JPH05182144A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To obtain the thin-film head having a low level difference by joining an upper core and a lower core apart a prescribed distance via a yoke on the opposite side of a gap part. CONSTITUTION:The magnetic cores 21, 61 of a gap depth range are respectively extended to the range exceeding the track width Tw on one side in the track width direction so as to have the component of the direction perpendicular to the gap depth direction of the flow of the magnetic fluxes in the cores 21, 61 heading toward the gap part 3a regulating the track width Tw. The inclination theta with the gap-facing surface is preferably 30 to 70 deg. in order to decrease the leak magnetic field between the upper and lower cores 21 and 61 at both ends of the track width. The spread width of Wa, Wb with respect to Tw is preferably above about the gap depth Gd so that the sufficient magnetic fluxes flow even at the front end of the gap. As a result, the distribution of the magnetic fluxes of the magnetic cores in the gap depth range is uniformed and the sufficient recording magnetic fields are obtd. even at a thin core thickness even if the gap depth is large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an HDD, a VT, etc.
The present invention relates to a novel structure of a thin film magnetic head used for R, FDD and the like.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing a conventional thin film magnetic head disclosed in, for example, Japanese Patent Laid-Open No. 61-110320.
In the figure, 1 is a non-magnetic substrate, 2 is a lower core, 3 is a gap material made of alumina or the like, 3a is a gap portion, 4 is an insulating layer, 5 is a coil, 6 is an upper core, and 7 is a protective layer. Gd is a gap depth, and K is a recording and reproducing surface for recording and reproducing information on the magnetic recording medium.

FIG. 8 is a plan view showing the conventional thin film magnetic head excluding the insulating layer 4 and the protective layer 7.
Tw is the track width. The lower core 2 and the upper core 6 are connected at one place, and the coil 5 is spirally wound around the connecting portion between the lower core 2 and the upper core 6. FIG. 7 is FIG.
2 is a cross-sectional view taken along line AA of FIG.

FIG. 9 is a front view showing the conventional thin film magnetic head as seen from the recording surface of the magnetic recording medium.

The conventional thin film magnetic head is constructed as described above, and in recording, the magnetic flux generated by the signal current flowing in the coil 5 flows through the cores 2 and 6, and the leakage magnetic flux in the gap portion 3a causes the magnetic recording medium. Record the signal at the track width. Further, the reproduction is performed by collecting the leakage magnetic flux from the magnetic recording medium in the gap portion 3a and converting the change of the magnetic flux flowing through the cores 2 and 6 into a voltage generated in the coil 5 by electromagnetic induction.

FIG. 10 (a) is an explanatory view showing the magnetic flux flowing in the cores 2 and 6 in the gap portion 3a, and the arrows show the flow direction of the magnetic flux. Further, FIG. 10B is a graph showing the relationship between the magnetic flux density and the gap depth Gd in the gap portion 3a. In the vicinity of the deepest position Gd of the gap depth Gd of this thin-film magnetic head, since there is a magnetic path in the direction of the gap depth in general, the magnetic flux density decreases from the deepest position Gd of the gap depth Gd toward the tip of the gap. I understand.

[0007]

In the conventional thin film magnetic head as described above, the magnetic flux density decreases from the deepest position of the gap depth Gd toward the tip of the gap. On the other hand, considering the application of a conventional thin film magnetic head to a VTR or an FDD, the magnetic head and the magnetic recording medium operate in sliding contact with each other, and the wear of the magnetic head becomes a serious problem. In order to secure the life of the magnetic head, the gap depth Gd should be 10 μm or more, and in order to obtain a sufficient magnetic flux density at the tip of the gap, the thickness of the magnetic core should be about the gap depth Gd or more. Good. However, there is a problem that it is difficult to form a thick magnetic core and to perform pattern processing of a narrow track width on this thick magnetic core.

Generally, the gap depth Gd is 0.5 to 2
It is very small, about μm, and requires highly accurate gap polishing.

