JP2975263B2 - Magnetic detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic detecting device such as a magnetoresistive element (hereinafter referred to as "MR element") or a Hall element mounted on an encoder or the like.

[0002]

2. Description of the Related Art Conventionally, an MR element has been used as a magnetic detection device for detecting a fine NS alternating magnetic field from a rotor magnet such as an encoder. Conventional MR elements
Because of its low sensing performance and weak magnetic signal,
In order to obtain a sufficient magnetic signal, it is necessary to set the position to a position where a sufficient magnetic signal can be obtained, adjust the position, and then fix the substrate to a substrate or the like. To adjust this position, M
Since it is necessary to electrically connect the R element to the circuit board and check the signal while performing the adjustment, the position of the MR element is generally adjusted via a lead wire. And lead wires were attached to the substrate using a holder.

[0003] Such a conventional example is disclosed in Japanese Utility Model Application Laid-Open No. 62-20.
As described in Japanese Patent Publication No. 313, a method of attaching a sensor chip to a sensor holder in which a lead frame is insert-molded and soldering a terminal of the sensor chip to a lead frame has been generally performed. As another example, as described in JP-A-61-279183, a sensor chip is mounted on a sensor holder in which a lead frame is insert-molded, and a terminal of the sensor chip and a lead frame are wire-bonded. ,
As described in JP-A-1-203922, a signal input / output member is connected to a movable holder, and the movable holder is held by a fixed holder so as to be movable in a direction perpendicular to the magneto-sensitive surface. was there.

[0004] However, in the above-mentioned conventional example, a holder, a lead wire, and the like are required, so that not only the number of components is increased, but also the process becomes complicated and the cost is increased.

[0005]

As a solution to the problem of the above conventional example, as described in Japanese Patent Application Laid-Open No. 4-118797, a magnetic sensing portion is formed on the surface of an insulating substrate. By forming a connecting part connected to the front and back surfaces of the insulating substrate, forming a conductive part that conducts with the magnetic detecting part at the connecting part, and directly connecting this conductive part to the circuit board, a lead wire or a lead frame is formed. There is a magnetic detection device that does not require wires or the like. Further, as another example, as described in Japanese Patent Application Laid-Open No. 2-111085, a resistor pattern is formed on one surface of an insulating substrate, and the resistor pattern is extended to a side surface of a printed wiring board. These technologies have become possible because the detection capability of the MR element itself has been improved today, so that position adjustment after mounting the MR element is not required.

However, Japanese Patent Application Laid-Open No. HEI 4-11897 describes
The invention described in Japanese Patent Application Publication No. 9 can exhibit excellent effects when it is surface-mounted on a circuit board. It was difficult to make the devices circumferentially opposed, and it was difficult to extract the output. On the other hand, according to the invention described in Japanese Patent Application Laid-Open No. H2-111085, an output can be obtained from a magnet rotor or the like on which high-density recording is performed as described above, but an electrode is partially formed on an end surface of an insulating substrate. It is necessary, and there is a problem that the method of construction is complicated and difficult. Even if electrodes are formed on the end face of the board, it is difficult not only to make the board stand upright from the circuit board due to the electrodes on the end face of the board floating or bulging from the board, but also to make the printed board from the board surface. There is a problem that the electrode extended to the side end surface is liable to cause pattern breakage at the edge of the substrate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is possible to directly mount an insulating substrate on a circuit board and to stand the insulating substrate vertically from the circuit board. Provided is a magnetic detection device that is capable of standing an insulating substrate accurately on a circuit board by the accuracy of an end face itself without a problem that an electrode is cut off at an edge of the insulating substrate. The purpose is to:

[0008]

In order to achieve the above object, the present invention provides an insulating substrate, a magnetic sensing portion formed on the surface of the insulating substrate, and a surface of the substrate formed on the insulating substrate. And a through hole connected to the back surface of the insulating substrate, and a magnetic sensor having an electrode portion provided on the back surface of the insulating substrate and electrically conductively connected to the magnetic detection portion through the through hole. In a magnetic detection device in which electric current is supplied from the circuit board to the detection unit, the magnetic sensor is fixedly held by directly contacting an end surface of the insulating substrate with a surface of the circuit board.

