JPH10105907A - Magnetic field modulation coil device for magneto-optical recording / reproducing device - Google Patents

Abstract

(57) [Problem] To reduce the size, weight, cost and improve performance of a magneto-optical recording / reproducing apparatus using a magneto-optical disk on which information signals are recorded at a high density. SOLUTION: A coil member 21 to which a DC input for reproduction and a high-frequency input for recording are applied, a center core portion 22b to which the coil member 21 is combined, and a coil member 21 which are positioned around the coil member 21 and excited by the DC input to generate DC. A first core member 22 having first side core portions 22c and 22d for generating a magnetic field is combined with the first core member 22 in a state of intersecting with the first core member 22 and is positioned around the coil member 21 to be excited by a high frequency input. And a second core member 23 having second side core portions 23b and 23c that generate a high-frequency magnetic field. First core member 2
The second core member 23 and the second core member 23 share the center core portion 22b to generate a DC magnetic field for reproduction and a high-frequency magnetic field for recording.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field modulation coil device provided in a magneto-optical recording / reproducing apparatus capable of recording / reproducing information signals on / from a disc-shaped optical recording medium.

[0002]

2. Description of the Related Art In a magneto-optical disk, a magnetic layer formed on a disk substrate is heated to a temperature higher than the Curie temperature by irradiating a laser beam, and in this state, an external magnetic field modulated by a magnetic field according to an information signal is applied. As a result, the magnetic layer is inverted and information signals are recorded. Also, since the reflected light of the irradiated laser beam rotates its deflection surface in accordance with the magnetization direction of the magnetic layer due to the Kerr effect, the information signal recorded by detecting this rotation angle difference Is played. Therefore, in such a magneto-optical disk, the recording density of the information signal is determined by the spot diameter of the laser beam to be irradiated.

In a magneto-optical disk, a high recording density of an information signal is addressed by shortening the wavelength of a laser beam and increasing the NA of an objective lens. On the other hand, in the case of a magneto-optical disk, the magnetic super-resolution technology (Magnetically-Indeced Super Resolution, hereinafter referred to as “M”) is designed to cope with a higher recording density of information signals without changing the basic configuration of the optical system.
Abbreviated as RS. ) Has also been proposed. This MRS technology makes it possible to reproduce an information signal from an area smaller than the spot diameter of a laser beam by utilizing the characteristics of a magnetic layer having different magnetic properties depending on temperature.

That is, the MRS technique uses a magneto-optical disk in which a magnetic layer having different magnetic properties is formed between a high-temperature region and a low-temperature region of a laser beam spot. FAD method (Front
Aperture Detection) and a RAD method (Rear Aperture Detection) in which a high-temperature area behind the spot is a detection range have been proposed. In the RAD system, the recording density in the radial direction as well as the track direction of the magneto-optical disk can be improved. Therefore, in a magneto-optical recording / reproducing apparatus employing MRS technology, in order to reproduce an information signal in a state where a magnetic field is applied to a magneto-optical disk, a magnetic head for reproducing an information signal is used together with a magnetic head for recording. Is provided.

Hereinafter, a magneto-optical disk 1 of the RAD system specification will be described.
The magneto-optical recording / reproducing apparatus 10 that can also use the information signal and the principle of recording / reproducing the information signal will be described with reference to FIGS. The magneto-optical disk 1 of the RAD system specification has two magnetic layers including a reproducing layer 3 and a recording layer 4 formed on the main surface of a disk substrate 2. The magneto-optical recording / reproducing apparatus 10 includes a recording magnetic head for recording an information signal on the magneto-optical disk 1 and a reproducing magnetic head as a reproducing magnetic head for reproducing the recorded information signal. And two types of magnetic heads for applying an activating magnetic field.

[0006] As shown in FIG. 5, the magneto-optical recording reproducing apparatus 10 includes an input / output unit 11, a system controller 12,
A motor control unit 13 controlled by the system controller 12 and a spindle motor 14 driven by the motor control unit 13 are provided. The magneto-optical recording / reproducing apparatus 10 also includes an optical pickup driving unit 16 that drives and controls the optical pickup 15 based on an output of the system controller 12, processes information signals and control signals detected by the optical pickup 15, and sends the information to the system controller 12. And a signal processing unit 17 for outputting a processed signal. Further, the magneto-optical recording / reproducing apparatus 10 includes a magnetic head control unit 18 controlled by the system controller 12 and a magnetic head unit 19 controlled by the magnetic head control unit 18.

