JPH10334424A - Magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high quality magnetic head wherein a sufficient strength is maintained, excellent solvent resistance is provided and environmental resistance is improved. SOLUTION: A magnetic head is provided with a head substrate 9, a head element formed on the head substrate 9, a guard member 10 arranged to hold the head element with the head substrate 9, an external connection terminal led from the head element and a flexible cable 11 whose one end is connected to the external connection terminal and whose other end is connected to an external circuit. For at least a part of sides opposite a connected part between the flexible cable 11 and the external connection terminal and a medium sliding surface on the guard member 10 is covered with an elastomar resin. Here, the elastomar resin is preferably a silicon resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head constructed by combining a plurality of thin film magnetic heads.
In particular, the present invention relates to a magnetic head having improved environmental resistance and solvent resistance.

[0002]

2. Description of the Related Art In recent years, higher density recording has been demanded for magnetic recording, and in order to cope with this, narrower tracks and lower inductance of magnetic heads have been promoted. As a magnetic head suitable for such high-density recording, demand for a thin-film magnetic head manufactured by applying a thin-film process, which is particularly advantageous in terms of a high transfer speed, is growing.

[0003] In particular, as a magnetic head using a thin-film magnetic head, for example, a compound magnetic head combining a recording magnetic head and a reproducing magnetic head, which is used in a magnetic recording device for a data cartridge or the like, is used. Is mentioned. In this composite magnetic head, an inductive magnetic head is used as a recording magnetic head, and a magnetoresistive magnetic head is used as a reproducing magnetic head.

In general, a thin-film magnetic head has a magnetic circuit formed by a fine thin-film pattern, so that it is difficult to directly connect to an external power supply required for recording and / or reproduction.

Therefore, in the thin-film magnetic head, for connection to an external power source, external connection terminals are formed by a film of Cu or the like on a head substrate, and a flexible cable is crimped to the external connection terminals and soldered. The flexible cable is connected to an external circuit.

[0006]

By the way, in the thin-film magnetic head, after the above-mentioned flexible cable is crimped, a processing process such as cleaning with various solvents is added. For this reason, the joint between the flexible cable and the external connection terminal is required to have sufficient reliability for cleaning with a solvent and other processing. For this reason, as shown in FIG.
Appropriate resin is disposed and sealed so as to cover the surface 102a of the guard member 102 constituting the magnetic head 100 opposite to the medium sliding surface, that is, to fill the portion E in the drawing.

In order to reinforce the adhesive strength of the joint 101 between the flexible cable 103 and the external connection terminal, a surface 104a of the head substrate 104 constituting the magnetic head, which is opposite to the medium sliding surface, is coated. Thus, an appropriate resin is disposed so as to fill the portion F in the drawing.

[0008] The resin disposed in the above-mentioned portions E and F includes a solvent resistance to acetone and the like, ferrite,
Adhesive strength to ceramics such as Altic Al ₂ O ₃ .TiC is required. Therefore, as a resin satisfying these conditions, an epoxy resin has been proposed. In particular, in a magnetoresistive head, an epoxy resin that cures at about 150 ° C. or lower, which does not damage the magnetoresistive element, is disposed on the junction between the flexible cable and the external connection terminal and sealed.

A composite magnetic head having a recording and reproducing thin film magnetic head is required to have sufficient reliability in an actual use environment. In particular, when the thin film magnetic head is used for a storage device of a computer, the environmental test conditions to be satisfied by the thin film magnetic head are extremely strict. Is a condition that must be maintained.

However, as described above, at least a part of the joint between the flexible cable and the external connection terminal and the surface of the guard member on the side opposite to the medium sliding surface, that is, part E in FIG. In a composite magnetic head in which an epoxy resin is disposed, the epoxy resin swells when exposed to a high humidity environment.

The epoxy resin is provided to improve the solvent resistance and the adhesive strength, and a resin having a considerably high hardness is used particularly from the viewpoint of reinforcement. For this reason, as described above, when the epoxy resin swells, as shown in FIG. 10, the external force generated by the swelling does not act in a dispersed manner, and the guard is disposed so as to face the side surface of the head substrate 104. The guard member 102 is
In the direction of pushing out, ie, the direction I in the figure.
As a result, there has been a problem that the guard member 102 is pushed up and the bonding surface between the guard member 102 and the head substrate 104 is destroyed, which hinders recording and reproduction.

