JPH06251309A - Manufacture of magnetic head - Google Patents

Abstract

PURPOSE:To obtain excellent recording/reproducing characteristics by butting a pair of magnetic core halves in which a gap film of SiO2 is formed on magnetic gap forming surfaces, and fusion-bonding glasses each having a predetermined viscosity when they are connected with the glasses. CONSTITUTION:A pair of magnetic core halves 31, 32 formed with gap films 33 made of SiO2 on magnetic gap forming surfaces are butted, and bonded with fusion-bonding glasses 36, 37. In this case, the viscosity of the glass 37 is 5000-10000Pa.S, its back side is glass fusion-bonded, and the viscosity of the glass 36 is 5000-20000Pa.S, and its front side is glass fusion-bonded. Thus, erosion of the glass 36 to the film 33 of the front side is suppressed, and even if the width of a track is set to about 25mum, a magnetic head in which excellent recording/reproducing characteristics are obtained can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic head, and more particularly to an improvement of a glass fusing method for fusing magnetic core halves together.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus such as a video tape recorder, a higher density recording of information signals is desired. In response to this, also in magnetic heads, studies are underway to reduce the track width to about 25 μm for the purpose of improving the track density.

FIG. 9 shows an example of a magnetic head used in a video tape recorder or the like.

In the above magnetic head, the pair of magnetic core halves 31 and 32 made of an oxide magnetic material such as ferrite are
A closed magnetic circuit is formed by abutting through the iO ₂ gap film 33, and a magnetic gap g is formed between the abutting surfaces.
Are formed. The magnetic core halves 31, 32
A winding groove 34 for winding the coil is formed in the middle of the butting surface. The winding groove 34 winds the coil and restricts the depth d _f of the magnetic gap g on the front side which is the sliding surface S of the magnetic recording medium. Further, the magnetic core halves 31 and 32 are notched at both edges of the abutting surfaces, and track width regulating grooves 35 and 36 for regulating the track width T _w of the magnetic gap g are provided at both ends of the magnetic gap g. The groove is formed as a groove having a substantially triangular shape in a plane. The fused glass 3 is provided in the track width regulating grooves 35 and 36 in order to ensure contact with the magnetic recording medium.
7 is filled.

In order to manufacture a magnetic head having such a structure, a track width regulating groove and a direction substantially orthogonal to the track width regulating groove are formed on one main surface of a magnetic core half block made of an oxide magnetic material. A winding groove and a glass fusing groove are formed. Here, the glass fusing groove side is the back side of the magnetic head with the winding groove as a boundary, and the side opposite to the glass fusing groove side is the front side of the magnetic head. Then, after forming a gap film on the magnetic core half body in which each groove is formed, the magnetic core half body block and the magnetic core half body in which each groove and gap film are formed in the same manner are subjected to butt glass melting. It is joined and integrated by wearing it.

Here, glass fusion for joining and unifying the magnetic core half blocks is performed as follows.

That is, a pair of butted magnetic core half blocks are attached to a jig so that a predetermined pressing force is applied in the butting direction. Then, the jig is adjusted so that the front side is the lower side, and the fused glass rods are inserted into the winding groove and the glass fused groove, respectively, and the fused glass is heated until it has a low viscosity. The fused glass having a low viscosity in the winding groove flows into the track width regulating groove on the front side and is filled in the track width regulating groove on the front side. On the other hand, the fused glass having a low viscosity inside the glass fusing groove flows into the track width regulating groove on the back side and is filled in the track width regulating groove on the back side. As a result, the magnetic core half blocks are fused with each other by glass fusion to form a magnetic core block.

In the magnetic head, one end surface on the front side of the magnetic core block thus joined and integrated is cylindrically polished to form a sliding surface of the magnetic recording medium, and further, slicing is performed for each head chip. Is completed.

[0009]

By the way, FIG. 10 shows that when the magnetic core half blocks are joined as described above, the fusing temperature is too high and the viscosity of the fusing glass is low. As described above, while the fused glass flows in the track width regulating grooves 35 and 36, it easily penetrates into the end portions of the gap portion g and erodes the SiO ₂ gap film 33.

Then, in the gap part g, the ferrite forming the magnetic core half block is diffused into the fused glass that corrodes the gap film 33 together with the stress generated inside by the pressurization. When the ferrite component diffuses into the fused glass that corrodes the gap film 33, the gap portion g
In the part where the ferrite component is diffused, magnetic coupling occurs between the magnetic core halves. In the magnetic head in which the magnetic coupling is generated in the gap portion g in this way, the gap portion g
The leakage magnetic flux generated at 1 is reduced and the recording / reproducing characteristics deteriorate.

