JPH01235012A - Magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic head for high-density magnetic recording and reproduction, and in particular, the area near the magnetic gap is formed of a metal magnetic thin film, and the surface facing the magnetic recording medium has an oblique surface. The present invention relates to a composite magnetic head, which is coated with a composite magnetic head.

[Conventional technology]

In magnetic recording and reproducing devices such as VTRs (video tape recorders), the recording signal density is increasing, and metal tapes with high coercive force are being used as recording media to accommodate high-density recording. Ta. The head material of the magnetic head used in this type of recording medium is also required to have a high magnetic flux density.

On the other hand, along with high-density recording, recording tracks recorded on magnetic recording media are also becoming narrower.

Correspondingly, the track width of the magnetic head is also required to be extremely narrow. Furthermore, improvements in wear resistance and narrowing of the spacing between the head and the medium during recording and reproduction are also required. In addition, in response to the demand for lower costs, improving mass production yield is also a major issue.

Therefore, the applicant of the present invention previously proposed a composite magnetic head suitable for high-density recording on a magnetic tape having a high coercive force, such as a metal tape, in Japanese Patent Laid-Open No. 58-155513. As shown in FIG. 9, this magnetic head has chevron-shaped protrusions formed on the abutting surfaces of a pair of core parts 11 and 11' formed of Mn-Zn ferrite, and a metal magnetic thin film is formed on the slopes of the protrusions. 12.12'
After forming and filling the valley with low melting point glass 13,
The protruding portion of the metal magnetic thin film 12, 12' is polished until a width corresponding to the track width appears, thereby forming a magnetic gap contact surface. A pair of cores made in this manner are bonded by remelting the low melting point glass 13 via a gap material, and have excellent characteristics in terms of reliability, magnetic properties, wear resistance, etc. It is.

[Problem to be solved by the invention]

However, the conventional heads described above were not necessarily sufficient for forming narrow track widths with high precision. For example, as shown in FIG. 10 showing the sliding contact surface of a magnetic recording medium, there are variations in dimensions during track extrusion polishing, variations in track width due to misalignment when butting two cores to form a gap 15, etc. This caused an impediment to improving mass production yield.

In addition, as shown in FIG. 11, the sliding contact surface of the magnetic recording medium has an oblique structure, so that a
, a', unnecessary recording/reproducing action occurred, resulting in deterioration of S/N. The first problem mentioned above becomes more severe as the recording density becomes higher.

Furthermore, in magnetic recording devices such as digital VTRs that require high-speed running, the spacing between the tape and the head becomes large, and deterioration of recording and reproducing characteristics due to spacing loss is a major problem.

The purpose of the present invention is to increase density (for example, linear recording density).

The objective of the present invention is to provide a magnetic head that has excellent recording and reproducing characteristics, reliability, and mass productivity in response to increased track density (improved track density) and higher frequencies.

[Means to solve the problem]

The above object is to provide a magnetic head in which a magnetic gap is formed by butting gold pA magnetic films diagonally deposited on a surface facing a magnetic recording medium, by forming grooves at both ends of the magnetic gap. achieved. It is desirable to fill the groove with a non-magnetic material such as glass.

The width of the metal magnetic film left between the grooves is formed to be equal to the track width.

The grooves are formed by a rotary grindstone such as a peripheral slicer or a dicer. Depending on the case, ion etching or chemical etching can also be applied.

[Effect]

The grooves formed at both ends of the magnetic gap can newly regulate the trunk width, so even if some dimensional deviation occurs during track width determination polishing or misalignment during gap matching during the head manufacturing process, It is also possible to achieve a track width with high dimensional accuracy.

Furthermore, the grooves can prevent unnecessary recording and reproducing operations near the outside of the track width, and a high S/N ratio can be obtained.

Further, since the groove serves as an air relief groove, the space between the magnetic tape and the magnetic head can be kept small and stable, thereby making it possible to record and reproduce wideband signals such as digital VTR signals.

