JPH0421906A - Magnetic head - Google Patents

Abstract

PURPOSE:To lessen the generation of cracks in soft magnetic thin films or substrates by providing a central region intersecting with the gap of the soft magnetic thin films in such a manner that the angle of inclination with the gap has the angle smaller than the angle of the regions at the ends. CONSTITUTION:The inclined wall surfaces symmetrical with a center line in-between are formed to the two-stepped inclined shape, the angle of inclination of which with the center line is sharper on a base 1b side than on a front 1a side at the time of providing grooves 5 having an approximately V-shaped section on substrates 1. Consequently, the soft magnetic thin films 2 exposed on the sliding surface (upper surface in Fig.) on which a magnetic tape slides are formed to the two-stepped inclined shape, the angle of inclination of which with the gap 12 is smaller in the center region 2c intersecting with the gap 12 than in the end regions 2b extending obliquely from both ends of this central region 2c respectively toward the side. The thermal stresses, etc., occurring in the difference in the coefft. of thermal expansion of the above- mentioned magnetic head are decreased at the time of joining the above-mentioned substrate blocks 11, 11 to each other under pressurization. Consequently, the generation of the cracks in the soft magnetic thin films 2 or the substrates 1 is lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head used in a magnetic recording/reproducing device such as a video tape recorder (hereinafter abbreviated as VTR).

[Conventional technology]

With the increase in the density of magnetic recording, the use of high coercivity media such as metal tapes has become mainstream. On the other hand, in response to such high coercive force media, core materials used in magnetic heads are required to have a high saturation magnetic flux density.

Therefore, as a magnetic head having such a high saturation magnetic flux density, for example, as shown in FIG. For example, a head chip 25 is used, which is manufactured by forming a soft magnetic thin film 22 made of a Fe-A 1-si alloy by vacuum evaporation or the like, and then bonding the soft magnetic thin film 22 to each other by sandwiching a low-melting point glass or the like and melting the film by heating. ing.

A magnetic head using such a head chip 25 has the soft magnetic thin film 2 exposed on the sliding surface on which the magnetic tape slides.
2 is formed obliquely so as to extend in a direction intersecting the gap 23.

As a result, when the tape is slid on the magnetic head, the substrate 22 that supports the soft magnetic thin film 22 is resistant to uneven wear.
For example, when an oxide magnetic material such as ferrite is used, if the boundary between the oxide magnetic material and the soft magnetic thin film 22 is parallel to the gap 23, the magnetic properties will become discontinuous on both sides of the boundary. It is also possible to avoid the problem that the performance of the magnetic head is adversely affected by the effect of a pseudo gap.

[Problem to be solved by the invention]

However, the magnetic head having the above structure has a problem in that cracks are likely to occur in the soft magnetic thin film 22 or the substrate 21 when the track width is increased.

That is, in the above structure, the soft magnetic thin film 22
Since the track width is given by the width in the gap direction at the portion that intersects with 3, in order to increase the track width, it is necessary to increase the thickness of the soft magnetic thin film 22. When the thickness of the soft magnetic thin film 22 is increased in this way, when the pair of substrates 21 are bonded to each other by heating and melting, for example, by sandwiching a low melting point glass or the like, the soft magnetic thin film 22 becomes thicker. Thermal stress due to the difference in thermal expansion coefficient with the substrate 21 also increases, making it easy for the soft magnetic thin film 22 or the substrate 21 to crack.

[Means to solve the problem]

In order to solve the above problems, a magnetic head according to the present invention is provided with a head chip consisting of a substrate and a soft magnetic thin film interposed on the substrate, and is provided with a head chip that is exposed on the sliding surface of a magnetic recording carrier in this head chip. The end face of the soft magnetic thin film to be released is
In a magnetic head that extends obliquely in a direction intersecting the gap, the soft magnetic thin film has an inclination angle with respect to the gap on the sliding surface such that the central region intersecting the gap is closer to the opposite end of the central region. They are each characterized in that they are formed smaller than the laterally extending end regions.

