JPS61260405A - Magnetic head - Google Patents

Abstract

PURPOSE:To reduce considerably the variable of a head output due to the variance of track width by uniforming the distribution of the magnetic characteristic in the gap depth direction of a magnetic pole forming material near a head gap to allow a geometrical head gap depth to coincide with an effective head gap depth. CONSTITUTION:An inside slope 19 of a coil wining window 3 is provided to form an acute angle theta' to ahead gap opposite face 4 in the direction of a head sliding face 14, and an end part 20 of a magnetic tin film layer 2 is chamfered at an angle theta smaller than the acute angle theta' between the head gap opposite face 4 and the inside slope 19 of the coil winding window 3 to form a chamfered part 11 on the inside slope 19 of the coil wining window 3. A position 12 where this chamfered part 11 intersects the head gap opposite face 4 is about 1-5mum off a bending position 13 of the magnetic thin film layer 2, which is provided on a core base body 17 on the side of a C type block, off to the head sliding face 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic head, and more particularly to a highly reliable ring-shaped magnetic head that has excellent magnetic recording and reproducing characteristics and has a magnetic pole structure with little variation in performance.

[Background of the invention]

A conventional method for manufacturing a ring-type magnetic head using a magnetic thin film having a high saturation magnetic flux density as a magnetic pole forming material is disclosed in Japanese Patent Laid-Open No. 59-8120, in which a coil shown in FIG. A C-shaped block 1 in which a magnetic thin film layer 2 is provided on a core base 17 having a coil winding window 3, and a C-shaped block 1 in which a magnetic thin film layer 2 is provided on a core base 17 without a coil winding window shown in FIG.
After polishing the surface of each magnetic thin film layer 2 to form a head gap facing surface 4, the magnetic thin film layer 2 is formed into a corresponding I-type block 5 with an SiO layer forming the magnetic gap. The magnetic head chip shown in FIG. 9 is obtained by bonding the head gap facing surface 4 and then cutting along a plane substantially perpendicular to the head gap facing surface 4 through the V-shaped groove 18. I can do it. FIG. 10 is a sectional view taken along the line C--C of the magnetic herad tip in FIG. 9, and FIG. 11 is an enlarged sectional view of section D in FIG. 10.

In such a conventional magnetic head, the depth of the head gap 6 extends from a position 12' where the magnetic thin film layer 2 on the inner inclined surface of the coil winding window of the C-shaped block intersects with the head gap facing surface to the head sliding surface 14. Fig. 11 shows the head output of the magnetic head when the distance to < , di', d, /, d3' changes.

As shown in FIG. 12, the depth of the head gap 6 is d1'.
.

As d2/ and d3/ become smaller, the head output increases, but when the depth becomes about 10 μm, for example, the head output hardly increases.
The manner in which the head output changes varies depending on the manufactured magnetic head, and the performance varies greatly.

When the depth of the head gap 6 is sufficiently large, for example, 10 μm or more (head gap depth d1'), the head sliding surface 14 becomes as shown in FIG. 13(a).
Although the track width tw can be clearly defined, when the head gap depth becomes small (head gap depth d2'), for example, 10 μm or less, and the increase rate of the head output becomes small, the head sliding surface becomes As shown in FIG.
5 appears, and when the magnetic properties of the core protective layer 16 and the magnetic thin film layer 2 are different, a pseudo gap effect occurs at the boundary 15, so that the magnetic head output during magnetic recording and reproduction is Waviness occurs in the frequency characteristics of
The so-called contour effect
) appears. This phenomenon can occur even when the core protective layer 16 is made of a non-magnetic material.

Furthermore, if the head gap depth is reduced to, for example, 2 to 3 μm (bed gap depth d3'), the head sliding surface becomes as shown in FIG. 13(C) (the head gap of the magnetic head On the opposing surface, a curved surface is formed at the end of the magnetic thin film layer 2 on the side of the C-shaped block 1, and a track width t'
w becomes a smaller value than the track width tw shown in FIG. 13(a), which causes a decrease in the magnetic head output, and also makes the definition of this track width t'w unclear.

As mentioned above, in the conventional magnetic head using the magnetic thin film layer 2 as the magnetic pole forming material, even if the depth of the head gap 6 is reduced, it is difficult to obtain the effect of increasing the head output (and the track There is also a drawback that the width tw gradually decreases and the head output decreases.Also, the magnetic thin film layer 2 and the core base 17 have a boundary 15 formed by the magnetic pole end parallel to the head gap. Therefore, there are problems such as a contour effect occurring during magnetic recording and reproduction due to the pseudo gap effect.

[Purpose of the invention]

The purpose of the present invention is to solve the problems of the prior art described above,
It is an object of the present invention to provide a ring-shaped magnetic head having a magnetic pole structure that has excellent magnetic recording and reproducing characteristics, small variations in performance characteristics, and high reliability.