[0009]

The through hole formed in the insulating substrate electrically connects the electrode portion formed on the back surface of the insulating substrate to the magnetic detection portion formed on the front surface. The electrode portion formed on the back surface and the electrode portion formed on the front surface form a conductive connection between a predetermined circuit on the circuit board and the magnetic detection portion. The magnetic detection unit detects an NS alternating magnetic field from the object to be detected, and can obtain a predetermined signal based on the output. Since the end surface of the insulating substrate is fixed in direct contact with the surface of the circuit board, the accuracy of the end surface itself of the insulating substrate can provide the vertical accuracy of the magnetic detection device. It is possible to accurately dispose and oppose a detection target such as a magnet rotor.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a magnetic detection apparatus according to the present invention. In FIG. 1 to FIG. 4, reference numeral 1 denotes an insulating substrate made of glazed alumina (alumina surface coated with glass and smoothed) or glass ceramic. As shown in FIG. 1A, a magnetic detection unit 2 made of a magnetoelectric conversion film is formed on the surface of the insulating substrate 1 in accordance with the pitch of one magnetic pole of the detection target. The detection unit 2 has a linear folded pattern extending in the up-down direction in FIG. 1A, and has a sharp pattern formed on a flat surface without irregularities.

In addition, a routing electrode 6 is formed in the center of the insulating substrate 1 in the left-right direction in FIG. The lead-out electrode 6 is formed at the center of the insulating substrate 1 from the upper end to the lower end of the substrate 1, and the upper end and the lower end of the lead-out electrode 6 are each formed with a connection portion elongated in the horizontal direction. 6a,
6b is provided. The connection portions 6a and 6b are formed at positions symmetrical with respect to the center point of the routing electrode 6.
The connection portions 6a and 6b are connected to one end of the detection portion 2, respectively.

At the lower end of the surface of the insulating substrate 1, an electrode portion 4 is formed at a position symmetrical with respect to a vertical line passing through the center of the substrate 1. The electrode section 4 is formed such that the lower end is located at the lower end of the insulating substrate 1. Note that the lower end of the electrode portion 4 does not need to extend to the lower end of the insulating substrate 1, and there may be a slight space between the lower end of the insulating substrate 1. One of the electrode portions 4
(The right electrode part 4 in FIG. 1A) is directly conductively connected to the detection part 2. Also, the other electrode part 4
The left electrode portion 4 in FIG. 1A is connected to the connection portion 6 b of the routing electrode 6.

On the other hand, at the upper end of the surface of the insulating substrate 1,
A through hole 3 is formed at a position symmetrical with respect to a vertical line passing through the center of the substrate 1. The through hole 3 is a through hole connecting the front surface and the back surface of the insulating substrate 1, and the through hole 3 is filled with a conductor 10 made of silver paste, copper paste, or the like. FIG.
In the embodiment shown in (a), the conductor 10 in the left through hole 3 is conductively connected to one end of the detection unit 2, and the conductor 10 in the right through hole 3 is connected to the leading electrode. 6 are connected to the connection portion 6a.

FIG. 1B is a diagram showing the back surface of the insulating substrate. In FIG. 1B, an electrode portion 5 is formed on the back surface of the insulating substrate 1 at a position corresponding to the formation position of the electrode portion 4 on the front surface side. The electrode portion 5 is formed symmetrically with respect to a vertical line passing through the center of the insulating substrate 1. The electrode portion 5 has a band shape from the upper end portion to the lower end portion of the back surface of the insulating substrate 1. The upper end of the electrode portion 5 is connected to a conductor 10 in the through hole 3, and the detection portion 2 formed on the surface of the substrate 1 via the conductor 10 and the electrode portion on the back surface. 5 are electrically connected.

