JPS6353702A - Generating device for high frequency modulated magnetic field - Google Patents

Abstract

PURPOSE:To attain the reduction of power consumption, and a fast operation, by constituting a device by arranging the soft magnetic material part, and the hard magnetic material part of a main magnetic pole in the longitudinal direction of the main magnetic pole. CONSTITUTION:In the main magnetic pole 2, the soft magnetic material parts S1 and S2 made of a soft magnetic material, and the hard magnetic material part H1 made of a hard magnetic material, are arranged in the longitudinal direction that is an axial direction, and the winding 3 for driving is wound about the main magnetic pole 2, and a tip part 5 that is one end of the main magnetic pole 2, is used confronting with a magneto-optical recording medium. Also, a yoke part 4 which forms the return path of a magnetic flux is arranged at the base end side of the main magnetic pole 2, from which a required magnetic field can be generated. The winding 3 is the one to magnetize the hard magnetic material H1 of the main magnetic pole 2, and by setting the direction of a current to be supplied to the in winding 3 adversely, it is possible to set the direction of a magnetic field adversely. In this way, since it is possible to generate the magnetic field in a prescribed direction of magnetic field by inversing the direction of magnetization, the fast operation can be performed, and the power consumption can be reduced to a minimum level.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Application Field The present invention relates to a high frequency modulated magnetic field generator for applying a modulated magnetic field to a magneto-optical recording medium. This is done while realizing the following.

B1 Summary of the Invention The present invention provides a high-frequency modulated magnetic field generator having a main magnetic pole facing a magneto-optical recording medium and a winding wound around the main magnetic pole, in which a soft magnetic material portion and a hard magnetic material portion are connected to each other along their longitudinal sides. By using main magnetic poles arranged in the same direction, magneto-optical recording can be performed while achieving low power consumption.

C3 Prior Art In magneto-optical recording and reproduction, one method for enabling override in real time is to perform recording using a magnetic modulation method.

Here, the method of recording and reproducing information signals using the magnetic field modulation method will be briefly explained with reference to FIG.
First, a laser device 101 for heating the magneto-optical recording medium 100 with a laser beam through a lens 102;
Recording and reproduction are performed by a magnetic field generating device 103 that generates a magnetic field that is modulated according to an input signal. That is, the portion of the magneto-optical recording medium 100 to be recorded is heated by the laser device 101, and by applying a magnetic field in a predetermined direction to the heated portion by the magnetic field generator 103, the heated portion is heated in that direction. It is magnetized, and recording and erasing are performed by this magnetization.

D0 Problems to be Solved by the Invention By the way, the magnetic field generating device 103 described above is required to have a function of generating a magnetic field in a predetermined direction. There are devices whose main magnetic pole is made of a hard magnetic material such as a permanent magnet.

However, in devices where the main magnetic pole is made of a soft magnetic material, it is necessary to excite the winding wound around the nuclear magnetic pole, and therefore, continuous energization is required to generate a magnetic field. , depending on such energization,
The power consumption will increase. In addition, in devices where the main pole is made of a soft magnetic material, a current is required to be supplied when excitation is performed, and this current is accompanied by winding resistance FM loss, and if this loss is not reduced, magneto-optical recording will occur. The loss of the magnetic field generator as a whole is large.

Additionally, in some devices where the main magnetic pole is made of hard magnetic material such as a permanent magnet, the direction of the magnetic field is reversed by mechanical operation, and in that case, it is difficult to increase the reversal speed. However, there are still concerns about reliability when used for a long period of time.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a high-frequency modulated magnetic field generating device that can generate a necessary magnetic field while reducing power consumption, and is excellent in high-speed operation and reliability.

Means for Solving the E0 Problem The present invention provides a main magnetic pole facing a magneto-optical recording medium at one end;
In the high frequency modulated magnetic field generating device having a winding for exciting the main magnetic pole, the main magnetic pole is configured such that a soft magnetic material portion and a hard magnetic material portion are arranged in the longitudinal direction of the main magnetic pole. The above-mentioned problems are solved by the characteristic high-frequency modulated magnetic field generator.

Further, the signal current for controlling such a high frequency modulated magnetic field generator may be a bidirectional pulse signal current A as shown in Fig. 3+al, or a bidirectional pulse signal current A as shown in Fig. 3 (bl).
The signal current α may be a signal current α that adds a level signal that corrects residual magnetization along with the pulse portion, as shown in FIG.

