JP6608255B2 - Magnetic sensor device - Google Patents

Description

  The present invention relates to a magnetic sensor device.

  As a conventional technique, a lid member formed in a disk shape, a tongue protruding from the lid member, a lead frame integrated with the tongue, and a back surface of the exposed surface of the lead frame are arranged to apply a bias magnetic field. A magnet to be generated, and a first sensor chip that is disposed at the tip of the tongue that is ahead of the end of the lead frame and is electrically connected to the lead frame by wire bonding, and detects a change in the bias magnetic field; (For example, refer patent document 1).

  This sensor device uses a cylindrical magnet, and the size of the magnet is reduced compared to a configuration in which a tongue is disposed in the hollow portion of the magnet.

JP 2007-40965 A

  However, in the conventional sensor device, after attaching the magnet to the back surface of the tongue portion, the first sensor chip or the like must be attached to the surface of the tongue portion and wire bonding is performed. There is a problem that the number of processes increases and the manufacturing cost increases.

  Accordingly, an object of the present invention is to provide a magnetic sensor device capable of suppressing the manufacturing cost.

  One embodiment of the present invention includes a plurality of lead frames arranged side by side, a magnetic sensor that is disposed on a surface of at least one lead frame and detects a change in a bias magnetic field, and a surface of at least one lead frame together with the magnetic sensor. And a bias magnet configured to generate a bias magnetic field.

  According to the present invention, the manufacturing cost can be suppressed.

FIG. 1A is a perspective view showing an example of a magnetic sensor device according to the embodiment, and FIG. 1B is a top view showing an example of the magnetic sensor device. FIG. 2A is a schematic diagram illustrating an example of a bias magnetic field of the magnetic sensor device according to the embodiment, and FIG. 2B is an example of magnetization of a bias magnet according to a modified example. c) is a schematic diagram showing an example of the shape of a bias magnet according to another embodiment.

(Summary of embodiment)
A magnetic sensor device according to an embodiment includes a plurality of lead frames arranged side by side, a magnetic sensor that is disposed on a surface of at least one lead frame, detects a change in a bias magnetic field, and at least one lead together with the magnetic sensor. A bias magnet disposed on the surface of the frame and generating a bias magnetic field.

  In this magnetic sensor device, the magnetic sensor and the bias magnet are arranged on the surface of the lead frame. Therefore, compared to the configuration in which the bias magnet is arranged on the back surface side, it is necessary to turn over the lead frame and attach the other after attaching one. Therefore, the number of processes can be reduced and the manufacturing cost can be suppressed.

[Embodiment]
(Outline of the magnetic sensor device 1)
FIG. 1A is a perspective view illustrating an example of a magnetic sensor device according to the embodiment, and FIG. 1B is a top view illustrating an example of the magnetic sensor device. 2A is a schematic diagram illustrating an example of a bias magnetic field of the magnetic sensor device according to the embodiment, and FIG. 2B is an example of magnetization of a bias magnet according to a modification, and FIG. c) is a schematic diagram showing an example of the shape of a bias magnet according to another embodiment. Note that, in each drawing according to the embodiment described below, the ratio between figures may be different from the actual ratio.

  As an example, the magnetic sensor device 1 detects a change in the bias magnetic field due to the approach of the detection target. As an example, the magnetic sensor device 1 is mounted on a vehicle, and is used for detection of mounting of a tongue plate of a seat belt device, detection of an operation amount of a brake pedal, an accelerator pedal, and the like, detection of on / off of various switches, and the like. .

  For example, as shown in FIG. 1A and FIG. 1B, the magnetic sensor device 1 is arranged on the surface of a plurality of lead frames arranged side by side and at least one lead frame. A magnetic sensor 2 for detecting a change and a bias magnet 3 that is arranged on the surface of at least one lead frame together with the magnetic sensor 2 and generates a bias magnetic field 30 are schematically configured.

  As an example, the magnetic sensor device 1 of the present embodiment includes lead frames 11 to 14 as a plurality of lead frames. The magnetic sensor device 1 also has a control IC (Integrated Circuits) 4 that controls the magnetic sensor 2. The magnetic sensor device 1 is sealed with a sealing body 10.

(Configuration of the sealing body 10)
The sealing body 10 is formed so that a part of the magnetic sensor 2, the bias magnet 3, the control IC 4, and the lead frame 11 to the lead frame 14 is sealed with resin. The sealing with the resin is performed using, for example, a thermosetting molding material in which an epoxy resin is a main component and a silica filler is added.

(Configuration of lead frame 11 to lead frame 14)
For example, as shown in FIGS. 1A and 1B, the lead frames 11 to 14 are formed in an elongated plate shape having the same width by punching or the like. The lead frames 11 to 14 are formed using, for example, a conductive metal material such as aluminum or copper, or an alloy material such as brass. Note that the lead frame 11 to the lead frame 14 may be plated on the surface using a metal material such as tin, nickel, gold, or silver.

