JPH07192217A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a magnetic head having excellent recording and degaussing characteristics by making a roll off small in particular while maintaining reproducing efficiently at about the same level as heretofore. CONSTITUTION:An apex part 8 of the magnetic head 1 constituted by joining a pair of core half bodies 2, 4 having magnetic thin films via a gap part 6 at their butt surfaces and forming the apex part 8 adjacently to the gap part 6 is delineated by a chamfered part formed at an apex angle alpha set at 130 deg.alpha<=170 deg..

Description

Detailed Description of the Invention

The present invention relates to a magnetic head constructed by abutting and joining two core halves having a magnetic thin film with a predetermined gap length, and particularly for a high frequency and having a high S / N ratio. The present invention relates to a magnetic head using a soft magnetic thin film such as a Fe—Si—Al alloy magnetic film, which is preferably used for a required high-density recording head, mainly a video head, a computer head, and the like.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a thin film laminated magnetic head using an Fe--Si--Al alloy magnetic film which has been used favorably in video heads, computer heads and the like in recent years. The structure will be briefly described.

As shown in FIG. 6, a thin-film laminated magnetic head 1 has a pair of core halves made of a thin-film laminated structure formed by, for example, depositing a Fe--Si--Al alloy thin film 100 on a ceramic substrate. Body, I core 2 and C core 4
The I core 2 and the C core 4 are integrally joined at their abutting surfaces via the gap portion 6. At this time,
Generally, in order to concentrate the magnetic flux in the gap portion 6, a chamfered portion adjacent to the gap portion 6 is machined,
That is, in order to form the apex portion 8 and to further increase the bonding strength, the apex glass 10 is filled in this portion. Further, the processing is performed according to the application such as computer and video.

Conventionally, a magnetic head 1 used in a composite type for a computer usually has an apex portion 8 in which a chamfered portion 14 is formed in a C core 4 at about α = 45 °.

[0005]

As described above, the shape of the apex portion 8, that is, the angle α of the chamfered portion 14 has a great influence on the magnetic characteristics of the magnetic head.
Conventionally, the angle α of the chamfered portion 14 is set to about 45 ° in consideration of recording and reproducing efficiency.

On the other hand, in Japanese Unexamined Patent Publication No. 5-174322, as shown in FIG.
The chamfered portions 12 and 14 are formed on the
There is proposed a magnetic head in which the angle α formed in 1 is set to 85 ° to 110 °.

The inventors of the present invention continued the research and experiment to further improve the magnetic characteristics of the magnetic head 1 of the type described in the above-mentioned publication, and as a result, the magnetic head 1 of this type is shown in FIG. As is understood from the above, it was found that the so-called “roll-off” phenomenon that the magnetic field gradient decreases with an increase in magnetomotive force is caused. This means that this type of magnetic head has a problem in terms of recording demagnetization, in which the reproduction output decreases as the recording current increases.

FIG. 3 is calculated by assuming that the flying height is 0.1 μm, the switching field is 1600 O _e , and the gap depth is 2 μm. Switching of the magnetic medium at a position separated from the magnetomotive force by a distance corresponding to the flying height. The gradient of the recording magnetic field from the head corresponding to the size of the field is shown.

It is an object of the present invention to provide a magnetic head which is excellent in recording demagnetization characteristics, in particular with a small roll-off, while maintaining the reproduction efficiency at a level comparable to the conventional one.

[0010]

The above object can be achieved by the magnetic head according to the present invention. In summary, the present invention relates to a magnetic head in which a pair of core halves having a magnetic thin film are joined at their abutting surfaces via a gap portion, and an apex portion is formed adjacent to the gap portion, The apex portion is defined by a chamfer formed at an apex angle α, and the apex angle α is 130
The magnetic head is characterized in that ° ≦ α ≦ 170 °.

According to another aspect of the present invention, a pair of core halves each having a magnetic thin film are joined at their abutting faces via a gap portion, and an apex portion is formed adjacent to the gap portion. In the magnetic head, the apex portion has a first chamfer formed at a first apex angle α adjacent to the gap portion and a second apex angle β connected to the first chamfer. And a second chamfer formed so that the first apex angle α is 130 ° ≦ α ≦ 170 °, and the second apex angle β is β <α. A magnetic head is provided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The magnetic head according to the present invention will be described below in more detail with reference to the drawings.

Embodiment 1 FIG. 1 illustrates an embodiment of the magnetic head 1 according to the present invention. According to the present embodiment, as in the conventional case, it is manufactured from a thin film laminated structure formed by depositing a Fe—Si—Al alloy thin film on a non-magnetic substrate such as ceramics,
In the present embodiment, a pair of core halves 2 which have substantially the same shape,
4, the abutting surfaces of the cores 2 and 4 are integrally joined via the gap portion 6.