20 Effects The main pole of the high frequency modulated magnetic field generator of the present invention is composed of a soft magnetic material portion and a hard magnetic material portion. Among these materials, hard magnetic materials generate a magnetic field in a predetermined magnetic field direction by reversing the direction of magnetization using a pulse current or the like due to their hysteresis characteristics. In addition, the soft magnetic material can reduce the demagnetizing field caused only by the hard magnetic material, compared to the case where the main pole is made of only the hard magnetic material.

That is, the high frequency modulated magnetic field generating device of the present invention has such soft magnetic materials and hard magnetic materials arranged in the longitudinal direction,
By supplying a current in a predetermined direction to the winding wound around the main VjL pole, the hard magnetic material is magnetized in a predetermined direction (bidirectional). A magnetic field is generated by the magnetization applied to this hard magnetic material, and the generated magnetic field is applied to the magneto-optical recording medium. However, in the high frequency modulated magnetic field generating device of the present invention, the demagnetizing field is generated by the soft magnetic material. Since the magnetism is reduced, the excitation current can be small, and the residual magnetization that generates the magnetic field applied to the magneto-optical recording medium can also be large.

G. Example Preferred embodiments of the present invention will be described with reference to the drawings.

】” γ-tabi ” L The high-frequency modulated magnetic field generating device 1 of the first embodiment of the present invention has the following features:
As shown in FIGS. 1 and 2, the main pole 2 has soft magnetic material portions S1 and S2 made of soft magnetic material and hard magnetic material portion H1 made of hard magnetic material in the axial direction. They are arranged in the longitudinal direction, and a winding 3 for excitation is wound around the main magnetic pole 2, and the tip 5, which is one end of the main magnetic pole 2, is used to face the magneto-optical recording medium. . In addition, from the base end side of the main magnetic pole 2, a yoke portion 4 serves as a return path for magnetic flux.
is installed to generate the required magnetic field.

The main magnetic pole 2 is excited (magnetized) in a predetermined direction by a signal supplied to the winding 3, and applies a modulated magnetic field to the magneto-optical recording medium 1 disposed on the tip side of the main magnetic pole 2. Can be done. Such a main magnetic pole 2 includes a soft magnetic material portion SL,
It has a structure in which the hard magnetic material part H1 and the soft magnetic material part S2 are laminated, and of these, the hard magnetic material part H1 is magnetized by the supply of current as described later due to its hysteresis characteristics, and residual magnetization occurs. Used as a magnetic field.

Since the soft magnetic material parts SL and S2 are each made of a high magnetic permeability material, the magnetic field generated by residual magnetization can be efficiently supplied to the magneto-optical recording medium, and
During magnetization, the excitation current can be reduced. The shape of the tip of the main magnetic pole 2 may be tapered, or the main magnetic pole 2 may be cylindrical, and when a disk or the like is used as a medium, the main magnetic pole 2 may have a shape that spans the entire width of the recording layer. It may be.

Here, the hard magnetic material portion H1 has a coercive force of 600 (O
e) Ba ferrite with a residual magnetic flux density of about 1900 (Oe) (in the vertical direction) can be used, but is not limited to this, and metal magnets such as Cu-Ni-Fe, oxides or metal fine particles can be used. A magnet, various molded magnets, etc. can be used.

In addition, as the soft magnetic material portions Sl and S2, for example, Mn-Zn ferrite or Ni-Zn ferrite having a magnetic permeability of 800 to 1000 (IMHz) can be used, but the material is not limited thereto, and various ferrites, laminated layers, etc. can be used. Permalloy, laminated amorphous, sendust, powdered iron core, etc. can be used. Note that the hard magnetic material H1 may be a thin film formed by a sputtering method or the like.

The winding 3 is for magnetizing the hard magnetic material H1 of the main pole 2, and by setting the direction of the current supplied to the winding 3 in the opposite direction, the direction of the generated magnetic field can be changed. It can be in the opposite direction.

Further, as will be described later, when the generated magnetic field is weak, it is possible to compensate for the magnetic field not only for magnetization but also for recording and erasing by energizing.

Here, an example of specific dimensions of the high frequency modulated magnetic field generating device l of this embodiment will be explained. For example, the high frequency modulating magnetic field generating device 1 has a height h of 5 mm and a width W of 811 mm.
．． The tip portion 5 of the main magnetic pole 2 is 2×11 m, the thickness t of the yoke portion 4 is 1 m, and the distance g between the tip of the yoke portion 4 and the tip portion 5 is 2
Also, the thickness 11 of the soft magnetic material portion S1 is lux
, the thickness 12 of the hard magnetic material portion H1 can be set to each dimension of the I-tsuru. Note that the shape of the yoke portion 4 may be such that it extends in the direction of the main magnetic pole 2.

