 a of the land 21 is located between the surface of the magnetic sensor 10 on the magnetic sensing part 12 side and the back surface 14.

In this state, by passing the circuit board 20 through a reflow furnace (not shown), the electrodes 13a, 13b, and 13c of the magnetic sensor 10 and the lands 21 of the circuit board 20 are solder 30 respectively. Joined. The magnetic sensor 10 is mounted substantially perpendicular to the circuit board 20, and a magnetic recording medium 40 provided on a rotating body is arranged with an appropriate gap from the magnetic sensor 10. The magnetic sensor 10 detects a change in the magnetic field with the rotation of the magnetic recording medium 40 and outputs rotation information of the rotating body.

By adopting such a mounting structure of the magnetic sensor 10, the solder 30 gathers on the back surface 14 side of the magnetic sensor 10 or the electrode portion 13a without the tug-of-war phenomenon as seen in the prior art. , 13b, and 13c are prevented from gathering on the land 21 before the land 21, and the electrode portion of the magnetic sensor 10 and the land 21 on the circuit board 20 can be reliably connected.

FIGS. 2A and 2B are views showing an embodiment for more stably mounting the magnetic sensor 10 on the land 21 of the circuit board 20, and FIG.
Is a sectional view, and FIG. 2B is a top view.

2A and 2B, the circuit board 2
A predetermined wiring pattern 22 is formed on the wiring pattern 0, and an insulating layer 23 is formed on most of the wiring pattern 22, but the conductor is exposed in the connection land 21.
At this time, the height (thickness) of the land 21 and the height (thickness) of the insulating layer 23 may be slightly different from each other at the end 21 a of the land 21. In a state where the height of the land 21 is different from the height of the insulating layer 23, the magnetic sensor 10 is positioned so that the end 21a of the land 21 is located closer to the surface having the magnetic sensing part 12 than the center line C.
Is placed alone on the circuit board 20, the contact area between the land 21 and the bottom surface 15 of the magnetic sensor 10 is reduced, and the mounting stability (particularly verticality) of the magnetic sensor 10 to the circuit board 20 may be deteriorated. There is. Magnetic sensor 10
Output greatly changes depending on the size of the gap with the magnetic recording medium 40. If the mounting stability is poor, it is impossible to obtain a high-precision magnetic sensor output.

In this embodiment, the end 21a of the land 21 is located on the back surface 14 side of the center line C between the surface of the magnetic sensor 10 having the magnetic sensing part 12 and the back surface 14 thereof. The magnetic sensor 10 is mounted on the land 21.

According to such an embodiment, even if the magnetic sensor 10 is independently mounted on the circuit board 20, the magnetic sensor 10 is stably arranged on the land 21, and the Verticality is ensured, and a highly accurate output can be obtained. Also, as in the previous embodiment,
Solder does not collect on the back side 14 of the magnetic sensor 10 or on the front side of the electrode part 13, and the electrode part 13 and the land 21
And can be connected.

Next, another embodiment according to the present invention will be described with reference to FIG.
Description will be made with reference to (a) and (b). FIG. 3A is an exploded perspective view before assembling, and FIG. 3B is a cross-sectional view after assembling. In the above-described embodiment, an example in which the magnetic sensor 10 is directly attached to the circuit board 20 alone has been described. However, in this embodiment, the magnetic sensor 10 is attached to the circuit board 20 while being held by the holder 50.

More specifically, the holder 50 has a substantially concave sensor housing portion 51 extending from the upper end to the lower end in the center of the front side, and holding portions 53, 53 are formed on both sides of the sensor housing portion 51. . The magnetic sensor 10 is provided in the sensor housing 5
1 and is held by holding portions 53, 53. Further, a projecting positioning portion 5 is provided on the bottom surface of the holder 50.
2 and 52 are provided, and the positioning portions 52 and 52 are provided.
Is engaged with the board positioning portions 24, 24, which are holes or grooves on the circuit board 20, whereby the holder 50 is assembled to the circuit board 20 and the magnetic sensor 10 is attached to a predetermined position. The predetermined position refers to a position where the bottom surface 15 of the magnetic sensor 10 covers one end 21a of the land 21 on the circuit board 20, as in the above-described embodiment. That is, the land 21
The magnetic sensor 10 is mounted such that the end 21a of the magnetic sensor 10 is located between the surface on the magnetic sensing part 12 side of the magnetic sensor 10 and the back surface 14 thereof. Then, the electrode portion 13 of the magnetic sensor 10
a, 13b, 13c and each land 21 are solder 30
Joined.

According to such a configuration, the bottom surface 15 of the magnetic sensor 10 is brought into contact with the land 2 only by engaging the positioning portions 52, 52 of the holder 50 with the substrate positioning portions 24, 24.
It can be mounted very easily at a predetermined position that covers the one end 21a.

