JP2002312906A - Magnetic head manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the recording and reproducing performance of a magnetic head more by carrying out a heat treatment (annealing) which greatly improves the head characteristics. SOLUTION: When a heat treatment, in which the peak temperature is equal to or lower than the glass transition point, carried out for a magnetic head chip to eliminate internal distortion during the formation of the magnetic head chip, the heat treatment is carried out by a temperature pattern having peaks twice or more (S103, S109).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic head for use with a magnetic tape as one of recording media.

[0002]

2. Description of the Related Art In recent years, magnetic recording technology has been required to have higher and higher recording density with the progress of digitization. For example, a magnetic head using a magnetic tape as a recording medium for a VTR (Video Tape Recorder) device has been demanded. With respect to the above, there is a demand for a recording / reproducing capability (hereinafter, simply referred to as "head characteristics") in the used frequency band.

As a magnetic head capable of coping with such a high recording density, for example, a bulk type MIG (Metal in G
ap) Heads are widely known. The bulk type MIG head is configured using a magnetic head chip 10 as shown in FIGS. 5A and 5B, for example. This magnetic head chip 10 is formed by joining a pair of magnetic core halves 11 made of a magnetic material such as ferrite and joining them together via a low-melting glass 12 so that the joined portion functions as a magnetic gap 13. Has become. A metal magnetic thin film 14 made of a ferromagnetic material such as sendust is disposed only in the vicinity of the magnetic gap 13, thereby improving the head characteristics. The magnetic head chip 10 includes a magnetic gap 13, a metal magnetic thin film 14 near the magnetic gap 13, and a pair of magnetic core halves 1 sandwiching the magnetic gap 13 for sliding with a magnetic tape.
1 is a sliding surface 1 formed in a substantially arc shape with one end edge exposed.
5 is provided. Furthermore, it also has a winding window 16 located at a substantially central portion of the pair of magnetic core halves 11, and a winding guide groove 17 located at each end edge. And FIG.
As shown in FIG.
The coil wire 20 is wound along the direction substantially parallel to the sliding surface 15 by utilizing the coil 7, thereby forming a MIG head.

The MIG head having such a configuration is generally manufactured by the following procedure. That is, in manufacturing the MIG head, first, FIG.
As shown in (a), a pair of magnetic core half blocks 18 in which a track width regulating groove group is machined on one surface, and a metal magnetic thin film 14 is sputtered on the track width regulating groove group, The thin film 14 is sandwiched therebetween. These magnetic core half blocks 18 are made of a magnetic material such as ferrite, and become the magnetic core half 11 by slicing later. Then, in this state, the low melting glass 12 is filled in the track width regulating groove group, and the pair of magnetic core half blocks 18 are joined to each other. At this time, the magnetic core half block 18 includes:
It is assumed that the winding window 16 has already been processed.

After the magnetic core half blocks 18 are joined to each other, as shown in FIG. 7B, winding guide grooves 17 are formed on both sides of the joined body,
Forming and cutting of the outer shape is performed, such as roughing one surface with the exposed edge of the surface 4 along the shape of the sliding surface 15. Then, as shown in FIG. 7 (c), the joined body after the outer shape is sliced so as to be separated for each head, and the rough-cut sliding surface 15 is subjected to lapping to form the magnetic head chip 10. I do. Thereafter, the winding window 1 is applied to each magnetic head chip 10 by an automatic winding machine, manual work, or the like.
The coil wire 20 is wound around the portion 6 and the winding guide groove 17. Thus, the MIG head having the above-described configuration is completed.

In the manufacturing process of the MIG head as described above, the difference in the coefficient of thermal expansion between the magnetic core half block 18, the metal magnetic thin film 14, and the low melting point glass 12 generated during the glass melting and curing is caused. Stress (strain)
And stress (strain) generated at the time of forming the magnetic core half block 18 or the magnetic head chip 10, etc.
It is conceivable that the magnetic head chip 10 remains inside or on the surface. Such a magnetic head chip 1
Internal strain remaining inside or on the surface of 0 may adversely affect head characteristics.

For this reason, usually, in the process of manufacturing a MIG head, a so-called anneal (annealing) is performed on the magnetic head chip 10 after forming the magnetic head chip 10 in a process close to the final stage. Is performed to alleviate internal distortion and the like in the magnetic head chip 10.