Next, as described above, the high frequency modulated magnetic field generating device 1 of this embodiment will be described.
The operation will be explained with reference to FIGS. 3 and 4, especially in comparison with the case where the main pole is made of only soft magnetic material and the case where the main pole is made of only hard magnetic material.

First, in Figure 3, the horizontal axis is time, the vertical axis of [al and (bl) is the current value 1, the vertical axis of (e) is the magnetization M, and the vertical axis of (dl is the intensity H (vertical) of the generated magnetic field. direction).

The waveform signal A shown in FIG. In other words, in this waveform signal A, the hard magnetic material portion H1 is magnetized in one direction by the current of pulse Al (A3), and then in the opposite direction by the current of pulse A2. The hard magnetic material portion H1 is magnetized.

Incidentally, FIG. 3 shows an example of a signal current when magnetic fields in opposite directions are sequentially generated.

On the other hand, when the main pole is entirely made of soft magnetic material, the waveform signal B becomes a waveform signal that requires continuous energization for a certain period of time, as shown by the broken line in (al).

Comparing this waveform signal B and the above waveform signal A, it is clear that waveform signal A, which is a pulsed current, is more advantageous in terms of power consumption. It is shown that the high-frequency modulated magnetic field generating device 1 of this embodiment, which has the main magnetic pole 2 having the above-mentioned shape, can realize low power consumption.

FIG. 3(C) shows the magnetization of the hard magnetic material portion H1, and a magnetization curve C shown by a solid line shows the magnetization of the hard magnetic material portion H1 when the signal current A is supplied. Here, the magnetization process in this hard magnetic material portion H1 is shown in Figure 4a.
To explain with reference to FIG. 4, the magnetization curve C also takes a value al of the pulse waveform in correspondence with the pulse current A1 of the signal current A, and this corresponds to al on the hereteresis loop as shown in Fig. 4a. do. Next, the signal current A becomes zero and the external magnetic field becomes zero, but due to the residual magnetic field and demagnetizing field, the magnetization of the hard magnetic material portion H1 is 51 on the magnetization curve C, which is shown in Figure 4a. bl is on the permeance line.

Next, in order to generate a magnetic field in the opposite direction, it is necessary to supply the pulse current A2 in the opposite direction, and the pulse current A2 of the signal current A is supplied to the high frequency modulated magnetic field generator 1 of this embodiment.
When the hard magnetic material portion H1 is supplied with a magnet, the hard magnetic material portion H1 undergoes a magnetization process opposite to that described above.

That is, the magnetization curve C becomes dl from the value c1 in the opposite direction,
These 'L+dL correspond to cl and dl on the hereteresis loop in FIG. 4a, respectively.

Comparing the high frequency modulated magnetic field generating device 1 of this embodiment, which exhibits such a history, with one in which the soft magnetic material portion is removed and the main magnetic pole is composed of only the hard magnetic material portion, it is found that Fig. 3 fC1
The waveform in the middle shows the magnetization process of a device whose main magnetic pole is made of only hard magnetic material, and points a3. on this waveform. b
3. c3. It is shown that the value of each point of d3 is a small value when compared with the magnetization curve C related to the above-described high frequency modulated magnetic field generating device 1. Further, the hysteresis loop at this time becomes a small loop as shown in FIG. 4C. In addition, a3. in FIG. 4C. Each point of b3°C3+d3 corresponds to each point of the same symbol on the waveform.

This means that if the main magnetic pole were made of only hard magnetic material without the soft magnetic material, the magnetic flux that was focused on the main magnetic pole would decrease due to the absence of the soft magnetic material, and the sithesis loop would become smaller. When the main pole is made of only a hard magnetic material, the generated magnetic field becomes smaller, and therefore the magnetic field that can be used in the magneto-optical recording medium also becomes smaller. Therefore, a high-frequency modulated magnetic field generating device made by arranging a hard magnetic material and a soft magnetic material as in this embodiment has better recording and erasing characteristics.

As described above, the magnetic field generated by the high frequency modulated magnetic field generating device 1 of this embodiment can be generated with lower power consumption than when the main pole is made of only soft magnetic material.
Furthermore, the magnetic field is stronger than when the main pole is made of only hard magnetic material.

