JPS6126919A - Composite type thin film magnetic head - Google Patents

Abstract

PURPOSE:To reduce the number of heads as well as the cost and to improve the mass productivity of composite thin film magnetic heads, by arraying plural magnetic head unit elements on a nonmagnetic substrate so as to set gaps between magnetic cores on a straight line. CONSTITUTION:A magnetic core 13' of a magnetic thin film is put on a nonmagnetic substrate 12 via a magnetic core 13 of a magnetic thin film and a gap 14 of a nonmagnetic film. Thus a closed magnetic circuit is obtained, and a conductor coil 16 is added to obtain a unit element 20. The gaps 14 of a pair of elements 20 are set on a straight line on the substrate 12 to form a composite magnetic head 21. Thus the length of a magnetic path is reduced greatly. This improve the recording/reproducing efficiency as well as the performance to a high frequency owing to a multi-layer structure of thin films. Then, both the mass productivity and the cost reduction are improved since a number of pairs of unit elements are arrayed on the substrate 12 of a large area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a composite thin film magnetic head used in a home helical scan video tape recorder (hereinafter referred to as VTR).

[Background of the invention]

Conventional home-use v'l'B's have become multi-functional by adding special playback functions such as long-time recording LP mode and field still and fine throw in addition to the so-called standard recording and playback SP mode. There is.

To realize these functions, various combinations of track width and azimuth angle are required, so the number of heads has been increased to accommodate this. Figure 1 is a schematic diagram of a conventional recording/playback device. This figure shows an example of the head arrangement on a rotating cylinder.
) shows the case of 3-head system.

In the method (a) above, the heads 1 to 5 are connected to the rotating cylinder 6.
The O of heads 1 to 5 is installed as shown above.
The sign of the ink pad indicates the sign of the azimuth angle. Standard SP
When recording and reproducing in the LP mode, the heads 4 and 5 with a large track width are operated, but when recording and reproducing in the LP mode,
By operating the head 1.2 with a small track width, the tape utilization efficiency can be set to the optimum conditions.

Furthermore, during special playback such as field stills, by operating the same azimuth head 1.3 and repeatedly playing back the field 1'), s and v are good and there is no pretension for high-speed motion screens. You can browse quality methyl paintings. However, in this case, the number of heads increases,
Moreover, there is a risk of high costs due to the difficulty of highly accurate positioning work, and from the viewpoint of downsizing the cylinder in the future, it would be extremely difficult to increase the number of heads in terms of space.

On the other hand, in the case of a three-head system consisting of heads 1 to 3 shown in FIG. 1(b), the 5P-LP mode is set to the same head 1.
2, the number of heads is reduced as it is used for both purposes. The track width is set as a compromise between the performance of both, but it is actually designed mainly for LP to eliminate reproduction interference from adjacent tracks. For this reason, in the SP mode, a guard band is generated on the tape, making it impossible to fully demonstrate the original performance of SP. On the other hand, special playback is performed using head 1.3, and its operation is shown in Figure 1 (&
), so the explanation will be omitted.

As a system other than the system shown in FIG. 1 (a3#(b)), there is also a 41-do system (not shown), but this system has performance intermediate between the systems (a) and (b).

Next, the structure of the head used in the above-mentioned VTR system is shown in FIG. That is, the figure (&) shows the structure of the heads 1 and 4.5 shown in FIG. The width of the track is controlled by a notch 10 provided in the head sliding surface.

FIG. 2(b) shows the structure of the heads 2 and 3 shown in FIG. 8 and 8' have different azimuth angles (not shown), and the interval X
ga is set to a predetermined value, for example IH.

Such heads 2 and 3 will hereinafter be referred to as double azimuth/rad 2A.

With these two double azimuth heads, since the two heads are close to each other, magnetic interference (hereinafter referred to as crosstalk) becomes a problem. In order to avoid this, the magnetic cores 7m and 7b provided facing each other are reduced in size, and a space 11 is provided between these magnetic cores 7m and 7b. Changing the shape of the magnetic cores 7m and 7b not only deteriorates the original characteristics of the head, but also causes reliability problems such as dust adhesion due to the space 11 during tape running.

On the other hand, FIG. 3 is a perspective view showing the structure of a head 7 whose core material is a soft magnetic metal, which has been proposed for use with high coercive force tapes. In this head 7', a magnetic core (head) 7 is formed by sandwiching a magnetic thin film 12 with a thickness corresponding to the track width 7w between non-magnetic substrates 13 and 13'. When constructing a double azimuth head using this magnetic core 7, the area facing the cores is slightly reduced, so although crosstalk is somewhat reduced, there is a problem with reliability.

