JPS6179174A - Magnetic sensor - Google Patents

Abstract

PURPOSE:To improve yield and to obtain an effective signal by adhering an organic film printed board to a magneto-resistance effect element made of a thin ferromagnetic film with a thin resin material, and reducing the overall thickness. CONSTITUTION:The magnetic sensor 9 is formed by adhering an organic film substrate 6 made of a polyimide film having printed wiring 5 to the magnetism sending part formation surface of a chip 1 of the magneto-resistance effect element made of the thin ferromagnetic film by solder bonding, and applying the resin material 7 over it thinly. Then, when the sensor 9 detects the magnetism of a magnetized scale disk 8, the gap S between the magnetized disk 8 and sensor 8 decreases because the sensor 9 is thin, an effective signal output is obtained, and further assembly is easy, so the yield is improved and the device is reduced in size on the whole.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magnetic sensor that utilizes the magnetoresistive effect of a ferromagnetic material.

<Prior Art> Conventionally, as an element for detecting a magnetic field, an electromagnetic induction type magnetic sensor, in which a conducting wire is wound around a magnetic core having high magnetic permeability such as iron or ferrite, or InSb or InAs has been used.

Magnetic sensors using semiconductors such as QaAs and Si are often used. However, in the electromagnetic induction type magnetic sensor, the signal output is generally obtained from the time change of magnetic flux, that is, d 12'/d t , so the output depends on the speed of magnetic flux change, and Output cannot be obtained when there is no magnetic flux fluctuation. In addition, magnetic sensors using the semiconductor described above basically take advantage of the property that the charge in the semiconductor is affected by an external magnetic field, increasing magnetic resistance, and for practical purposes, a magnetic field greater than IKG is required. Moreover, it has the disadvantage of relatively low resolution due to the shape of the element.

In addition, in recent years, as video tape recorders have become more sophisticated, there has been an increasing demand for still images, frame-by-frame feeding, etc., and conventional magnetic sensors have not been sufficient to perform such tape operations. For this reason, there is an increasing demand for magnetic sensors that utilize the magnetoresistive effect of ferromagnetic thin films.

FIG. 2 shows an external view of a conventional magnetoresistive magnetic sensor. FIG. 2 shows a chip of a 1f''i magnetoresistive element, in which magnetically sensitive parts are formed in two regions by vapor deposition and photoetching. Also, an electrical terminal 3 is taken out from this chip. 4I/' After the i-chip 1 and the electrical terminal 3 are connected by soldering or electric welding, this resin coat is applied to the joint part in order to improve mechanical strength and protect it from the outside. If this is done, ■Resin coating 4 is applied to two areas of the magnetic sensor chip 1.
In addition, the resin wraps around the back surface of the chip 1 (opposite the area 2), reducing the yield. This included defects such as 0, which made it impossible to detect a valid signal.

The present invention has been made to solve the above-mentioned problems of magnetoresistive magnetic sensors, and aims to improve the yield of magnetic sensors and improve the signal detection mode. Embodiment> Hereinafter, an embodiment of the magnetic sensor according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an organic film substrate 6 such as a polyimide film or a polyester film on which a lint wiring 5 of an embodiment of a magnetic sensor according to the present invention is arranged, and is connected by solder bonding or welding, and then a chip 1 and an organic film substrate 6 are connected to each other by solder bonding or welding. 6. Apply a thin layer of resin material 7 onto 6. At this time, the resin material 7 is also sucked between the chip 1 and the film substrate 6 by capillary action, and the adhesion strength between the chip 1 and the film substrate 6 can be increased. Here, the resin material 7 acts as a protective film by covering the entire surface of the chip 1, and acts to strengthen the adhesion between the chip 1 and the film substrate 6.

Next, as can be seen by comparing the structures in FIG. 2 and FIG. 1, by using a film substrate 6 with printed wiring,
In the case shown in FIG. 1, the layer thickness of the resin material 7 can be made thinner.

FIG. 3 shows an example of the use of a magnetic sensor. Reference numeral 8 denotes a magnetized scale disk, and the periphery of the disk 8 is magnetized at a constant wavelength, and the magnetic field generated from this magnetized portion is detected by the magnetic sensor 9 of the present invention.

In such a case, in the conventional magnetic sensor shown in FIG. 2, as the resin layer 4 becomes thicker, the distance S between the magnetizing disk 8 and the magnetic sensor 9 increases, and the magnetic field acting on the magnetic sensor 9 is reduced. However, no signal output can be obtained. However, the first
It is possible to obtain an effective signal output by utilizing the structure of the present invention shown in the figure.

Furthermore, if the magnetic sensor according to the present invention is used, it can be more easily handled by using a flexible printed circuit board, and the overall thickness can be reduced, so it can be stored compactly in a smaller area. This makes it possible to downsize the entire device.

Effects> According to the present invention, since assembly is easy, the yield can be improved, and on the other hand, since the overall thickness of the sensor can be made thinner, the distance between the magnetic field generating part and the magnetic sensor can be made as short as possible, and signals can be detected effectively. can do 0

[Brief explanation of the drawing]

FIG. 1 is an external view of an embodiment of a magnetic sensor according to the present invention;
FIG. 2 shows an external view of a conventional magnetic sensor, and FIG. 3 shows an external view of a rotation detector incorporating a magnetic sensor.

Claims (1)

[Claims] 1. A magnetic sensor characterized in that a magnetoresistive element made of a ferromagnetic thin film and an organic film printed circuit board for extracting the output of the element are bonded with a thin resin material.