The magnetic field generated by the high frequency modulated magnetic field generator l of this embodiment is based on the magnetization curve C of the hard magnetic material portion H1.
Correspondingly, a magnetic field curve E as shown in FIG. 3 fdl is obtained, and this magnetization curve E becomes the magnetic field applied to the magneto-optical recording medium with respect to the signal current A for excitation.

By the way, the high-frequency modulated magnetic field generating device 1 of the present embodiment is more suitable for applying a magnetic field to a magneto-optical recording medium than when the main pole is made of only soft magnetic material or only hard magnetic material as described above. In addition, the high-frequency modulated magnetic field generating device 1 of this embodiment generates a level signal that corrects residual magnetization accompanying the pulse portion, as shown in FIG. 3 (bl). By adding the signal current α, it is possible to compensate for the insufficient residual magnetization and realize good and reliable magneto-optical recording.

That is, as shown in FIG. 3(b), a signal current B consisting of a pulse current section B1 and a level signal section B2 is supplied to the high frequency modulated magnetic field generating device 1. In this case, the pulse current section B1 has the function of magnetizing and reversing the direction of magnetization of the hard magnetic material section +11 in the same way as the pulse current A1 of the signal current A described above; It is possible to generate a strong magnetic field by compensating for the residual magnetization that decreases when the current is reduced to zero. The magnetization curve β shown by the two-dot chain line in Figure 3 (C1) shows the value of magnetization of the hard magnetic material portion H1 formed by the signal current α, and here the hysteresis curve shown in Figure 4 First, when the pulse current section B1 is added, the state of the hard magnetic material section H1 is at point a2, but the level signal section B attached to this pulse current section B1 is
In response to the signal No. 2, the magnetization of the hard magnetic material portion H1 becomes point b2. This point b2 is located on the permeance line b, which has a steeper slope than the permeance line in Fig. 4a in Fig. 4.
It can be seen that the demagnetizing field is canceled out by the level signal section B2 located above 2d and for compensating the residual magnetization, and the effective generated magnetic field is increased. Regarding the generation of a magnetic field in the opposite direction, as shown at point d2 on the magnetization curve β and the hereteresis loop in Figure 2,
The demagnetizing fields cancel each other out, increasing the effective generated magnetic field. Further, in FIG. 3 Cdl, the waveform T shown by the two-dot chain line shows the generated magnetic field of the high frequency modulated magnetic field generating device 1 of this embodiment in which the residual magnetic field is compensated by the level signal section B2 in this way.

As mentioned above, the high frequency modulated magnetic field generating device 1 of this embodiment has the following features:
Compared to magnetic field generators in which the main pole is made of only soft magnetic materials that require continuous energization, the current required for excitation is smaller, resulting in lower current consumption. In this case, it is also possible to reduce power loss due to winding resistance. In addition, compared to a case where the main pole is made of only hard magnetic materials, since the soft magnetic materials are arranged nearby, it is possible to generate a strong magnetic field more efficiently, and bidirectional magnetization is also easier. .

Here, to explain the effective range of such a high frequency modulated magnetic field generator 1, it is assumed that the power loss due to the winding resistance exceeds the core loss of the arranged hard magnetic material parts, so the formula +2 R>fvS (I: winding effective current (A), f: current frequency (Hz),
R: Winding resistance [Ω], S: Cross-sectional area of hard magnetic material (wb-
A/V], V: The hard magnetic material deposition Cm1 determines the effective range.

Note that the hard magnetic material portion is not particularly limited in shape as long as it is disposed over one cross section of the main magnetic pole 2. Moreover, a plurality of hard magnetic material parts may be provided.

■1 Toyomi Odor Doctor A high-frequency modulated magnetic field generating device 50 according to a second embodiment of the present invention has approximately E-shaped magnetic poles, as shown in FIG.
The main magnetic pole 52 includes a hard magnetic material portion S51 and a soft magnetic material portion 35.
1, the hard magnetic material portion 1151
are arranged at one end facing the magneto-optical recording medium. In this way, it can be used not only by being sandwiched between the soft magnetic material parts like the hard magnetic material part H1, but also by placing it at the end (similarly, it can generate a strong magnetic field with low power consumption and efficiency). Note that the materials, operations, etc. are the same as those of the high frequency modulated magnetic field generating device 1 of the first embodiment.

As shown in FIG. 6, a high-frequency modulated magnetic field generating device 60 according to a third embodiment of the present invention has a structure in which the above-described high-frequency modulated magnetic field generating device 1 is rotated about its central axis. have.