In particular, in the read head, the bonding surface between the head substrate and the guard member forms a read gap of the magnetoresistive element formed on the head substrate. Therefore, in the reproducing head, when the bonding surface between the guard member and the head substrate is broken as described above, the reproducing gap is broken, and the reproducing characteristics are deteriorated.

Accordingly, the present invention has been proposed in view of such conventional circumstances, and has sufficient strength, excellent solvent resistance, and environmental resistance to high humidity and the like. It is an object of the present invention to provide a high-quality magnetic head in which recording and / or reproduction is performed favorably with improved performance.

[0014]

According to the present invention, there is provided a magnetic head having a head substrate, a head element formed on the head substrate, and a head element sandwiched between the head substrate and the head element. It has a guard member, an external connection terminal derived from the head element, and a flexible cable having one end joined to the external connection terminal and the other end connected to an external circuit. Moreover, in the magnetic head according to the present invention, the joint between the flexible cable and the external connection terminal, and at least a part of the surface opposite to the medium sliding surface on the guard member are covered with the elastomer resin. It is characterized by being.

According to the magnetic head of the present invention configured as described above, at least a part of the joint between the flexible cable and the external joint terminal and at least a part of the surface of the guard member on the side opposite to the medium sliding surface are formed. This elastomeric resin is covered with an elastomeric resin having excellent elasticity without high hardness like epoxy resin,
Even when swelling under high humidity, it easily deforms in a direction to disperse the external force generated by the swelling. Thereby, the external force generated by the swelling of the resin can be absorbed, and the external force can be prevented from directly acting on the guard member. Therefore, according to the magnetic head of the present invention, it is possible to prevent the bonding surface between the guard member and the magnetic head from being broken.

Further, when the elastomer resin is a silicone resin, the solvent resistance can be further improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a magnetic head according to the present invention will be described below in detail with reference to the drawings. Here, as a magnetic head to which the present invention is applied, a composite magnetic head having a recording magnetic head and a reproducing magnetic head will be described. Incidentally, the magnetic head according to the present invention is not limited to this composite type magnetic head,
It is applied to a general thin film magnetic head.

As shown in FIG. 1, a magnetic head 1 according to the present invention comprises a recording magnetic head 2 (hereinafter simply referred to as a recording head 2).
Call. ) And a pair of reproducing magnetic heads 3A, 3B (hereinafter simply referred to as reproducing heads 3A, 3B) disposed in parallel on both sides of the recording head 2. The composite magnetic head 1 includes an erasing magnetic head 5 (hereinafter, simply referred to as an erasing head 5) disposed on one side of a reproducing head 3B and an erasing head 5 disposed on one side of a reproducing head 3A. Outriggers 4 to be provided.

The composite magnetic head 1 further includes a support member 6 for integrally supporting the recording head 2, a pair of reproducing heads 3A and 3B, an erasing head 5, and an outrigger 4. The actuator 7 is connected to the composite magnetic head 1 via the support member 6. That is, in the magnetic head 1 according to the present embodiment, the outrigger 4, the reproducing head 3B, the recording head 2, the reproducing head 3A, and the erasing head 5 are attached to the support member 6 in this order.

In the composite type magnetic head 1,
In a state where the reproducing head 3B, the recording head 2, and the reproducing head 3A are integrally joined in this order, one main surface of these heads is used as a medium sliding surface 8. This medium sliding surface 8
The cross-sectional shape is a curved surface.

When recording a magnetic signal, the recording head 2
When a desired current is supplied to a coil disposed therein, a leakage magnetic field is generated through a magnetic gap. The recording head 2 records a magnetic signal by applying the leakage magnetic field to the tape-shaped magnetic recording medium T.

On the other hand, in the reproducing heads 3A and 3B, when reproducing the magnetic signal, the head element detects a leakage magnetic field generated from the magnetic signal recorded on the tape-shaped magnetic recording medium T.
Thereby, the reproducing heads 3A and 3B reproduce the magnetic signal of the tape-shaped magnetic recording medium T.

