JPS5954022A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain a compact thin film magnetic head which consumes a small amount of electric power, by using a thin film producing means and forming a magnetic head part and the transformer group which is connected in series to the magnetic head part on the same substrate. CONSTITUTION:A magnetic head part 12 consisting of the 1st and 2nd conductor layers 15 and 19 and an upper magnetic layer 22 (with an insulated layer 18) is provided on a substrate 10 made of a magnetic material together with the 1st (2nd) transformer 13 (14) consisting of the 1st and 2nd conductor layers 16 (17) and 20 (21) and the layer 22. While the layers 15-17 are connected vertically to the layers 19-21 at areas A and A', B and B', C and C', D and D', E and E', and F and F', respectively. Thus a thin film magnetic head is formed. In such a way, for instance, the reproduction power equal to a head having a 8-turn conductor layer is obtained if a 1-turn structure and a 2-turn structure are given to the primary side and the secondary side respectively for the part 12 as well as transformers 13 and 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a thin film magnetic head, and more particularly to a magnetic induction type thin film magnetic head.

Thin film magnetic heads have been in the spotlight as magnetic heads for magnetic recording and reproduction.

This thin film magnetic head is formed by a thin film deposition method such as a vapor deposition method or a sputtering method, and has many advantages as follows.

(1) Since the overall size is small, the magnetic head is shifted toward the inductor region of the coil, and can be driven at a higher frequency than a conventional magnetic head, increasing the signal transmission speed.

(2) By forming the magnetic core with a thin film, eddy currents are suppressed, core loss during high frequency recording and reproduction is reduced, and the frequency characteristics of the magnetic head are improved.

(3) Since it is manufactured by thin film deposition means, multi-tracking is easy.

Taking advantage of these advantages, thin film magnetic heads have been put into practical use as magnetic heads for magnetic disks in computers.

Prior Art FIG. 1 shows an example of the conventional structure of such a thin film magnetic head, in which the conductor forms a two-turn winding.

In FIG. 1, a first layer conductor 2 is formed on a magnetic substrate 1, and a second layer conductor 3 and an upper magnetic layer 4 are formed thereon. Reference numeral 5 indicates a magnetic gap portion.

Each layer is formed by a thin film deposition method and a photolithography technique, respectively. Note that in FIG. 1, the insulating layer between each layer is not shown.

When recording is performed using a thin film magnetic head having such a structure, a magnetic field is generated in the magnetic gap 5 by passing a recording current through the conductors 2 and 3, and a magnetic recording medium (not shown) located near the gap is generated. Recording is performed by magnetizing the

On the other hand, when reproducing a magnetic signal, the magnetic flux generated from the recorded magnetized portion of the magnetic recording medium located near the magnetic gap 5 passes through the magnetic substrate 1 and the upper magnetic layer 4 and intersects with the conductors 2 and 3 (4), which causes magnetic flux. This is done by detecting the induced voltage generated in the conductors 2 and 3, which changes as the recording medium moves.

At this time, the induced voltage due to signal magnetization of the same wavelength is proportional to the number of turns of the conductor of the magnetic head and the moving speed of the magnetic recording medium.

However, the conventional structure shown in FIG. 1 requires only two turns, and the number of turns is too small to obtain a sufficient reproduction output, making it difficult to use it as a reproduction head in practice. Therefore, when performing reproduction, it is necessary to increase the number of turns.

Furthermore, if the running speed of the magnetic recording medium is slow, the number of turns may be further increased, but with the structure shown in Figure 1, it is impossible to increase the number of turns unnecessarily.
In fact, playback cannot be performed at low speeds.

As a result, when using a magnetic recording medium that runs at a low speed, the magnetic head with the above structure is not used as a recording-only head, but for playback, a magnetoresistive magnetic head whose output does not depend on the medium speed is used. It is common to be told that
Two types of heads were required, one for recording and one for playback.

On the other hand, the current value required for recording is determined by the current and the number of turns. Therefore, the larger the number of windings, the more recording is possible.In this case, the Joule loss is expressed as R■2 for the resistance value R and the current value ■, and is proportional to the square of the recording current, so it is difficult to reduce the recording current. This has an extremely large effect on reducing Joule loss.

