JPH03178059A - Magnetic head for magneto-optical recording device - Google Patents

Abstract

PURPOSE:To obtain uniform magnetic field distribution over a wide range by forming two gaps between a main magnetic pole and a return path core on the both sides of the main magnetic pole and specifying the length of the gap. CONSTITUTION:The two gaps are formed between a main magnetic pole 1 and a return path core 2b with the main magnetic pole 1 as an axis and the length of the gap is determined to 50-300mu. In the gap length 50-300mum, the dispersion of magnetic field intensity (difference between the maximum magnetic field and the minimum magnetic field) is made small for a magnetic core having the two gaps and the uniform magnetic field can be obtained. Thus, since two magnetic pathes are formed as a return path connecting the both end parts of the main magnetic pole, the magnetic flux density of a tip part in the main magnetic pole and the uniform magnetic field can be generated over the wide range on a magnetic recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a magnetic head for magnetic field modulation used in a magnetic field modulation recording method of a magneto-optical recording device.

(Prior Art) As is well known, a magneto-optical recording device using a magnetic field modulation recording method heats a part of the magnetic recording medium by irradiating the magnetic recording medium with a laser beam, lowering the coercive force, and then recording in that state. Recording is performed using a magnetic head, and the feature is that perpendicular magnetic recording can be performed using a relatively small magnetic field. FIG. 6 is a schematic diagram showing a conventional example. The magnetic recording medium 7 has a structure in which a perpendicular magnetization film 9 (the material used is generally TbFeCo or the like) is provided on a transparent substrate 8 (the material used is generally polycarbonate or the like). The surface of 9 is covered with a protective film 10 (the material used is generally 5ilN, etc.). The perpendicularly magnetized film 9 is focused by a condensing lens 11.
The laser beam L is irradiated to heat the irradiated area.

On the other hand, the magnetic head 12 performs perpendicular magnetic recording on the heated portion of the perpendicularly magnetized film 9, and has a configuration in which a coil 6 is wound around a rod-shaped magnetic core l. The perpendicularly magnetized film 9 is perpendicularly magnetically recorded by the magnetic field H caused by the magnetic flux φ generated by the flow, thereby having the function of performing magnetic recording.

(Problem to be solved by the invention) Regarding the magneto-optical recording device based on the above principle.

Theoretically, it is preferable that the strength of the recording magnetic field due to the magnetic flux emitted from the tip of the magnetic core 1 is strongest at the perpendicularly magnetized film 9. However, since the magnetic recording medium 7C substrate 8 is generally made of a solid material such as synthetic resin, its rigidity is low and there is a limit to the flatness of the casing.
Surface runout accompanying the b-rolling of the magnetic recording medium is unavoidable, and in order to avoid contact with the magnetic head 12 due to this surface runout, it is necessary to provide a predetermined spacing between the two C. Due to the existence of this spacing and the fact that the end face of the magnetic core 1 has a flat shape as shown in the figure, a large magnetic field is required to achieve a predetermined perpendicular magnetization, and a small magnetic field is required. The problem has been that the advantage of magneto-optical recording devices, which is the ability to record data, is not fully utilized. Furthermore, in a magneto-optical recording device, a combination of an optical head that irradiates a laser beam onto the surface of a recording medium and a magnetic head for magnetic field modulation that faces the recording medium WJ and generates a magnetic field modulated according to an information signal is used. Although this function can be improved, a problem often arises in that if a sound is misaligned in the relative position of the two, it cannot be recorded reliably on the magnetic recording medium. The present invention aims to improve the following points.

a. To obtain a uniform magnetic field distribution over a wide range.

b. Improving electromagnetic conversion efficiency.

(Means for Solving the Problems) In order to achieve the above object, the present invention irradiates a magnetic recording medium with a laser beam to heat it, writes it under heating, and performs magnetic recording on the magnetic recording medium with a magnetic head. A magnetic head for a magneto-optical recording device that has at least one main magnetic pole, two return path cores are arranged around the main magnetic pole, and two VC gears are completely formed between the main magnetic pole and the return path core. The gap length was set to 50μ to 300μ.

(Function) With the above keyaki, two magnetic paths are formed as return paths connecting both ends of the main magnetic pole, so the magnetic flux density at the tip of the main magnetic pole is high, and the magnetic flux density at the tip of the main magnetic pole is high. The magnetic core can generate a uniform magnetic field over a wide range on the magnetic recording medium.

(Example) The present invention will be described in detail below with reference to one drawing.

1 to 3 show one embodiment of the present invention. As shown in FIG. 2, this magnetic head 300 is supported by a gimbal suspension 7, which is moved by a head drive mechanism, and a slider 200 supported with a predetermined spacing between it and the magnetic recording medium. The basic configuration is that a magnetic core 100'i is supported on the slider 200.

One method of combining the magnetic core 100 and the slider 200 is, for example, by providing a groove 200a in the slider 200 into which the magnetic core 100 can be inserted, and by bonding the two with glass or the like.

