JPS5954021A - Magnetic head - Google Patents

Abstract

PURPOSE:To perform recording with high density as well as reproduction with high output, by having larger thickness at the center part than the thickness at both end parts for the section of a main magnetic pole which is set oppositely to a recording medium with a recording/reproducing head of vertical magnetic recording system. CONSTITUTION:A vertical magnetic recording system performs recording/reproducing to a magnetic recording medium 1 traveling between a main magnetic pole 2 set at the recording side of the medium 1 and an auxiliary magnetic pole 3 set at the other side of the medium 1 by making use of the vertical magnetization of the medium 1. This recording system includes a coil 4. The pole 2 has its section having larger thickness t2 at the center part than thickness t1 at both end parts, e.g., a semicircular section (a), a semicircular section having large thickness (b), a house-shaped section (e), etc. An arrow shows the traveling direction of the medium in the figure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic pole tip, that is, a magnetic pole head in which the cross-sectional shape of the surface facing the magnetic recording medium is thick at the center and thin at both ends.

High-density magnetic recording technology is essential for making VTRs, Winchesters, floppies, etc. compact and high-density.
There is. However, the recording density of the conventional magnetic F recording method, ie, horizontal magnetization recording, is already reaching its limit. In contrast, the perpendicular magnetization recording method is attracting attention as a high-density RF recording method. This method uses co-
A thin alloy film mainly composed of co such as Or or the like is used. By subjecting these alloys to a substrate made of PET, aluminum, or the like under certain conditions, the direction of magnetization becomes perpendicular to the surface of the recording medium. In such a vertically oriented recording medium, as the recording density increases, the demagnetization effect decreases, so that it is possible to significantly improve the recording density compared to the conventional horizontal magnetization method. For such vertical FL recording, the conventional so-called ring type F recording/reproducing head is inappropriate, and a head with a new idea is required. One example is a so-called shore magnetic pole head having a main magnetic pole and an auxiliary magnetic pole, which is described in Japanese Patent Publication No. 134706/1983.

Figures 1 and 2 show the basic structure of a perpendicularly magnetized helide.

FIG. 1 shows an example of a structure in which the head is placed on both sides of the recording medium (l111), and FIG. 2 shows a structure in which one head is placed only on the C side of the recording medium. A main magnetic pole 2 is arranged on the recording surface side of the magnetic recording medium 1, an auxiliary magnetic pole 2 is arranged on the opposite side, and a coil 4 is wound around the auxiliary magnetic pole 3. In the figure, a main magnet 5 is arranged on the recording surface side of the recording medium 1, a ferrite block 6 is attached behind it, and a coil 7 is wound around them. The example shown in Fig. 2 is called the main magnetic pole excitation type.In both the auxiliary magnetic pole excitation type and the main magnetic pole excitation type, the main magnetic stop film 2 and , fa The deaf bowl body 1 is arranged at an angle of approximately [M] with respect to the direction of travel (indicated by an arrow) K, and the front side in the head travel direction and the rear side in the travel direction are straight and parallel. The relative relationship between recording media remains unchanged regardless of whether the F-recording type is a tape, a flexible disk, or a rigid disk.

Usually, the main magnetic pole is formed of a thin film such as permalloy or Co-Zr-Nb amorphous alloy, and the thickness of the thin film determines the distribution density.

Basically, the thickness is equal to the recording bit length, but due to the edge effect, strictly speaking, recording of even shorter wavelengths is the rotation part.However, during playback, the bit length is less than 1W of the main magnetic pole. It is impossible to re-record.

If the thickness of the main pole becomes thinner as the density increases, the recording and reproducing efficiency will deteriorate as the recording density increases. Regarding recording efficiency, the influence of the thickness is small due to the edge effect, but regarding reproduction efficiency, the influence of the thickness of the main pole is directly observed, and the reproduction output on the high density side becomes small ζ, which is a big problem in practice. .

The present invention takes these points into account and enables efficient high-density recording while increasing the thickness of the main magnetic pole.

An object of the present invention is to enable high-density recording with high reproduction output.