Therefore, it is necessary to reduce the number of turns of the conductor even in the case of recording.

However, in a structure in which windings are laminated as shown in FIG. 1, attempting to increase the number of turns of the conductor increases the number of manufacturing steps and makes the manufacturing itself extremely difficult.

By the way, as a structure for increasing the number of turns without increasing the manufacturing process, a structure as shown in FIG. 2 has been proposed.

In Fig. 2, the same parts as in Fig. 1 are given the same reference numerals.
The explanation will be omitted. In the embodiment shown in FIG. 2, the conductor indicated by reference numeral 6 has three turns. The reference numeral 7 is an electrode.

In the embodiment shown in FIG. 2, the conductor 6 is formed in a spiral shape, and if such a structure is adopted, the total number of conductors and the process will not change even if the number of turns of the conductor is increased.

However, since the area occupied by the conductor 6 increases, the magnetic path formed by the substrate 1 and the upper magnetic layer 4 becomes long, resulting in an increase in magnetic resistance and leakage magnetic flux.

As a result, the recording efficiency and reproduction efficiency deteriorate, and since the conductor spreads in the track direction, there are drawbacks such as the inability to reduce the track pitch when making multi-tracks.

Furthermore, even if such a structure is adopted, reproduction is virtually impossible if the speed of the magnetic recording medium is slow.

Purpose The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology, and to provide a thin film magnetic head that can achieve much the same effects as the increase in the manufacturing process and track (7). There is.

In order to achieve the above object, the present invention forms a thin film magnetic head and a group of transformers connected in series on the same substrate by a thin film deposition method, and one of the group of transformers connected in series. A structure is adopted in which a lead terminal pair of a thin film magnetic head is connected to a terminal pair of the thin film magnetic head.

Hereinafter, details of embodiments of the present invention will be described based on embodiments shown in the drawings.

3 is a longitudinal sectional side view, and FIGS. 4(8) to 4(0) show the conductors of the first and second layers and the upper magnetic layer, respectively.

In FIG. 3, the reference numeral 10 indicates a magnetic substrate, on which a magnetic head section 12 and a first transformer 13 are mounted.
, a second transformer 14 are formed, respectively.

(8) Magnetic head section 12, first transformer 13, second transformer 1
4 is the first conductive layer 1 as shown in FIG.
5 to 17 are formed.

That is, Af', zO
First conductive layers 15, 16, 17 made of a conductive material such as Aε, Cu, Au, etc. are formed through an insulating layer 18 made of S, 5iO1Sin, PiQ, etc.
I- through the insulating layer 18 as shown in ) of FIG.
Conductive layers 19, 20, and 21 are formed. and,
A two-part magnetic layer 2 made of a high permeability magnetic material such as permalloy is placed on these second conductive layers 19 to 21 with an insulating layer 18 interposed therebetween.
2 are formed respectively.

Then, the first conductive layers 15 to 17 and the second conductive layers 19 to
21 are a and a', b and bl, c and C, respectively.
'.

Only the points d and dl, e and el, and f and f' are vertically connected and conductive.

Further, the upper magnetic layer 22 has a structure in which the upper magnetic layer 22 is in direct contact with the magnetic substrate 10 except for the magnetic gap 23 .

In this way, the conductive layer 15, 19, the two-part magnetic layer 22, the magnetic gap 23, and the magnetic substrate 10 become magnetic.

Still the first transformer 13 each has one part of the conductor layer 16.
The secondary winding, the conductive layers 16 and 20 are the secondary winding, and the magnetic substrate 1
0 and the upper magnetic layer 22 constitute a magnetic core.

In the second transformer 14, part of the conductive layer 17 forms a primary winding, the conductive layer 17 and the conductive layer 21 form a secondary winding, and the substrate 10 and the upper magnetic layer 22 form a magnetic core. are doing.