Although the details of the magnetic head section 19 are omitted,
A high-frequency magnetic field modulation magnetic head 19a for recording, which applies a high-frequency magnetic field Hw as an external magnetic field modulated when recording an information signal on the magneto-optical disk 1, and information recorded on the magneto-optical disk 1 at high density It comprises a DC magnetic field modulation magnetic head 19b for applying a DC magnetic field Hr as an external magnetic field when reproducing a signal, and an initialization magnetic head 19c for applying an initialization magnetic field Hini as an external magnetic field for initializing a reproduction layer 4 described later. Is done. A high frequency magnetic field signal, a DC magnetic field signal, or an initialization magnetic field signal is supplied to the magnetic head unit 19 via the magnetic head control unit 18. The initialization magnetic head 19c is arranged prior to the DC magnetic field modulation magnetic head 19b in the rotation direction of the magneto-optical disk 1.

On the other hand, as shown in FIG. 6, a magneto-optical disk 1 has a recording layer 3 and a reproducing layer 4 laminated on a transparent disk substrate 2. The first recording layer 3 is, for example, T
The second reproducing layer 4 is made of DdFeCo while the material is made of bFeCo. 6A is a plan view showing a part of the recording area of the information signal on the magneto-optical disk 1, and FIG. 6B is a sectional view showing the recording area. 5a is a pit on which an information signal is recorded, and a white portion 5b is a bit on which no information signal is recorded.

The recording operation of the information signal on the magneto-optical disk 1 by the magneto-optical recording / reproducing apparatus 10 compatible with the RAD system is almost the same as that of a normal magneto-optical recording / reproducing apparatus. That is, when an information signal to be recorded is input to the magneto-optical recording / reproducing apparatus 10, the spindle motor 14 is driven via a route of the input / output unit 11, the system controller 12, and the motor control unit 13, and is provided on the spindle shaft. Magneto-optical disk 1 mounted on a mounted disk table
Is driven to rotate. In the magneto-optical recording / reproducing apparatus 10, an optical pickup driving unit 16 is driven via a controller 12, and a laser beam is emitted from the optical pickup 15 to the magneto-optical disk 1.

In the magneto-optical recording / reproducing apparatus 10, a magnetic head control unit 18 is driven via a controller 12, and a high-frequency magnetic field Hw is applied to a magnetic layer of the magneto-optical disk 1 from a high-frequency magnetic field modulation magnetic head 19a of a magnetic head unit 19. I do. As a result, in the magneto-optical disk 1, the directions of magnetization of the recording layer 3 and the reproducing layer 4 are kept constant. The magneto-optical recording / reproducing device 10 irradiates the magneto-optical disk 1 with a laser beam in a direction opposite to the high-frequency magnetic field Hw, thereby raising the recording layer 3 and the reproducing layer 4 to the Curie temperature and partially degaussing. State. When the laser beam is cut off, the magneto-optical disc 1 is magnetized in the opposite direction as shown in FIG. 6, so that an information signal is recorded in the recording pit. Of course, the magnetization directions of the recording layer 3 and the reproducing layer 4 are the same.

In the magneto-optical recording / reproducing apparatus 10, a spindle motor 14 is driven through a route of an input / output unit 11, a system controller 12, and a motor control unit 13 in accordance with a reproducing operation. Is driven to rotate.
In the magneto-optical recording / reproducing apparatus 10, an optical pickup driving unit 16 is driven via a controller 12, and a laser beam is emitted from the optical pickup 15 to the magneto-optical disk 1.

In the magneto-optical recording / reproducing apparatus 10, a magnetic head control unit 18 is driven via a controller 12, and an initializing magnetic head 19c moves an initializing magnetic field Hini ahead of a spot position of a laser beam with respect to the magneto-optical disk 1. Is applied. In addition, the magneto-optical recording / reproducing apparatus 10 applies the DC magnetic field Hr from the DC magnetic field modulation
Is applied.