  In the lead frame 11 to the lead frame 14, end portions exposed from the sealing body 10 are terminals to be connected to the mating connector. As an example, the end portions of the lead frame 11 to the lead frame 14 function as power supply terminals, ground terminals, output terminals, and the like.

  As a modification, for example, the lead frame may not have an elongated shape with the same width, but may have a shape having a mounting portion on which the magnetic sensor 2 and the like are mounted with a width wider than other portions.

(Configuration of magnetic sensor 2)
For example, the magnetic sensor 2 is attached to the surface 120 of the lead frame 12 and the surface 130 of the lead frame 13 via an adhesive or an adhesive sheet.

  The magnetic sensor 2 is a sensor that outputs a detection signal corresponding to a change in the bias magnetic field 30, such as a Hall sensor or an MR sensor (Magneto Resistive Sensor). As an example, the magnetic sensor 2 is electrically connected to the control IC 4 by wires 5 as shown in FIG. The magnetic sensor 2 may be, for example, a bare chip or packaged.

  For example, one of the wires 5 connected to the magnetic sensor 2 is for supplying a voltage, and the other is for outputting a detection signal. As an example, the wire 5 and the wire 6 to be described later are fine metal wires such as gold. For example, the wires 5 and 6 are connected by a wire bonding method using a thermocompression bonding method, an ultrasonic (Ultra Sonic) thermocompression bonding method, or the like.

  As shown in FIG. 2A, the magnetic sensor 2 has a surface 120 of the lead frame 12 and a lead frame so that a bias magnetic field 30 with a component in a direction perpendicular to the surface 20 larger than a component in a parallel direction acts. 13 on the surface 130. The magnetic sensor 2 is disposed in the through hole 35 of the bias magnet 3.

  The magnetic sensitive surface 200 of the magnetic sensor 2 is assumed to be parallel to the surface 20. Therefore, the bias magnetic field 30 forms a magnetic path that penetrates the magnetosensitive surface 200.

  When the magnetic sensor 2 is a Hall sensor, a detection signal is output based on the vertical component of the bias magnetic field 30 on the magnetosensitive surface 200. When the magnetic sensor 2 is an MR sensor, a detection signal is output based on a change in the parallel component of the bias magnetic field 30 on the magnetosensitive surface 200.

(Configuration of bias magnet 3)
For example, the bias magnet 3 is attached to the surface 110 of the lead frame 11 to the surface 140 of the lead frame 14 via an adhesive or an adhesive sheet. The bias magnet 3 is formed of, for example, an insulating ferrite magnet or plastic magnet.

  The bias magnet 3 is, for example, a conductive neodymium magnet or alnico magnet when insulation from the lead frame 11 to the lead frame 14 is maintained by an adhesive, an adhesive sheet, a lead frame coating, or the like. Also good.

  The bias magnet 3 has a donut shape having a through hole 35. The bias magnet 3 may be, for example, a size that allows wire bonding, and is desirably as small as possible.

  The bias magnet 3 of the present embodiment has a cylindrical shape that is a perfect circle when viewed from above, but is not limited thereto, and may be an elliptical cylinder when viewed from above. The magnetization direction of the bias magnet 3 is the S pole on the lower side and the N pole on the upper side in FIG. This magnetization direction may be reversed.

  The bias magnetic field 30 generated by the bias magnet 3 forms a magnetic path that springs from the N pole and is sucked into the S pole, and penetrates the magnetic sensor 2.

  As a modified example, as shown in FIG. 2B, the bias magnet 3 has a magnetization direction in which one side portion has an N pole and the opposite side portion has an S pole, and the surface 20 of the magnetic sensor 2. The bias magnetic field 30 may be configured to act in a substantially parallel direction.

  As another modification, the bias magnet 3 is not limited to a cylindrical shape as long as it has a shape having a through hole 35. As an example, as long as the bias magnet 3 has a shape that generates an appropriate bias magnetic field 30 for the magnetic sensor 2, the bias magnet 3 may have a shape having a through-hole 35 in the center of the prism.

  Further, as an example, the position of the upper surface 31 of the bias magnet 3 is preferably higher than the magnetic sensitive surface 200 of the magnetic sensor 2.

(Configuration of control IC 4)
The control IC 4 includes, for example, a CPU (Central Processing Unit) that performs operations and processing on acquired data according to a stored program, a RAM (Random Access Memory) that is a semiconductor memory, a ROM (Read Only Memory), and the like. Microcomputer. In this ROM, for example, a program for operating the control IC 4 is stored. For example, the RAM is used as a storage area for temporarily storing calculation results and the like.

  For example, the control IC 4 is configured to perform A / D conversion on the detection signal output from the magnetic sensor 2 and output a digital signal of “0” or “1”.