The output terminal of the conductive layer 15.19 of the magnetic head section 12 is connected to the primary side (the head side is the primary side) of the first transformer 13 located at the next stage. The first transformer 13 has one turn on the primary side and two turns on the secondary side, and the secondary output end of the first transformer 13 is connected to the second turn.
is connected to the primary side input terminal of the transformer 14.

In this case, the second transformer 14 has one turn on the primary side and two turns on the secondary side.
The secondary output terminal of the second transformer 23 is connected to the final output terminal of the magnetic head section 12.

When such a structure is adopted, a reproduction voltage corresponding to the voltage not shown is induced, but this output is stepped up by a factor of two by the first and second transformers 13 and 14, and finally A voltage four times the induced voltage at the output end of the magnetic head section 12 is obtained as an output.

This corresponds to forming an 8-turn conductive layer in order to obtain the same reproduction voltage by increasing the number of turns of the conductive layer in the magnetic head section.

If a head having an 8-turn conductive layer is constructed as shown in FIG. 1, it is necessary to form 8 conductive layers, but in this example, the conductive layer is Only two layers are required, and the manufacturing steps are significantly reduced.

Since it is only necessary to form two conductive layers, (11) The manufacturing process itself is also extremely simplified.

The track pitch can also be made sufficiently small.

On the other hand, the primary side of the first and second transformers 13.14 and the
By increasing the turn ratio of the conductive layer on the next side or increasing the number of stages of directly connected transformers, it is possible to obtain a magnetic head with an equivalent number of turns of winding. Even when running at a low speed, the same magnetic head can be used for recording and reproducing, which has the advantage of eliminating the need for a magnetoresistive magnetic head, which in the past had to be used only for reproducing.

When recording with a magnetic head with this structure, the recording current is supplied from the secondary terminal.
When converted from the secondary side to the primary side of each transformer, it is multiplied by the reciprocal of the i-ratio of the respective conductive layer. That is, in this embodiment, the current in the first and second transformers 13, 14 increases by a factor of two. Therefore, the current flowing through the conductive layer of the magnetic head section 12 is four times the supplied current (12).

Conversely, this means that the supplied current is only % of the recording current required for the magnetic head section.

Furthermore, the Joule loss generated in the series lead section due to the flow of the recording current is proportional to the square of the recording current, so if such a structure is adopted, the Joule loss can be reduced to approximately %.
This results in an extremely large effect on reducing power consumption.

Also, in this case, as in the case of reproduction, the conductive layer actually forms only two turns in the magnetic head part, and the same effect is obtained as if it were formed for eight turns. become.

■ Considering the advantage of being able to reduce the number of turns, it is desirable to select a turns ratio of 1:2.

[Second Embodiment] FIGS. 5 to 7 are for explaining other embodiments of the present invention. In this embodiment, FIGS. First conductive layers 24 to 26 having a pattern as shown in FIG. , third conductive layers 31 and 32 are formed, and an upper magnetic layer 33 is formed thereon with an insulating layer 27 interposed therebetween.

The magnetic substrate 23 is made of Mn-Zn7m light or Ni-Z
The first to third conductive layers are each made of a conductive material other than AQ or Au.
The upper magnetic layer 33 is made of a high permeability magnetic material such as permalloy.

Frozen, the insulating layer 27 is Ark's, S i02,
It consists of insulation elements such as P + Q and is insulated from each other, but it is only insulated at the points A and A', B and B' to H and H' shown in Figure 3 (A) to The layers are removed so that mutual conduction is maintained.

In addition, the portion indicated by the reference numeral 34 in FIG. 5 forms a head portion similarly to the first embodiment.

In addition, in FIG. 5, the parts indicated by numerals 35 and 36 are the first turn of the primary side (head side) and the second turn of the secondary side.
and a second transformer.

By the way, among the three first to third conductive layers, the first conductive layers 24 to 26 cover one turn on the primary side, and the second to third conductive layers 28 to 30 cover two turns on the secondary side. forming a turn.

Further, the magnetic substrate 23 and the upper magnetic layer 33 form a closed magnetic path, and constitute an external iron type transformer.