In the composite type magnetic head 1, the above-described reproducing head 3B, recording head 2 and reproducing head 3A are joined in this order. For this reason, in the composite type magnetic head 1, regardless of the direction in which the tape-shaped magnetic recording medium T runs, immediately after the magnetic signal recorded by the recording head 2 is recorded, the reproduction heads 3A and 3B The magnetic signal is reproduced on either side.

The erasing head 5 has a wide magnetic gap exposed on the medium sliding surface 8, and a coil (not shown) is disposed inside the wide magnetic gap. In the erase head 5, a constant DC current is supplied to the coil. As a result, a magnetic field is generated in the erase head 5 from the coil, and a uniform leakage magnetic field is generated through the magnetic gap. The erasing head 5 erases the magnetic signal by applying the leakage magnetic field to the tape-shaped magnetic recording medium T.

The outrigger 4 is provided at an end opposite to the above-mentioned erasing head 5 and is for stably running the tape-shaped magnetic recording medium T. In the composite magnetic head 1, the outrigger 4 increases the contact area between the tape-shaped magnetic recording medium T and the medium sliding surface 8, so that the tape-shaped magnetic recording medium T runs stably.

In the composite type magnetic head 1, an information signal is recorded on the tape-shaped magnetic recording medium T as a magnetic signal, and the magnetic signal recorded on the tape-shaped magnetic recording medium T is reproduced. The tape-shaped magnetic recording medium T contacts the composite magnetic head 1 such that its longitudinal direction is parallel to the directions indicated by arrows G and H in FIG. At this time, the tape-shaped magnetic recording medium T is combined with the composite magnetic head 1 by an urging means (not shown) provided via the composite magnetic head 1.
To be pressed.

The composite type magnetic head 1 to which the present invention is applied as described above is designed to ensure the reliability of data when recording data on the tape-shaped magnetic recording medium T.
At the same time that data is recorded on the tape-shaped magnetic recording medium T by the recording head 2, the recorded data is read out by the reproducing head 3A.
Alternatively, the data is reproduced by the reproducing head 3B and the recorded data is verified.

That is, when the tape-shaped magnetic recording medium T is slid with respect to the composite type magnetic head 1 in the direction indicated by the arrow G in FIG. Immediately after, the recorded data is reproduced by the reproducing head 3A, and the recorded data is verified. When the tape-shaped magnetic recording medium T is slid with respect to the composite magnetic head 1 in the direction indicated by the arrow H in FIG. 1 for recording, the recording is performed by the recording head 2 and immediately after the recording. The recorded data to the reproducing head 3
B reproduces and verifies the recorded data.

As shown in FIG. 2, the reproducing heads 3A and 3B of the composite type magnetic head 1 constructed as described above have a head substrate 9 and a thin film magnetic circuit (not shown) formed on the side surface thereof. A guard member disposed opposite to the head substrate so as to sandwich the thin-film magnetic circuit with the head substrate;

In particular, the reproducing head 3 used in the present invention
As shown in FIG. 2, A and 3B have external connection terminals 1 derived from a thin-film magnetic circuit as shown in FIG.
2 are arranged in a state of being joined. This flexible cable 11 is connected to an external circuit (not shown).

The reproducing heads 3A, 3
B is such that a current from an external circuit necessary for reproduction is guided to a thin film magnetic circuit sandwiched between the guard member 10 and the head substrate 9 via the flexible cable 11 and supplied to the head element. ing.

Reproducing heads 3A and 3B used in the present invention
As shown in FIG. 3, the thin film magnetic circuit 15 includes four head elements 13 integrally formed on the head substrate 9 by a thin film process, and a pair of lead conductors 14 derived from each head element 13. And an external connection terminal 12 formed at the tip of the lead conductor 14. At this time, the external connection terminal 12 is formed from a thin film such as Cu.

Here, the reproducing heads 3A and 3B are magnetoresistive heads for detecting a signal from a recording medium using the magnetoresistive effect, and a magnetoresistive element is used as the head element 13. .

As described above, the reproducing heads 3A, 3A
In B, the external connection terminal 12 formed at the tip of the lead conductor 14 is joined to the flexible cable 11. Here, FIG. 4 shows a state of a joint portion between the external connection terminal 12 and the flexible cable 11.

