JPH05174308A - Magnetic field generating device for magneto-optical recording - Google Patents

Abstract

PURPOSE:To provide a magnetic field generating device for magneto-optical recording capable of reducing the electromagnetic emitting noise from a magnetic head main magnetic coil and an auxiliary coil to a driving circuit, carrying out a measure to eliminate the electromagnetic emitting noise from the magnetic head, the auxiliary coil and the driving circuit to a peripheral circuit effectively with a small space and at a low cost, making the high frequency operation of the driving circuit possible and executing a high density recording easily. CONSTITUTION:This device is provided with the first core 18 opposed to an optical disk 2 at one end, the first coil 19 for exciting the first core 18 by a recording signal, the second core 20 different from the first core 18, the second coil 21 wound on the second core 20, a back core 22 magnetically connected with the first core 18 and a driving circuit 23 for flowing current to the first coil 19 utilizing voltage generated on the second coil 21. The driving circuit 23 is constituted integrally with at least one coil of the first and second coils 19 and 21 closely and integrally via the back core 22 in between.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field generator for magneto-optical recording which enables a recording signal to be overwritten by applying a modulating magnetic field to a magneto-optical recording medium.

[0002]

2. Description of the Related Art There are roughly two types of magneto-optical recording methods: an optical modulation method and a magnetic field modulation method. The optical modulation method is to apply a constant bias magnetic field having a polarity different from that at the time of erasing to a recording medium, and irradiate a beam whose emission level changes according to a recording signal from the optical head.
When the light emission level is high, the recording film in the irradiation spot portion is heated to the Curie temperature or higher, and when the temperature is lowered, it is magnetized in the direction of the bias magnetic field.

On the other hand, the magnetic field modulation method irradiates a light beam of a constant intensity all the time, and controls the direction of the bias magnetic field according to the recording signal, so that the same as the recording by the magnetic head in a magnetic recording device which does not use the light beam. It is possible to erase and record at the same time, that is, overwrite (overwrite).

FIG. 5 shows a conventional example of a magnetic field modulation type magneto-optical recording apparatus. That is, a constant laser beam emitted from the semiconductor laser 38 is focused on the perpendicular magnetization film 34 of the magneto-optical disk 36 through the lens 37, and the temperature of the perpendicular magnetization film 34 is changed through the disk substrate 35. The magnetic field generated by the magnetic head 31 is modulated according to the recording signal through the magnetic field modulation circuit 33 by leaving the magnetic field corresponding to the change of the magnetic field in the magnetizing film 34, and the magnetic pattern corresponding to the change of the magnetic field is left. It is to record.

When recording is performed by such a magnetic field modulation method, the magnetic field required to reverse the magnetization of the perpendicular magnetization film 34 depends on the film characteristics, but generally a large magnetic field of several hundred Oe or more is required. .. Moreover, in order to take advantage of the non-contact recording of the magneto-optical recording, the magnetic head 1 needs to be separated from the magneto-optical disk 36 by several hundreds of μm or more, and for this purpose, the magnetic head 1 has a large size of several tens ampere turns or more. Magnetomotive force is required. Further, in order to perform high density recording, it is necessary to make the rise time of the magnetic field generated by the head sufficiently fast.

In order to satisfy such a condition, it is necessary to generate a magnetic flux that changes at high speed according to a recording signal inside the core around which the exciting coil of the magnetic head is wound. Therefore, as means for instantly applying a high voltage to both ends of the coil with low power consumption, auxiliary coils 40 and 4 as shown in FIG.
Magnetic head drive circuit using back electromotive force of 1
-94406) have been devised. This magnetic head drive circuit includes auxiliary coils 40 and 41 having an inductance sufficiently larger than that of the head coil 42, and switching elements 43 and 44 are alternately turned ON and OF.
By performing F, the sum of the counter electromotive voltage generated in the auxiliary coils 40 and 41 and the voltage Vc of the DC power supply 45 is added to the head coil 4
2 is applied to generate a magnetic flux that changes at high speed in the head by using a low-voltage power supply.

However, in this drive circuit, the exciting current is not constant due to the action of the counter electromotive voltage generated in the head coil 42, but varies greatly when a steady magnetic field is generated. Further, in high-density recording, the pulse width of the recording signal becomes short, so the time for releasing the energy stored in the auxiliary coils 40, 41 becomes short, the current that can be passed through the head becomes small, and the stored energy becomes small. Become. For this reason,
In the high density recording, there is a problem that the magnetic field generated by the head is lowered.

