JP2790716B2 - Magneto-optical recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording apparatus, and more particularly, to a magneto-optical recording apparatus that records information using two recording methods.

[Prior Art] Conventionally, as this type of magneto-optical recording apparatus, for example,
There is a configuration as shown in the figure.

In the figure, reference numeral 1 designates a substrate 2 made of glass or plastic, on which a perpendicular magnetization film 3 is applied, and a protective film 4 on the surface thereof.
Is formed on the magneto-optical disk. The magneto-optical disk 1 is rotatably supported by magnet chucking or the like, and has a structure that rotates about a central axis. The optical head 5 is an information recording / reproducing head disposed on the lower surface of the magneto-optical disk 1, and includes an actuator 6, a semiconductor laser 7, and an objective lens 8. Laser light emitted from the semiconductor laser 7 is condensed by the objective lens 8 and is emitted to the magneto-optical disk 1. In this case, the objective lens 8 moves in the optical path direction under the control of the actuator 6, and is controlled so that the laser beam is focused on the perpendicular magnetization film 3. The optical head 5 has a structure capable of moving in the radial direction of the magneto-optical disk 1.

The electromagnet 9 is provided on the flying head 22 and applies a magnetic field to the laser beam irradiated portion of the perpendicular magnetization film 3. The electromagnet 9 is disposed opposite to the optical head 5 with the magneto-optical disk 1 interposed therebetween.
The electromagnet 9 includes a coil 10 wound around the outer periphery, and a current having a phase corresponding to a recording signal is supplied to the coil 10 from a magnetic field modulation circuit 11. The flying head 22 moves in the radial direction of the magneto-optical disk 1 in conjunction with the optical head 5, and records information on the magneto-optical disk 1 by sequentially applying a magnetic field to the laser-irradiated portion of the perpendicular magnetization film 3.

Next, an information recording operation will be described with reference to FIG.

First, when information is recorded, the perpendicular magnetic film 3 of the magneto-optical disk 1 is locally and continuously irradiated with laser light of a constant intensity from the optical head 5. As a result, the temperature of the irradiated portion of the perpendicular magnetization film 3 is raised near the Curie point or above the Curie point. At the same time, when a recording signal as shown in FIG. 5A is to be recorded, a magnetic field as shown in FIG. 5B is applied to the laser-irradiated portion of the perpendicular magnetization film 3 in accordance with the recording signal. That is, when the recording signal is “1”, a magnetic field of + H is applied, and when the recording signal is “0”, the negative polarity −
An H magnetic field is applied. In this case, the applied magnetic field generated from the electromagnet 9 has the opposite polarity and the same magnetic field strength.

As described above, by modulating the magnetic field in accordance with the recording signal, the direction of magnetization of the laser-irradiated portion at the information recording point of the perpendicular magnetization film 3 changes according to the recording signal. Therefore, by making the direction of magnetization correspond to “1” and “0” of the recording signal,
Binary data can be recorded. Fig. 5 (c)
5 schematically shows a recording pattern formed on the perpendicular magnetization film 3 by the above-described laser beam irradiation and magnetic field application. In the figure, the portion indicated by white outline has the magnetization direction set to be upward, and the recording signal “1” is recorded. The portion indicated by oblique lines is downward with the magnetization direction reversed, and the recording signal “0” is recorded. Therefore, since the polarity of the applied magnetic field is modulated in accordance with the recording signal, no matter what information has been written on the perpendicular magnetization film 3 of the magneto-optical disk 1, if it is overwritten on it, new information can be obtained. Information can be recorded.

[Problems to be Solved by the Invention] However, the magnetic field modulation recording apparatus using the above-mentioned conventional flying head may not be used depending on the type of the magneto-optical disk. For example, a recording film of a magneto-optical disk whose characteristics are optimized for light modulation or a recording film whose protective film is not optimized for a flying head cannot be used. That is, in such a magneto-optical disk, the surface of the protective film is not smooth or the thickness of the protective film is 100 μm or more, and a sufficient applied magnetic field cannot be obtained by the magnetic field generating means of the flying head. There was a problem that could not be done.

The present invention has been made in order to solve such a problem, and an object of the present invention is to make it possible to record information by using another recording method even if the recording medium is not suitable for the magnetic field modulation method. An object of the present invention is to provide a magneto-optical recording device.

[Means for Solving the Problems] An object of the present invention is to provide an optical head that converges a light beam on a magneto-optical recording medium into a minute spot and irradiates the optical head with the optical head. And a magnetic head for applying a bias magnetic field modulated according to a recording signal to a light spot irradiating portion of the medium, wherein the magnetic head is positioned above the optical head so as to face the magnetic head. Magnetic field applying means for generating a magnetic field using the magnetic head as a counter magnetic pole; and means for modulating a light beam of the optical head according to a recording signal to irradiate a magnetic field applying portion of the medium by the magnetic field generating means. This is achieved by a magneto-optical recording device characterized by having:

Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the features of the present invention best, and is a configuration diagram showing one embodiment of the magneto-optical recording apparatus of the present invention. In FIG. 1, the same parts as those of the conventional device are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, reference numeral 5 denotes an optical head disposed on the lower surface of the magneto-optical disk 1, and has an air core coil 12 on the upper part. The air-core coil 12 is wound along the outer peripheral portion of the objective lens 8 so as not to block the optical path of the laser light of the semiconductor laser 7. The air-core coil 12 is disposed so as to face the electromagnet 9 provided on the flying head 22. The current supply circuit 13 is a circuit for supplying a current to the air core coil 12, and a current supply operation is controlled by a recording / erasing switching signal. The light modulation circuit 14 is a circuit that outputs a modulation signal to the optical head 5 and modulates the laser light of the semiconductor laser 7 according to a recording signal. The air-core coil 12 may of course have a core.

