JPS6180510A - vertical magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a perpendicular magnetic head.

Conventional configurations and their problems Perpendicular magnetic recording allows signal recording at a much higher density than conventional longitudinal magnetic recording.

The following heads have been proposed for recording and reproducing such perpendicular magnetization signals.

FIG. 1 shows a first example, in which a main magnetic pole 1 and an auxiliary magnetic pole 3 provided with a winding 2 face each other with a medium 4 interposed therebetween. A second example of an improved version of such an auxiliary pole excitation type perpendicular head is a main pole excitation type head that allows recording and reproduction from one side of the medium (FIG. 2).

In all of these, recording is performed by applying a recording current to the winding 2, and reproduction is performed by a voltage induced in the winding from magnetization on the medium.The closer the winding is placed to the medium, the more efficient it is. I know what I'm getting.

In order to bring the winding closer to the medium side in the main pole excitation head, it is effective to use a thin film head configuration.

FIG. 3 shows an example of this configuration. A main magnetic pole 1 made of a ferromagnetic thin film is disposed on a non-magnetic substrate 6. A thin film coil 6 and a return yoke 7 made of a ferromagnetic thin film are sequentially formed. An insulating layer (not shown) is formed between these films.

A thin film head having such a structure can have high efficiency because the overall size, especially Ll in the figure, can be made small.

Around 10 turns as a thin film coil, 10 turns as Ll
A thickness of about 0 μm has been realized.

Furthermore, in order to bring the winding closer to the medium, a fourth example shown in FIG. 4 has been proposed.

A thin film coil 6 is formed on a ferromagnetic substrate 8, and a main magnetic pole 1 held by a nonmagnetic substrate 9 is bonded thereon. With such a configuration, L2 in the figure can be further reduced,
It is possible to obtain a head with higher efficiency.

The vertical heads that have been proposed so far have been listed above, and a comparison of these is as follows.

In the heads with the configurations listed as the first and second examples, the winding can be provided with several tens to hundreds of turns, but since the winding wire with a diameter of several tens of micrometers is used, the dimensions of the entire coil are several hundred micrometers or more, which is not very practical. There is a limit to how high efficiency can be achieved because it cannot be made smaller.

Next, the third. In the head having the configuration mentioned as the fourth example, since a coil having a width and thickness of several micrometers is used, the coil size and therefore the head size can be made small and high efficiency can be realized.

Consider the problems when increasing the number of coil turns with the thin film configuration described above.

FIGS. 5a and 5b are diagrams showing the flow of magnetic flux in the heads of FIGS. 3 and 4, respectively. Magnetic flux flows like an arrow,
It can be seen that there is magnetic flux that leaks without interlinking with the entire coil. Here, when increasing the number of turns of the thin film coil as described above in a planar manner, the person shown in FIG. 5a.

Although it is necessary to increase B in b, it can be seen that by doing so, the magnetic flux that interlinks with the coil located away from the tip of the main pole decreases, resulting in a decrease in efficiency.

Therefore, realizing a coil with several tens to hundreds of turns with such a configuration does not contribute much to improving the absolute output.

On the other hand, if the number of turns is increased by converting the thin film coil into a multilayer coil (for example, 10 turns x 10 layers), the efficiency can be expected to be quite good, but the manufacturing process will be very complicated and this is not practical. Not the point.

To summarize the above, 1. The second example is a head with low efficiency and a large number of windings, and the third example is a head with low efficiency and a large number of windings. In the fourth example, only a head with high efficiency and a small number of windings could be realized, and it had both advantages and disadvantages in terms of the isolated output of the head, which is important in a practical sense.

OBJECTS OF THE INVENTION The present invention provides a perpendicular magnetic head with high efficiency and high output equivalent to that of a multi-winding head.

Structure of the Invention In order to realize a high-output vertical head, the present invention uses a thin film coil of at most several turns for the signal winding directly coupled to the main magnetic pole, and increases efficiency by arranging the coil close to the recording medium. In other words, the signal magnetic field is detected in a state where the induced electromotive force per turn is large), and a highly efficient Gaitetsuo transformer placed close to this is coupled to perform step-association of the signal. The basic idea is to obtain a head configuration that provides a large output per turn and a large number of windings.

For this purpose, the perpendicular magnetic node of the present invention includes: (1) ferromagnetic substrate (2) main magnetic pole (3) first thin film coil (4) second thin film coil (5) return yoke (6) closed circuit yoke It's working. The main magnetic pole and the return yoke constitute a first closed magnetic path together with the recording medium, and the first thin film coil interlinks with this. The ferromagnetic substrate and the closed circuit yoke form a second closed magnetic path as an external iron type transformer, and the first thin film coil and the second thin film coil are interlinked with this closed magnetic path to form the primary of the transformer.

It constitutes both secondary windings.

According to the above configuration, the signal winding is miniaturized, the number of turns is reduced, and the winding position is brought as close to the medium as possible.
The efficiency per turn can be increased, while the decrease in absolute output due to the number of body turns can be compensated for by a step-up transformer, which is especially effective for vertical heads.