Then, as shown in FIG. 2A, a protective film 9 for protecting the detecting portion 2 and the like is provided on the surface of the insulating substrate 1.
Are formed except for the lower end portion of the electrode portion 4.
Similarly, as shown in FIG. 2B, a protective film 9 is also formed on the back surface of the insulating substrate 1 except for the lower end of the electrode portion 5, thereby forming a magnetic sensor 13.

FIG. 4 is a diagram showing an example of a mounting state of the magnetic detection device. In FIG. 4, the lower end of the magnetic sensor 13, that is, the lower end of the insulating substrate 1 is in direct contact with the circuit board 12. When the insulating substrate 1 is mounted on the circuit board 12,
The insulating substrate 1 is precisely finished so as to be perpendicular to the circuit board 12. Then, the electrodes 4 and 5 of the magnetic sensor 13 are soldered on the circuit board 12 with the solder 11 so that the magnetic sensor 13 is mounted on the circuit board 1.
2 is fixedly held. In this case, when the solder 11 comes into contact with the surfaces of the electrode portions 4 and 5 where the protective film 9 is not formed, an electrical connection between a predetermined circuit formed on the circuit board 12 and the magnetic sensor 13 is made. A connection has been made. In the state shown in FIG. 4, the detection unit 2 faces a magnetized surface of a detection target such as a rotor magnet (not shown), detects NS alternating magnetic flux from the detection target, and generates a magnetic signal corresponding to the above-described signal. The signal is output to a predetermined circuit on the circuit board 12 via the routing electrode 6, the electrode unit 4, and the electrode unit 5. Further, all the electrode portions electrically connected to the circuit board 12 may not be formed on the back surface, and a part of the electrode portion on the front surface may be electrically connected to the circuit board.

According to the magnetic detecting device configured as described above, the end face of the insulating substrate 1 is directly fixed and held on the surface of the circuit board 12 so that the vertical accuracy of the end face of the insulating substrate 1 can be improved. , The insulating substrate 1 can be made to stand vertically from the circuit board 12 with high accuracy. The electrode portions 4 and 5 may be formed on the front surface or the back surface of the insulating substrate 1, respectively, and it is not necessary to form the electrode portions 4 and 5 by bypassing to the lower end surface side of the insulating substrate 1. There is no problem that the electrode portions 4 and 5 are cut at the edge of the substrate 1. Further, since it is not necessary to detour the electrode portions 4 and 5 to the end faces, the manufacture is easy, and a circumferentially opposed magnetic detection device can be obtained at low cost.

As described above, since the front surface side electrode portion 4 and the rear surface side electrode portion 5 are arranged at overlapping positions, the size of the magnetic detection device itself can be reduced. Manufacturing costs can be reduced. In addition, since the terminals adjacent on each surface are separated by the protective film 9, more stable operation can be performed.

In the above embodiment, the circuit board 1
The end surface of the insulating substrate 1, which is the contact surface with the substrate 2, can be made vertical by simply cutting the insulating substrate 1 by dicing or the like, and easily maintain the perpendicularity and stability of the magnetic sensor. be able to. Further, if a small space is formed between the lower end of the electrode section 4 and the lower end of the insulating substrate 1, it is effective as a measure against migration at the end face. Here, migration refers to an electrochemical action that causes a short circuit between terminals due to migration of ions.

Next, another embodiment according to the present invention shown in FIGS. 5 and 6 will be described. 1 to 3 described above.
The same components as those of the embodiment shown in FIG. The embodiment shown in FIGS. 5 and 6 is an embodiment in which the positions of the electrode portion 24 on the front surface side and the electrode portion 25 on the rear surface side do not overlap with each other and are staggered in the horizontal direction.
The other points are the same as in the above embodiment.