As shown in FIG. 4, the external connection terminals 12
Are joined by soldering a contact portion 12a with the flexible cable 11. At this time, the flexible cable 11 has a contact portion 1 with the external connection terminal 12.
A gap 16 is formed in a portion other than 2a, so that the external connection terminals 12 are not electrically connected to each other.

In particular, the flexi cable 11 used in the present invention is partially covered with an elastomer resin on both sides thereof. Here, FIG. 5 shows a state of being covered with the elastomer resin.

As shown in FIG. 5, a portion including the joint portion 11a between the flexible cable 11 and the external joining terminal 12 and the surface 10a of the guard member 10 on the side opposite to the medium sliding surface, ie, the portion shown in FIG. The portion indicated by C is covered with the elastomer resin. As the elastomeric resin used here, silicone resin is preferable from the viewpoint of solvent resistance.

Further, the portion including the flexible cable surface 11b on the head substrate 9 side and the surface 9a on the head substrate 9 opposite to the medium sliding surface 8, that is, the portion indicated by D in FIG. Coated with a conductive resin. By disposing these resins, the flexible cable 1
1 and the external bonding terminal 12 are reinforced. As the thermosetting resin, an epoxy resin is preferable.

In particular, in the reproducing heads 3A and 3B, since the elastomer resin is disposed in the above-mentioned portion C, even in a high-humidity environment, unlike the conventional reproducing head in which the epoxy resin is disposed. In addition, the phenomenon that the resin swells and pushes up the guard member can be avoided.

That is, since the hardness of the elastomeric resin is smaller than the hardness of the epoxy resin, even if the elastomeric resin swells in a high humidity environment, as shown in FIG. 6, the external force generated by the swelling is dispersed. It can be easily deformed in any direction. As a result, the external force generated by the swelling of the resin does not directly act on the guard member 10, but the elastomer resin itself absorbs the external force. For this reason, since the external force generated by the swelling of the resin does not directly affect the guard member 10, the destruction of the bonding surface 9b between the guard member 10 and the head substrate 9 can be avoided, and stable reproduction can be performed.

In particular, in the reproducing heads 3A and 3B, the bonding surface 9b where the head substrate 9 and the guard member 10 are bonded by resin forms a part of the reproducing gap of the head element 13 formed on the head substrate 9. Make up. In the conventional reproducing head, when the resin disposed in the portion C swells in a high humidity environment, the resin pushes up the guard member 10,
The bonding surface 9a between the guard member 10 and the head substrate 9, that is, the reproducing gap has been destroyed.

Therefore, the reproducing head 3 used in the present invention
In A and 3B, the phenomenon of destruction of the reproducing gap due to swelling of the resin, which is seen in such a conventional reproducing head, can be avoided. Thereby, further reliability in the reproduction characteristics can be obtained.

The resin used for the C portion and the D portion has a thermosetting temperature of 1 to prevent the head element 13 from being destroyed.
It is required to have a solvent resistance of 50 ° C. or less and a resistance to washing with acetone or the like. That is, the resin disposed in the D portion has a thermosetting temperature of 150 ° C. or lower, has excellent solvent resistance, and reinforces the adhesive strength between the external connection terminal 12 and the flexible cable 11. good.

The resin disposed in the portion C has a thermosetting temperature of 150 ° C. or lower and has excellent solvent resistance.
Moreover, any material that does not exert an external force due to swelling of the resin on the guard member 10 may be used.

The recording head 2 used in the present invention
As in the case of the reproducing heads 3A and 3B, a head substrate, a guard member, four head elements integrally formed on the head substrate by a thin film process, a lead conductor derived from each head element, An external connection terminal formed at the tip of the conductor. And the recording head 2
The flexible cable is joined to the external connection terminal. Here, the recording head 2 is an inductive type magnetic head that writes a signal on a recording medium using electromagnetic induction, and includes a magnetic core having a magnetic gap and a winding coil wound around the magnetic core. .

In particular, the recording head 2 used in the present invention
Is a portion including the joint between the flexible cable and the external joining terminal and the surface of the guard member on the side opposite to the medium sliding surface, that is, the portion corresponding to the portion C in the read head, like the read heads 3A and 3B. Are covered with an elastomer resin.