As shown in FIG. 1, the magnetic core 100#'i has a main magnetic pole 1 around which a coil 6 is wound, and return path cores 2-a and 2- that connect both ends of the nuclear main magnetic pole 1 to form a magnetic path. gap materials 4-a and 4- interposed between one end of the return path x=r and the lower end of the main magnetic pole 1 (the end facing the magnetic recording medium). It is composed of b.

The main magnetic pole 1 and litter/bass cores 2-a and 2-b
Fi is formed of a ferromagnetic material such as Mn-2n ferrite, and gap materials 4-a and 4-b F'
It is formed of a non-magnetic material such as Ca Ti On.

Among them, the gap may be filled with glass without using a gap material.

FIG. 3 is a schematic diagram of the magnetic core 100 according to the present invention when used in a magneto-optical recording device. In principle,
Similar to FIG. 6 showing the conventional example, perpendicular magnetic recording is performed on the perpendicularly magnetized film 9 of the magnetic recording medium 7 by the magnetic flux φ generated from the magnetic core 1oo.

FIG. 4 shows an embodiment of the structure in which one of the return path cores of the magnetic core 100 explained in FIG. 1 is removed. Elaborate on efficiency.

The conventional magnetic core shown in Fig. 6 does not form a magnetic circuit for the return path of the magnetic field generated from the main magnetic pole.
It is clear that the electromagnetic conversion efficiency is lower than that of the magnetic core shown in FIG. 1 or Vi FIG. 4.

Currently, for magnetic heads for magnetic field modulation of magneto-optical recording devices, a magnetic core 100 having one gap 4 as shown in FIG. 4 is often proposed.

Hereinafter, the embodiment of the present invention shown in FIG. 1 will be explained in comparison with the magnetic core 100 shown in FIG. 4 due to its superiority in electromagnetic conversion efficiency.

The seventh factor is a graph showing the actual measured evaluation results of the perpendicular magnetic field strength for the magnetic head samples using the magnetic core 100 shown in FIGS. 1 and 4.

First, evaluation conditions will be explained. Spacing with magnetic recording medium #i50μm, magnetomotive force to the magnetic head is 3A
T (ampere-turn), the evaluation area for magnetic field generation on a magnetic recording medium is within 0.2 life squares, and the effective magnetic field in that area is /! This is an evaluation of the large magnetic field and the minimum magnetic field. The horizontal axis of the graph is the gap length.

The vertical axis represents the vertical magnetic field strength. In the figure, 'I*al
lam is shown in FIG. 1, a graph illustrating the magnetic field strength of a magnetic core with two gaps according to one embodiment of the present invention. In the figure, b, , b, , b are graphs showing the magnetic field strength of the magnetic core having one gap in FIG. 4. a,
and bl each indicate an effective magnetic field (average magnetic field) within a 0.2 mm square magnetic field generation region. at and.

Each indicates the maximum magnetic field within a 0.2u square magnetic field generation area. A, S, and B each indicate the minimum magnetic field within the magnetic field generation area of 0.2n square. Each graph has a gap length of 1O
pfl@, 60/Jff! , 110μfi,
160μffl, 210/”PI, 260/
Jffl, the actual measurement data for each of the 310pm 7voices/t. From Figure wI7, it can be seen that the effective perpendicular magnetic field strength of the 2-gap magnetic core is larger at each gap length (10 μfn to 310 #tn) than the 1-gap magnetic core, and the magnetic efficiency is better. Also.

When the gap length is 50 μfn to 300 μm, a magnetic core having two gaps can provide a small and uniform magnetic field due to the variation in magnetic field strength (the difference between the maximum magnetic field and the minimum magnetic field υ) Fi.

FIG. 8 shows the perpendicular magnetic field strength in FIG. 7 converted into magnetic field generation efficiency K. The evaluation conditions are the same as those for the perpendicular magnetic field strength shown in FIG.

In the figure, al, at+ amill, FIG. 1 is a graph showing the magnetic field strength of a magnetic core with two gaps according to an embodiment of the present invention. In the figure, t) In b
y, bs are graphs showing the magnetic field strength of the magnetic core with one gap in FIG. a, and Vi each indicate the effective magnetic field within the magnetic field generation area of 0.211 square meters.

a, #'i, and #'i each indicate the maximum magnetic field within the magnetic field generation area of 0.21 m square. a and bs each indicate the minimum magnetic field within the magnetic field generation area of 0.2 u square. Each graph has a gap length of 10. cam, 60μfF! , 110
/jfFm, 160/ZfFl, 210μm, 26
This is actual measurement data for each of the 7 points of 0 pwl and 310 pf2m. It is expressed as magnetic field generation efficiency Kii. Even if we look at the evaluation results for magnetic field generation efficiency, the same as the evaluation results for the vertical magnetic field strength in Figure 7, the magnetic core with two gaps has high electromagnetic conversion efficiency. It is possible to obtain a uniform magnetic field distribution with a small amount of magnetic field.