Description of examples A first embodiment of the present invention is shown in FIGS. 5a and 5b.

In the figure, 10 is a ferromagnetic substrate, 11 is its thin film forming surface, and 12 is a recording medium contacting surface. The substrate 10 has a first non-magnetic filling part 13a at its front end, and a second non-magnetic filling part 14 in the form of a closed channel on the thin film forming surface 11 rearward thereof. A perspective view of only the substrate is shown in FIG.

In FIG. 5, 1 is a main magnetic pole υ made of a ferromagnetic thin film, and in order to avoid magnetic saturation during recording, the first coil 22
It is preferable that the thickness of the main magnetic pole at the rear of the position a is thicker than that at the front.

Reference numeral 7 denotes a return yoke made of a ferromagnetic thin film, the rear part of which is magnetically coupled to the rear end of the main magnetic pole 1, and the front part extending to the vicinity of the surface in contact with the medium.

The main magnetic pole 1 and the return yoke are the soft magnetic injection film 1 in the recording medium 4.
4 together form a first closed magnetic path 15a.

Reference numeral 16 denotes a closed circuit yoke made of a ferromagnetic block or a thin film thereof, and is connected to the second non-magnetic filling portion 1 of the ferromagnetic substrate 10.
4 inner area (Figure 7 17) and outer area (Figure 7 18)
are magnetically coupled to form an outer iron type transformer core together with the ferromagnetic substrate 1o. Figure 5 Middle 19.2
The portion indicated by 0 is the magnetic core portion around which the primary and secondary coils of the outer iron type transformer are to be wound, and 21 is a typical magnetic path (second closed magnetic path) thereof.

In FIG. 5, reference numeral 22 is a first thin film coil which is itself a one-turn closed circuit, its front part 22a interlinks with the first closed magnetic circuit 15 as a signal winding for the main magnetic pole, and its rear part 22b is a transformer primary coil. It interlinks with the second closed magnetic path 21 as a winding.

23 is a second thin film coil, which interlinks with the second closed magnetic path 21 as a transformer secondary winding.

The rear part 22b of the first coil and the second coil 23 are both installed so as to coaxially revolve on the second non-magnetic filling part 14.

In the above description, the circuit-closing yoke 16 is omitted from illustration in FIG. 5a.

As for the connection between the inner region 1a and the outer region 18 of the second non-magnetic filling part by the closing yoke 16, it goes without saying that the coupling between the inner region 1a and the outer region 18 of the second non-magnetic filling section is done by the inner regions of the first and second coils (i.e., 24 and 24 in FIG. 25 area) must be avoided. Because the closed magnetic path passing through 24 is the first coil 2
This is because the magnetic path that does not interlink with coil 2 and passes through 25 has one less linkage with the second coil 23, resulting in a decrease in efficiency.

Further, although not shown in the drawings, an appropriate insulating layer is provided in areas where insulation is required, such as between each coil.

Regarding the operation of the first embodiment as described above, during reproduction, when the reproduction magnetic flux flows through the first closed magnetic path 15a due to the reproduction magnetic field from the recording medium 4, an electromotive force proportional to the time change of the reproduction magnetic flux flows into the first closed magnetic path 15a. A signal current is generated in the coil 22 of No. 1 and flows through the same coil. This current excites the transformer, and an electromotive force corresponding to the stamp-up ratio is generated in the second coil 23, which is the secondary winding of the transformer, and a signal output voltage is obtained. During recording, a recording magnetic field is applied to the medium from the tip of the main magnetic pole 1 through the reverse process of the above operation.

In the first embodiment, the number of linkages between the first closed magnetic circuit and the first coil is N1. The number of linkages between the first coil and the second closed magnetic circuit is N2
．． When the number of linkages between the second closed magnetic path and the second coil is N3, N, =N2=1. Although an example of N5=6 has been shown, these numerical values should of course be determined according to the specific purpose and circumstances of each case. From the purpose of the present invention, N1≧
N2. It is preferable that N2 minus N3 and N1 be several turns at most. This also applies to other embodiments described below.

FIG. 8 shows a second embodiment of the invention. In this example, the return yoke for the main pole is also formed at the front end of the ferromagnetic substrate 1o, and for this purpose, a cut that includes at least a part of the ridge formed by the thin film forming surface 11 and the medium contacting surface 12 is formed. A first nonmagnetic filling portion 13b is provided in the notch.

The rear end of the main magnetic pole 1 is magnetically coupled to the ferromagnetic portion of the substrate 1o, and the first closed magnetic path at this time is like 15b. The front portion 22a of the first coil is connected to the first closed magnetic path 15b.
It is installed between the first non-magnetic filling part 13b and the main magnetic pole 1 so as to be interlinked with each other.

In this embodiment, the structure related to the transformer portion is the same as that in the first embodiment, so the same reference numerals are given and the explanation thereof will be omitted.