In order to solve the above problems of the drive circuit, the present applicant has proposed in Japanese Patent Application No. 2-116114.
A resonance type magnetic head drive circuit is proposed. This head drive circuit 49 is shown in FIG. As shown in FIG. 7, the head drive circuit 49 includes a head coil 42 and an auxiliary coil 4.
Represents excluding 7.

In FIG. 7, a head coil 42 is a coil of a magnetic head for magnetic field modulation, and its inductance is L. A capacitor 46 is connected in series to the head coil 42.
Are connected, and the capacity is C. Capacitor 4
6 and the head coil 42 form a series resonance circuit. This resonance circuit is connected to the DC power supply 45 via the first switching element 43.

An auxiliary coil 47 is connected in parallel to both ends of the capacitor 46 of the series resonance circuit. The auxiliary coil 47 has an inductance Le larger than the inductance L of the head coil 42. Is connected to the DC power supply 45 via the second switching element 44.

Here, each of the switching elements 43 and 44 is
For example, the recording signal RS is applied directly and via the inverter 48, respectively, and accordingly, the first switching element 4 is turned on and off alternately according to the recording signal RS.
When 3 is OFF and the second switching element 44 is ON, the auxiliary coil 47 is connected to the DC power supply 45, and the auxiliary coil 47 has 1 / 2.Le as the auxiliary coil exciting current i.
-I. Energy corresponding to i is stored.

Further, the second switching element 44 is turned off.
At some time, the counter electromotive voltage generated at both ends of the auxiliary coil 47 is applied to the capacitor 46 of the series resonance circuit by the stored energy of the auxiliary coil 47, and at the same time, the first switching element 4
Since 3 is ON, a resonance current is made to flow through the magnetic head coil 42 under the resonance condition of the series resonance circuit.

According to this prior art example, the counter electromotive voltage generated by the auxiliary coil 47 is applied to the resonance capacitor 46, and the magnetic field generating head coil 4 constituting the head under the resonance condition.
If a counter electromotive voltage is large by applying a resonance current to 2,
Even if the power supply voltage Vc is low, the current flowing through the head can be reduced, and if the series resonance condition is satisfied,
The current flowing through the head is determined only by the loss resistance of the circuit, not by the inductance of the head. Therefore, a large current can be passed, and low power consumption and high-density magnetic field modulation recording can be performed.

However, in the drive circuit utilizing the counter electromotive voltage of the auxiliary coil in the prior art shown in FIGS. 6 and 7, many coils are wound or cores are used in order to make the inductance of the auxiliary coil equal to or higher than that of the head. There is a problem that an auxiliary coil having a size equal to or larger than that of the magnetic head having a large cross-sectional area is required, and the space occupied by the auxiliary coil in the drive circuit becomes large.

Further, in order to reduce the core loss of the auxiliary coil, it is necessary to form the core with a magnetic material having an excellent high frequency characteristic similar to that of the magnetic head. Has a problem that the cost is as high as that of the magnetic head. In order to solve the problem of the drive circuit using the counter electromotive voltage of the auxiliary coil as described above, the applicant of the present invention is characterized in that the auxiliary coil and the magnetic head are formed on the same core in Japanese Patent Application No. 2-289586. Has proposed a magnetic field generator for magneto-optical recording. This magnetic field generator is shown in FIG.

In FIG. 8, a magnetic head 51 includes a main magnetic pole portion 52, a main magnetic pole exciting coil 53 wound around the main magnetic pole portion 52, a drive circuit auxiliary inductor portion 54 and an auxiliary coil 55 wound around the main magnetic pole exciting coil 53.
And a portion 56 that connects the main magnetic pole portion 52 and the core of the auxiliary inductor portion 54. Auxiliary inductor section 5
The inductance L21 of No. 4 is set larger than the inductance L20 of the main magnetic pole exciting coil 53.