In particular, when the track width is narrowed to about 25 μm, the stress generated in the magnetic core half in the vicinity of the gap portion g becomes large. Therefore, the diffusion of the ferrite component into the fused glass that corrodes the gap film is promoted, and the magnetic coupling is further increased. When a large magnetic coupling occurs in the gap portion g in addition to the narrow track width, the leakage magnetic flux generated in the gap portion g becomes extremely small, and the deterioration of the recording / reproducing characteristics becomes serious.

On the other hand, if the fusion temperature is low and the viscosity of the fusion glass is high at the time of joining the magnetic core half blocks, the fusion glass with high viscosity has low fluidity,
In particular, the back side track width regulation groove in which the length of the groove is lengthened is not completely filled. As a result, the joint strength becomes insufficient, and the bending strength is, for example, 30 to 35 g · f.
The disadvantage is that only a product with low mechanical strength and frequent chip cracks and the like is obtained with a low yield.

As described above, in the conventional glass fusing methods, the gap film is eroded by the fusing glass to deteriorate the recording / reproducing characteristics, or the fusing glass is sufficiently filled in the track width regulation groove on the back side. Any inconvenience such as lack of filling and insufficient mechanical strength occurs, and particularly deterioration of recording / reproducing characteristics accelerates as the track width becomes narrower. Therefore, it is necessary to manufacture a magnetic head compatible with high-density recording. It is difficult.

Therefore, the present invention has been proposed in view of the above-mentioned conventional circumstances, and it is possible to suppress the erosion of the gap film by the fused glass, obtain good recording and reproducing characteristics, and obtain sufficient mechanical strength. It is an object of the present invention to provide a method of manufacturing a magnetic head that can secure the above.

[0015]

In order to achieve the above object, a method of manufacturing a magnetic head according to the present invention comprises a pair of magnetic core halves having a gap film made of SiO ₂ formed on a magnetic gap forming surface. Butt and join the pair of magnetic core halves to each other with a fused glass, the fused glass has a viscosity of 5000 to 10000 Pa · s, and the back side is glass fused, and the fused glass has a viscosity of 50,000 to 200.
The front side is glass-melted at 000 Pa · s.

The track width of the magnetic gap regulated by the track width regulation groove of the magnetic core half is 25 μm.
It is characterized by the following.

[0017]

According to the present invention, when the pair of magnetic core halves are joined by filling the track width regulating groove with the fused glass, the viscosity of the fused glass is 5000 to 10000 Pa.
・ As s, a fused glass is filled in the track width regulation groove on the back side, and the viscosity of the fused glass is 50,000 to 20,000.
The fused glass is filled in the track width regulation groove on the front side at 0 Pa · a.

A fused glass having a low viscosity of 5000-10000 Pa · s exhibits relatively high fluidity. Therefore, it smoothly flows into the track width regulating groove on the back side and is evenly filled in the track width regulating groove, whereby the magnetic core halves are joined together with sufficient joining strength.

Further, the viscosity is 50,000 to 200,000 P.
The fused glass having a high viscosity of a · s exhibits relatively low fluidity, and is difficult to flow into a narrow gap such as a gap.
Therefore, the viscosity of the fused glass at the time of filling the track width regulation groove on the front side of the winding groove should be 50000 to 20
When the pressure is set to 0000 Pa · s, the erosion of the front side gap film, which contributes to the generation of the leakage magnetic flux, by the fused glass is suppressed. As a result, the reduction of leakage flux caused by the diffusion of ferrite into the fused glass that erodes the front gap film is suppressed, and the deterioration of the recording / reproducing characteristics is prevented.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described below with reference to the drawings.

In order to fabricate a magnetic head, a rectangular magnetic core half block made of an oxide soft magnetic material such as Mn-Zn ferrite or Ni-Zn ferrite is prepared, and the opposite surface is the opposite surface. Etching is performed by the sputtering method to reduce the surface roughness. The size of the magnetic core half block used in this example is 30.0 in length.
mm and the width is 2.9 mm.

Then, as shown in FIG. 1, a gap portion g is formed on one main surface of the magnetic core half block 1 along the width direction.
The track width restricting groove 2 for restricting the track width is formed in a substantially trapezoidal cross section. At this time, the side surface of the track width regulating groove 2 forms an angle of 8 to 45 ° with respect to the other side surface, and the depth is 20.
It is formed to have a thickness of about 0 to 300 μm.