Since this embodiment adopts the above structure, the first
Similar to the embodiment, a 2-turn magnetic head and a turns ratio of 1:2 are used.
It has a configuration in which two transformers are connected in series, and is equivalent to the magnetic head shown in Fig. 1.The manufacturing process is increased by that much compared to the first embodiment. The coupling between the primary and secondary sides of the Kawashi transformer is extremely good,
This has the effect of improving signal transmission efficiency.

In the above embodiment, the number of turns of the conductive layer (15) of the magnetic head is 2 turns, but 3 turns does not increase the number of manufacturing steps, so 3 turns may be used.

By the way, the equivalent circuits of the first and second embodiments described above have a configuration as shown in FIG.

As is clear from FIG. 8(A), each transformer T1, T
The primary and secondary sides of 2 are not electrically coupled,
The potential of each circuit to ground is not regulated.

Therefore, stray capacitances existing between the primary side and the secondary side of the transformer, between the transformer and the ground, etc. fluctuate the potential with respect to the ground, resulting in noise. To prevent this, see Figure 8 ■
As shown in Figure 2, it is best to provide a common terminal between each transformer and the head side, and install these all at once.

In FIGS. 8A and 8, the symbol H indicates the head portion.

The embodiments shown in FIGS. 9(a) to 0 and FIG. 10(5) to 0 realize a magnetic head having a structure as shown in FIG. 8(B).

[Third Embodiment] The third embodiment of the present invention is shown in Figure 9 (5).
16) This is an example in which a common terminal C is provided in the first conductive layers 15 to 17 of the first embodiment shown in FIGS. 4(6) to 0.

In FIGS. 9(5) to (Q), the same parts as in FIGS. 4(A) to 0 are given the same reference numerals.

In FIG. 9(5), (g), A and A' and F and F' are insulated by an insulating layer except that they are electrically connected.

By providing the common terminal C in this way, it is possible to provide an insulating layer with an equivalent circuit as shown in FIG.
Stray capacitance can be removed and noise generation can be prevented.

A structure in which a common terminal C is provided on the first conductive layer of the example shown in FIGS. 6(A) to (6) is adopted. In addition, Figure 10 (11
) and FIG. 60, the patterns of the second conductive layers 28 to 30 are slightly different.

Also in the first to third conductive layers in FIG. 10 (5) to (C'), conduction is maintained between symbols A and A' to H and H', but the other regions are insulating layers. It is well insulated.

It is possible to reduce noise and improve the SZN ratio.

In the embodiments shown in Figures 9 and 10, a structure is shown in which the common terminal is connected from one side of each winding, but a structure in which the ground is connected from the center of each winding can also be achieved by changing the pattern of the conductive layer. There's no way to say it's possible.

By the way, in the first to fourth embodiments described above, each conductive layer and the like can be formed by a thin film deposition method.
The track pitch can be reduced, and multi-tracking is easy.

In this case, instead of providing the transformer immediately adjacent to the rear end of the magnetic head, the transformer may be provided after the conductive layer, which is the output line from the magnetic head, has been drawn out to a wide area. At this time, the track pitch of the head tip can be made smaller than the width occupied by the transformer.

Here, the number of transformers connected to the magnetic head will be explained as follows.

In the first embodiment described above, the number of transformers is two, but it does not necessarily have to be two, but it may be one or more. However, there is an appropriate number of transformers.

That is, the purpose of providing the transformer is to improve the S/N ratio of the reproduced signal in the case of reproduction.

At this time, it is necessary to consider the signal system shown in FIG. 11. The part indicated by numeral 37 in FIG.
The part designated by the reference numeral 38 in the head section is a rear-stage transformer.

An external circuit such as an amplifier 39 is further connected after the transformer 38.

A signal is input from the magnetic head section 37, and noise includes noise 81 that is included simultaneously with the signal such as modulation noise, and system noise 88 that is generated by an external circuit such as an amplifier. System noise S8 is unrelated to the number of transformers in the preceding stage, and if the reproduction output of the magnetic head (19) is small compared to noise S8, the number of transformers is increased to increase the reproduction output. By this, it is possible to improve the S/N ratio. When the reproduced output signal becomes sufficiently larger than the noise S8, the noise S included during signal reproduction becomes dominant in determining the S-ratio.