  Further, the control IC 4 is disposed together with the magnetic sensor 2 in the through hole 35 as shown in FIG. As an example, the control IC 4 is disposed on the surface 120 of the lead frame 12 and the surface 130 of the lead frame 13 via an adhesive or a pressure sensitive adhesive sheet.

  The control IC 4 is electrically connected to the magnetic sensor 2 by the wire 5 and is also electrically connected to the lead frame 11 to the lead frame 14 by the wire 6.

  In the magnetic sensor device 1, electronic components other than the magnetic sensor 2 and the control IC 4 may be disposed in the through hole 35 of the bias magnet 3.

  An example of the operation of the magnetic sensor device 1 will be described below. Here, it is assumed that the magnetic sensor device 1 is connected to an electronic device of the vehicle and detects the approach of the detection target. In the magnetic sensor device 1, as an example, it is assumed that the lead frame 11 is a voltage supply terminal and the lead frame 12 is a digital signal output terminal.

  The control IC 4 of the magnetic sensor device 1 is supplied with a voltage via the lead frame 11 and the wire 6 when the vehicle is powered on, and supplies a voltage to the magnetic sensor 2 via the one wire 5 and the other. A detection signal is obtained from the wire 5.

  The control IC 4 determines whether or not the detection target is approaching from the acquired detection signal. When the approach of the detection target is detected, the control IC 4 generates a digital signal indicating “1” and outputs it to an electronic device connected via the wire 6 and the lead frame 12. The magnetic sensor device 1 continues to operate until the vehicle is powered off.

(Effect of embodiment)
The magnetic sensor device 1 according to the present embodiment can reduce the manufacturing cost. Specifically, the magnetic sensor device 1 has a configuration in which the magnetic sensor 2, the bias magnet 3, and the control IC 4 are disposed on the same surface side of the lead frame 11 to the lead frame 14, and therefore the bias magnet 3 is disposed on the back surface side. In comparison, since it is not necessary to turn the lead frame upside down and attach the other after attaching one, the number of steps can be reduced and the manufacturing cost can be reduced.

  In the magnetic sensor device 1, since no bias magnet is arranged on the back surface side, the back surface becomes flat, and it is necessary to form a recess for the bias magnet by processing the stage on which the lead frame 11 to the lead frame 14 are mounted when performing wire bonding. There is no. When the wire bonding is performed by the ultrasonic thermocompression bonding method, the ultrasonic wave propagation property is deteriorated by the concave portion, and there is a possibility that adhesion failure occurs. However, since the magnetic sensor device 1 has no components arranged on the back side of the lead frame 11 to the lead frame 14, it can perform wire bonding to the magnetic sensor 2, the control IC 4 and the like arranged on the same side. Sound propagation is good and adhesion failure hardly occurs.

  As another embodiment, the magnetic sensor device 1 has, for example, a shape in which the bias magnet 3 does not have a through hole, as shown in FIG. In the magnetic sensor device 1, since the magnetic sensor 2, the bias magnet 3, and the control IC 4 are arranged on the lead frame on the same surface side, as described above, the number of processes is reduced, and the manufacturing cost is suppressed. Sound propagation is good and adhesion failure hardly occurs.

  As mentioned above, although some embodiment and modification of this invention were demonstrated, these embodiment and modification are only examples, and do not limit the invention based on a claim. These novel embodiments and modifications can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the scope of the present invention. In addition, not all combinations of features described in these embodiments and modifications are necessarily essential to the means for solving the problems of the invention. Further, these embodiments and modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Magnetic sensor apparatus, 2 ... Magnetic sensor, 3 ... Bias magnet, 4 ... Control IC, 5 ... Wire, 6 ... Wire, 10 ... Sealing body, 11-14 ... Lead frame, 20 ... Surface, 30 ... Bias magnetic field 31 ... upper surface, 35 ... through hole, 110 ... surface, 120 ... surface, 130 ... surface, 140 ... surface, 200 ... magnetic sensitive surface

Claims (3)

A plurality of lead frames arranged side by side;
A magnetic sensor disposed on the surface of at least one lead frame to detect a change in bias magnetic field;
A bias magnet disposed on a surface of at least one lead frame together with the magnetic sensor to generate the bias magnetic field;
Equipped with a,
The bias magnet has a through hole;
The magnetic sensor is disposed in the through hole.
Magnetic sensor device. A plurality of lead frames arranged side by side;
A magnetic sensor disposed on the surface of at least one lead frame to detect a change in bias magnetic field;
A bias magnet disposed on a surface of at least one lead frame together with the magnetic sensor to generate the bias magnetic field;
Equipped with a,
The bias magnet has a donut shape having a through hole,
The magnetic sensor is disposed in the through hole of the bias magnet;
Magnetic sensor device. A control IC for controlling the magnetic sensor;
The control IC is disposed with the magnetic sensor in the through hole of the bias magnet.
The magnetic sensor device according to claim 1 or 2.

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