Further, FIG. 4 shows a means for switching the track width by stacking two heads la and lb in the upper and lower directions, apparently in order to reduce the number of heads above. In other words, if only one head, for example head 1a, is operated,
The track width is Tw, but if 9bt is connected in series with each winding 91 of both heads la and lb, the track width is (
Tw + Tw').

In this case, each gap of both heads la and lb is 8 m,
8b on the same line, and the gap Ts between both heads la and lb must be set to the minimum. This gap T8
There is a limit due to deterioration of crosstalk between both heads la and lb and securing space for windings @9m and 9b.

Furthermore, in the head structure shown in FIGS. 2 and 3, the thickness of the notch 10 and the nonmagnetic substrate 12 is added to the head, making it difficult to put it into practical use.

[Purpose of the invention]

The present invention eliminates the drawbacks of the prior art as described above, and reduces the number of heads without impairing head performance.
The purpose is to significantly reduce costs and improve mass productivity.

[Summary of the invention]

In order to achieve the above object, the present invention sequentially laminates a first magnetic core, a nonmagnetic film constituting a gap, a signal conductor coil, and a second magnetic core, and sets the track width of this laminate to the first magnetic core. A thin film magnetic head unit element is formed by determining the width of the core or the second magnetic core, and a plurality of the thin film magnetic head unit elements are placed on a non-magnetic substrate between the first magnetic core and the second magnetic core. 41F11 is that the gaps are arranged in a straight line.

[Embodiments of the invention]

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

First, the thin film magnetic head unit element used in each of the above embodiments will be described in detail with reference to the perspective view shown in FIG. - This thin film magnetic head unit element is added to the non-magnetic substrate 12.
A gap 1 is formed on the first magnetic core 13 made of a magnetic thin film.
A closed magnetic circuit is formed by laminating a second magnetic core 13' made of a magnetic thin film through a non-magnetic film constituting the second magnetic core 13, 13', and an insulating layer 1 is provided at the center of the gap between the two magnetic cores 13, 13'. A signal conductor coil 16 is provided via the layer 15, and the first and second magnetic cores 13 and 13' on the non-magnetic substrate 12 are provided.
A wear-resistant protective film (10 to 20 μm ALzO5M!) (not shown) is attached by sputtering to cover the conductor coil 16 and the like.

The non-magnetic substrate 12 has a coefficient of thermal expansion of 100 x 13
It is a crystallized glass with good wear resistance of 0 x 10-'/°C. The first magnetic gore 13 is formed by sputtering a CO-based amorphous alloy onto the non-magnetic substrate 12 in the form of a thin film, and by etching, the width of the tip which becomes the sliding surface is set to the track width Tv ( = 20-60 μm),
It was buttered to have a depth of 0.2 to 0.3 m, and the thickness Tm was 10 to 30 μmK, and it was insulated with interlayer material 5iO2 (thickness 10006A) every 5 μm to create a multilayer structure. .

The gap 14 is formed by forming a SiO2 film with a thickness of 0.3 to 0.5 μm by sputtering, and then forming a conductor coil 16, which will become a signal winding, on this film by repeating evaporation and etching using a KL material for 5 turns ( In the figure, one turn is omitted for convenience). Insulating layers 15 made of 8102 film having a thickness of 1 to 2 μm are provided on the upper and lower portions of the conductor coil 16, respectively.

Further, the second magnetic core 13' is made of the same material as the first magnetic core 13 described above, and is formed so as to cross over the conductor coil 16. Further, the front part 13'a and the rear part 13'b of the second magnetic core 13' are
It is joined to the front part 13x and the rear part (not shown) of the first magnetic core 13, respectively, to form a closed magnetic path and a gap 14 as a head.

Thin film magnetic head unit element 201 configured as described above
When used as a kVTR head, it has been confirmed that it has the following excellent characteristics.

(1) Since the magnetic core is made of a thin film and the magnetic path length is reduced to about 1/10 of that of a conventional head, the head recording and reproducing efficiency is good, and the inductance is also reduced.

(2) Since a magnetic thin film with high magnetic flux density and high magnetic permeability is used as the magnetic core and has a multilayer structure, loss in the high frequency band is reduced, and a high frequency compatible and high performance head can be used.