By filling the groove with glass, it is possible to eliminate scratches on the magnetic tape when the magnetic tape and the magnetic head come into sliding contact. Note that it is preferable that the nonmagnetic material filled in the groove be a material that wears more easily than ferrite so that the groove is always formed.

〔Example〕

Embodiment 1 The present invention will be described below based on the illustrated embodiment. FIG. 1 is a perspective view showing an example of groove formation of a magnetic head according to the present invention. In the same figure, 11.11' is a magnetic core made of Mn-Zn ferrite material, and these magnetic cores 11.
The surface of 11' facing the magnetic gap 15 has a chevron-shaped protrusion. An alloy magnetic material 12.12' having a high saturation magnetic flux density such as amorphous is deposited on both slopes of this protrusion by sputtering or the like, and the alloy magnetic film 12.1
The protrusion 2' is ground or polished to form a flat surface.

A magnetic gap 15 is formed by depositing a thin film layer of a non-magnetic material such as glass to a predetermined thickness on this flat surface. 13 is a joining member for joining the left and right magnetic cores, and glass is mainly used. 14 is a window for winding. One feature of the present invention is that two parallel grooves 17 and 17' are formed at both ends of the magnetic gap 15, that is, at an interval corresponding to the track width TW, on the sliding surface 1G that contacts the recording medium.

First, the track width TW is precisely defined by these two grooves 17, 17'. Next, unnecessary recording and reproducing operations outside the magnetic gap 15 can be prevented. In particular, at the end of the track width Tw, the opposing alloy magnetic films 12.12
'The recording and reproducing effect is strong because the distance is close. Therefore, the alloy magnetic film 12.1 on the sliding surface is formed by the groove 17.17'.
2' is removed. Furthermore, this groove 17.1
7' serves as an air escape when the magnetic tape and the magnetic head are running in contact with each other, so that it has the effect of reducing the increase in spacing loss. Note that the width of this groove is preferably about 10 μm to 40 μm, and the depth is about 20 μm, which is about the depth of the magnetic gap.
It is preferable to set the thickness to 30 μm.

<Embodiment 2> Next, FIG. 2 is a perspective view of a magnetic head showing another embodiment of the present invention. Below, the symbols and amounts to be added are the same as those in Figure 1 for the same materials and shapes.

This will be explained using the amount.

FIG. 2 shows a structure in which the depth of the grooves 17 and 17' is varied with respect to the running direction arrow A of the magnetic head with respect to the magnetic tape.

In this case, the groove is shallow on the entrance side to the magnetic tape and deep on the exit side. By doing so, the spacing can be kept small and stable even when the magnetic tape and magnetic head are running at high speed.

<Embodiment 3> FIG. 3 shows another embodiment of the present invention. FIG. 3(A) is an enlarged plan view showing the sliding surface of the magnetic head with the magnetic tape. FIG. 3(B) is an enlarged plan view showing the side surface.

In this embodiment, grooves 17 and 17' formed at both ends of the magnetic gap are filled with a non-magnetic material 18 such as glass to prevent the edges of the grooves from damaging the magnetic tape. In this case, the nonmagnetic material 18 is filled with a material whose hardness is lower than that of the ferrite core. Then, the recess 19 is always formed from the ferrite core. This serves to protect the alloy magnetic films 12, 1.2' in the vicinity of the magnetic gap. Furthermore, if the non-magnetic material 18 is filled with a material with good lubricity such as metal soap or carbon, sliding properties will be improved, resulting in stable running and long life.

<Example 4> 4, 5 and 6 show other embodiments of the invention.

This figure is an enlarged plan view showing the sliding surface of the magnetic head with the magnetic tape, similar to FIG. 3.

In this embodiment, as shown in FIG. 4, the alloy magnetic film 12 on one core is
alloy magnetic film 1 on the abutting surface and the other core.
The case where the abutting surfaces of 2' are different is shown. In this case, if the track width Tw is made wider than the required track width Tw in advance, a new required track Tw can be formed using the two grooves 17 and 17'.