Further, since the coil of the conventional thin film magnetic head is formed by using a thin film forming technique such as sputtering, vapor deposition and plating, the film thickness is about several μm and the resistance is large. Also, the number of turns of the coil is usually about 20 turns or less per layer, and the reproduction output is proportional to the number of turns of the coil.
Multiple windings are desired. In order to obtain a coil having a low resistance or a coil having a large number of windings, there is a method of forming the coil in two or more layers, but not only the number of steps is increased, but also the gap inside the head becomes large, which makes the manufacturing difficult. There is a problem.

Further, since the lower core of the conventional thin film magnetic head is smaller than the size of the coil, there is a problem that the coil is likely to be broken at the step at the end of the lower core.

The present invention has been made to solve the above-mentioned problems, and it is possible to make the distribution of the magnetic flux of the core uniform in the range of the gap depth, and to reduce the core thickness even if the gap depth is increased. It is an object of the present invention to obtain a thin film magnetic head in which a sufficient magnetic flux density can be obtained at the tip of the gap and which has a coil with a low resistance or a large number of windings as compared with the prior art and which has a small step inside the head.

The inventor of the present invention sets the cores in the gap depth direction in the track width direction in the track width direction so that the direction of the magnetic flux flowing in the core toward the gap portion has a direction component perpendicular to the gap depth direction. We have found that the thin-film magnetic head extended above has the effect that a sufficient magnetic flux density can be obtained at the tip of the gap even with a thin core thickness, and we have already applied for a patent (Japanese Patent Application No. 3-105666). The present invention was found as a result of further studies to obtain a thin film magnetic head having a small step inside the head and capable of easily forming a coil having a low resistance or a coil having a large number of turns.

[0013]

A thin film magnetic head of the present invention comprises a lower core, a gap, a coil, an insulating layer, an upper core, a yoke and a protective layer, and the upper core and the lower core are opposed to each other via a gap portion. Is a thin film magnetic head that records and reproduces a signal with a track width on the magnetic recording medium by the leakage magnetic flux in the gap portion, and the direction of the magnetic flux flowing to the lower core and the upper core toward the gap portion is the gap depth. The lower core and the upper core extend beyond the track width in the track width direction so as to have a direction component perpendicular to the depth direction, and the upper core and the lower core have a predetermined distance on the opposite side of the gap. They are separated by a yoke and are joined together.

Further, in order to reduce crosstalk, a core extended in the track width direction is formed in a non-parallel manner at a portion adjacent to the track width, inclined by a predetermined angle with respect to the gap facing surface. ..

Further, a plurality of spiral coils are arranged two-dimensionally around the connecting portions between the upper core and the lower core and the yoke.

The lower core or yoke is larger than the coil forming region.

The directional component perpendicular to the gap depth direction referred to in the specification is, in other words, the recording of the thin film magnetic head,
It is a direction component parallel to the reproduction surface.

[0018]

In the thin film magnetic head constructed as described above,
A part of the core in the gap depth range extends in the track width direction to a range exceeding the track width. Therefore, the flow of the magnetic flux toward the gap portion has a direction component perpendicular to the gap depth direction rather than the gap depth direction. Therefore,
The distribution of magnetic flux density in the gap becomes uniform. Also, with a thin core thickness, a sufficient recording magnetic field can be obtained even if the gap depth is large, and since the upper core and the lower core are joined via the yoke, the connection part between the yoke and each of the upper core and the lower core. A plurality of spiral-shaped coils can be arranged in a plane with the center being as a center, and low resistance or a large number of turns can be realized with a low step.

Since the lower core or the yoke is formed to be larger than the coil forming region, the coil can be formed on the lower core or the yoke without any step.