This noise to reproduction signal ratio is independent of the number of transformers located in the subsequent stage. Therefore, if you increase the reproduction voltage by adding a transformer, the overall S/N ratio will increase,
becomes constant at a certain value. However, in reality, there is impedance noise generated by transformers, and this increases with the number of transformers, so if the number of transformers is increased too much, the S/N ratio will deteriorate. An example of this relationship is shown in FIG.

FIG. 12 shows a case where the same configuration as the first embodiment is adopted. As is clear from FIG. 12, the S/N ratio is maximum when the number of transformers is three. Although this relationship differs depending on the number of turns in the conductive layer, the dimensions of each part, and the method of construction, it is generally desirable to determine the number of transformers between two (20) and five.

Further, in the second embodiment described above, a magnetic substrate was used, but the same effect can be obtained by using a non-magnetic substrate in which a high permeability magnetic material such as permalloy is formed by a thin film deposition method. can be obtained.

However, when using a magnetic substrate or a non-magnetic substrate with a uniformly formed high permeability magnetic thin film, when multi-track is used, the magnetic field can easily pass to adjacent tracks, causing Crosstalk occurs.

Therefore, in order to reduce this crosstalk, it is preferable to remove the portion of the high permeability magnetic thin film formed on the nonmagnetic substrate that communicates between the tracks by a method such as etching.

In this way, the magnetic field that propagates into adjacent tracks is reduced, and crosstalk between tracks is reduced. In addition, by removing all unnecessary parts of the high permeability magnetic thin film provided on the non-magnetic substrate and forming it in the same shape as the upper magnetic layer, crosstalk between tracks can be reduced and leakage in the transformer area can be reduced. Inductance is reduced, and ultimately the SIN ratio can be improved.

When dealing with twisted, high-frequency signals, high-frequency losses occur in the magnetic body that constitutes the iron core of the transformer, and the signal transmission efficiency decreases. This results in a reduction in signal output and an increase in magnetic noise generated within the iron core, ultimately deteriorating the S/N ratio. As a countermeasure to this problem, it is sufficient to remove the magnetic material that constitutes the iron core of the transformer section.

In addition, if a non-magnetic material is used for the substrate, leave only the magnetic layer of the head part and remove both the upper magnetic layer and the lower high permeability magnetic thin film that make up the core of the transformer part, and then remove the transformer part. It has an air core structure. When such a structure is adopted, the high frequency loss generated within the iron core is limited to only the magnetic material of the head portion, so it becomes extremely small.

If a magnetic substrate is still used, it is sufficient to remove the upper magnetic layer that constitutes the iron core of the transformer section. In this case too, high frequency loss is reduced. With such an air-core structure or a semi-air-core structure, the inductance of the transformer winding is reduced, but because the frequency is high, reactance is ensured, and the transmission efficiency of the transformer does not deteriorate.

However, in this case, it is necessary that the coupling coefficient between the primary conductor and the secondary conductor of the transformer be large even in the case of an air core.

Therefore, it is preferable to adopt the structure of the second embodiment as the structure of the transformer.

Effects As is clear from the above explanation, according to the present invention, a thin film magnetic head and a group of transformers connected in series are formed on the same substrate by thin film deposition means, and a group of transformers connected in series is formed on the same substrate. By adopting a structure in which the pair of terminals of the pleural magnetic head is connected to the pair of terminals of the pleural magnetic head, the manufacturing process can be simplified, the track pitch can be made small, and a large reproduction voltage can be obtained. On the other hand, an excellent effect can be obtained in that the recording current can be reduced.