According to this embodiment, in each of the core halves 2 and 4, the chamfered portion 12 is formed by machining adjacent to the gap portion 6, that is, from a predetermined gap depth (D) position (apex). 14 are formed with chamfer angles α ₁ and α ₂ , respectively, so that the chamfers 12, 1 of both core halves 2, 4 are therefore formed.
At 4, an apex portion 8 having an apex angle α (= α ₁ + α ₂ ) is defined. Here, the chamfering angles α ₁ and α ₂ of the two core halves ₂ and 4 refer to the core 2 as shown.
And the opening angle of the core 4 from the butting surface 6.

According to the invention, the apex angle α is 1
30 ° or more and 170 ° or less (130 ° ≦ α ≦ 1
70 °). Further, in the present embodiment, α ₁ ≈α ₂ ≈α / 2. Therefore, 65 ° ≦ α ₁ (≈α ₂ ) ≦ 85 °.

In the magnetic head 1 having the structure shown in FIG. 1, the present inventors have an external shape (H, W) of the magnetic head 1.
And the gap depth (D) by changing the chamfering angles α ₁ and α ₂ of the two core halves 2 and 4, that is, the apex angle α, without changing the dimensions (h and w) of the winding window 20. Was set to 2 μm and the magnetic characteristics were examined. Of course, the height (H) of the winding window 20 changes according to the change of the apex angle α.
H ', H ", etc. The results are shown in FIG.

In the configuration of the first embodiment, the apex angle α is 1
As can be seen from FIG. 3, in the magnetic head 1 of the present invention in which the angle is 30 ° or more, that is, α ₁ = α ₂ = 65 ° or more, the magnetic field gradient is substantially constant even if the magnetomotive force increases. As compared with the conventional magnetic head having an apex angle α of 85 to 110 ° shown in FIG. 5, the roll-off can be suppressed to be small, and the problem of recording demagnetization does not occur. That is,
The playback output does not decrease even if the recording current is increased.

Further, when the reading (reproducing) efficiency (η) in the gap portion 6 was calculated, the results shown in Table 1 were obtained. As can be seen from Table 1, the magnetic head of the first embodiment can achieve a reproducing efficiency equal to or higher than that of a conventional magnetic head having an apex angle α of 85 ° to 110 °.

However, when the apex angle α exceeds 150 °, particularly 170 ° or more, the roll-off can be reduced, but the reproduction efficiency is remarkably lowered, and a magnetic head having good reproduction efficiency is required. In particular, the apex angle α is preferably 150 ° or less. It is also preferable to set the apex angle α to 170 ° or less, preferably 150 ° or less from the viewpoint of mechanical strength of the apex portion 8 of the magnetic head.

The read (reproduction) efficiency (η) in the gap portion is expressed by the following equation.

[0021]

[Equation 1]

[0022]

[Table 1]

Further, referring to Table 1, the magnetic head 1 of the present invention
Shows that the reproduction efficiency is highest when the apex angle α is 70 °, but this is because the winding window 20 approaches the gap portion 6 and the winding position approaches the gap portion 6 as the apex angle α increases. Therefore, the effect of increasing the magnetic flux leakage during the period and the increase of the reproducing efficiency and the increasing the apex angle α increase the leakage of the magnetic flux from the portion A of the core 2 (core 4) shown in FIG. It is considered that this is because the effect that the magnetic flux to the gap portion 6 becomes difficult to flow and the reproduction efficiency is reduced is offset.

Embodiment 2 FIG. 2 shows a second embodiment of the present invention. The magnetic head 1 of this embodiment has the same structure as that of the first embodiment, except that the apex portion 8 is defined by first and second chamfered portions formed on the cores 2 and 4. Different in.

That is, in each of the cores 2 and 4, the first chamfered portions 12a and 14a are machined from the predetermined gap depth (D) position (apex), respectively, to obtain the chamfering angle α.
The second chamfered portions 12b and 14b are formed of ₁ and α ₂ .
Are connected to the first chamfered portions 12a and 14a and are machined to form chamfering angles β ₁ and β ₂ , respectively.
Therefore, the apex portion 8 has the first apex angle α (= α ₁ + α which is close to the gap portion 6 of both core halves 2 and 4.
₂ ) and the second chamfered portions 12a, 12b; 14 formed by the second apex angle β (= β ₁ + β ₂ ).
It is defined by a and 14b. Where both core halves 2, 4
Chamfering angles α ₁ , α ₂ ; β ₁ , β ₂ are opening angles from the abutting surfaces of the core 2 and the core 4, as shown in the drawing.