Conventionally, the magnetic head chip 10 is annealed by placing the magnetic head chip 10 to be processed in a furnace. The peak (Max) temperature in the furnace does not impair the function of the magnetic head, that is, Generally, the temperature is set to be equal to or lower than the transition point (Tg) of the low melting point glass 12 which is a glass material. Then, as shown in FIG. 8, the inside of the furnace is heated to a peak temperature (see part A in the figure), and after maintaining the peak temperature for a certain time (see part B in the figure), the furnace is gradually cooled (C in the figure). Section)).
At this time, various proposals have been made for the peak temperature holding time and the rate of change (for example, ° C./min) at the time of temperature rise / fall, but in each case the temperature pattern has one peak.

[0009]

By the way, the effect obtained by performing the annealing is as follows.
An object of the present invention is to improve the adverse effect on the head characteristics due to internal distortion at 0. However, since it is not easy to quantitatively measure the internal distortion or the like in the magnetic head chip 10, usually, the recording / reproducing ability is measured after the MIG head is completed, and as a result, the adverse effect due to the internal distortion or the like is improved. It is just checking whether it is. That is, although the improvement of the recording / reproducing ability by the annealing can be grasped from the measurement result or the like, it is difficult to confirm whether the internal distortion or the like is completely removed by this.

Therefore, in the above-described conventional annealing, it is determined whether or not the adverse effect on the head characteristics due to the internal distortion or the like is completely eliminated, that is, until the state where all the capabilities inherent to the magnetic head can be fully exhibited. It is not clear whether the characteristics are improved. From this, the inventor of the present application has concluded that the degree of improvement in the head characteristics has not reached the characteristic level originally possessed by the magnetic head in the conventional annealing.

The present invention has been made in view of the above circumstances, and a magnetic head capable of further improving the recording / reproducing ability by performing a heat treatment (annealing) with a higher degree of improvement in head characteristics than in the past. It is an object of the present invention to provide a method for producing the same.

[0012]

In order to achieve this object,
The present invention joins a pair of magnetic core halves via a butt glass material, forms a magnetic head chip in which the butt portion functions as a magnetic gap, and then configures a magnetic head using the magnetic head chip. In the method of manufacturing a magnetic head, the magnetic head chip is subjected to a heat treatment having a peak at a temperature equal to or lower than the glass transition point to remove internal strain when the magnetic head chip is formed, and has two or more peaks. The heat treatment is performed in a temperature pattern.

According to the method of manufacturing a magnetic head according to the above procedure, the heat treatment is performed in a temperature pattern having two or more peaks. Therefore, for example, the magnetic head chip is formed of a composite material such as a magnetic material or a glass material forming a magnetic core half. Thus, the internal strain of each material can be reduced, and as a result, the internal strain remaining in the inside, the surface, and the like of the magnetic head chip can be sufficiently reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a magnetic head according to the present invention will be described below with reference to the drawings. However, here, only differences from the conventional magnetic head manufacturing method will be described.

The method of manufacturing a magnetic head according to the present invention differs from the conventional method in the annealing process performed on the magnetic head chip. The magnetic head to be manufactured (for example, a MIG head)
(See FIGS. 5 and 6) and the manufacturing procedure other than the annealing process (see FIG. 7) are substantially the same as in the prior art.
Here, the description is omitted.

The annealing process of the present invention is also performed in a state where the magnetic head chip 10 is placed in a furnace after the formation of the magnetic head chip 10, as in the conventional case. Then, for the magnetic head chip 10 to be processed,
Heating and gradual cooling are performed with the temperature equal to or lower than the glass transition point (Tg) as a peak, and the internal distortion when the magnetic head chip 10 is formed is removed.

The magnetic head chip 10 is made of a composite material (for example, a magnetic material such as ferrite or a non-magnetic material such as glass) as described above. In order to reduce the stress (internal strain) caused by each material, there is an annealing condition suitable for each material. However, after the magnetic head chip 10 is configured, the upper limit of the peak temperature of the annealing process is set as a magnetic field. A temperature that does not impair the function of the head is selected. Usually, this is the glass transition point. However, when the temperature at which the glass transition point is not exceeded is set as a peak, the degree of improvement in the head characteristics reaches the characteristic level originally possessed by the magnetic head if there is only one peak as in the conventional case. It is not considered. This is because although the internal strain caused by the glass material is moderated to some extent, for example, when a glass material having a high melting point is used or a material other than glass (a ferrite material, a metal magnetic thin film, a gap material, etc.) is used. This is because there is a possibility that the resulting internal strain may not be sufficiently reduced. This is because, as a result of performing the annealing treatment by changing the peak temperature delicately or changing the peak temperature holding time in the temperature pattern having one peak, no remarkable improvement was observed. it is obvious.