(3) The so-called contour effect, which is the waviness of the frequency characteristics that has been considered a problem in the past, has become practically no longer a problem as a result of countermeasures such as slanting the core edge and interlayer film, which serve as pseudo gaps, or using a blurring method.

(4) Since the space for the winding coil is small and multi-layer winding is difficult, there is a limit to the number of windings, but this can be countered by the combined use of a step-up transformer.

(5) By forming a large number of head unit elements on a large-area nonmagnetic substrate], mass production is possible and costs can be reduced.

(6) Since conventional machining is not required and production can be performed using processes similar to semiconductors, dimensional accuracy such as gap length and track width and yield can be improved.

Next, various embodiments of the present invention using a thin film magnetic head unit element having many advantages as described above will be described with reference to the drawings.

FIG. 6(a) is a perspective view showing a first embodiment of the present invention. In this first embodiment, a plurality of head unit elements (sixth head unit element) having the same structure as the thin film magnetic head unit element 20 (hereinafter referred to as head unit element) shown in FIG.
In the figure (&) there are two, namely 21A.

21B) and each head unit element 21A.

21B's first magnetic cores 13m, 13b and second magnetic core 13'a.

13′b and the respective gaps 14m, 14
It consists of a structure in which b is numbered so that it is located on a straight line.

the respective first and second magnetic cores 13a, 13'a and 13b of the head unit elements 21A and 21B;
13'b has a track width at its tip Tvrt, T
W2, respectively. Both track width T
The gap between wl and TW2 is such that the tip part is the narrow part T8,
By forming the rear part into an enlarged part T/8,
A space is secured to insert the conductor coils 16m and 16b.

In the composite thin film magnetic head 21 of this first embodiment,
The above 'I'wl, Tvtr2 dimensions are in blade μm, the above T8 and T'! l t Ti = 5~30 fi
m and T/ are each set to ≧50 μm.

Moreover, each conductor coil 16a.

By selecting one connection or series connection of the 16b via a changeover switch (not shown), the operating track width can be changed from Twl (for LP) to TWI +T.
It becomes possible to switch to V2 (for SP).

On the other hand, when operating independently, crosstalk between elements becomes a problem, but in this first embodiment, the distance 1!1Ta=5μm
However, the cross stroke is within the permissible range, so we confirmed that there is no problem in practical use.

FIG. 6(b) tri Method for mass-producing the composite thin-film magnetic head of the first embodiment (FIG. 6(a))
This is an example of . That is, a large number of the head unit elements 21A are provided on a large-area non-magnetic substrate.

21B is formed in one go by batch processing, and then cut into head chip sizes as shown by broken lines 31 using a high-speed slicer (not shown) to form a composite thin-film magnetic head (first embodiment) 21. It can be manufactured.

In this case, the pair of head unit elements 21A, 21B are installed adjacently on the same substrate (material), and each head unit element 21A, 21B is manufactured with the same performance and shape. Further, the precision of the size of the head chip and the reference surface (for example, the bottom surface of the substrate) is increased, and the assembly work for attaching it to the head base or rotating cylinder becomes easy, so automation becomes possible.

According to the first embodiment described above, there are various effects listed below.

(1) First. Since the second magnetic core is formed in the form of a thin film with a small depth, the facing area can be significantly reduced, so that crosstalk between head elements can be significantly reduced.

(2) Since it is easy to arrange the head elements close to each other, the guard band width Ts, which is a problem in the SP mode, can be made extremely small. That is, Ts/Tp,
(Rack pitch)) can be reduced by about 10 cm.

(3) By using a conductor coil, space for winding can be easily secured and the device can be made smaller.

(4) In terms of manufacturing, by providing a large number of heads with a composite structure consisting of a pair of head unit elements on a large-area substrate, mass production is possible and costs can be reduced.

(5) Since the gaps of the pair of head unit elements are formed simultaneously on the same substrate, there is no danger that the linearity (in-line accuracy) of the gaps will be essentially disturbed. Further, since the gap depth can be formed with high accuracy by patterning, a composite head with high dimensional accuracy and good yield can be obtained.

FIGS. 7(a) and 7(b) are perspective views of a second embodiment of the present invention, that is, a composite thin-film magnetic head 4 with a double azimuth structure, and a perspective view showing an example of a mass-produced manufacturing method for this magnetic head ρ. It is a diagram.

The second embodiment (FIG. 7(a)) is similar to the first embodiment (FIG. 7(a)).
A set of magnetic heads having the same configuration as in Figure 6(a)).