By adopting the configuration shown in FIGS. 5 and 6, as in the embodiment shown in FIGS.
Since the end surface of the insulating substrate 1 is fixed in direct contact with the end surface of the insulating substrate 1 on the surface of the circuit substrate 12, the vertical accuracy of the end surface of the insulating substrate 1 is improved, so that the insulating substrate 1 is
Can be made to stand vertically with high accuracy. The electrode portions 24 and 25 may be formed on the front surface or the back surface of the insulating substrate 1, respectively, and it is not necessary to detour the electrode portions 24 and 25 to the lower end surface side of the insulating substrate 1. There is no problem that the electrode portions 24 and 25 are cut off at the edge portions, and the insulating substrate 1 can be accurately placed on the circuit board 12 by the accuracy of the end surface itself. Further, since it is not necessary to detour the electrode portions 24 and 25 to the end faces, the manufacture is easy, and the circumferentially opposed magnetic detection device can be obtained at low cost.

In each of the above embodiments, in order to fix the magnetic sensor on the circuit board, a high-viscosity, low-flow solder having crosslinkability may be used.
No. 60667, solder consisting of eutectic cream solder and high-temperature cream solder, solder consisting of eutectic cream solder, high-temperature cream solder and metal powder, or eutectic cream solder containing metal powder And so on. Further, when the magnetic sensor is set up on the circuit board, it may be supported by a holder, so that the vertical accuracy and stability of the magnetic sensor can be further improved.

In each of the above embodiments, the power supply terminal having the largest potential difference and the GND terminal may be arranged in a diagonal direction and separated from each other, which is effective as a measure against migration. In each of the above embodiments, silver or the like can be used for the electrode portion of the magnetic sensor, but copper is better used as a measure against migration.

[0024]

According to the present invention, the end face of the insulating substrate is directly held in contact with the surface of the circuit board, and is fixed and held. It is possible to stand upright from the circuit board with high precision. Further, the electrode portion may be formed on the front surface or the back surface of the insulating substrate, and it is not necessary to detour the electrode portion to the end surface of the insulating substrate. In addition, the insulating substrate can be accurately placed on the circuit board by the accuracy of the end face itself. Further, since the electrode portion does not need to be detoured to the end surface of the insulating substrate, manufacturing is easy, and a circumferentially opposed magnetic detection device can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a magnetic detection device according to the present invention, wherein (a) is a front view and (b) is a rear view.

FIGS. 2A and 2B are views showing a state in which a protective film is formed on the magnetic detection device in the embodiment, wherein FIG. 2A is a front view and FIG.

FIG. 3 is a sectional view of an upper end portion of the magnetic detection device in the embodiment.

FIG. 4 is a side view showing an attached state of the magnetic detection device according to the embodiment.

5A and 5B show another embodiment of the magnetic detection device according to the present invention, wherein FIG. 5A is a front view and FIG. 5B is a rear view.

FIGS. 6A and 6B show a state in which a protective film is formed on the magnetic detection device in the embodiment, wherein FIG. 6A is a front view and FIG. 6B is a rear view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Magnetic detection part 3 Through hole 4 Electrode part 5 Electrode part 12 Circuit board 13 Magnetic sensor 24 Electrode part 25 Electrode part

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-111085 (JP, A) JP-A-4-118979 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) H01L 43/08 G01R 33/07 G01R 33/09

Claims (1)

(57) [Claims] An insulating substrate, a magnetic sensing portion formed on a surface of the insulating substrate, a through hole formed on the insulating substrate and connected to a front surface and a back surface of the substrate; A magnetic sensor having an electrode portion provided on the back surface and having an electrode portion conductively connected to the magnetic detection portion through the through hole is fixedly held on a circuit board, and a current is supplied from the circuit board to the detection portion. The magnetic sensor according to claim 1, wherein the end surface of the insulating substrate is in direct contact with and fixed to the surface of the circuit board.