[Summary of the invention]

In order to achieve the above object, the present invention provides a ring-type magnetic head using a magnetic thin film layer having a high saturation magnetic flux density, at a position where the head gap facing surface intersects with the inner inclined surface of the coil winding window. A non-magnetic reaction layer is formed on the surface of a magnetic thin film layer by chamfering the edges of a certain magnetic thin film layer using processing methods such as polishing, which causes deterioration of magnetic recording and reproducing characteristics. by removing
The main idea is to match the geometrical head gap depth with the effective head gap depth to improve recording and reproducing characteristics.

The magnetic head according to the present invention has a C-shaped block in which a magnetic thin film layer having a high saturation magnetic flux density is provided on a core substrate having a coil winding window, and a head gap facing surface formed by the above magnetic thin film layer, and a coil winding. A core base without windows,
The head gap opposing surface formed by the magnetic thin film layer of the I-type block provided with the magnetic thin film layer having a high saturation magnetic flux density is joined via the head gap, which is a magnetic gap formed by a nonmagnetic thin film. In a ring-type magnetic head in which a magnetic circuit is formed by forming a magnetic circuit, the inner inclined surface of the coil winding window of the C-shaped block provided with the magnetic thin film layer faces the head gap formed by the C-shaped block or the ■-shaped block. The coil winding window is provided at an acute angle (90 degrees or less) in the direction of the head sliding surface, and the inner inclined surface of the coil winding window on which the magnetic thin film layer is provided intersects with the surface facing the head gap. The inner sloped surface of the magnetic thin film layer at the position where the magnetic thin film layer is located is chamfered at an angle smaller than the acute angle formed by the head gap facing surface and the inner sloped surface of the coil winding window. The later inner inclined surface (chamfered part) of the coil winding window is
The position where the head gap facing surface intersects with the above C
It is characterized in that lζ is provided so as to be located closer to the head sliding surface than the bending position of the magnetic thin film layer near the head gap provided on the core base on the mold block side.

In the magnetic head of the present invention, when the head gap depth is reduced to improve magnetic recording and reproducing efficiency, the boundary between the core base and the magnetic thin film layer does not form a part parallel to the head gap on the head sliding surface. A magnetic head with a magnetic pole structure that prevents pseudo-gap effects during recording and reproduction and has a contour that causes undulations in the frequency characteristics of the head output.
This is a high-performance and highly reliable magnetic head that prevents the effects from appearing.

Furthermore, in the magnetic head of the present invention, even if the head gap depth is extremely small, the end of the magnetic thin film layer, which is the magnetic pole on the C-shaped block side, becomes a curved surface in the head gap portion of the head sliding surface. This is a magnetic head with excellent recording and reproducing characteristics, which eliminates the reduction in track width that would otherwise lead to a decrease in head output.

[Embodiments of the invention]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing one embodiment of the present invention, a method for manufacturing a magnetic head according to a prior art and its performance will be described as a comparative example with reference to the drawings.

In the figures, parts with the same symbols are the same parts or parts having the same performance.

(Comparative Example) As an example of a conventional method for manufacturing a magnetic head, after joining a C-shaped block shown in FIG. 7 and an I-shaped block shown in FIG. Cut out a surface that passes through the provided V-shaped groove 18 and is approximately perpendicular to the head gap facing surface 4, and has an outer diameter of, for example, 3 x 3 mm.
, core thickness 150 μm.

A magnetic herad chip with a track width of 30 μm is manufactured.

Now, in the magnetic head, if the magnetic permeability of the magnetic material forming the magnetic pole near the head gap 6 is constant,
Regarding the relationship between the head gap depth and the magnetic recording/reproduction efficiency, as shown by curve 9 in FIG. 14, the reproduction efficiency increases as the head gap depth becomes smaller. However, when a magnetic thin film layer is used as the magnetic pole forming material, as shown in FIG. The dependence of the magnetic permeability on the gap depth in the vicinity of the gap 6 is not uniform as shown in the curve 10 shown in FIG. The dependence of the head output on the gap depth in FIG. It appears as a composite characteristic with curve 10 showing the gap depth dependence of magnetic permeability when the gap depth is not uniform, and the head output is the 12th
As shown by the curve shown in the figure, when the head gap depth becomes smaller than a certain value, the head output decreases.

The non-magnetic reaction layer of the magnetic thin film is also formed on the head gap facing surface of the magnetic head, but before joining the C-shaped block and ■-shaped block, the head gap facing surface is made flat. Since the surface of each block facing the head gap is polished, the nonmagnetic reaction layer is removed.