In the conventional recording head, when the resin disposed in the portion C swells in a high-humidity environment, the resin pushes up the guard member, and the adhesive surface between the guard member and the head substrate is destroyed. The sliding surface 8 could not be kept constant, and stable recording could not be obtained. In the recording head 2 used in the present invention, the destruction phenomenon of the bonding surface between the guard member and the head substrate, which is seen in such a conventional recording head, can be avoided. Thereby, the medium sliding surface 8 can be kept constant, and further reliability in recording characteristics can be obtained.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below based on experimental results.

Example 1 A read head in which a guard member made of Ni-Zn ferrite was bonded to a head substrate made of Ni-Zn ferrite with a resin was used.

The destruction phenomenon of the bonding surface between the head substrate and the guard member depends not only on the characteristics of the resin disposed near the flexible cable but also on the aspect ratio (height / thickness) of the guard member. That is, when the aspect ratio is small, the bonding surface is likely to be broken. This is because an external force generated by swelling of the resin is applied to the guard member as a torque.

As for the reproducing head, the guard member as shown in FIG. 7 has an aspect ratio of about 0.79 (0.604 / 0.604).
0.762).

In this reproducing head, a portion corresponding to the portion C in FIG.
It was kept at 30 ° C. to 150 ° C. for 1 hour to cure and coat. The portion corresponding to the portion D in FIG. 5 was covered with an epoxy resin in the same manner as the conventional reproducing head.

<Characteristics of Silicon Resin Used in This Example> Type Rubber type, two-pack type Viscosity 8000 cp to 15000 cp Solid content 100% Specific gravity 1.0 Hardness (after curing) 21 (rubber JISA) Curing conditions 130 ° C. 150 ° C., 1 hour High humidity environment A where the reproducing head is 40 ° C. and the humidity is 93%.
, The breakage rate of the bonded surface between the head substrate and the guard member was measured after 10 days and 20 days, and the stability over time was examined.

Similarly, this reproducing head is set to 1
The temperature was alternately changed to 25 ° C. and 40 ° C. every 2 hours, and the temperature was maintained under a high humidity environment B of 95% humidity. 2
The measurement was performed 0 days later, and the stability over time was examined.

Embodiment 2 As a recording head, Al ₂ O ₃ .TiC (Altic)
A guard substrate made of alumina ceramic was adhered to a head substrate made of resin with a resin.

Here, a guard member having an aspect ratio of about 1.27 (0.604 / 0.475) was used.

In this recording head, a portion corresponding to the portion C in FIG. 5 was cured and coated using the same silicone resin as in the first embodiment.

Embodiment 1 for such a recording head
In the same high humidity environment A and high humidity environment B, the same measurement as in Example 1 was performed.

Comparative Example 1 As a reproducing head, the same one as in Example 1 was used except that the upper portion of the flexible cable was coated by holding the following epoxy resin at 90 ° C. for 1 hour and curing it. .

<Characteristics of Epoxy Resin Used in Comparative Example> Type Solvent-free type, one-pack type Viscosity 20,000 cp, (25 ° C., 5 rpm) Glass transition temperature 129 ° C. Hardness about 90 (Shore D) Curing condition 90 ° C., 1 hr With respect to such a reproducing head, the same measurement as in Example 1 was performed under the same high humidity environment A and high humidity environment B as in Example 1.

Comparative Example 2 As a recording head, as shown in FIG. 8, Al ₂ O ₃ .Ti
A head substrate 9d made of C (Altic) was bonded to a guard member 10d made of alumina-based ceramic with a resin.

Here, as the guard member 10d, FIG.
As shown in the figure, the aspect ratio is about 1.27 (0.604
/0.475).

In this recording head, a portion corresponding to the portion C in FIG. 5 was cured and coated using the same epoxy resin as in Comparative Example 1.

Embodiment 1 for such a recording head
In the same high humidity environment A and high humidity environment B, the same measurement as in Example 1 was performed.

Table 1 shows the results of the above measurements.