Here, 52, 54 and 56 are integral cores, and the tip of the main magnetic pole portion 52 faces the optical pickup 57 via the magneto-optical disk 6 as a magneto-optical recording medium. Here, the coil 53 wound around the main magnetic pole portion 52 corresponds to the head coil 42 of the drive circuit shown in FIGS. 6 and 7, and the auxiliary coil 55 wound around the auxiliary inductor portion 54.
Are auxiliary coils 40, 4 of the drive circuit shown in FIGS.
Equivalent to 1,47.

According to this magnetic head 51, the first coil 5 is used as a magnetic head coil on the same core of the magnetic head.
3 and the space for winding the second coil 55 as an auxiliary coil, the auxiliary coil of the magnetic head drive circuit can be integrated with the magnetic head, so that it is not necessary to provide the auxiliary coil in the space of the drive circuit, It is possible to reduce the size and cost of the entire circuit.

Further, the material of the magnetic head core has a large magnetic characteristic in high frequency excitation, for example, a high magnetic permeability in a high frequency magnetic field, a large saturation magnetic flux density, and a small iron loss. Therefore, an auxiliary coil of a drive circuit excited at a similar frequency is used. It is also suitable as a core material, and a small and low loss auxiliary coil can be formed on the head core.

On the other hand, as a conventional example of the optical modulation method, there is Japanese Patent Application Laid-Open No. 2-54453. In this conventional example, a pair of bias coils are arranged so as to sandwich the disk, and these are connected by an iron-based substrate to serve also as a yoke for a magnetic circuit. On this substrate, I of the circuit element used for the amplifier
C, resistance, etc. are mounted.

[0021]

By the way, in the magnetic field generator in which the magnetic head core and the auxiliary coil core of the drive circuit are integrated as shown in FIG. 8, the magnetic field generator and the drive circuit for driving the magnetic field device are close to each other. In this case, electromagnetic radiation noise due to high-frequency excitation from the magnetic head or the auxiliary coil is mixed in the drive circuit, or is similar to the recording signal flowing in the connection line that supplies the exciting current from the drive circuit to the magnetic head and the auxiliary coil. There is a problem that electromagnetic radiation noise from a connection line caused by a high-frequency large current causes noise in a circuit portion in the magneto-optical recording device, which hinders circuit operation.

Further, in order to prevent electromagnetic radiation noise generated from the connection line or the drive circuit itself, when an electromagnetic shield is to be applied to the connection line or the drive circuit, the magnetic head and the auxiliary coil are driven by the drive circuit. If it is separated, the surface area of the shield cover will increase, the space and cost for the shield will increase, and the noise source will be concentrated in a small space, and effective noise reduction measures by one-point ground cannot be implemented. Met.

Further, in the case of increasing the frequency of the drive circuit to increase the recording density, if the line connecting the magnetic head coil and the auxiliary coil and the drive circuit excluding the auxiliary coil is long,
There is also a problem that the longer the connecting line is, the more parasitic inductance and parasitic capacitance of the connecting line increase, which makes it difficult to operate the drive circuit at high frequencies.

On the other hand, in the optical modulation method, the intensity of light is modulated by the recording signal, and the bias magnetic field may be a DC magnetic field having a constant intensity, and electromagnetic radiation noise due to this bias magnetic field causes almost no problem. For example, the conventional example of Japanese Patent Laid-Open No. 2-54453 has a structure in which a pair of coils are connected by a substrate that also serves as a yoke. Does not prevent

The present invention has been made in view of the above points, and reduces electromagnetic radiation noise from the main magnetic coil and the auxiliary coil of the magnetic head to the drive circuit, which is a problem when recording in the magnetic field modulation system. And, as a countermeasure against electromagnetic radiation noise from the magnetic head, auxiliary coil and drive circuit to the peripheral circuit,
An object of the present invention is to provide a magnetic field generator for magneto-optical recording which can be effectively realized in a small space and at low cost, and which enables a high frequency operation of a drive circuit to easily perform high density recording.