In the magnetic head of the present invention, the cross-sectional shape of the magnetic poles facing the recording medium in contact or non-contact is not the conventional polygonal shape, but is thicker at the center and thinner at both ends. When recording is performed with a head having such a tip cross-sectional shape, residual magnetization is left along the shape of the side of the magnetic pole on the medium outflow side. In the case of reproduction, a change in the magnetic flux of the medium magnetization due to the movement of the head appears as a magnetic flux density change due to the difference between the magnetization on the side of the magnetic pole on the medium inflow side and the magnetization on the medium outflow side. In the present invention, in the cross section of the magnetic pole, the shape of the side on the medium inflow side is different from the shape of the side on the medium outflow side, and only the magnetization of the side shape on the medium outflow side remains on the recording medium. On the side, the magnetic flux change is equalized and reduced due to azimuth loss, and ultimately only the magnetic flux change due to the side on the medium outflow side contributes to the reproduction voltage. In other words, the present head has a structure in which the magnetic rights holders have no effect on the recording density characteristics at all during arrangement and reproduction. Therefore, even if the magnetic pole thickness is increased, high-density recording is possible, and the recording efficiency and reproduction efficiency are also dramatically improved compared to conventional heads. It was also possible to record and play F on a 10 KBP tool. # In the main pole excitation type, during conventional reproduction, the magnetic flux sucked up due to the thin magnetic pole film does not reach the coil [
However, in the present invention, since the magnetic pole is thick, it efficiently reaches the coil part, improving the regeneration efficiency.

Conventionally, a thin film has been used as the main pole material to reduce the thickness in order to achieve high-density recording, but in the present invention, it is not necessarily necessary to stick to a thin film, and blocks such as ferrite, dust, etc. , a soft magnetic amorphous alloy foil or plate can also be used.

Figure @4 shows an example of a magnetic pole cross section of the magnetic head of the present invention. The direction of movement of the magnetic recording medium 1 is indicated by an arrow.

A semicircular cross section is shown. b is an example in which the thickness is further increased with a semicircular cross section. As is clear from the figure, the thickness t2 of the central portion is larger than the thickness h of both ends. This is an example of thickening the center part in summer. d shows the cross section of the roof type. A cross section of the e-house type is shown.

6- In all of these examples, the medium outflow side is a straight line, so the recorded residual magnetization is linear. In this case, the straight portion does not need to be perpendicular to the medium traveling direction.

The greatest feature of the magnetic head of the present invention can be seen when the traveling direction of the recording medium is reversed from the example shown in FIG. 4 and is fc.

In other words, if the straight part moves forward in the direction of travel, the residual magnetization will not be straight but arcuate. Therefore, during recording, the tracks are closely approached, and even when the magnetic head straddles adjacent tracks during reproduction, the azimuth loss is large due to the residual magnetization of the adjacent tracks, and normal pressure for reproduction does not occur. In other words, an erase head for trimming is not required.

FIG. 5 shows a further example of the present invention. It has a convex lens shape. This is an example with a thicker wall. C has a concave lens shape, and the two sides have different curvatures.

As detailed above, it is clear that the head of the present invention exhibits great effects on high-density recording.

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[Brief explanation of drawings]

1 to 3 are diagrams illustrating a conventional example. FIGS. 4 and 5 are diagrams illustrating the present invention. 1...Magnetic recording medium 2... Main magnetic pole 3...Auxiliary magnetic pole 4... Coil 5...Magnetic pole film 6... Ferrite 7... Coil that's all Applicant: Suwa Seikosha Co., Ltd. 8-

Claims (3)

[Claims] (1) A magnetic head having a magnetic pole having a thickness thinner at both ends of a surface facing a magnetic recording medium than at the center. (2) The magnetic head according to claim 1, wherein in the cross section of the magnetic pole facing the magnetic recording medium, the front side and the rear side in the traveling direction are non-parallel. (3) The magnetic spatula 5 according to claim 1, wherein at least one side of the cross section f of the magnetic pole facing the magnetic recording medium is a straight line.