After the track width regulating groove 2 is formed in this manner, the main surface is polished so that the surface roughness Ra is about 20 to 100Å. Then, as shown in FIG. 2, a winding groove 3 is formed in a direction orthogonal to each track width regulating groove 2, and a glass fusing groove 4 is further formed so as to be parallel to the winding groove 3. Form. At this time, the winding groove 3
At the boundary, the glass fusing groove 4 side is the back side of the magnetic head, and the side opposite to the glass fusing groove 4 is the front side of the magnetic head. That is, the winding groove 3 regulates the depth d _F on the front side of the gap portion g, and the glass fusing groove regulates the depth d _B on the back side of the gap portion g by the wall surface on the front side.

In this way, the magnetic core half block 1 in which the track width regulating groove 2, the winding groove 3, and the glass fusing groove 4 are formed, and the magnetic core half block in which each groove is similarly formed 5 and 5 are subjected to etching treatment by a reverse sputtering method on at least one of the groove formation surfaces, but they are butted with each other through a gap film and bonded and integrated by glass fusion.

To perform glass fusion, a pair of butted magnetic core half blocks 1 and 5 are attached to a jig so that a predetermined pressure is applied in the butting direction. Then, the jig is adjusted so that the front side is on the lower side, and fused glass rods are inserted into the winding groove 3 and the glass fused groove 4, respectively, and heated until the fused glass is melted. The fused glass whose viscosity has decreased in the winding groove flows into the track width regulating groove on the front side and is filled in the track width regulating groove on the front side. On the other hand, the fused glass whose viscosity has decreased in the glass fusing groove flows into the track width regulating groove on the back side and is filled in the track width regulating groove on the back side. As a result, the magnetic core half blocks are joined and integrated to form a magnetic core block.

When the glass is fused in this way,
In the present invention, as shown in FIG. 3, first, the first fused glass rod is inserted only in the glass fused groove 4. Then, the first fused glass rod is heated and melted to have a viscosity of 5,000 to 1
0000 Pa · s. Viscosity is 5000-10000
The fused glass 7, which has a low viscosity of Pa · s and a low viscosity, exhibits relatively high fluidity. Therefore, it smoothly flows into the track width regulation groove 2 on the back side and is uniformly filled in the track width regulation groove 2.

After fusing the back side with glass, this time with reference to FIG.
As shown in, the second fused glass rod is inserted into the winding groove 3. Then, the second fused glass is heated and melted to have a viscosity of 50,000 to 200,000 Pa · s. Viscosity 5
The fused glass 8 having a high viscosity of 20,000 to 200,000 Pa · s exhibits a relatively low fluidity and is difficult to flow into a narrow gap such as the gap part g. Therefore, when the viscosity of the fused glass when filling the track width regulation groove 2 on the front side of the winding groove is set to 50,000 to 200,000 Pa · s, the fusion of the front side gap film 6 that contributes to the generation of the leakage magnetic flux is performed. Erosion due to glass is suppressed. This allows
A reduction in leakage magnetic flux caused by diffusion of ferrite into the fused glass that erodes the front gap film 6 is suppressed.

The viscosity of the fused glass 7, 8 when filling the track width regulating grooves 2 can be adjusted, for example, by controlling the temperature at which the fused glass 7, 8 is melted.

FIG. 5 shows the relationship between the temperature and the viscosity of the fused glass that is usually used.

From FIG. 5, the viscosity of the fused glass decreases with increasing temperature, and when the temperature rises to 515 to 535 ° C., the viscosity becomes 50,000 to 200,000 Pa · s, and further to 555 to 570 ° C. When it rises, the viscosity drops to 5000-10000 Pa · s. Accordingly, the fusing temperature of the fusing glass when filling the back side track width regulating groove is 555 to 570 ° C., and the fusing temperature of the fusing glass when filling the front side track width regulating groove is 515. By setting the temperature to ˜535 ° C., the above effect can be obtained.

The filling property of the fused glass into the track width regulating groove 2 on the front side, that is, the track width regulating groove 2
The easiness of the fused glass falling on the glass varies somewhat depending on the shape of the winding groove. Therefore, it is preferable that the viscosity of the fused glass at the time of filling the front track width regulation groove 2 is optimized according to the shape of the winding groove. For example, in the case of the double groove winding groove type in which the winding grooves 3 are formed in both the magnetic core half blocks 1 and 5 shown in FIG. 4, the viscosity of the fused glass 8 is 1
A suitable range is about 00000-200000 Pa · s,
In the case of the single groove winding groove type in which the winding groove is formed only on one magnetic core half block, the viscosity of the fused glass is 500.
The suitable range is about 00 to 100,000 Pa · s. In order to set the viscosity of the fused glass to 100,000 to 200,000 Pa · s, the fusing temperature is set to 515 to 525 ° C. and 50,000 to 1
To achieve 00000 Pa · s, the fusion temperature should be 525-53
It may be set to about 5 ° C.