[0026]

According to the present invention, a first core having one end facing a magneto-optical recording medium, a first coil for exciting the first core with a recording signal, and the first core are provided. A second core different from the core; a second coil wound around the second core; a back core magnetically coupled to the first core; and a voltage generated in the second coil. In a magneto-optical recording magnetic field generation device including a drive circuit for flowing an electric current through the first coil by utilizing the drive circuit, the drive circuit includes at least one of the first coil and the second coil, The first core and the second coil of the magnetic field generation device are configured by closely integrating the back core with the back core interposed therebetween.
The electromagnetic radiation noise from the coil to the drive circuit can be reduced, and the electromagnetic radiation noise from the magnetic field generator to the peripheral circuits can be effectively realized in a small space and at a low cost. This makes it possible to easily perform high density recording.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic structure of a magneto-optical recording / reproducing apparatus equipped with a magnetic field generator according to a first embodiment of the present invention. The magneto-optical recording / reproducing apparatus 1 shown in FIG. 1 is opposed to one surface of a magneto-optical disk 2 serving as a magneto-optical recording medium which is rotationally driven by a spindle motor (not shown), and the magnetic field generating apparatus 3 of the first embodiment.
Is arranged, and an optical pickup 4 is arranged so as to face the other surface of the magneto-optical disc (also simply referred to as a disc) 2, and a portion irradiated with a beam from the optical pickup 4 to a recording film 2b through a substrate 2a. On the other hand, the magnetic field generated by the magnetic field generator 3 is applied.

The optical pickup 4 is mounted on a carriage 5 and, for example, a VCM 6 as a pickup moving means.
Is movable in the radial direction of the disk 2, that is, in the direction T traversing the tracks, so that any track can be accessed. Further, the magnetic field generator 3 is also moved in this direction T by a means (not shown) in conjunction with the movement of the optical pickup 4.

The laser beam of the laser diode 7 constituting the optical pickup 4 is shaped into a parallel beam by the collimator lens 8 and is then incident on the beam splitter 9. The beam transmitted through this beam splitter 9 is 1 /
The azimuth of the polarization direction is set by the two-wave plate 10, is condensed by the objective lens 11, and is irradiated with the linearly polarized light on the recording film 2b of the disk 2 to form a beam spot.

The beam reflected by the disk 2 is condensed by the objective lens 11, transmitted through the half-wave plate 10, and a part of the beam is reflected by the beam splitter 9.
The beam splitter 12 divides the light into transmitted light and reflected light. The reflected light passes through the critical angle prism 13 and is received by the photodetector 14 for generating a control signal.

On the other hand, the transmitted light passes through the analyzer 15 and is received by the photodetector 16 for generating a reproduction signal. The outputs of the photodetectors 4 and 16 are input to, for example, a signal processing unit 17 arranged on the carriage 5 and subjected to signal processing to generate a track error signal TE, a focus error signal FE, and a magneto-optical reproduction signal RF during reproduction. I do. The track error signal TE and the focus error signal FE are used for the track servo and the focus servo, respectively.

The laser diode 7 emits a weak level and a constant emission intensity during reproduction. During recording, light is emitted with a large level of constant emission intensity, and the portion of the recording film 2b irradiated with this beam is heated to the Curie temperature or higher. During this recording, the magnetic field generator 3 of the first embodiment applies a magnetic field corresponding to the recording signal RS to the recording film 2b portion irradiated with the beam.

The magnetic field generator 3 includes a first core 18 for applying a recording magnetic field to the disk 2 and a first core 18.
First coil 1 for exciting the magnetic field in response to the recording signal RS
9, a second core 20 different from the first core, a second coil 21 for exciting the second core 20, and a magnetic coupling with the first core 18 and the second core 20. The back core 22 and a drive circuit 23 for driving the first and second coils 19 and 21, and the second core 20,
The second coil 21, the drive circuit 23, and the first core 18
The first coil 19 and the first coil 19 are integrally disposed close to the front and back sides with the back core 22 interposed therebetween.

Further, when the drive circuit 23 has the configuration of the drive circuit 49 shown in FIG. 7, for example, it is formed of a permanent magnet or the like in the vicinity of the first core 18 and the first coil 19 constituting the magnetic head 24. Bias magnetic field generating means is arranged. The bias magnetic field generating means generates a constant bias magnetic field in the direction opposite to the magnetic field direction generated by the magnetic head 24. A magnetic field generator base 25 is attached to the opposite side of the drive circuit 23 to which the back core 22 is attached, and the optical pickup 4 is moved by moving means such as a VCM.
Is driven in conjunction with the VCM 6 that moves the.