[For production]

According to the above configuration, since the central region intersecting with the gap of the soft magnetic thin film is provided at a smaller inclination angle with the gap than the end region, The track width given by the width in the gap direction becomes larger when the film thickness is the same as the conventional one.

This makes it possible to reduce the thickness of the soft magnetic thin film and obtain a larger track width. The occurrence of scratches on the substrate is reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

In the magnetic head of this embodiment, as shown in FIG. 1, the head chip 10 is made of a non-magnetic material such as photosensitive crystallized glass, crystallized glass, or ceramics, or an oxide magnetic material such as soft magnetic ferrite. It is manufactured by bonding a pair of substrates 1 made of a material with excellent wear resistance to each other with a low melting point glass 3. Then, on each bonding surface of the substrates 1, 1, for example, Fe-A I
! A soft magnetic thin film 2 made of a -5i alloy is formed.

The manufacturing process of the magnetic head having the above structure will be explained in order below.

First, as shown in FIG. 2, a substrate 1 made of the above-mentioned non-magnetic material or oxide magnetic material has a substantially rectangular parallelepiped shape, and has a plurality of grooves 5 and 5 on its surface 1a with a predetermined pitch dimension A. ... are formed in shapes that are adjacent to each other and extend parallel to each other. These grooves 5...
are each formed in a cross-sectional shape of seven sections sandwiched between symmetrical inclined wall surfaces with the center line in between.

Each inclined wall surface has a surface la side and a bottom surface lb side,
It has a two-stage inclined shape with mutually different inclination angles with respect to the center line, and the cross-sectional shape is more acute on the bottom surface lb side than on the surface la side.

Next, as shown in FIG. 3, the soft magnetic thin film 2 is deposited on the negative groove wall surface 5b of each groove 5 to a predetermined thickness by vacuum evaporation or sputtering. , is formed to have a film thickness corresponding to the track width of the gap 12, which will be described later.

Next, as shown in FIG. 4, each groove bottom is filled with low-melting glass 3, and then, as shown in FIG. It is polished flat until each vertex on the surface side is reached.

At this time, the regions of the soft magnetic thin film 2 that protrude from the surface-side apexes of the valley grooves 5 are also removed, and the polished surface 1c has areas adjacent to the surface-side apexes of the valley grooves 5. An end surface 2a of the soft magnetic thin film 2 extending in a direction perpendicular to the plane of the paper.
...is appearing.

Thereafter, as shown in FIG. 6, internal winding grooves 6 are formed on the polished surface 1c of the substrate 1, and external winding grooves 7 are formed on the bottom surface 1b of the substrate 1. Then, the polished surface 1c
Then, a non-magnetic gap material (not shown) such as silicon oxide is applied to a film thickness corresponding to a predetermined gap length by vacuum evaporation or the Svanter method to form a gap surface 8, and a substrate block 11 is formed. is produced.

Next, as shown in FIG.
11 is pressurized and fixed with the gap surfaces 8, 8 facing each other and the end surfaces 2a, 2a of the soft magnetic thin films 2 facing each other, and bonded to each other to form a core block. Formed as 9. At this time, the gap 12 is formed between the end surfaces 2a, 2a of each soft magnetic thin film 2 facing each other with the nonmagnetic gap material in between.

The core block 9 is then cut at a predetermined pitch dimension B along the positions indicated by two-dot chain lines to produce the head chip 10 shown in FIG. 1. This head chip 1
0 was then adhesively fixed to a head base (not shown), and the coil winding and magnetic tape sliding surface were polished.
Completed as a magnetic head.

As described above, in the above embodiment, when providing the groove 5 having a V-shaped cross section in the substrate 1, as shown in FIG. ,
It has a two-step inclined shape in which the angle of inclination with respect to the center line is more acute on the bottom surface 1b side than on the surface la side.