The magneto-optical recording / reproducing apparatus 10 produces a reproduction output based on a rotation angle difference between the irradiated laser beam and reflected light whose deflection surface is rotated in accordance with the magnetization direction of the reproduction layer 4 described later by the Kerr effect. The signal is output from the optical pickup 15 to the signal processing unit 17. The magneto-optical recording / reproducing apparatus 10 includes a signal processing unit 17-a system controller 12-
The information signal is reproduced and output via the first route.

The magneto-optical disk 1 includes an initialization magnetic head 1
Due to the initialization magnetic field Hini applied from 9c, only the reproduction layer 4 has a constant magnetization direction as shown in FIG. When the laser beam is applied to the magneto-optical disk 1, an area L behind the center of the spot area S gradually becomes a high-temperature area. Therefore, in the magneto-optical disk 1, the coercive force gradually decreases in the high temperature region L, the exchange coupling force with the recording layer 3 becomes larger than the coercive force of the reproducing layer 4, and the magnetization direction of the recording layer 3 is changed. Transferred to layer 4.

In the magneto-optical disk 1, a recording pit and a non-recording pit for an information signal are included in a spot area S of a laser beam. The magneto-optical recording / reproducing apparatus 10 performs the masking of the reproducing layer 4 in the low-temperature region by the initialization magnetic head 19c, and releases the masking of the reproducing layer 4 in the high-temperature region L to reproduce the information signal. Therefore,
The magneto-optical recording / reproducing apparatus 10 can reproduce information signals recorded at high density regardless of the spot diameter of the laser beam. Of course, the magneto-optical recording / reproducing apparatus 10 can also reproduce information signals from a magneto-optical disc on which information signals are recorded at a normal density.

[0016]

As described above, the RA
In the magneto-optical recording / reproducing apparatus 10 capable of conforming to the D system specification, the high-frequency magnetic field modulation magnetic head 1 for recording information signals is used.
9a, a DC magnetic field modulation magnetic head 19b for reproducing an information signal recorded at high density, and an initialization magnetic head 19c. The conventional magneto-optical recording / reproducing device 10
Each of these magnetic heads 19a to 19c was independently configured and attached to the device.

Therefore, the magneto-optical recording / reproducing apparatus 10
Since the magnetic head unit 19 including these magnetic heads 19a to 19c becomes large and heavy, there is a problem that the seek time becomes long.
The magneto-optical recording / reproducing device 10 includes a plurality of magnetic heads 1.
The provision of the components 9a to 19c complicates the structure, complicates wiring and other processes, and raises costs due to an increase in man-hours.

Therefore, the present invention has a reproducing magnetic field generating function and a recording magnetic field generating function in order to solve the above-mentioned problems in the magneto-optical recording / reproducing apparatus compatible with the MRS technology. It has been proposed for the purpose of providing a magnetic field modulation coil device for a magneto-optical recording / reproducing device which achieves down and performance improvement.

[0019]

A magnetic field modulation coil device for a magneto-optical recording / reproducing apparatus according to the present invention, which achieves the above object, comprises:
A coil member to which a DC input for reproduction and a high frequency input for recording are selectively applied, a first core member, and a second core member. The first core member is located around the center core portion where the coil member is combined with the outer peripheral portion, and is located around the coil member combined with the center core portion, and is excited when a DC input for reproduction is applied to the coil member. And a first side core portion for generating a reproducing magnetic field. The second core member is combined with the first core member so that the center core portion is located at the center, and is positioned around the coil member, and is excited by a recording high-frequency input applied to the coil member. And a second side core portion for generating a recording magnetic field. Therefore, in the magnetic field modulation coil device for a magneto-optical recording / reproducing device, the first core member and the second core member share the center core with the first side core and the second side core. It is configured to be shared as a center core unit.