That is, in the main pole 63 having a cylindrical shape, soft magnetic material parts S61 and S62 made of soft magnetic material and hard magnetic material part H61 made of hard magnetic material are arranged in the longitudinal direction which is the axial direction. The main magnetic pole 63 is wound with a winding 64 that can be effectively excited by a signal current as shown in FIG.
5 is used facing the magneto-optical recording medium. Further, a yoke portion 66 is provided from the base end side of the main magnetic pole 63 in a substantially cylindrical shape and serves as a return bus for magnetic flux, so that a required magnetic field can be generated.

Even with such a rotating body-shaped high frequency modulated magnetic field generating device 60, it is possible to similarly generate a strong magnetic field with low power consumption and efficiency. Regarding materials, operation, etc.,
This is similar to the high frequency modulated magnetic field generating device 1 of the first embodiment.

A high-frequency modulated magnetic field generator 70 according to a fourth embodiment of the present invention has a structure in which the above-described high-frequency modulated magnetic field generator 50 is rotated about its central axis, as shown in FIG. have. That is, a hard magnetic material portion H71 is formed on one end side facing the magneto-optical recording medium, and the main magnetic pole 72 is formed into a cylindrical shape in appearance by this hard magnetic material portion H71 and a soft magnetic material S71 which is a high magnetic permeability material. ing. A winding 74 for excitation is disposed on this, and this winding 74 can be supplied with a pulse current or a signal consisting of a combination of a pulse current and a level signal as shown in FIG. can. Further, the yoke portion 75 is also formed in a cylindrical shape.

Even with such a rotating body shape, a strong magnetic field can be generated with low power consumption and efficiency. Note that the materials, operation, etc. are the same as those of the high frequency modulated magnetic field generating device 1 of the first embodiment.

A high-frequency modulated magnetic field generating device 80 according to a fifth embodiment of the present invention is a high-frequency modulated magnetic field generating device having a substantially I-shaped main magnetic pole 83, as shown in FIG. 80, and its main magnetic pole 8
3 is formed by laminating and arranging a soft magnetic material portion S81°, a hard magnetic material portion H81, and a soft magnetic material S82. The main magnetic pole 83 has a substantially prismatic shape, but may also have a triangular column shape, a cylindrical shape, or a hexagonal column shape. A winding 84 for excitation is wound around the main magnetic pole 83, which is made by arranging a soft magnetic material and a hard magnetic material, and receives a pulse current or level signal current as shown in FIG. generating an effective magnetic field by means of a signal current to compensate for the residual magnetization;
It can be used for magneto-optical recording.

It goes without saying that the materials, operation, etc. are the same as those of the high-frequency modulated magnetic field generating device 1 of the first embodiment, and that low power consumption can be realized and a strong magnetic field can be efficiently generated.

A high-frequency modulated magnetic field generating device 90 according to a sixth embodiment of the present invention is a high-frequency modulated magnetic field generating device having a main magnetic pole 93 having a substantially I-shape, as shown in FIG. 90, and its main magnetic pole 9
A hard magnetic material portion H91 having a large coercive force and large residual magnetization, such as Ba ferrite, is formed at one end of the magneto-optical recording medium facing surface of No. 3, and the other main pole 93 is formed by a soft magnetic material portion S91. It is made up of. Also, the winding 9
4 is also wound, and is similar to the fifth embodiment in terms of operation, shape, material, etc.

First Minor Disaster■ The high frequency modulated magnetic field generating device 30 according to the seventh embodiment of the present invention is the same as the high frequency modulated magnetic field generating device 80 according to the fifth embodiment, in which the main magnetic pole 83 has a substantially U-shaped shape. It is something.

As shown in FIG. 10, this main magnetic pole 33 has a soft magnetic material portion S31.
A hard magnetic material portion H31 and a soft magnetic material S32 are formed in a stacked arrangement. It is similar to the fifth embodiment in terms of operation, shape, material, etc.

The high frequency modulated magnetic field generating device 40 of the eighth embodiment of the present invention has a main pole 83 of the high frequency modulated magnetic field generating device 90 of the sixth embodiment, as shown in FIG. Shape is abbreviated as U
It is shaped like a letter. At one end of the surface of the U-shaped main pole 43 facing the magneto-optical recording medium, a hard magnetic material portion H41 is formed over the end surface, and the other portions of the main magnetic pole 43 are formed with soft magnetic material portions. It is configured by S41.