A perspective view illustrating an example, FIG. 3 shows the first fruit (23
4(A) to (q are respectively explanatory views explaining the shapes of the first and second conductive layers and the upper magnetic layer, and FIG. 5 is a longitudinal side view illustrating the present invention. FIG. 6(8) to σ are explanatory diagrams showing the first to third conductive layers and the upper magnetic layer, respectively, and FIG. 7 is a plan view illustrating the second embodiment of FIG.
A sectional view taken along line A, FIG. 8 (8) is an equivalent circuit diagram of the second embodiment, FIG. 8 (C) is an equivalent circuit diagram of the third and fourth embodiments,
Figures 9(G) to (Q are explanatory diagrams showing the first and second conductive layers and the upper magnetic layer, Figures 10(A) to 0) are the illustrations of the first to third conductive layers and the upper magnetic layer. Explanatory diagram, Figure 11 is a block circuit diagram of the signal system including the head, Figure 12 is the number of transformers and S
FIG. 3 is a diagram showing the relationship with the /N ratio.

10... Magnetic substrate 12... Head part 13.
...First transformer 14...Second transformer 15-1
7...First conductive layer 19-21...Second conductive layer 22..."Two-part magnetic layer 31, 32...Third
Conductive layer (241) Figure 1 '31 / 111 1 Section 4 Figure 23 (A) (B) (C
) 8 Figure 5 Figure 7 Figure 8 (A) Figure 9 (A) (B) (C: 11) (D) Figure 9 (A) (B) (C)
-54022 (9) Procedural Amendment (Effective January 1211, 1980 Mr. Commissioner of the Japan Patent Office ■, Indication of Case 1982 Patent Application No. 163809 2,
Name of the invention Thin-film magnetic head 3, relation to the Nagisa incident with correction Name of patent applicant (100) Canon Corporation 4
, agent telephone 03 (288) 2481
(Substitute) Drawing 6, contents of the amendment As shown in the attached sheet Supplementary contents ■) Page 6, line 12 of the specification] "Reduce" in 1 is corrected to "increase".

2) Correct "total number" in line 6 of page 7, +j+, to "number of layers."

3) Correct "16" in the 5th line of page 10 to "15".

4) Correct "17" in line 9 of page 10 to "16".

5) Correct "23" in the first line of page 11 to "14".

6) Correct "r(B)" on page 14, line 15 of the same page to "(C)".

7) In the 13th line of page 16, "common terminal between and the head side" is corrected to "common terminal between the - next side and the secondary side P1゜P2J.

8) Correct "installation" in line 14 of page 16 to "grounding".

9) r on page 17, line 2, line 9, and line $16
Correct CJ to rPt and P2J, respectively.

10) Change “provide an insulating layer” on page 17, line 10 to “
Structure (A) and Figure 10 (A) are corrected as shown in the attached sheet.

Claims (1)

[Claims] (1) A thin film magnetic head and a group of transformers connected in series with the thin film magnetic head are formed on the same substrate by thin film forming means, and one of the group of transformers connected in series with the thin film magnetic head is formed on the same substrate. For the terminal pair,
A thin film magnetic head characterized in that a pair of lead terminals of the thin film magnetic head are connected. (2) A thin film magnetic head according to claim 1, characterized in that a plurality of thin film magnetic heads are formed side by side on the same substrate to form a multi-track system. (3) When the thin-film magnetic head side of each stage of the transformer connected in series with the thin-film magnetic head is taken as the primary side, the turn ratio of the conductor on the primary side and the secondary side is set to 1=2 ( 4) The thin film magnetic head according to any one of claims 1 to 3, wherein the number of transformers connected in series to the thin film magnetic head is 2 to 5. . (5) Claims 1 to 5, characterized in that each of the transformers connected in series to the thin film magnetic head is air-core.
The thin film magnetic head according to any one of items 4 to 4. (6) The transformer according to any one of claims 1 to 4, wherein each of the transformers connected in series to the thin-film magnetic head is provided with a core made of a magnetic material. Thin film magnetic head. (7) A thin film magnetic head according to claim 6, characterized in that the magnetic material forming the core is permalloy. (8) A patent characterized in that a common terminal is provided by connecting a part of the primary conductor and a part of the secondary conductor of one or more transformers connected in series to a thin-film magnetic head. A thin film magnetic head according to any one of claims 1 to 7.