According to the magnetic field modulation coil device for a magneto-optical recording / reproducing apparatus according to the present invention having the above-described configuration, a high-frequency input for recording is applied to a coil member at the time of recording an information signal. A magnetic loop is formed between the center core portion of the member and the second side core portion of the second core member to generate a high frequency magnetic field for recording, and the high frequency magnetic field is applied to the magneto-optical disk. Further, according to the magnetic field modulation coil device for a magneto-optical recording / reproducing device, a DC input for reproduction is applied to the coil at the time of reproducing the information signal, so that the center core portion of the first core member and the first side core portion are interposed. A magnetic loop is configured to generate a DC magnetic field for reproduction, and this DC magnetic field is applied to the magneto-optical disk. Therefore, the magnetic field modulation coil device can reduce the size and weight of the magneto-optical recording and reproducing device and simplify the structure by forming a magnetic head having recording and reproducing functions.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. The magnetic field modulation coil device 20 shown in FIGS. 1 to 3 as an embodiment of the present invention.
Is provided in the magneto-optical recording / reproducing apparatus 10 which can also use the magneto-optical disc 1 of the above-mentioned RAD system specification, and operates a high-frequency magnetic field modulation magnetic head 19 which operates when recording an information signal.
a and the DC magnetic head for magnetic field modulation 19b acting upon reproduction of the information signal are integrally formed.

The magnetic field modulation coil device 20 includes a bobbin 21a
Member 2 formed by applying a predetermined winding 21b to the outer peripheral portion of
1, a first core member 22 combined with the coil member 21, and a second core member 23 combined with the first core member 22. The first core member 22 generates a DC magnetic field when a DC input is applied to the coil member 21 when an information signal is reproduced, as described later. The second core member 23 generates a high-frequency magnetic field by applying a high-frequency input to the coil member 21 at the time of recording an information signal, as described later.

The first core member 22 has a resistivity of 100Ω.
As shown in FIG. 1, a manganese-zinc-based ferrite material or a metal magnetic material having a size as small as less than 1 cm is used as a material, and a horizontal base portion 22a and a center core portion that is integrally formed at the center of the base portion 22a. 22b, and first side core portions 22c and 22d formed of a pair of core pieces erected in parallel with each other at opposite ends of the base portion 22a. The first side core portions 22c and 22d have an overall upward E-shape. You. Each of the constituent parts 22a to 22d of the first core member 22 is formed in a prismatic shape having substantially the same cross-sectional shape as each other. Also, the center core portion 22b and the first side core portion 2
2c and 22d have substantially the same height.

The first core member 22 has a base 22a
A mortise groove 22e in the width direction is provided on the bottom surface of the base member at the center in the longitudinal direction. The tenon groove 22e has a groove width dimension substantially equal to the width dimension of the center core portion 22b, and a height dimension substantially equal to half the thickness dimension of the base portion 22a. The first core member 22 is combined with the second core member 23 via the tenon groove 22e as described later.

The first core member 22 has a base 22a,
A first magnetic gap 24a and a second magnetic gap 24 are provided at equal intervals on both sides from the center in the longitudinal direction.
b are formed. These first magnetic gaps 24
The second magnetic gap 24a and the second magnetic gap 24b are formed by filling the gap grooves with fused glass as described later. The magnetic field modulation coil device 20 forms a magnetically saturated portion by the first magnetic gap 24a and the second magnetic gap 24b, and saves power of a DC power supply by suppressing generation of magnetic flux.

The second core member 23 has a resistivity of 100Ω.
cm and larger than the first core member 22, for example, a manganese-zinc ferrite material or the like, and the length in the longitudinal direction and the outer dimensions of the cross section are the first core member 22.
A second side core comprising a base 23a formed substantially equal to the length dimension and the cross-sectional outer dimension of the base section, and a pair of core pieces erected in parallel from each other from both sides of the base section 23a. The portions 23b and 23c are formed so as to have an overall upward U-shape. Each of the constituent parts 23a to 22c of the second core member 23 has a prismatic shape having substantially the same cross-sectional shape as each other. Further, the second side core portions 23b and 23c have the same height and the center core portion 22b and the first side core portions 22c and 22d of the first core member 22 have substantially the same height.

The second core member 23 has a base 23a
Is provided with a tenon groove 23d in the width direction at the central portion in the longitudinal direction. The tenon groove 23d has a groove width dimension substantially equal to the width dimension of the tenon groove 22e of the first core member 22, and a height dimension substantially equal to half the thickness dimension of the base 23a. The second core member 23 is combined with the first core member 22 by relatively engaging the tenon groove 23d with the tenon groove 22e.