The magnetic sensor 10 is held by the holder 50 in a state where the bottom surface 15 is separated from the land 21 without contacting the land 21 of the circuit board 20, and the magnetic sensor 10 is connected to the electrode portions 13a, 13b, 13c. Each land 21 is joined by solder 30. In this way, when attaching the magnetic sensor 10 to the circuit board 20, the solder 3
Even if 0 is pressed by the magnetic sensor 10, the solder 30 does not spread and reach the adjacent lands 21, so that a short circuit between the solders 30 can be eliminated.

As described above, the invention made by the inventor has been specifically described based on each embodiment. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. Needless to say, for example, in the above-described embodiment, the magneto-resistive effect element has been described as an example of the magnetic sensor 10, but the present invention is also applicable to a Hall element chip having a Hall effect element formed on a chip substrate. It is.

Further, in each of the above embodiments, the structure in which the wiring pattern extends from the land 21 formed on the circuit board 20 to the side of the magnetic sensor 10 having the magnetic sensing portion 12 is shown. However, the wiring pattern may be extended to the back surface 14 side of the magnetic sensor 10. That is, for example, in FIG. 2B, the present invention is also applied to a case where the wiring pattern extends from the land 21 to the right side in the drawing. However, in this case, the end 21a of the land 21 corresponds to the boundary between the conductor and the insulating layer.
The magnetic sensor 10 is placed so that the bottom surface 15 of the magnetic sensor 10 covers the upper surface.

Further, the wiring pattern may be alternately extended to the side of the surface of the magnetic sensor 10 having the magnetic sensing part 12 and the side of the back surface 14 thereof. That is, for example, in FIG. 2B, a wiring pattern extends to the left side from the lands 21 connected to the electrode portions 13a and 13c, respectively, and a wiring pattern extends from the lands 21 connected to the electrode portions 13b. The pattern may extend rightward in the figure. Also in this case, one end 2 of each land
The magnetic sensor 10 is mounted on 1a so as to cover the bottom surface 15 of the magnetic sensor 10.

[0029]

As described above, according to the magnetic sensor mounting structure of the present invention, the bottom surface of the magnetic sensor is placed so as to cover the end piece of the land of the circuit board, and the electrode portion of the magnetic sensor is provided. Is connected to the land, preventing the concentration of solder on the back side of the magnetic sensor and the concentration of solder on the land in front of the electrode without the tug-of-war phenomenon as seen in the prior art. Thus, the electrode portion of the magnetic sensor and the land on the circuit board can be reliably connected.

Further, even when the magnetic sensor is independently mounted on the circuit board, the magnetic sensor is stably arranged on the land, and the perpendicularity of the surface having the magnetically sensitive portion is ensured.
A highly accurate output can be obtained.

Further, by engaging the positioning portion of the holder holding the magnetic sensor with the substrate positioning portion,
The magnetic sensor can be easily mounted such that the bottom surface is located at a desired position.

[Brief description of the drawings]

FIG. 1 illustrates one embodiment of the present invention;
(A) is a sectional view showing a state immediately before mounting the magnetic sensor on the circuit board, (b) is a cross-sectional view showing a state after mounting, and (c) is a perspective view of the magnetic sensor alone.

FIG. 2 illustrates one embodiment of the present invention;
(A) is a sectional view, and (b) is a top view.

3A and 3B show another embodiment according to the present invention, wherein FIG. 3A is an exploded perspective view before assembling, and FIG. 3B is a cross-sectional view after assembling.

FIG. 4 is a sectional view showing a conventional magnetic sensor mounting structure.

FIG. 5 is a cross-sectional view showing a mounting structure of the magnetic sensor, in which (a) is a cross-sectional view showing a state immediately before mounting;
(B) is sectional drawing which shows the state after attachment.

FIG. 6 is a cross-sectional view showing a mounting structure of the magnetic sensor, in which (a) is a cross-sectional view showing a state immediately before mounting.
(B) is sectional drawing which shows the state after attachment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetic sensor 11 Chip board 12 Magnetic sensing part 13a, 13b, 13c Electrode part 14 Back surface 15 Bottom 20 Circuit board 21 Land 21a Land end 24 Board positioning part 30 Solder 40 Magnetic recording medium 50 Holder 52 Positioning part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H02K 11/00 C

Claims (3)

[Claims] 1. A magnetic sensor having a magnetic sensing part formed on an insulating chip substrate and an electrode part for solder joint connected to the magnetic sensing part is provided on a land formed on a circuit board. In the mounting structure of the magnetic sensor connected by soldering, the magnetic sensor is mounted such that the bottom surface covers one end of the land, and the electrode portion and the land are connected to each other. A mounting structure for a magnetic sensor. 2. The mounting structure of a magnetic sensor according to claim 1, wherein the end of the land is located on the back side of a center line between the surface having the magnetic sensing portion and the back surface of the magnetic sensor. A magnetic sensor mounting structure, wherein the magnetic sensor is mounted on the land. 3. The mounting structure for a magnetic sensor according to claim 1, wherein the magnetic sensor is held by a holder having a positioning portion, and a substrate positioning portion formed near the positioning portion of the holder and the land. And a mounting structure for the magnetic sensor.