[0066]

[Table 1]

From the results shown in Table 1, it can be seen that the reproducing head of Example 1 and the recording head of Example 2 have the joint between the flexible cable and the external connection terminal and the side opposite to the medium sliding surface on the guard member. It was found that since the surface was covered with the elastomer resin, no destruction of the bonding surface between the guard member and the head substrate occurred.

On the other hand, in the reproducing head of Comparative Example 1 and the recording head of Comparative Example 2 in which the epoxy resin is provided as in the prior art, the bonding surface between the guard member and the head substrate was considerably damaged after 10 days. I was In particular, as is clear from Table 1, the reproduction head had a bonded surface breakdown occurrence rate of 50% after 10 days and 80% or more after 20 days.
This is because the reproducing head has a smaller aspect ratio than the recording head, so that the adhesive surface is easily broken.

From the above results, the joint between the flexible cable and the external connection terminal, and the surface of the guard member opposite to the medium sliding surface are covered with the elastomer resin so that a high humidity environment can be obtained. It has been found that it is possible to avoid the destruction of the bonding surface between the guard member and the head substrate below. As a result, it has been found that the environmental resistance can be improved, and that the recording and reproduction can be further stabilized.

[0070]

As is apparent from the above description, in the magnetic head according to the present invention, the joint between the flexible cable and the external connection terminal and the surface of the guard member opposite to the medium sliding surface are formed. Even when the elastomer resin swells under high humidity, the external force generated by the swelling is dispersed because the hardness of the elastomer resin is smaller than the hardness of the epoxy resin that has been conventionally used by being coated with the elastomer resin. It can be easily deformed in the direction in which it is made to move. Therefore, it is possible to avoid an external force generated by the swelling of the resin from directly acting on the guard member, and it is possible to prevent the bonding surface between the guard member and the head substrate from being broken. Therefore, according to the present invention, it is possible to provide a magnetic head which is excellent in environmental resistance and in which recording and reproduction characteristics are stabilized.

Further, in the magnetic head according to the present invention, the use of a silicone resin as the elastomeric resin can improve the solvent resistance.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a composite magnetic head to which the present invention is applied.

FIG. 2 is a perspective view showing an example of a reproducing head in a composite magnetic head to which the present invention is applied.

FIG. 3 is a front view of an essential part showing an example of a reproducing head in a composite magnetic head to which the present invention is applied.

FIG. 4 is a main part front view showing an example of a flexible cable in the composite magnetic head to which the present invention is applied.

FIG. 5 is a cross-sectional view showing an example of a reproducing head in a composite magnetic head to which the present invention has been applied.

FIG. 6 shows a composite magnetic head to which the present invention is applied.
FIG. 3 is a cross-sectional view illustrating an example of a reproducing head in a high humidity environment.

FIG. 7 is a side view of the reproducing head used in the embodiment.

FIG. 8 is a side view of the recording head used in the embodiment.

FIG. 9 is a sectional view showing an example of a reproducing head in a conventional composite magnetic head.

FIG. 10 is a cross-sectional view showing a state in which a bonding surface between a guard member and a head substrate is broken in a conventional reproducing head of a composite magnetic head.

[Explanation of symbols]

1 composite magnetic head, 2 recording head, 3A, 3B
Reproduction head, 9 head substrate, 10 guard member, 11
Flexible cable, 12 External connection terminal, 13
Head element, 14 lead conductor

Claims (5)

[Claims] A head element, a head element formed on the head substrate, a guard member arranged to sandwich the head element with the head substrate, and an external connection terminal derived from the head element. A flexible cable having one end joined to the external connection terminal and the other end connected to an external circuit; a joint between the flexible cable and the external connection terminal; and a medium sliding surface on the guard member. A magnetic head, characterized in that at least a part of a surface on the opposite side is coated with an elastomer resin. 2. The magnetic head according to claim 1, wherein the elastomer resin is a silicone resin. 3. A composite magnetic head comprising at least one magnetic head for recording and at least one magnetic head for reproduction arranged near the magnetic head for recording. The magnetic head as described. 4. A part of the main surface of the flexible cable on the head substrate side and at least a part of a surface of the head substrate opposite to the medium sliding surface are covered with a thermosetting resin. The magnetic head according to claim 1, wherein: 5. The magnetic head according to claim 4, wherein the thermosetting resin is an epoxy resin.