However, as shown in FIG. 11, since the nonmagnetic reaction layer 8 on the inner inclined surface 19 of the coil winding window remains unpolished, the magnetic permeability of the magnetic thin film near the magnetic head gap is as shown in FIG. 14. It changes as shown by curve 10 and becomes non-uniform, resulting in a significant drop in head output.

Then, as the head gap depth of the magnetic head is decreased, the magnetic head sliding surface 14 is formed as shown in FIG. The boundary portion 15 between the magnetic thin film layer 2 and the magnetic thin film layer 2 appears as a magnetic pole tip, and a pseudo gap effect occurs because the magnetic properties of the core supplementary layer 16 and the magnetic thin film layer 2 are different, and the frequency of the head output during magnetic recording and reproduction is A contour effect appears that causes waviness in the characteristics.Furthermore, as the depth of the head gap is made smaller, the sliding surface of the magnetic head becomes smaller than the magnetic thin film on the side of the C-shaped block l, as shown in Fig. 13(C). A curved surface is formed at the end of the layer 2, which reduces the track width t'w and causes a decrease in the output of the magnetic head.

(Example) Next, an example of the present invention will be described in more detail based on the drawings.

FIGS. 1 and 2 are perspective views showing the general appearance of a C-type block 1 and an I-type block 5 for manufacturing a magnetic head according to the present invention. As shown in the figure, coil winding window 3
In the C-shaped block l having the following structure, the inner inclined surface 1 of the coil winding window 3 provided with the magnetic thin film layer 2 on the head sliding surface 14 side
The non-magnetic reaction layer 8 formed at the edge portion (end portion) of the magnetic thin film layer 2 at a position 12 where 9 intersects with the head gap facing surface 4 is chamfered and polished to form a chamfered portion 11. The head gap facing surface 4 of the magnetic thin film layer 2 provided on the core substrate 17 of the C-shaped block 1 and the ■-shaped block 5 is polished flat, and the nonmagnetic reaction layer 8 on the magnetic thin film layer 2 is polished flat. All have been removed. Above C
The corresponding head gap opposing surfaces 4 of the mold block 1 and I-type block 5 are joined via a head gap, which is a magnetic gap made of a non-magnetic thin film, and the head passes through the V-shaped groove 18 of the core base 17. By cutting along a plane substantially perpendicular to the gap facing surface 4, the magnetic herad tip of the present invention shown in FIG. 3 is obtained. Figure 4 is A- in Figure 3.
5 is an enlarged sectional view of section B in FIG. 4.

As shown in the figure, the structure of the magnetic head of the present invention includes a C-type block 1 having a coil winding window 3 corresponding to an I-type block 5 having no coil winding window.
The inner inclined surface 19 is provided so as to form an acute angle θ' in the direction of the head sliding surface 14 with respect to the head gap facing surface 4 formed by the above-mentioned ■-shaped block 5 or C-shaped block 1, and the above-mentioned magnetic thin film The end portion 20 of the magnetic thin film layer 2 is located at a position where the inner inclined surface 19 of the coil winding window 3 on which the layer 2 is provided intersects with the head gap facing surface 4.
An angle θ smaller than the acute angle θ′ formed between the head gap facing surface 4 and the inner inclined surface 19 of the coil winding window 3
A chamfering process (method such as polishing) is performed to form a chamfered part 11, and a position 12 where this chamfered part 11 intersects with the head gap facing surface 4 is located on the core base on the side of the C-shaped block 1. It is provided at a position approximately 1 to 5 μm closer to the head sliding surface 14 than the bending position 13 of the magnetic thin film layer 2 provided at the magnetic thin film layer 17 .

Then, a position 13 where this chamfered portion 11 intersects with the head gap facing surface 4 and a core base 1 of the C-shaped block l.
The head gap facing surface 4 with the bending position 13 in the vicinity of the head gap 6 of the magnetic thin film layer 2 provided in the magnetic thin film layer 7
If the distance in the direction substantially parallel to is less than 1 μm, there will be a problem with processing accuracy, and if it exceeds 5 μm, the head output will decrease, so it is preferably in the range of 1 to 5 μm, and more preferably in the range of 2 to 3 μm. It is.

In the magnetic head according to the present invention having the above-mentioned magnetic pole structure, the head gap depth is set to d, in order to increase the head output.
d! , d, the dependence of the head output on the gap depth is shown in Figure 6.The head output continues to increase until the head gap depth approaches 0, and the head output continues to decrease. (The track width tw of the head sliding surface does not decrease at all, and the joint between the core base and the magnetic thin film layer appears parallel to the head gap on the head sliding surface, forming the magnetic pole tip.) Therefore, the contour effect that causes fluctuations in the frequency characteristics of the head output during magnetic recording and reproduction does not occur.As explained above, the magnetic head of the present invention has no effect on the magnetic recording and reproduction characteristics. It has an excellent magnetic pole structure with little variation in performance characteristics, resulting in high performance and extremely high reliability.