That is, the first core member 22 and the second core member 23 are combined so as to intersect each other at the center in the longitudinal direction as shown in FIG. In the combined state, the first core member 22 and the second core member 23 are arranged around the center core portion 22b around the first core portion 22c, the second side core portion 23b, and the first side core portion 22b. The side core portion 22d and the second side core portion 23c are located at an angle interval of 90 degrees from each other in this order.

The first core member 22 and the second core member 23 combined in this manner include a center core portion 22.
By passing through the center hole 21c formed in the bobbin 21a from the free end side of b, the coil members 21 are combined as shown in FIGS. 2 and 3 to complete the magnetic field modulation coil device 20. The magnetic field modulation coil device 20 initializes the magnetic head 1 with respect to the rotation direction of the magneto-optical disk 1.
The first core member 23 of the magnetic head unit 19 constitutes the DC magnetic field modulation magnetic head 19b and the second core member 22 is provided with the high frequency magnetic field. The modulation magnetic head 19a is configured.

As described above, the DC input is applied to the coil member 21 when reproducing the information signal, and the high-frequency input is applied to the coil member 21 when recording the information signal. When a DC input is applied to the coil member 21, the magnetic field modulation coil device 20
Core member 22 is excited to generate DC magnetic field Hr. As described above, the DC magnetic field Hr is applied to the high-temperature region L of the magneto-optical disk 1 irradiated with the laser beam while the initialization magnetic field Hini is applied from the initialization magnetic head 19c arranged in advance. The magnetic field modulation coil device 20 applies the initialization magnetic field Hini to the magneto-optical disk 1 from the initialization magnetic head 19c as described above.

Therefore, the magnetic field modulation coil device 20
In the high temperature region L of the magneto-optical disk 1 in which the reproducing layer 4 has been masked in the low temperature region by the initialization magnetic head 19c, the masking of the reproducing layer 4 is released by the applied DC magnetic field Hr. As a result, the magneto-optical recording / reproducing apparatus 10 reproduces the information signal recorded from the high-temperature area L in which the masking has been released in the spot area S of the laser beam, regardless of the spot diameter of the laser beam.

On the other hand, when a high-frequency input is applied to the coil member 21, the magnetic field modulation coil device 20 causes the second core member 23 to be in an excited state to generate a high-frequency magnetic field Hw to act on the magneto-optical disk 1. Thus, the magnetization directions of the recording layer 3 and the reproducing layer 4 are kept constant. Magneto-optical recording / reproducing device 10
In this state, the magneto-optical disk 1 is irradiated with a laser beam in a direction opposite to the high-frequency magnetic field Hw applied from the magnetic field modulation coil device 20 to raise the recording layer 3 and the reproducing layer 4 to the Curie temperature. It is demagnetized state. When the irradiation of the laser beam is stopped, the magneto-optical disk 1 is magnetized in the opposite direction and the information signal is recorded in the recording pit.

The above-described magnetic field modulation coil device 20 has a first
The core member 22 and the second core member 23 of FIG.
After being manufactured by another process shown in FIG. In the following description, for convenience of explanation, a process of forming a large number of pieces by slicing the first core member 22 and the second core member 23 in the thickness direction is shown. The step of forming a large number of pieces by slicing also in the longitudinal direction is adopted.

In the first step of manufacturing the first core member 22, a block 25 made of a manganese-zinc (Mn-Zn) ferrite material or the like having a resistivity of less than 100 Ωcm as described above is formed. This is the blocking step S-1. The block 25 manufactured in the first blocking step S-1 is formed so that its width and height are equal to the longitudinal dimension of the first core member 22 and equal to the height of the center core portion 22b. Is done.

In the second grooving step S-2, one of the main surfaces of the block 25 is subjected to grooving in the width direction. That is, the block 25 has a pair of parallel gap grooves 26a, 26b for forming magnetic gaps 24a, 24b on its main surface, and the gap grooves 2
A concave groove 26c for forming a tenon groove 22e is formed at the central portion of 6a, 26b. The gap grooves 26a and 26b are formed to have a small groove width and a depth slightly larger than the thickness of the base 22a. The concave groove 26c is formed such that its groove width is equal to the width of the base 22a and its depth is １ ／ of the thickness of the base 22a.

