JPH08138206A - Production of magnetic head - Google Patents

Abstract

PURPOSE: To produce a magnetic head having improved reproducing characteristics in a high frequency region as a magnetic head having a structure with metallic magnetic films inserted between nonmagnetic substrates. CONSTITUTION: In a magnetic head having a structure with each laminated film 3 consisting of metallic magnetic films 1 and insulating films 2 inserted between nonmagnetic substrates 4, a winding groove part 5, a winding fixing groove 7, etc., are mirror-finished by brush polishing. Burrs, etc., causing a magnetic short circuit to the laminated magnetic films are removed and characteristics of the head especially in a high frequency region are improved.

Description

Detailed Description of the Invention

[0001]

The present invention relates to VTR, DAT, FDD
In particular, the present invention relates to a magnetic head used for the above, and particularly to a method of manufacturing a magnetic head having a main magnetic path formed by laminating a soft magnetic thin film and an insulating film.

[0002]

2. Description of the Related Art In recent years, in a magnetic recording device such as a VTR, the amount of information has increased and there is a strong demand for high density recording. As for media, high coercive force metal media have been commercialized, and in order to cope with this, development of a magnetic head having a sufficient recording / reproducing capability has been vigorously pursued.

Regarding magnetic heads, high saturation magnetic flux density Bs
A wide variety of magnetic heads using Co-based amorphous alloys and Fe-based alloys have been developed, and some of them have already been put to practical use.

Among them, the main magnetic path is constituted by laminating a metal magnetic thin film having a high Bs and an insulating film (reduction of eddy current loss), and a laminated type having a structure in which a nonmagnetic substrate is sandwiched from both sides. The head is excellent in high-frequency characteristics, has no sliding noise, and is suitable for high-density recording.

In the magnetic head, the recording and reading of signals on the tape are performed through the windings. In the combination head as shown in FIG. 6, particularly the tape entry side and the tape output side are largely shaved during the front surface polishing of the head (gap depth adjustment), so that the winding easily comes out to the tape sliding surface. In order to prevent this, a winding fixing groove 7 is formed on the side surface of the head.

The method of manufacturing a magnetic head includes a step of processing by a grinding action with a diamond grindstone such as groove formation and cutting, and a step of performing heat treatment such as glass molding and gap bonding.

[0007]

However, in the above manufacturing method, since the winding groove and the winding fixing groove are formed by grinding, the metal magnetic thin film laminated via the insulating film is processed. A short circuit occurs and a closed magnetic circuit is formed.

That is, when the metal magnetic thin film is ground, burrs (plastic flow) during grinding of the metal magnetic thin film are generated along the grinding streaks, and the burrs come into contact with the adjacent metal magnetic thin film. The adjacent metal magnetic thin films are magnetically connected to each other to form a closed magnetic circuit.

Further, the cause of the formation of the closed magnetic circuit is not limited to the flash generated during grinding, but is also generated by heat treatment of the head, for example. That is, when the heat treatment of the head is performed in a state where the atmosphere is not sufficiently replaced with the inert gas, the heat treatment causes the adjacent metal magnetic thin film to be magnetically short-circuited on the side surface of the head.

In this case, in our experiment, since a magnetic short circuit occurs when the oxygen component in the atmosphere is not sufficiently replaced, a certain kind of oxide formed on the side surface of the head short-circuits the magnetic circuit. It is presumed that

As described above, since the side surfaces of the laminated film are short-circuited by processing or heat treatment, eddy current loss occurs, which is a cause of significant deterioration in head characteristics in the high frequency region.

[0012]

In order to solve the above problems, a method of manufacturing a magnetic head according to the present invention includes a short-circuit magnetic circuit formed in a winding groove, a winding fixing groove, a side surface of a head chip, or the like. It is provided with a step of removing constituent short-circuit substances (for example, the above-mentioned flash and oxide).

[0013]

According to the present invention, by providing the above steps, it is possible to eliminate the short circuit of the metal magnetic thin film and reduce the eddy current loss, so that the magnetic head having excellent high frequency characteristics can be obtained.

[0014]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1A shows a metal magnetic film 1 and a laminated film 3 of an insulating film 2 sandwiched by the metal magnetic film 1.
At least one of the pair of core halves sandwiched by the non-magnetic substrate 4 has the winding groove 5 processed with a diamond grindstone.

The laminated film 3 in the winding groove portion at this time is shown in FIG.
As shown in (b), the metal magnetic film 1 is in a short-circuited state.

That is, as a result of performing the groove processing with the diamond grindstone, a plastic flow (burr) 10 of the metal magnetic thin film is generated along the grinding streaks of the grindstone, and the flash 10 comes into contact with the adjacent metal magnetic thin film, It is a factor that constitutes a short-circuited magnetic circuit.

Therefore, the winding groove portion is made of an abrasive (GC #
4000) and water, the brush wheel is rotated at 2000 rpm for polishing (hereinafter referred to as brush polishing) to polish the laminated film 3 to a mirror surface as shown in FIG. 1 (c). The short circuit is eliminated, and the head characteristics can be improved (a brush containing abrasive grains may be used instead of supplying abrasive grains).

The brush wheel is a cylinder in which resin fibers such as nylon are planted on the outer peripheral surface of the cylinder, and the above-mentioned brush polishing is to polish the side surface of the head with rotating resin fibers.

As described above, in the brush polishing, since a material softer than the material to be polished is rubbed against the material to be polished with the abrasive interposed, the material to be polished is polished. Unlike grinding with a grindstone, burrs generated by grinding with a diamond grindstone can be effectively removed without generating new burrs by brush polishing.