As a result, as shown in FIG. 1, the soft magnetic thin film 2 exposed on the sliding surface (top surface in the figure) on which the magnetic tape slides has an inclination angle with the gap 2 that intersects the gap 12. The central region 2C has a two-step inclined shape smaller than the end regions 2b extending laterally from both ends of the central region 2C.

FIG. 8 shows a soft magnetic thin film 2 inclined with respect to the gap 12.
The relationship between the thickness of the soft magnetic thin film 2, the width in the gap direction, the track width, and the width of the soft magnetic thin film 2 is shown.
The track width Tw is the dimension obtained by dividing the film thickness t of the soft magnetic thin film 2 by l sin θ. Therefore, in the above embodiment, as shown in the figure, the central region 2C with respect to the gap 12
Since the inclination angle θ2 of is smaller than the inclination angle θ of the end region 2b, the track width 'hz given in the central region 2C
is larger than the track width Tw+ obtained by extending the end region 2b to the gap 12.

As a result, in the above embodiment, the end region 2b is formed with almost the same inclination angle as the conventional one, and the inclination angle of the local central region 2C intersecting the gap 12 is changed, so that The soft magnetic thin film 2 is resistant to uneven wear, substantially maintains the effect of suppressing the effect of the pseudo gap, and can obtain a larger track width by making the soft magnetic thin film 2 thinner.

As a result, in the magnetic head, thermal stress caused by the difference in coefficient of thermal expansion when the substrate blocks 11 are bonded to each other under pressure is reduced. As a result, the soft magnetic thin film 2
Alternatively, the occurrence of cracks in the substrate 1 is reduced, and the yield of the magnetic head is improved.

In the above embodiment, the soft magnetic thin film 2 is made of Fe-APSi.
Although a magnetic alloy is used, it is also possible to use other soft magnetic materials.

〔Effect of the invention〕

As described above, in the magnetic head according to the present invention, the soft magnetic thin film interposed on the substrate changes the inclination angle with respect to the gap on the sliding surface of the magnetic recording carrier toward the central region intersecting the gap. are formed to be smaller than the end regions extending laterally from both ends of the central region.

Therefore, it is possible to obtain a larger track width by making the soft magnetic thin film thinner.
This has the effect of reducing the occurrence of wrinkles in the soft magnetic thin film or the substrate due to the difference in thermal expansion coefficient between the soft magnetic thin film and the substrate.

[Brief explanation of the drawing]

1 to 8 show one embodiment of the present invention. FIG. 1 is a perspective view of the Herad tip. FIG. 2 is a sectional view of a main part of the substrate after grooves are formed. FIG. 3 is a sectional view of a main part of the substrate after a soft magnetic thin film is formed on one of the walls of the groove. FIG. 4 is a sectional view of the main part of the substrate after the grooves are filled with low melting point glass. FIG. 5 is a sectional view of the main part of the substrate after the surface side of the low melting point glass has been polished. FIG. 6 is a perspective view of a substrate block in which internal winding grooves and external winding grooves are formed on the substrate after the steps indicated in -. FIG. 7 is a perspective view of a core block formed by joining two of the above substrate blocks to each other. FIG. 8 is an explanatory diagram showing the relationship between the soft magnetic thin film and the track width. FIG. 9 shows a conventional example, and is a perspective view of a head chip. 2 is a substrate, 2 is a soft magnetic thin film, 2C is a central region, 2b is an end region, 10 is a Herad chip, and 12 is a gap.

Claims (1)

[Claims] 1. A head chip consisting of a substrate and a soft magnetic thin film interposed on the substrate is provided, and the end surface of the soft magnetic oil film exposed on the sliding surface of the magnetic recording carrier in this head chip. However, in a magnetic head that extends obliquely in a direction intersecting the gap, the soft magnetic thin film has an inclination angle with respect to the gap on the sliding surface such that the central region intersecting the gap is larger than that in the central region. A magnetic head characterized in that it is formed smaller than end regions extending laterally from both ends.