The block 25 is subjected to glass fusing in a third glass grooving step S-3. That is, the block 25 is filled with molten glass 27 into the gap grooves 26a and 26b formed in the second grooving step S-2 in a nitrogen atmosphere at, for example, about 700 ° C. and solidified. The block 25 includes gap grooves 26a, 2
6b is magnetically insulated in the divided two side regions by the glass 27 filled and solidified so that the magnetic gap 24 is formed.
a and 24b.

In the block 25, in the fourth core portion forming step S-4, a pair of widthwise core forming grooves 28a and 28b are formed parallel to each other from one main surface side. The one core forming groove 28a is formed at a position equal to the width dimension of the one first side core portion 22c from one end side of the block 25. The other core forming groove 28b is formed at a position equal to the width dimension of the other first side core portion 22d from the other end of the block 25. These core forming grooves 28
a and 28b are formed so that the interval is equal to the width dimension of the center core portion 22b. In addition, these core forming grooves 28a,
28b has a depth dimension equal to the height dimension of the center core portion 22b and the first side core portions 22c and 22d. Therefore, the block 25 has a thickness dimension of the bottom surface of the core forming grooves 28a and 28b of the first core member 2
The glass 27 formed to have a thickness equal to the thickness of the second base portion 22a and filled and solidified in the gap grooves 26a and 26b is exposed on these bottom portions.

The block 25 is sliced into a predetermined thickness in the fifth slicing step S-5 to complete a large number of first core members 22. The first core member 22 is combined with a second core member 23 formed in another step described later in a sixth combination step S-6.

In the first step of manufacturing the second core member 23, as described above, the nickel-zinc-based (Ni
-Zn) is a block forming step T-1 in which the block 30 is formed using a ferrite material as a material. The block 30 manufactured in the first blocking step T-1 is formed such that its width and height are equal to the length and height of the second core member 23.

In the block 30, in the second core portion forming step T- 2, the core forming groove 31 in the width direction is formed on one main surface.
Is formed. The core forming grooves 31 leave side core forming regions 32a and 32b equal in width to the second side core portions 23b and 23c from both end sides of the block 30 and reduce the thickness of the bottom surface of the second side core member 2
The third base 22a is formed on the main surface of the block 30 so as to have the same thickness as the base 22a. In other words, block 30 includes the second
In the core portion forming step T-2, a cross section is formed in a shape having an upward U-shape. In the block 30, a concave groove 33 for forming a tenon groove 23d is formed on the bottom surface of the core forming groove 31 at the center in the longitudinal direction. The concave groove 33 has a groove width dimension equal to the width dimension of the base 23a and a depth dimension equal to 1 / th of the thickness dimension of the base 23a.
2 is formed.

In the third slicing step T-3, the block 30 is sliced into a predetermined thickness to complete a plurality of second core members 23. In the second core member 23, the first core member 22 formed through the above-described steps positioned in a state of crossing over the core member in the core member assembling step S-6 is fitted to the tenon groove 23d. The mortise grooves 22e are combined by relative engagement. The first core member 22 and the second core member 23 are relatively engaged with a tenon groove 22e and a tenon groove 23d.
Are integrated by bonding with an adhesive or the like. In the first core member 22 and the second core member 23, the coil member 21 is combined with the center core portion 22b in the coil member combining step S-7 to complete the magnetic field modulation coil device 20 described above.

The above-described magnetic field modulation coil device 20
Has been described in connection with a magneto-optical recording / reproducing apparatus 10 which also allows the use of a magneto-optical disc 1 of the RAD system specification. Of course, it is also adopted. Further, the magnetic field modulation coil device 20 is configured such that the cross-sectional shapes of the respective portions of the first core member 22 and the second core member 23 are substantially equal. Along with the specification conditions such as characteristics, the shape specifications of the magneto-optical disk 1 are appropriately determined so that a predetermined DC magnetic field Hr and a high-frequency magnetic field Hw are applied to the magneto-optical disk 1.