One of the characteristics of brush polishing is that the inner peripheral surface of the groove can be polished. That is, the bottom surface of the groove can be sufficiently polished by using the brush wheel having the resin fiber whose length corresponds to the groove depth.

(Embodiment 2) A second embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2A, a winding groove 5 is formed in at least one of a pair of core halves in which a laminated film 3 of a metal magnetic film 1 and an insulating film 2 is sandwiched by a non-magnetic substrate 4, and a gap material is formed. 6
It is a core block joined by heat treatment through (SiO ₂ , glass film).

The laminated film 3 on the side surface of the core block joined by this heat treatment is in a state where the metal magnetic film 1 is short-circuited as shown in FIG. 2 (b).

When the side surface of the core block is polished by brush polishing, the laminated film 3 is mirror-finished as shown in FIG. 2C, and the short-circuit substance formed on this side surface (probably some kind of oxidation as described above). It is possible to improve the head characteristics by removing the (10) which is considered to be a thing and eliminating the short circuit state of the magnetic circuit.

In this embodiment, as described above, the side surface of the core block is polished to a mirror surface state. However, it is important to remove the short-circuit substance, and it is not always necessary to polish the mirror block surface. Is not mandatory.

However, in the actual manufacturing process, the judgment method for judging that the short-circuit substance is removed in the state of being polished to the mirror surface state is one of the simplest judgment methods as in the present embodiment.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3A, a winding groove 5 is formed in at least one of a pair of core halves in which a laminated film 3 of a metal magnetic film 1 and an insulating film 2 is sandwiched by a non-magnetic substrate 4, and a gap material is formed. 6
It is a core block which is gap-bonded by heat treatment through (SiO ₂ , glass film) and whose winding fixing groove 7 is processed by a diamond grindstone.

The laminated film 3 of the winding fixing groove 7 is shown in FIG.
As shown in (b), the metal magnetic film 1 is in a short-circuited state.

When the winding fixing groove 7 is polished by brush polishing, the laminated film 3 is mirror-finished and short-circuit is eliminated as shown in FIG. 3 (c). After that, the head chip 8 shown in FIG. 4A is obtained by cutting.

FIG. 4 (b) shows a case in which two head chips 8 having such winding fixing grooves 7 are attached to a base, and the entrance side and the exit side of tape running are greatly polished. However, the winding fixing groove 7 prevents the winding from appearing on the sliding surface.

FIG. 5 shows the frequency characteristics of the relative output of the magnetic head according to the present invention. The winding groove, head chip side surface, and winding fixing groove processed by the manufacturing method of the present invention into a mirror surface by brush polishing have higher output in a high frequency region than the conventional manufacturing method (b). There is.

The present invention can be applied to a method other than the above-mentioned manufacturing method. For example, when the laminated film is made into a mirror surface by brush polishing when the head shape is formed by cutting, grinding, etc., the one shown in FIG. The same effect as can be obtained.

A ring-type head using an oxide magnetic substrate instead of the non-magnetic substrate sandwiching the laminated film is disclosed in Japanese Patent Laid-Open No. Sho 5 (1999).
Similar effects can be obtained by performing the brush polishing in the structures such as those disclosed in JP-A-5-64619 and JP-A-2-78007.

Although burrs and oxides were removed by brush polishing in the above embodiment, other methods such as buff polishing, chemical etching, electrolytic polishing, etc.
The material forming the short circuit magnetic circuit can be removed.

[0037]

As described above, according to the present invention, the laminated film of the winding groove portion and the winding fixing groove of the magnetic head core, which has been impossible by the conventional method, can be mirror-finished, and the side surface portion of the head core can be finished by the conventional method. Compared to lapping (abrasive polishing), the need for attachment is eliminated, so the number of steps can be reduced. Therefore, the side surfaces of the laminated film can all be mirror-finished, and eddy current loss in the high-frequency region can be reduced and high. Head output is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of a magnetic head manufacturing method according to the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the magnetic head manufacturing method of the invention.

FIG. 3 is an explanatory diagram of a third embodiment of the magnetic head manufacturing method of the invention.

FIG. 4 is an explanatory diagram of a magnetic head chip obtained in the same example.

FIG. 5 is a frequency characteristic diagram of an output of a magnetic head manufactured by the present invention.

FIG. 6 is an external view showing a configuration of a combination type head.

[Explanation of symbols] 1 metal magnetic film 2 insulating film 3 laminated film 4 non-magnetic substrate 5 winding groove 6 gap material 7 winding fixing groove 8 head chip

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Yoda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A method of manufacturing a magnetic head comprising a laminated film of a metal magnetic thin film and an insulating film laminated in the thickness direction, comprising:
A method of manufacturing a magnetic head, comprising a step of removing a short-circuit substance that magnetically short-circuits the metal magnetic thin film separated by the insulating film. 2. The method of manufacturing a magnetic head according to claim 1, wherein the short-circuit substance is generated in a grinding process or a heat treatment process in the manufacturing process of the magnetic head. 3. The step of removing the short-circuit substance is performed by rubbing a soft material, which is softer than the constituent material of the magnetic head, against the surface of the magnetic head on which the short-circuit substance is formed, with an abrasive interposed therebetween. The method of manufacturing a magnetic head according to claim 1, wherein the substance is removed. 4. The magnetic head according to claim 3, wherein the short-circuit substance is removed by rubbing a soft material on the surface of the magnetic head until the surface of the magnetic head on which the short-circuit substance is formed becomes a mirror surface. Production method. 5. The method of manufacturing a magnetic head according to claim 3, wherein the soft material is a fibrous resin material.