[0020]

【Example】

[Embodiment 1] FIG. 1 is a front view showing a recording / reproducing surface K of a thin film magnetic head according to an embodiment of the present invention. In the figure, 21 is a lower core and 61 is an upper core. Reference numerals 1, 3a, 4 and 7 are the same as those of the conventional thin film magnetic head.
In this embodiment, the core 21 in the gap depth range is arranged so that the flow of magnetic flux in the magnetic cores 21, 61 toward the gap portion 3a defining the track width Tw has a component in the direction perpendicular to the gap depth direction. , 61 are extended to one side in the track width direction to a range exceeding the track width Tw. In this embodiment, the spreads Wa and Wb of the magnetic cores 21 and 61 to one side in the track width direction are the track width T.
In a portion adjacent to w, the portion extends so as to be non-parallel to the gap facing surface, whereby the track width Tw can be regulated and crosstalk can be reduced. The inclination θ with respect to the gap facing surface is preferably 30 to 70 ° from the viewpoint of reducing the leakage magnetic field between the upper and lower cores at both ends of the track width. The track width Tw is set according to the specifications. Further, the spread widths of Wa and Wb with respect to Tw depend on the gap depth Gd, and it is desirable that the gap depth is about Gd or more so that a sufficient magnetic flux flows at the tip of the gap.

The arrows in FIG. 1 indicate the flow of magnetic flux. In the upper core 61, the magnetic flux flowing from the direction of the track width Tw passes vertically through the gap portion 3a, flows into the lower core 21, and flows in the direction opposite to the upper core 61.

FIG. 2 is a plan view showing the thin film magnetic head of the present embodiment, excluding the insulating layer 4 and the protective layer 7. Reference numerals 51 and 52 are coils, 8 is a yoke, Gd is a gap depth, C1 and C2 are connecting portions of the yoke 8 and the lower core 21 and the upper core 61, and a G portion indicated by diagonal lines is a gap facing portion. The arrows show the flow of magnetic flux. The magnetic flux flows in the gap facing portion G
Then, it goes around once through the lower core 21, the yoke 8, and the upper core 61.

FIG. 3 is a sectional view taken along line BB of FIG.

In the thin-film magnetic head constructed as described above, the magnetic flux generated by the signal current flowing through the two coils 51, 52 on the left and right flows through the yoke 8 and the upper core 61 and faces the gap in the direction of the track width Tw. It flows into part G, and after this,
As shown in FIG. 1, it passes through the gap portion 3 a vertically and flows to the lower core 21.

FIG. 4A is an explanatory diagram showing the magnetic flux in the surface direction, which represents the gap depth Gd, in the gap facing portions G of the magnetic cores 61 and 21. Further, FIG. 4B shows the gap portion 3
It is a graph which shows the relationship between the magnetic flux density and the gap depth Gd in a. In the figure, the solid line x indicates the relationship in this embodiment, and the dotted line y indicates the relationship in the conventional thin film magnetic head. Comparing the same core thickness, in the range of the gap depth Gd, the magnetic flux density distribution uniformity is shown by the dotted line y.
It can be seen that the relationship is significantly improved over the conventional relationship shown in.

In the thin film magnetic head of this embodiment, the magnetic flux density at the tip of the gap can be made higher than before as described above, so that the same recording performance as before can be obtained even with a thin core thickness of about the track width Tw or less. be able to.

Further, in this embodiment, two coils 51 or 52 are two-dimensionally provided around the connecting portions C1 and C2 between the yoke 8 and the upper core 61 and the lower core 21, respectively. By arranging in this way, compared to a conventional thin-film magnetic head having two layers of coils, an equivalent number of coil turns can be realized without increasing the step of the head.

[Embodiment 2] In FIG. 5, the yokes 81 and 82 are each made of a lower core material and an upper core material, and the lower core 21 and a part of the yoke 81 are larger than the forming regions of the coils 51 and 52. It is a top view showing a thing. This way, the coil
Since 51 and 52 are formed on the lower core 21 and the yoke 81, the steps of the coil are not broken.