[0043]

As described above in detail, according to the magnetic field modulation coil device for a magneto-optical recording / reproducing apparatus according to the present invention,
A high-frequency magnetic field modulation coil device for generating a high-frequency magnetic field applied when recording an information signal on a magneto-optical disk and a DC magnetic field modulation coil device for generating a DC magnetic field to be applied when reproducing an information signal recorded at high density; Since the first core member and the second core member are combined and integrated so as to have a common center core portion, the magneto-optical recording / reproducing apparatus on which the first core member and the second core member are mounted is reduced in size and weight, and wiring and the like are simplified. Achieve cost reduction by simplifying the assembly process.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a magnetic field modulation coil device according to the present invention.

FIG. 2 is a longitudinal sectional view of the magnetic field modulation coil device taken along line AA of FIG. 1;

FIG. 3 is a vertical cross-sectional view of the magnetic field modulation coil device taken along a line BB in FIG. 1;

FIG. 4 is an explanatory diagram of a manufacturing process of the magnetic field modulation coil device.

FIG. 5 is a schematic configuration diagram of a magneto-optical recording / reproducing apparatus using a magneto-optical disk on which information signals are recorded at a high density.

FIG. 6 is a schematic diagram for explaining the principle of reproducing an information signal recorded at high density in the magneto-optical recording and reproducing apparatus. FIG. 6A is a schematic plan view of a recording pit, and FIG. )
Is a schematic vertical cross-sectional view.

[Explanation of symbols]

1 magneto-optical disk, 2 disk substrate, 3 reproduction layer,
Reference Signs List 4 recording layer, 10 magneto-optical recording / reproducing device, 15 optical pickup, 19 magnetic head section, 19a high-frequency magnetic field modulation magnetic head, 19b DC magnetic field modulation magnetic head, 19
c initialization magnetic head, 20 magnetic field modulation coil device, 2
1 coil member, 22 first core member, 22a base, 22b center core, 22c, 22d first side core, 22e tenon groove, 23 second core,
23a base portion, 23b, 23c second side core portion,
23d mortise, 24 magnetic gap

Claims (5)

[Claims] 1. A coil member to which a DC input for reproduction and a high-frequency input for recording are selectively applied, a center core portion in which the coil member is combined with an outer peripheral portion, and a coil member positioned around the combined coil member And a first core member comprising a first side core portion which is excited when a reproduction DC input is applied to the coil member to generate a reproduction magnetic field, and the center core portion is located at the center. A second side core portion that is combined with the first core member and that is positioned around the coil member and that is excited when a high-frequency recording input is applied to the coil member to generate a recording magnetic field. A first core member and a second core member, wherein the center core portion has a first side core portion and a second side core portion. A magnetic field modulation coil device for a magneto-optical recording / reproducing device, which is also used as a common center core portion with the side core portion 2 and is selectively excited by the coil member to generate a reproducing magnetic field or a recording magnetic field. 2. The magneto-optical recording / reproducing apparatus according to claim 1, wherein the first core member and the second core member are combined so as to intersect each other around the center core. Magnetic field modulation coil device. 3. The magneto-optical recording / reproducing apparatus according to claim 1, wherein a magnetic gap is formed between the center core portion and the first side core portion in the first core member. Magnetic field modulation coil device. 4. The magnetic field modulation for a magneto-optical recording / reproducing apparatus according to claim 1, wherein the first core member is formed of a material having a smaller resistivity than the second core member. Coil device. 5. A coil member to which a DC input for reproduction and a high-frequency input for recording are selectively applied, a center core member in which the coil member is combined with an outer peripheral portion, and a magnetic material having a small resistivity, A first side core member which is positioned around the coil member combined with the center core member and which is excited when a reproducing DC input is applied to the coil member to generate a reproducing magnetic field; A second side core formed of a magnetic material and positioned around the coil member combined with the center core member and excited by applying a recording high-frequency input to the coil member to generate a recording magnetic field; And the center core member is the first side core member or the second side core member. Re or the other member and the magneto-optical recording and reproducing apparatus for magnetic field modulation coil apparatus characterized by also serves the other of the center core is formed in a piece.