In this embodiment, since the first closed magnetic path and the second closed magnetic path are continuous through the ferromagnetic portion of the substrate 10, they may interfere with each other. There wasn't. If the overall size of the head is extremely small and the first closed magnetic path and the second closed magnetic path body are very close to each other,
It is preferable to provide a third non-magnetic filling part as shown in 6 to separate both open magnetic paths.

FIG. 9 shows a third embodiment of the invention, especially the second embodiment.
As this relates to a non-magnetic filling part, a perspective view of only the substrate is shown. In this embodiment, instead of forming the second non-magnetic filling part in the shape of a closed circuit groove, it is formed into a convex shape as shown in the figure, and the broken line 2
The circumferential region No. 7 corresponds to the closed channel groove-shaped nonmagnetic filling portion in the first and second embodiments. According to this configuration, the formation of the second non-magnetic filling part is practically very easy,
It is highly mass-producible. Just the first thing. Compared to the second embodiment, the effective magnetic path cross-sectional area of the outer iron type transformer core is reduced, so there is a concern that the efficiency of the transformer will decrease, but in the actual embodiment, the first embodiment. There was almost no difference in performance compared to the transformer in the second example. This is considered to be because the high efficiency of the external iron type transformer largely depends on the fact that both the primary and secondary coils are wound closely and coaxially.

Effects of the Invention According to the present invention, the drawback of the vertical head, which tends to be low in efficiency compared to conventional ring heads, etc. is compensated for, and the efficiency per turn is high, and the number of turns of the signal winding is isometrically reduced. It is possible to realize a vertical head that is large and therefore has a large absolute output value. The structure is easy to actually manufacture and has a great effect on mass production.

[Brief explanation of drawings]

Figures 1 to 4 are cross-sectional views showing conventional examples of perpendicular magnetic heads, and Figures 5(a) and (b) are cross-sectional views showing the flow of magnetic flux during reproduction of the head in Figures 3 and 4, respectively. 5(a) and 5(b) are a plan view and a cross-sectional view showing the first embodiment of the present invention, respectively. FIG. 7 is a perspective view showing the substrate portion of the first embodiment, and FIG. The figure is a sectional view showing the second embodiment, and FIG. 9 is a perspective view showing the substrate portion of the third embodiment. 1...Main magnetic pole, 7...Return yoke, 1o...Ferromagnetic substrate, 13a...Nonmagnetic filling part, 15a... first closed magnetic circuit, 16.
! ...Closing yoke, 21...Second closed magnetic circuit, 22...First thin film coil, 23...
-Second thin film coil. Name of agent: Patent attorney Toshio Nakao and 1 bubble volume: 1
Figure 2 Figure 3 Figure 5 (C) (b) Figure 5 ((i,,)
(b) Figure 7, Section 13, Figure 8, Figure 9

Claims (7)

[Claims] (1) A ferromagnetic substrate having a thin film formation surface substantially perpendicular to the recording medium contact surface, a main magnetic pole made of a ferromagnetic thin film, a first thin film coil, and a second thin film coil, each made of a ferromagnetic material. The ferromagnetic substrate has a first non-magnetic filling portion near the front end thereof that includes at least a portion of the ridge formed by the medium contacting surface and the thin film forming surface. , the main magnetic pole is provided such that its tip is in contact with the ridge and at least a portion thereof occupies the thin film forming surface of the first non-magnetic filling part, and the rear end of the return yoke is provided with the rear end of the main magnetic pole. The ferromagnetic substrate is magnetically coupled to the ferromagnetic substrate, and the front end is arranged so as to extend near the medium contacting surface to form a first closed magnetic path including the main magnetic pole, the return yoke, and the recording medium. has a closed circuit groove-shaped second non-magnetic filled portion on the thin film formation surface rearward of the main magnetic pole, and the closed circuit yoke magnetically connects the inner and outer regions of the second non-magnetic filled portion. The second transformer core is connected to the
The front portion of the first thin film coil is interlinked with the first closed magnetic path, and the rear portion of the first thin film coil and the second thin film coil are connected to the second thin film coil. A perpendicular magnetic head, characterized in that the perpendicular magnetic head coaxially interlinks with the second closed magnetic path on the non-magnetic filled part. (2) The thickness of the main magnetic pole on the side of the medium with respect to the interlinking position of the main magnetic pole and the first thin film coil is thinner than the thickness on the side opposite to the medium. magnetic head. (3) The perpendicular magnetic head according to claim 1, wherein the closing yoke is formed of a thin film. (4) The perpendicular magnetic head according to claim 1, wherein the return yoke is formed of a thin film. (5) The perpendicular magnetic head according to claim 1, wherein the return yoke is formed by sharing a part of the ferromagnetic substrate. (6) A third non-magnetic filling part is provided between the first non-magnetic filling part and the second non-magnetic filling part to separate the first closed magnetic path and the second closed magnetic path. A perpendicular magnetic head according to claim 5. (7) The perpendicular magnetic head according to claim 1, wherein the second non-magnetic filling portion is formed by a protruding groove.