FIG. 6 is a sectional view showing a section taken along the line BB of FIG. As is clear from this figure, the yoke 81 is
When forming the upper core 61, the yoke 82
Can be formed at the same time when the coil 51 is formed, so that the head forming process can be significantly reduced.

Further, in the above-described embodiments, the coil has a spiral shape, but it may have a helical shape.

The core extending in the track width direction beyond the track width may be either the lower core or the upper core, but in order to increase the magnetic flux density at the tip of the gap, the lower core and the upper core may be used. It is more preferable that both of them extend beyond the track width.

[0032]

As described above, according to the present invention, the gap depth range is such that the direction of the magnetic flux flowing to the lower core and the upper core toward the gap has a direction component perpendicular to the gap depth direction. The lower core or the upper core is extended in the track width direction to a range exceeding the track width, and the upper core and the lower core are joined via the yoke on the opposite side of the gap, so that the magnetic field is reduced in the gap depth range. The magnetic flux distribution in the core can be made uniform, a sufficient recording magnetic field can be obtained even with a thin core thickness and a large gap depth, and a thin film head with a low resistance or a coil with many turns can be easily formed. it can.

Further, by defining the core extending in the track width direction to be non-parallel by inclining it at a portion adjacent to the track width with respect to the gap facing surface by a predetermined angle, the definition of the track width and the reduction of crosstalk are achieved. Can be done easily.

[Brief description of drawings]

FIG. 1 is a front view showing a thin film magnetic head of Example 1. FIG.

2 is a plan view showing a thin film magnetic head of Example 1. FIG.

FIG. 3 is a cross-sectional view showing a thin film magnetic head of Example 1.

FIG. 4 is an explanatory diagram showing magnetic flux in the core according to the first embodiment.

FIG. 5 is a plan view showing a thin-film magnetic head of Example 2.

FIG. 6 is a cross-sectional view showing a thin film magnetic head of Example 2.

FIG. 7 is a cross-sectional view showing a conventional thin film magnetic head.

FIG. 8 is a plan view showing a conventional thin film magnetic head.

FIG. 9 is a front view showing a conventional thin film magnetic head.

FIG. 10 is an explanatory diagram showing magnetic flux in a core of a conventional thin film magnetic head.

[Explanation of symbols]

 3 Gap material 3a Gap part 4 Insulating layer 7 Protective layer 8, 81, 82 Yoke 21 Lower core 51, 52 Coil 61 Upper core

[Procedure amendment]

[Submission date] May 15, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (5)

[Claims] 1. A lower core, a gap portion, a coil, an insulating layer,
An upper core, a yoke, and a protective layer are provided, and the upper core and the lower core are arranged to face each other via the gap portion, and a signal is recorded / reproduced in a track width on a magnetic recording medium by a leakage magnetic flux in the gap portion. A thin film magnetic head for
The lower core and the upper core in the gap depth range are arranged in the track width direction so that the direction of the magnetic flux flowing to the lower core and the upper core toward the gap portion has a direction component perpendicular to the gap depth direction. A thin film magnetic head, which is formed by extending to a range exceeding a track width, and wherein the upper core and the lower core are joined to the opposite side of the gap portion at a predetermined distance via a yoke. 2. The core extended in the track width direction has a gap facing surface at a portion adjacent to the track width.
2. The thin film magnetic head according to claim 1, wherein the thin film magnetic head is formed so as to be non-parallel with a predetermined angle. 3. The thin-film magnetic head according to claim 1, wherein a plurality of spiral coils are arranged in a plane centering on the connecting portion between each of the upper core and the lower core and the yoke. 4. The thin film magnetic according to claim 1, 2 or 3, wherein the yoke is made of a bonded body of two magnetic materials, and each of the two magnetic materials is made of an upper core material and a lower core material. head. 5. The thin-film magnetic head according to claim 1, wherein the lower core or yoke is larger than the coil forming region.