The anti-element forming surfaces of the non-magnetic substrates 12m and 12b are joined to each other via a low melting point glass 18 to form a single unit. One of the magnetic heads 22A
The first . A gap regulating non-magnetic film (insulating layer) is provided between the second magnetic cores 13a and 1B- and the gap 14m between them.
A thin film magnetic head unit element 22a (hereinafter referred to as head unit element) consisting of a signal conductor coil (not shown) inserted through a signal conductor coil (not shown) and a non-magnetic substrate 12a are provided with a gap of 14b. 1st. It is composed of a head unit element 22B consisting of second magnetic cores 13b, 13'b and a small signal conductor coil 16b inserted into the gap 14b with an insulating layer 15b interposed therebetween. The other magnetic head 22B is also constructed in the same manner as the magnetic head 22A.

The substrates 12* and 12b each have an azimuth angle θ (=6°) as shown in FIG. 6(b) and a predetermined thickness Xg/2 as shown in FIG. (
= 0.1 to 0.2 m ==), and the cross section is formed into a truncated conical shape. By bonding the two processed surfaces together via the low melting point glass 18, a desired composite thin film magnetic head η having an azimuth angle of 10, -0 and a gap distance of Xg is obtained. ' Fig. 7(b) shows the magnetic heads 22A, 22 of Fig. 7(a).
6 is a perspective view showing an example of a method for mass-producing B. Since the method is the same as that shown in the first embodiment (FIG. 6(b)), a description thereof will be omitted.

According to the second embodiment described above, there are various effects listed below.

(1) Not only is it possible to perform special playback such as field stills, but by switching between SP and LP via the selection switch, each can be used with the optimal track width.

(2) Crosstalk between each element is small, especially between conductor coils 16b and 16c or (16a+16
The crosstalk between b) and (16c +16d) is very small. This has a magnetic core of 13 m, 13'bO
This is because the reduction in size and the thin thickness Tm of the magnetic cores 13a and 13b have the effect of increasing the distance between the magnetic cores 13m and 13d by 11"xg.

(3) To reduce the gap interval Xg,
An ultra-compact magnetic head with a composite structure can be realized.

(4) Since the conventional four head unit elements are integrated,
Assembly work is easy and costs can be reduced.

(5) Mass production is possible because the back surface of the substrate can be bonded in a block state in which a large number of elements are formed.

Next, FIGS. 8(a) and 8(b) are perspective views showing a third embodiment of the present invention, that is, another embodiment of a composite thin film magnetic head with a double azimuth structure, and a mass-produced version of this magnetic head n'. It is a perspective view showing an example of a manufacturing method.

The third embodiment has the same structure as the second embodiment, but is designed for mass production, and is effective when the azimuth angle θ' is smaller than θ.

That is, the element formation surfaces (outer surfaces) of the substrates 12m and 12b are tapered at an azimuth angle θ', and a pair of head unit elements Z2' a and 2 are formed on these outer surfaces.
2'b, 22'c, and Z2'd are respectively provided to constitute the magnetic head η'A I 22'B, and the anti-element forming surface (inner surface) of the substrate 12m + 12b is connected via the low melting point glass 18. By joining them together, a desired composite thin film magnetic head n' can be formed.

FIG. 8(b) shows the magnetic head 22'A of FIG. 8(m),
22'B is a perspective view showing an example of a method for mass-producing 22'B. Since the method is the same as the method shown in the second embodiment (FIG. 7(b)), a description thereof will be omitted.

According to the third embodiment as described above, by bonding the large-area substrates 12m and 12b in the form of wafers, mass productivity can be greatly improved. In this case, magnetic cores 13m, 13'a, 13b, 13'b
Since the formation surfaces of the substrates 12a and 12b, that is, the outer surfaces of the substrates 12a and 12b, are uneven surfaces having tapered grooves, dimensional accuracy during patterning is slightly reduced. However, in this third embodiment, when the azimuth angle θ' is 10° or less and the element size (thickness Tm) is 0.1 m, it is possible to secure the same level of accuracy as the conventional head, so it is not practical. There is no problem from that point of view.

Next, FIG. 9(a) is a schematic diagram showing an example of a recording/reproducing apparatus using the above-mentioned example (composite type thin film magnetic head), and FIG. 9(b) and (c) show its implementation. FIG. 3 is an explanatory diagram of an example operation.