Even with the high frequency modulated magnetic field generating device 40 having such a shape, low power consumption can be achieved and a strong magnetic field can be generated efficiently.

H. Effects of the Invention In the high frequency modulated magnetic field generator of the present invention, since its main magnetic pole is composed of a soft magnetic material part and a hard magnetic material part, first, it is generated by a pulsed current or the like based on the hysteresis characteristic of the hard magnetic material part. It is possible to generate a magnetic field in a predetermined magnetic field direction by reversing the direction of the magnetic field.Therefore, there is no need for mechanical reversal of the magnetic poles, and it is superior in terms of high-speed operation and reliability, and only requires soft magnetic materials. It is possible to apply a magnetic field in a predetermined direction to the magneto-optical recording medium without the need for continuous energization in cases such as the above, and the power consumption becomes small.

The high-frequency modulated magnetic field generator of the present invention reduces the demagnetizing field by the soft magnetic material, requires only a small excitation current due to its high magnetic permeability, and has residual magnetization that generates the magnetic field applied to the magneto-optical recording medium. will also be large.

Furthermore, the signal current for magnetization is not abrupt when simply using a pulse current, and a signal current that compensates for residual magnetization can be supplied, making it extremely suitable for magneto-optical recording.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view for explaining a high-frequency modulated magnetic field generator according to the first embodiment of the present invention, FIG. 2 is a perspective view thereof, and FIG.
The figures are waveform diagrams for explaining the operation of the high-frequency modulated magnetic field generator of the present invention, in which Fig. 3(a) is a waveform diagram applied to pulse current A, and Fig. 3(bl indicates residual magnetization? FIG. 3 tc+ is a waveform diagram showing the magnetization of the hard magnetic material part, and FIG. 3 fdl is a waveform diagram showing the strength of the generated magnetic field. 4a to 4c are characteristic diagrams showing the magnetization process of the hard magnetic material portion, respectively, and FIG. 4a is a characteristic diagram corresponding to magnetization curve C, and FIG. 4 is a characteristic diagram corresponding to magnetization curve β. , FIG. 4C is a characteristic diagram corresponding to the waveform.Furthermore, FIG. 5 is a perspective view for explaining a high frequency modulated magnetic field generating device according to a second embodiment of the present invention, and FIG. 6 is a characteristic diagram corresponding to the waveform. FIG. 7 is a perspective view for explaining the high frequency modulated magnetic field generating device according to the fourth embodiment of the present invention, and FIG. 8 is a perspective view for explaining the high frequency modulated magnetic field generating device according to the fourth embodiment of the present invention. FIG. 9 is a perspective view for explaining a high frequency modulated magnetic field generating device according to a fifth embodiment of the present invention; FIG. 9 is a perspective view for explaining a high frequency modulated magnetic field generating device according to a sixth embodiment of the present invention; FIG. The figure is a perspective view for explaining a high frequency modulated magnetic field generator according to a seventh embodiment of the present invention, and FIG. 11 is a perspective view for explaining a high frequency modulated magnetic field generator according to an eighth embodiment of the present invention. Also, Fig. 12 is a schematic diagram for explaining the principle of the magnetic field modulation method. 1.30, 40, 50, 60, 70.80.90---
- - - - - - = - - - - - - - - - - - - - - - - - - - - - - - - High frequency modulation magnetic field generator 2.33, 43, 52, 63,
72,83.93-------1-------Main magnetic pole 3.34.44,53
．． 64,73,84.94-・・・・・・−−１−−−・・−１−−−−−−・−Winding ill,
H31, H41, H51, H61, H71°H81, H
91--...----------Hard magnetic material portion SL, S2. S31. S32. S41. S51゜S
61. S62. S71. S81. S82. S91 ・-
・・−１−−−−−−−−−−−−−−・−・−・
Soft Magnetic Materials Department Patent Applicant Sony Corporation Representative Patent Attorney Tezuki Mima
Ei Tamura - Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 4 a Fig. 4 b Fig. 4 C Fig. 5 Rumeki Martyr's Punishment Figure 9 Yan gfi**4 Kuri Figure 11

Claims (1)

[Claims] A high-frequency modulated magnetic field generator having a main magnetic pole facing a magneto-optical recording medium at one end and a winding for exciting the main magnetic pole, wherein the main magnetic pole has a soft magnetic material portion and a hard magnetic material portion. A high frequency modulated magnetic field generating device characterized in that material portions are arranged in the longitudinal direction of the main magnetic pole.