The back core 22 is made of a magnetic material having good high frequency characteristics similar to that of the first core 18, for example, a metal magnetic material such as ferrite or sendust or an amorphous alloy. Therefore, if the back core 22 is made of a material having high magnetic permeability and high saturation magnetic flux density at high frequency excitation and relatively high conductivity, the first coil 19 is used.
By applying a high-frequency exciting current according to the recording signal to the magnetic field, high-frequency electromagnetic radiation noise generated from the first core 18 and the first coil 19 is magnetically and electrically shielded from the drive circuit 23. Therefore, the drive circuit 23 can be operated stably.

Further, in this embodiment, since the first coil 19 and the drive circuit 23 are arranged close to each other, the connecting line for flowing the exciting current from the drive circuit 23 to the first coil 19 is shortened. It is possible to minimize the electromagnetic radiation noise caused by the high frequency exciting current flowing through the connection line, which is caused by the long connection line, and reduce the noise induction to the drive circuit 23 and other peripheral circuits inside and outside the device. Therefore, the peripheral circuit is prevented from malfunctioning and stable circuit operation is enabled (in FIG. 1, the connection line for connecting the first coil 19 to the drive circuit 23 bypasses the back core 22. However, in reality, a small through hole is formed in the back core 22 and the first through the through hole.
Drive circuit 23 arranged close to the back side of the coil 19
, Can be connected with a short connecting line).

Further, since the parasitic inductance and the parasitic capacitance of the connecting line, which become larger as the connecting line becomes longer, are reduced, it is easy to increase the frequency of the driving circuit, and it is possible to realize a recording magnetic field generator capable of coping with high density recording.

Further, since the magnetic head 24 composed of the first core 18 and the first coil 19 and the drive circuit 23 are integrated, the magneto-optical recording apparatus 1 can be easily reduced in size and weight. In addition, the signal processing unit 17 includes the back core 22.
With respect to the second core 20 and the second coil 21, the second core 20 and the second coil 21 (and the drive circuit 23 and the short connection (not shown) connected to the second core 20 and the second coil 21 are spaced apart from each other. Line) to reduce the effect of electromagnetic radiation noise. Further, the magnetic head 24 is the back core 22.
As a result, the generation of electromagnetic radiation noise can be reduced, so that the noise given to the signal processing units 17 arranged apart can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. The configuration of the magnetic field generator 3 of the second embodiment shown in FIG. 2 is basically the same as that of the first embodiment, but the first core 18 and the first coil 19, the second core 20 and The second coil 21 includes the drive circuit 23 and the back core 2.
2 is formed on the same surface, and an end portion of the back core 22 is formed with an extension portion 22a extending to the back surface side (upward in FIG. 2) to accommodate the drive circuit 23. It is different from the first embodiment in that it has a box shape and is formed so as to cover the drive circuit 23 (excluding the surface in contact with the magnetic field generator base 25).

That is, in the second embodiment, similarly to the first core 18 and the first coil 19, the second core 20 and the second core 20 which are another noise source associated with the high frequency excitation.
The coil 21 of the back core 2
By separating via 2 in between, it is possible to reduce electromagnetic induction noise to the drive circuit 22 as compared with the first embodiment. In addition, the back core 2 having an electromagnetic noise shielding effect
2 is extended and formed so as to wrap around the drive circuit 22,
The lead shielding effect by the back core 22 can be further increased by joining the magnetic field generating device base 25 having an electromagnetic noise shielding effect.

Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a sectional view of the magnetic field generator of the third embodiment, and FIG. 4 is a perspective view of a flexible printed circuit board of the magnetic field generator of the third embodiment.

In FIG. 3, the structure of the magnetic field generator 3 is as follows.
Basically the same as the second embodiment, but the first coil 1
9 and the second coil 21 and the drive circuit are configured on the same printed circuit board 28, and a shield cover 29 that covers the drive circuit 23 is provided.

That is, as shown in FIG. 4, the printed circuit board 28 comprises a thin flexible first (excitation) coil 19, a second coil 21, and a drive circuit conductor portion made of copper on a foldable flexible substrate. The first core 18 is formed of a conductor such as aluminum and has the drive circuit chip component 30 mounted thereon. The first core 18 is formed on the back core 22 at the central portions of the first coil 19 and the second coil 21, respectively. Since there is an insertion hole for the second core 20 and the back core 2
The magnetic field generator can be easily configured by simply adhering it to the back core 22 so as to sandwich it. The shield cover 2
Reference numeral 9 is a conductor having a high conductivity and is set to a material having a high magnetic permeability. For example, the surface of a material having high magnetic permeability may be coated with a metal having high conductivity.