In FIG. 9(&), 6 is a rotating cylinder, and on this rotating cylinder 6 is mounted a composite thin film magnetic head 2 consisting of two head unit elements 21m and 21b shown in FIG. 6(&).
1, and a composite thin film magnetic head 22t or n having a dub-shaped azimuth structure consisting of four head unit elements 22&~22d or η-~ρ'd shown in FIG. 7(,) or FIG. 8(1). ' and each track width expanding head unit element 21a, 22m, 22e f 2).
μm1 head unit element 21b.

22b and 22d are 40fim, and between the tracks! I (guard bar, throat) was set to 5 μm. In the figure (jl), the ink pad symbol OO indicates the sign of the azimuth angle.

Figure 9(b) shows how to switch the LP78P and how to switch between normal and special playback.
Changeover switch 6, no-pull/special playback changeover, changeover switch %
, a rotary transformer, equipped with a recording/reproducing amplifier and a delay element, which are connected as shown.

Figure 9(c) shows the operating modes and operating elements.
By setting the track width at the time of LP-8P% to be equal to the track pitch, the best image quality could be achieved. In this case, the cylinder assembly is a composite head t-2.
Since it is only necessary to attach a holder, and the work is easy, the cost of the entire cylinder can be reduced.

The number and arrangement of elements of the composite thin-film magnetic head in each of the above-mentioned embodiments are not limited to those in the embodiments, and by increasing the number of elements and combining various track widths and azimuth angles, heads with various functions and It is possible to realize a VTR.

[Start-〇effect]

As explained above, according to the present invention, a plurality of head unit elements made of a magnetic thin film as a magnetic core are arranged in the track width direction or the running direction, integrated, and integrated, thereby improving the head performance compared to the conventional one. By using a thin multifunctional VTRK, the number of heads can be reduced and costs can be significantly reduced.

[Brief explanation of drawings]

Figure 1(,)(b) is a schematic diagram of each conventional recording/reproducing device, Figures 2(a),(b), 3 and 4.
The figure is a perspective view of each conventional magnetic head, FIG. 5 is a perspective view of a thin film magnetic head unit element used in the composite thin film magnetic head of the present invention, FIG. 6 (1), FIG. 7 (a) and FIG. FIG. 8(a) is a perspective view showing the first to third embodiments of the composite thin film magnetic head of the present invention, FIG. 6(b), FIG. 7(b) and FIG. 8(b). FIG. 3 is a perspective view showing the method of manufacturing each of the first to third embodiments. FIG. 9(a) is a schematic diagram showing an example of a recording/reproducing device using the composite thin-film magnetic head of the present invention, and FIG. 9(b) is an explanatory diagram of its operation. 12.12a, 12b...Nonmagnetic substrate, 13, 13
m, 13b-first magnetic core, 13', 13'a
, 13'b...Second magnetic core, 14°14m,
14b...Gap (non-magnetic film), 15, 15
m, 15b...insulating layer, 16, 16m, 1
6b...Signal conductor coil, 20, 21m, 2
1b, 22a-Zl! d... Thin film magnetic head unit element, 21, 22, 22'... Composite thin film magnetic head. Agent Patent Attorney Tadashi Akimoto Figure 1 Figure 2 (0) ' (b) Figure 3 Figure 5 Figure 6 District 7 Figure 8 (b) Figure 9

Claims (1)

[Claims] 1. A first magnetic core, a nonmagnetic film constituting a gap, a signal conductor coil, and a second magnetic core are sequentially laminated, and the track width of this laminated body is set to be the same as that of the first magnetic core or the second magnetic core. 2. A thin film magnetic head unit element is formed by determining the width of the first magnetic core and the second magnetic core, and each gap between the first magnetic core and the second magnetic core is determined by forming a plurality of thin film magnetic head unit elements on a non-magnetic substrate. A composite thin film magnetic head characterized in that the magnetic heads are arranged in a straight line. 2. In the composite thin film magnetic head according to claim 1, two magnetic heads are combined, and the anti-element forming surfaces of the respective non-magnetic substrates of both magnetic heads are joined to each other to form an integral structure. A composite thin-film magnetic head characterized by: 3. In the composite thin film magnetic head according to claim 2, the element forming surface and the anti-element forming surface of each nonmagnetic substrate of the two composite thin film magnetic heads are formed non-parallel, A composite thin film magnetic head characterized in that both gaps between the first magnetic core and the second magnetic core of both magnetic heads are formed non-parallel.