Incidentally, in the case of the double groove winding groove type and the case of the single groove winding groove type, the relationship between the fusing temperature of the fusing glass and the flow length of the fusing glass to the track width regulating groove on the back side. 6 and 7 show the relationship between the fusing temperature of the fusing glass and the erosion length of the front side gap film. These Figure 6,
From FIG. 7, by controlling the temperature of the fused glass, the filling property of the fused glass in the track width regulation groove on the back side,
It is suggested that the erosion of the fused glass on the front side gap film can be controlled. Here, the magnetic head used for the measurement of the characteristic diagrams of FIGS. 6 and 7 has a back side depth d _B of 8
The thickness is 00 μm.

The present embodiment is an example of the double groove winding groove type in which the winding grooves 3 are formed in both the magnetic core half blocks 1 and 5, so that the track width regulating groove 2 on the back side is formed. The temperature of the fused glass 7 at the time of filling was set to 560 ° C., and the temperature of the fused glass 8 at the time of filling the inside of the track width regulating groove 2 on the front side was set to 530 ° C.

In this way, the magnetic core half blocks 1 and 5 are joined and integrated to form the magnetic core block 9 shown in FIG. 8, and one end surface of the magnetic core block 9 on the front side is cylindrically polished. To form the sliding surface of the magnetic recording medium,
Further, the magnetic head is completed by slicing across the magnetic core block at the positions indicated by aa 'and bb' in the figure.

The magnetic head thus manufactured is
Since the ferrite component is not diffused in the front side gap portion g, good recording / reproducing characteristics can be obtained even when the track width is narrowed to 25 μm or less. For example, it is manufactured without controlling the viscosity of the fused glass. The recording and reproducing characteristics are greatly improved to 1 to 1.5 dB as compared with the magnetic head. Further, the track width regulation groove on the back side is sufficiently filled with the fused glass, and the magnetic core halves are glass-bonded with sufficient strength, and it is possible to obtain an excellent bending strength of 100 g · f.

[0036]

As is clear from the above description, in the method of manufacturing a magnetic head of the present invention, a pair of magnetic core halves having a gap film made of SiO ₂ formed on the magnetic gap forming surface are butted to each other. When joining the pair of magnetic core halves to each other with the fused glass, the viscosity of the fused glass is set to 5000 to 10000 Pa · s, the back side is glass-fused, and the viscosity of the fused glass is set to 50,000 to 2000.
Since the front side is fused with glass at 00 Pa · s,
Corrosion of the fused glass to the front side gap film is suppressed, and a magnetic head can be manufactured which exhibits good recording and reproducing characteristics even when the track width is set to about 25 μm. Moreover, in the manufactured magnetic head, the magnetic core halves are glass-bonded with sufficient strength and exhibit excellent mechanical characteristics.

Therefore, according to the present invention, it is possible to obtain a highly practical magnetic head suitable for high density recording.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a track width regulating groove forming step in a magnetic head manufacturing step.

FIG. 2 is a schematic perspective view showing a winding groove and glass fusing groove forming step in the manufacturing process of the magnetic head.

FIG. 3 is a schematic perspective view showing a glass fusion-bonding process on the back side in the manufacturing process of the magnetic head.

FIG. 4 is a schematic perspective view showing a glass-fusing step on the front side in the manufacturing process of the magnetic head.

FIG. 5 is a characteristic diagram showing the relationship between the fusing temperature and the viscosity of fused glass.

FIG. 6 is a characteristic diagram showing the relationship between the fusing temperature of the fusing glass and the flow length to the track width regulation groove on the back side.

FIG. 7 is a characteristic diagram showing the relationship between the fusing temperature of the fusing glass and the erosion length of the gap depth film.

FIG. 8 is a schematic perspective view showing a magnetic core block blaming step in the manufacturing process of the magnetic head.

FIG. 9 is a schematic perspective view showing a general configuration of a magnetic head.

FIG. 10 is a schematic diagram showing a state in which a fused glass is eroded in a gap film.

[Explanation of symbols]

 1, 5 ... Magnetic core half block 2 ... Track width regulation groove 3 ... Winding groove 4 ... Glass fusion groove 6 ... Gap film 7, 8 ... Fused glass

Claims (2)

[Claims] 1. A fused glass, wherein a pair of magnetic core halves having a gap film made of SiO ₂ formed on the magnetic gap forming surface are abutted against each other and the pair of magnetic core halves are joined with a fused glass. The back side is glass-fused, and the viscosity of the fused glass is 500.
A method of manufacturing a magnetic head, characterized in that the front side is glass-melted at a pressure of 200 to 200,000 Pa · s. 2. The method of manufacturing a magnetic head according to claim 1, wherein the track width of the magnetic gap restricted by the track width restriction groove of the magnetic core half is 25 μm or less.