From the above, in the annealing treatment in the present invention, the peak temperature is equal to or lower than the glass transition point because the function as the magnetic head is not hindered, but the number of peaks is set to 2 or more.

Specifically, for example, as shown in FIG. 1, a temperature pattern having two peaks can be considered. That is, the temperature in the furnace is raised to a peak temperature (for example, about 410 ° C.) (steps 101 and 102; steps are abbreviated as “S”), and the peak temperature is kept for a certain time (for example, 1 ° C.).
(S103) and then slowly cooled to a predetermined temperature (for example, a peak temperature of about −20 ° C.) (S10).
4, 105). After a lapse of a predetermined time (S106),
The temperature is raised again to substantially the same peak temperature (S107, 10
8) After maintaining the peak temperature for substantially the same time (S1
09), and gradually cooled to normal temperature (S110, 111).

At this time, the heating rate and the cooling rate are, for example, 0.3 to 2.0 ° C./min. However, when the temperature rises to the peak temperature and when the temperature falls from the peak temperature,
It goes without saying that since the cooling is performed, the cooling rate is smaller (the temperature curve is gentler).

Further, two types of rates are set for the temperature gradient when the temperature is raised to the peak temperature and when the temperature is lowered from the peak temperature. That is, the temperature gradient has a gentle rate near the peak temperature (S102, 1).
04, 108, and 110), and the others have sharper rates than near the peak temperature (S101, 105, 107, and 110).
111). The temperature at which the two types of rates change may be appropriately set in consideration of the peak temperature, furnace performance, and the like.

As described above, according to the temperature pattern having two peaks, it is almost the same as repeating the annealing process based on the glass transition point twice, so that the magnetic head chip 10 is made of a composite material. Even if it is performed, it becomes possible to alleviate the internal strain of each material including the glass material. As a result, internal distortion remaining inside or on the surface of the magnetic head chip is sufficiently mitigated, and the magnetic recording / reproducing characteristics when the magnetic head is formed can be further improved than before.

In addition, in performing the annealing process with the temperature pattern having two peaks, the temperature is raised to the peak temperature and lowered from the peak temperature by two types of temperature gradients, respectively, so that the temperature is moderate near the peak temperature. A steep temperature gradient in other temperature ranges,
It is possible to raise and lower the temperature respectively. Therefore,
Even if the annealing process based on the glass transition point is repeated twice, it is possible to sufficiently improve the magnetic recording / reproducing characteristics when the magnetic head is configured, while suppressing the deterioration of the productivity as much as possible. become. This is because, in the vicinity of the glass transition point, it is preferable to raise and lower the temperature as slowly as possible (reducing the temperature gradient) in order to eliminate internal strain, but in other temperature regions, it is preferable to raise and lower the temperature in consideration of productivity. This is because a temperature (a large temperature gradient) is more preferable.

From these facts, if the annealing process is performed according to the above-mentioned temperature pattern, the resulting MIG can be obtained.
It can be said that the head can sufficiently realize excellent head characteristics as compared with the MIG head obtained by the conventional annealing treatment (see FIG. 8). Specifically, the recording / reproducing output (frequency band to 20 MHz) is 0.5
It was found to improve by about 1.0 dB.

Since only the temperature pattern is different from the conventional one, the above-described annealing can be performed using the same equipment (furnace or the like) as the conventional one, and the magnetic head can be used without requiring a new configuration or the like. The head characteristics can be improved.

In the above-described temperature pattern, the temperature increase / decrease range, the temperature rising rate, the temperature decreasing rate, the peak temperature holding time, and the like are set as in the above specific example (for example, about 410 ° C. for the peak temperature). Is preferred. This is to ensure the improvement of the head characteristics and to suppress the original improvement effect when performed under other conditions (for example, the head characteristics are worse than when performed under the conventional annealing conditions). , And the productivity may be deteriorated).

The annealing treatment in the present invention is not limited to the above-mentioned temperature pattern, that is, a temperature pattern in which the same peak temperature is repeated twice. Here, another temperature pattern of the annealing process in the present invention will be described.

As another temperature pattern, as shown in FIG. 2, for example, as in the case described above, the number of peaks is two, but each peak temperature (S203, 209)
Are different from each other. In this case, even if the magnetic head chip 10 is made of a composite material, each peak temperature can be set according to each material.