FIG. 5 shows another magnetic head structure. In this magnetic head, alloy magnetic films 12 and 12' are formed only on the opposite slopes of ferrite cores 11 and 11', and a magnetic gap 15 is formed on the opposing surfaces of the 1-alloy magnetic films. Even in this case, by excessive polishing, even if the ferrite surface appears on the gap abutting surface, it can be prevented from appearing on the sliding contact surface by the grooves 17, 17'. Therefore, unnecessary recording and reproducing operations do not occur at the ends of the track width. In addition, since products that are rejected due to misalignment of the trunk can be saved, mass production yields can be greatly improved.

Furthermore, even track widths of 10 μm or less can be easily processed with an accuracy of ±1 μm or less.

Note that the groove of the present invention may be formed obliquely with respect to the magnetic gap 15.

Also, the number of grooves is not limited to two, and the trunk width is restricted as shown in Figure 6! +'! ! 17, another groove 2 on the outside of 177
0.20' may be provided. In this way, the track width regulating groove 17, 17' and the air exhaust i/no,
20' to reduce the spacing loss. In this way, each groove can serve a different role.

<Embodiment 5> FIG. 7 and FIG. 8 further show another embodiment of the present invention. In this embodiment, the grooves 17 and 17' are formed such that the width of the grooves increases in the direction toward the exit side of the magnetic tape. In this way, a negative pressure is generated at the contact portion on the exit side of the magnetic tape, and the magnetic tape is attracted to the magnetic head, so that recording and reproduction can be performed in a small space. As a result, wide frequency 'ii! There is little deterioration in recording and reproducing characteristics even in the ' range.

[Effects of the Invention] As explained above, according to the present invention, in a magnetic head in which a magnetic gap is formed by butting metal magnetic films diagonally deposited on the surface facing a magnetic recording medium, the magnetic gap can be reduced. By forming it+￥ on both ends, (1) Even if some dimensional deviation occurs due to track width determination polishing or misalignment during gap butting, the problem can be corrected and the trunk with high dimensional accuracy can be created. Width can be regulated. This greatly improves mass production yield.

(2) Unnecessary recording and reproducing operations at the ends of the magnetic gap (ends of the track width) can be eliminated, and a magnetic head with a high S/N ratio can be obtained.

(3) Since the above-mentioned groove plays the role of an air release groove, it is possible to record and reproduce high frequency bands without increasing the space between the magnetic tape and the magnetic head.6 (4) Other details regarding the shape of the groove, By changing the filler in various ways, reliability such as lifespan and running stability can be improved.

The above effects provide a magnetic head suitable for high-density recording and reproduction.

[Brief explanation of the drawing]

1 and 2 are perspective views of a magnetic head for explaining one embodiment of the present invention, and FIGS. 3 to 8 are perspective views of a magnetic head and a magnetic tape for explaining other embodiments of the present invention. FIG. 9 is a plan view showing the sliding surface, and FIG. 9 is a perspective view of a conventional magnetic head.
0 and 11 are enlarged plan views of the recording medium sliding surface of a conventional magnetic head. 1.1, 1.1'...core part, 1.2.12'...
Metal magnetic film, 13... Filling, bonding glass, 14...
Coil winding window, 15...Magnetic gap, 17.17'
... Track width regulating groove, 18... Non-magnetic material for protection, 20.20'... Air relief groove. Bud,? -Diagram 7

Claims (1)

[Claims] 1. In a magnetic head in which a magnetic gap is formed by abutting metal magnetic films diagonally deposited on a surface facing a magnetic recording medium, grooves are formed at both ends of the magnetic gap. A magnetic head characterized by the following characteristics: 2. The magnetic head according to claim 1, wherein the grooves at both ends of the magnetic gap are deeper on the exit side than on the entrance side of the magnetic medium with respect to the running direction. 3. The magnetic head according to claim 1 or 2, wherein the grooves at both ends of the magnetic gap are filled with a non-magnetic material. 4. The magnetic head according to claim 1, wherein a gap matching width is formed that is wider than a required track width, and a groove is provided in the center portion so as to leave the required track width. 5. The magnetic head according to claim 1, wherein the grooves at both ends of the magnetic gap are wider on the exit side than on the entrance side of the magnetic medium with respect to the running direction.