Next, the distribution of magnetic field generation strength in the direction indicated by A in FIG. 1 will be explained using FIGS. 9 and 10.

FIG. 9 shows the distribution of the magnetic field intensity of the magnetic core having the two gaps shown in FIG.

Main pole width is 200μm, gap length is 110/Jfi
.

The evaluation results are shown when the spacing is 50 μm and the magnetomotive force is 3AT. As for the vertical magnetic field strength, a uniform magnetic field generation distribution can be obtained over the width of the main magnetic pole, which is 200 pm, centered on the center of the main magnetic pole.

FIG. 10 shows the distribution of the magnetic field intensity of the magnetic core shown in FIG. 4 and having one gap 7'c. Similar to the 2-gap magnetic core, the width of the main pole is 200 μm, the gap length is 110 ptlL, the spacing is 50 μm,
The magnetomotive force is the evaluation result at 3AT.

The perpendicular magnetic field strength shows a peak value at a position shifted by 80 μm from the core center of the main magnetic pole in the direction of gap formation, and a uniform magnetic field generation distribution cannot be obtained as in a two-gap magnetic core.

FIG. 5 shows another embodiment of the magnetic head of the present application, and when compared with the magnetic head shown in FIG.
00° 90 degrees to slider 200.

It is combined with the slider 200 in a state where the direction metal is rotated. The magnetic core 100 is attached to the end of the slider 200 in the thickness direction, and the two are bonded together by glass or the like.

As can be seen from the description of the embodiments above.

The magnetic field strength generated by a two-gap magnetic head can vary over a wide range (
In the example, Fio is uniform across 2111 squares). From this, the magnetic head of the embodiment shown in FIG.

As shown in FIG. 5, a structure in which the magnetic core is rotated 1-90 degrees horizontally to the recording medium can also provide the same magnetic recording effect. Even if the direction of the magnetic core is rotated from 0 degrees to 360 degrees, the same magnetic recording effect is obtained.

This allows the combination direction of the slider and magnetic core in the magnetic head to be freely changed, providing greater structural freedom.

It was. When installing the magnetic head to a gold-optical magnetic recording device,
It is possible to attach it to the recording medium in any horizontal direction.

(Effects of the Invention) As is clear from the above description, the present invention has the following effects. A magnetic head with two gaps can spread over a wide range at a position a predetermined distance from the magnetic recording medium.
A uniform perpendicular magnetic field distribution can be obtained, and the magnetic recording medium can be reliably magnetized perpendicularly regardless of relative positional deviation between the optical head and the magnetic head.

In addition, since it is possible to obtain a uniform perpendicular magnetic field distribution over a wide range, there is a greater degree of freedom in considering the structure of the magnetic head, such as the combination of the magnetic core and slider, resulting in higher magnetic efficiency. A magnetic head structure, a magnetic head structure that is easier to assemble, etc. can be made.

[Brief explanation of drawings]

Figures 1 and *2 show an embodiment of the present invention. Figure 1 is a perspective view showing the external appearance of the magnetic core, and Figure 2 (at~(
cl is a schematic diagram of a magnetic head combining a magnetic core and a slider; FIG. 3 is a schematic diagram illustrating the principle of a magneto-optical recording device using a magnetic core of the first frame. FIG. 4 is a perspective view showing the external appearance of the magnetic core from which one return path core and one gap (one side) of the magnetic core of FIG. 1 have been removed, and FIGS. Fig. 6 is a schematic diagram illustrating the principle of a magneto-optical recording device using a conventional magnetic head.
8 and 8 are graphs showing the relationship between the gap length, the generated magnetic field, and the generated magnetic field efficiency for the magnetic core (2-gap) and the 1-gap magnetic core of the present application, and FIG. 9 and WJ10
The figure is a graph showing the vertical magnetic field strength in the horizontal direction for the magnetic core (2-gap) and the 1-gap magnetic core of the present application. 1... Main engine l 2, 2-a, 2-b... Return path core, 4, 4-a, 4-b... Gap, 7...
Magnetic recording medium, 100...Magnetic core, 200...Slider, 300...Magnetic head Fig. 3 Fig. 4 Fig. 4 Fig. 4 (a) Intrigue and profit, 1000 ~゛ya, ヮpu tψm)

Claims (2)

[Claims] (1) In a magnetic head for a magneto-optical recording device in which a magnetic recording medium is irradiated with a laser beam to heat it and the magnetic head performs magnetic recording on the magnetic recording medium under heating, returns are returned to both sides of at least one main magnetic pole. Place the path core, form two gaps between the main magnetic pole and the return path core,
A magnetic head for a magneto-optical recording device, comprising a magnetic core having a gap length in the range of 50 μm to 300 μm. (2) The magnetic head for a magneto-optical recording device according to item (1), wherein the magnetic core is attached to a slider made of a non-magnetic material.