As another temperature pattern, for example, as shown in FIG. 3, as in the case described above, the number of peaks is two, and the temperatures are substantially the same (S303, 310). After the respective peaks are reached, the same temperature is not maintained and gradually decreases (S304, 3).
11) Examples are given. In this case, since the temperature gradually decreases after reaching the peak, the time required for cooling can be slightly shortened as compared with the case where the same temperature is maintained, and the productivity can be further improved.

Further, as another temperature pattern,
For example, as shown in FIG.
3) There is an example in which the subsequent temperature amplitudes (S404 to S415) are set in a wave shape. As a result, the number of peaks becomes two or more times (for example, four times). Therefore, when the magnetic head chip 10 is made of various types of composite materials,
It is possible to flexibly cope with setting each peak temperature and its holding time according to each material.

Since each of these examples has a temperature pattern in which the peak is repeated twice or more, the same as the above-described temperature pattern in which the same peak temperature is repeated twice, the conventional magnetic head has The head characteristics can be improved.

In each of the examples, the temperature pattern has two or more peaks. However, the temperature between the peaks (valleys) is determined by the peak temperature in order to ensure the repetitive effect of each peak. It is preferable that there is a certain difference (for example, −20 ° C. or more). In addition, between each peak, the temperature may be left for a long time (for example, several hours) after the temperature has dropped, or the temperature may be lowered to room temperature. Even in this case, the repetitive effect of each peak can be obtained.

In the present embodiment, the magnetic head chip 10 to be processed is M
The case of forming an IG head has been described as an example, but the present invention is not limited to this, and a composite material in which a pair of magnetic core halves are joined via a butt glass material is used. As long as it is a bulk type magnetic head, other magnetic heads can be applied in exactly the same manner.

[0034]

As described above, according to the method of manufacturing a magnetic head of the present invention, heat treatment (annealing) is performed in a temperature pattern having two or more peaks. High heat treatment can be realized, and the recording / reproducing ability of the magnetic head can be further improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a temperature pattern in an example of an annealing process according to the present invention.

FIG. 2 is an explanatory diagram (part 1) illustrating a temperature pattern in another example of the annealing process according to the present invention.

FIG. 3 is an explanatory diagram (part 2) illustrating a temperature pattern in another example of the annealing process according to the present invention.

FIG. 4 is an explanatory diagram (part 3) illustrating a temperature pattern in another example of the annealing process according to the present invention.

5A and 5B are diagrams showing an outline of an example of a conventional magnetic head, wherein FIG. 5A is a perspective view thereof, and FIG. 5B is a partially enlarged view thereof.

FIG. 6 is a perspective view showing a specific example of a magnetic head in a state where a coil wire is wound.

FIGS. 7A and 7B are perspective views showing an example of a general magnetic head manufacturing procedure, in which FIG. 7A is a view showing a state after a pair of magnetic core half blocks are joined, and FIG. FIG. 3C is a diagram illustrating a state after processing, and FIG. 3C is a diagram illustrating a state after separation and slicing for each head.

FIG. 8 is an explanatory diagram showing a temperature pattern in an example of a conventional annealing process.

[Explanation of symbols]

10 magnetic head chip, 11 magnetic core half, 12 ...
Low melting point glass, 13: magnetic gap, 15: sliding surface, S
103, S109, S203, S209, S303, S
310, S403, S407, S411, S415 ... peak temperature

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahiro Konno 30th Kagano Border, Takae Niida, Nakata-cho, Tome-gun, Miyagi Prefecture Sony Miyagi Co., Ltd. F-term (reference) 5D093 AA01 FA09 FA21 HB15

Claims (2)

[Claims] 1. A pair of magnetic core halves are joined via an abutting glass material to form a magnetic head chip whose abutting portion functions as a magnetic gap, and thereafter, a magnetic head is formed using the magnetic head chip. In the method of manufacturing a magnetic head, a heat treatment is performed on the magnetic head chip with a peak at a temperature equal to or lower than the glass transition point to remove internal strain when the magnetic head chip is formed.
A method for manufacturing a magnetic head, wherein the heat treatment is performed in a temperature pattern having at least two times. 2. The method of manufacturing a magnetic head according to claim 1, wherein the heat treatment is performed in a temperature pattern having at least two types of temperature gradients when the temperature is raised to a peak temperature and when the temperature is lowered from the peak temperature. .