Also in this embodiment, the first apex angle α is equal to or larger than 130 °, 170, and 170, as in the first embodiment.
Is less than or equal to 130 ° (130 ° ≦ α ≦ 170 °), and the second apex angle β is β <α. Further, in this embodiment, α ₁ ≈α ₂ ≈α / 2 and β ₁ ≈β ₂ ≈β / 2. Therefore, 65 ° ≦ α ₁ (≈α ₂ ) ≦ 85 °, β ₁ <
α ₁ and β ₂ <α ₂ .

In the magnetic head 1 having the structure shown in FIG. 2, the present inventors have an external shape (H, W) of the magnetic head 1.
And the dimensions (h, w) of the winding window 20 are not changed, and the second
The apex angle β of 90 °, that is, β ₁ = β ₂ = 45
And the gap depth (D) was set to 2 μm, the first apex angle α was variously changed and calculations were performed to examine the magnetic properties. Of course, depending on the change in the first apex angle α,
The height (H) of the winding window 20 varied such as H ′ and H ″. The same result as in the case of Example 1 shown in FIG. 3 could be obtained.

Further, when the reading (reproducing) efficiency (η) in the gap portion 6 was calculated, the results shown in Table 2 were obtained.

[0029]

[Table 2]

As shown in Table 2, in the magnetic head 1 of the second embodiment, the apex portion 8 is closer to the gap portions of the core halves 2 and 4 as compared with the magnetic head 1 of the first embodiment. The first apex angle α (= α ₁ + α ₂ ) and the second apex angle β (= β ₁ + β ₂ ) are defined by the first and second chamfers. Even if the apex angle α is set to be large, the mechanical strength of the gap portion 6 is increased, and even if the first apex angle α is increased, A shown in FIG. There is an effect that the problem of magnetic flux saturation in the part is alleviated, and the reduction rate of the reproduction efficiency is suppressed.

Embodiment 3 FIG. 4 shows still another embodiment of the present invention. In this embodiment, the apex angle α is set to 130 ° or more and 170 ° or less, similarly to the magnetic head of the first embodiment (130).
° ≤ α ≤ 170 °), but in the present embodiment, each core half 2,
The chamfering angles α ₁ and α ₂ formed in _No. 4 are different. However, neither chamfering angle α ₁ or α ₂ is set to 85 ° or more. This is the chamfer angle α ₁ , α ₂
Is more than 85 °, not only the regeneration efficiency is significantly lowered, but also the mechanical strength of the apex portion 8 is largely reduced, which is not preferable.

Although not shown, also in the magnetic head of the second embodiment shown in FIG. 2, chamfering angles α ₁ and α ₂ , and β ₁ formed in the core halves 2 and 4 are the same as in the third embodiment. And β ₂ can be set to different values. However, none of the chamfering angles α ₁ , α ₂ , β ₁ , and β ₂ is 85 ° or more.

In each of the above embodiments, the magnetic head 1 of the present invention is used.
The magnetic film 100 has been described in relation to the Fe-Si-Al alloy magnetic body, but an amorphous magnetic body, an iron nitride magnetic body, or the like can be used as well.

[0034]

As described above, in the magnetic head according to the present invention, the apex angle α in the apex portion formed by the pair of core halves is 130 ° ≦ α ≦ 170 °.
Therefore, while maintaining the same regeneration efficiency as before,
In particular, the roll-off can be reduced and the recording demagnetization characteristic can be improved.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of a magnetic head according to the present invention.

FIG. 2 is a front view of another embodiment of the magnetic head according to the present invention.

FIG. 3 is a graph showing roll-off characteristics of the magnetic head of the present invention and the conventional magnetic head.

FIG. 4 is a front view of still another embodiment of the magnetic head according to the present invention.

FIG. 5 is a perspective view showing an example of a conventional magnetic head.

FIG. 6 is a front view showing an example of a conventional magnetic head.

[Explanation of symbols]

 1 Magnetic Head 2, 4 Core Half 12, 14 Chamfer 6 Gap 8 Apex 10 Apex Glass 20 Winding Window

Claims (2)

[Claims] 1. A magnetic head in which a pair of core halves each having a magnetic thin film are joined at their abutting surfaces via a gap portion, and an apex portion is formed adjacent to the gap portion. Is the apex angle α
The apex angle α defined by the chamfered portion formed in 1. is 130 ° ≦ α ≦ 170 °. 2. A magnetic head in which a pair of core halves each having a magnetic thin film are joined at their abutting surfaces via a gap portion, and an apex portion is formed adjacent to the gap portion. Is a first chamfer formed at a first apex angle α adjacent to the gap, and a second chamfer connected to the first chamfer at a second apex angle β. The first apex angle α is defined by a chamfered portion, and the first apex angle α is 130 ° ≦ α ≦ 1.
The magnetic head is 70 °, and the second apex angle β is β <α.