〔Effect of the invention〕

As described above in detail, the magnetic head according to the present invention has a uniform distribution of magnetic properties in the gap depth direction of the magnetic pole forming material in the vicinity of the head gap, and a geometrical head gap depth and an effective Since the head gap depth matches the head gap depth, the reproducing efficiency of the magnetic head increases reliably as the head gap depth is reduced, and there is also almost no variation in track width. For this reason, even if the head gap depth is set to a small value of 10 μm or less, the recording and reproducing characteristics of the magnetic head will always increase, and variations in head output due to variations in track width can also be significantly reduced. Furthermore, since there is no magnetic pole tip that causes a pseudo-gap effect on the head sliding surface, there is no negative effect during magnetic recording and reproduction, making it a high-performance, highly reliable magnetic head that is suitable for industrial use. The utility value is extremely large.

[Brief explanation of drawings]

1 and 2 are perspective views showing the outline of the C-shaped block and ■-shaped block of the magnetic head used in the embodiment of the present invention, and Fig. 3 shows the outline of the magnetic helad chip in the embodiment of the present invention. A perspective view, FIG. 4 is a sectional view taken along line A-A in FIG. 3,
FIG. 5 is an enlarged sectional view of part B in FIG. 4, FIG. 6 is a graph showing the gap depth dependence of the head output in the magnetic head used in the embodiment of the present invention, and FIGS. 7 and 8 are conventional FIG. 9 is a perspective view showing the general appearance of a conventional magnetic helad chip; FIG. 10 is a sectional view taken along line C-C in FIG. 9; FIG. 11 is an enlarged sectional view of section D in FIG. 10, FIG. 12 is a graph showing the gap depth dependence of head output in a conventional magnetic head, and FIG. 13(a). (b), (C1 is a plan view showing the shape of the head sliding surface in the case of head gap depths d, /, d, /, d3/ in a conventional magnetic head, and Figure 14 is a transparent view of the magnetic pole forming material. Relationship between head gap depth and reproduction efficiency when the magnetic permeability is constant and when the magnetic permeability of the magnetic pole forming material is not constant (
2 is a graph showing the relationship between head gap depth and magnetic permeability of a magnetic thin film layer. 1...C-type block 2...Magnetic thin film layer 3...
・Coil winding window 4...Head gap opposing surface 5...■ type block 6...Bed gap 7
...Reinforcement is lath 8...Nonmagnetic reaction layer 9...
・Change in regeneration efficiency 10... Change in magnetic permeability 11...
- Chamfered portion 12...Position 13 where the chamfered portion intersects with the head gap facing surface...Bending position 14 of the magnetic thin film layer of the C-shaped block.
...Head sliding surface 15...Boundary portion between the core base of the C-shaped block and the magnetic thin film layer 16...Core protection layer 17...Core base 18
... ■ shaped groove 19 ... inner inclined surface 20 of coil winding window ... end of magnetic thin film layer

Claims (1)

[Claims] 1. A C-shaped block in which a magnetic thin film layer with high saturation magnetic flux density is provided on a core base having a coil winding window, and a head gap facing surface formed by the above magnetic thin film layer and a coil winding. A magnetic gap formed by a non-magnetic thin film is formed between the head gap opposing surface formed by the magnetic thin film layer of the I-type block in which a magnetic thin film layer having a high saturation magnetic flux density is provided on a core base having no line window. In a magnetic head in which a magnetic circuit is formed by joining the magnetic thin film layer through a head gap, the inner inclined surface of the coil winding window of the C-shaped block provided with the above-mentioned magnetic thin film layer is connected to the above-mentioned C-shaped block or I-shaped block. The block is configured to form an acute angle in the direction of the head sliding surface with respect to the head gap facing surface, and the inner inclined surface of the coil winding window provided with the magnetic thin film layer is formed on the head gap facing surface. A chamfered portion is formed by chamfering the end of the magnetic thin film layer at the position where it is intersected at an angle smaller than the acute angle formed by the head gap facing surface and the inner inclined surface of the coil winding window. The position where the chamfered portion intersects with the head gap facing surface is set closer to the head sliding surface than the bending position of the magnetic thin film layer near the head gap provided on the core base on the C-shaped block side. A magnetic head characterized in that it is provided so as to be positioned. 2. The position where the chamfered portion intersects with the head gap facing surface and the bending position of the magnetic thin film layer provided on the core base on the C-shaped block side are substantially parallel to the head gap facing surface. The magnetic head according to claim 1, wherein the magnetic head is located at a distance of 1 to 5 μm in the direction.