Therefore, in the third embodiment, the drive circuit 23, the first coil 19, and the second coil 21 are integrally formed on the printed circuit board 28, so that the step of winding the coil is not required, so that mass production is possible. And the magnetic field generator 3 can be produced at low cost, and the coil and circuit can be easily downsized. Further, since the connecting lead wire between the coil and the circuit can be designed to be the shortest, it is easy to increase the frequency of the drive circuit 23.

Further, by providing the electromagnetic shield cover 29 so as to cover the drive circuit 23 and connecting it to the back core 22, the electromagnetic shielding effect of the back core 22 can be further increased. Moreover, if this cover is formed using a material having good electromagnetic shielding properties and good thermal conductivity, such as iron, the heat radiation fins of the drive circuit components and the shield cover are thermally joined to form a heat radiation component. It is possible to have the function of.

The circuit configuration of the drive circuit 23 is not limited to that shown in FIG.
The drive circuit proposed by the applicant such as No. 5754 can be used. Further, in addition to the two cores and the coils, a magnetic field generator having a core and a coil for generating a DC bias magnetic field may be provided.

[0047]

As described above, according to the present invention, at least one of the first coil for exciting the core for applying the recording magnetic field to the magneto-optical recording medium and the second coil for generating the voltage is provided. , The first and second coil drive circuits and the back core are provided close to each other with the back core interposed therebetween to form an electromagnetic shielding effect, and the first coil and the second coil are provided. By separating and shielding the electromagnetic radiation noise source of the connecting conductor between the coils and the drive circuit from the circuit, it is possible to reduce noise mixing in the drive circuit. In addition, by concentrating the noise source in a small space and magnetically and electrically shielding the entire magnetic field generator from the peripheral circuits, the electromagnetic radiation noise countermeasure can be effectively realized in a small space and at a low cost. The size and weight of the magnetic field applying device including the drive circuit can be easily reduced. Further, according to the present invention, by shortening the connecting conductor wire between the first and second coils and the drive circuit, reducing the parasitic inductance and parasitic capacitance of the connecting conductor wire, and facilitating the high frequency operation of the drive circuit, A magnetic field generator suitable for high-density recording can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a magneto-optical recording / reproducing apparatus including a magnetic field generator according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a magnetic field generator according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a configuration of a magnetic field generator according to a third embodiment of the present invention.

FIG. 4 is a perspective view showing a flexible printed circuit board of the magnetic field generator of the third embodiment.

FIG. 5 is a block diagram of a conventional magnetic field modulation type magneto-optical recording / reproducing apparatus.

FIG. 6 is a circuit diagram showing a configuration of a conventional magnetic head drive circuit of a magnetic field modulation system.

FIG. 7 is a circuit diagram showing a configuration of a magnetic head drive circuit of a prior example by the present applicant.

FIG. 8 is a diagram showing a schematic configuration of a magneto-optical recording / reproducing apparatus of a prior example by the present applicant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magneto-optical recording / reproducing apparatus 2 ... Magneto-optical disk 3 ... Magnetic field generator 4 ... Optical pickup 6 ... VCM 7 ... Laser diode 11 ... Objective lens 14, 16 ... Photo detector 17 ... Signal processing part 18 ... 1st core 19 ... first coil 20 ... second core 21 ... second coil 22 ... back core 23 ... driving circuit 24 ... magnetic head 25 ... base

Claims (2)

[Claims] 1. A first core having one end facing a magneto-optical recording medium, a first coil for exciting the first core with a recording signal, and a second core different from the first core. , The second
Second coil wound around the core, a back core magnetically coupled to the first core, and a current flowing through the first coil by using the voltage generated in the second coil In a magnetic field modulation-type magnetic field generator for a magnetic field modulation method, the drive circuit is provided with at least one of the first coil and the second coil and the back core interposed therebetween. A magnetic field generating device for magneto-optical recording, characterized in that they are formed in close proximity and integrally formed. 2. The first coil wound around the first core and the drive circuit component including the second coil are formed on the same printed circuit board.
A magnetic field generator for magneto-optical recording as described above.