On the other hand, the flying head 22 disposed above the magneto-optical disk 1 has a structure capable of moving up and down a predetermined distance with respect to the magneto-optical disk 1. The position of the flying head 22 is determined by the type of the magneto-optical disk used as will be described later in detail. The flying head 22 moves in the radial direction of the magneto-optical disk 1 in conjunction with the optical head 5.

Next, the operation of the present embodiment will be described. In this embodiment, the recording method differs depending on the magneto-optical disk used. That is, when a normal magneto-optical disk is used, the magnetic field modulation method by the flying head 22 is used, and when the magneto-optical disk is not suitable for this, the optical modulation method is switched.

First, in a normal magneto-optical disk, a laser beam having a constant intensity is locally and continuously irradiated from the optical head 5 to the perpendicular magnetization film 3 of the magneto-optical disk 1 as in the related art. As a result, the temperature of the irradiated portion of the perpendicular magnetization film 3 is raised near the Curie point or above the Curie point. At the same time, the magnetic field modulated according to the recording signal from the electromagnet 9 by the driving of the magnetic field modulation circuit 11 is applied to the laser irradiation portion of the perpendicular magnetization film 3. That is, when the recording signal is "1", a magnetic field of "+ H" sufficient for recording is applied, and when the recording signal is "0", a magnetic field of "-H" having a reverse polarity and sufficient for recording is applied. . In this case, the polarity of the applied magnetic field generated from the electromagnet 9 is opposite, and the strength of the magnetic field is the same. As described above, by modulating the magnetic field in accordance with the recording signal, the direction of magnetization of the laser-irradiated portion at the information recording point of the perpendicular magnetization film 3 changes according to the recording signal. Therefore, binarized data is recorded by associating the direction of magnetization with “1” and “0” of the recording signal.

Next, the operation when using a magneto-optical disk that is not suitable for the magnetic field modulation method will be described. First, when the magneto-optical disk 1 is loaded in the apparatus, the flying head 22 is moved away from the magneto-optical disk 1 by a predetermined distance by a driving mechanism (not shown). Therefore, there is no contact between the magneto-optical disk 1 and the flying head 22, and the magneto-optical disk 1 is not scratched. When the moving operation is completed, the current supply circuit 13
Current is supplied to the air core coil 12 from the
Outputs a modulation signal corresponding to the recording signal to the optical head 5. The current switching circuit 13 switches the direction of the current supplied to the air-core coil 12 between the recording operation and the erasing operation by the recording / erasing switching signal, and switches the direction of the generated magnetic field. Here, since the recording operation is being performed, the air-core coil 12 generates a magnetic field in a direction corresponding to the recording operation. As a result, a magnetic field generated in the recording direction of the air-core coil 12 is applied to the magneto-optical disk 1. FIG. 2 shows the state of the lines of magnetic force at this time and the distribution of the magnetic field intensity at the laser irradiation site of the magneto-optical disk 1. In FIG. 2, only the air core coil 12 generates a magnetic field, and the electromagnet 9 is not used.
The air-core coil 12 is provided on the magneto-optical disk 1 above the optical head 5.
In this case, the size of the optical head 5 cannot be increased because it is provided in a narrow gap between the optical head 5 and the seek speed of the optical head 5. for that reason,
As shown in FIG. 2, when the air-core coil 12 is used in an open loop, the lines of magnetic force diverge in all directions, and a sufficient magnetic field intensity cannot be obtained at the recording point of the magneto-optical disk 1, and information cannot be recorded. .

Therefore, the electromagnet 9 of the flying head 22 is effectively used as the opposing magnetic pole of the air core coil 12. FIG. 3 shows the state of the lines of magnetic force and the distribution of the magnetic field intensity at the laser irradiation site at this time. As is apparent from FIG. 2, the magnetic lines of force of the air-core coil 12 converge on the electromagnetic force 9, and the magnetic field intensity is greatly increased as compared with FIG. Thereby, the magnetic field intensity at the information recording point of the magneto-optical disk 1 can be made sufficiently strong. In addition,
At this time, the electromagnet 9 does not need to supply a current to the coil 10.
DC current may be supplied to 10 in a direction to increase the magnetic field strength of the air core coil 12.

As described above, the air-core coil 12 is
And a magnetic field intensity amplifying action of the electromagnet 9 provides a magnetic field having a strength sufficient for recording. On the other hand, the magneto-optical disk 1 is irradiated with laser light modulated according to a recording signal from the optical head 5, and information is recorded by a light modulation method. When erasing information from the magneto-optical disk 1, the direction of the current of the current supply circuit 13 is switched by a recording / erasing switching signal. Then, a magnetic field having a polarity opposite to that at the time of recording is applied to the magneto-optical disk 1 from the air-core coil 12, and the semiconductor laser 7 is simultaneously turned on by DC, thereby erasing the recorded information on the magneto-optical disk 1.

In addition, as the flying head 22, one having a slider portion made of ceramics or the like and having the electromagnet 9 may be used.
When used as an opposing magnetic pole, the slider section and the electromagnet 9
It is more effective to use a monolithic structure in which the core portions are made of the same material.

[Effects of the Invention] As described above, according to the present invention, the magnetic field generating means for generating a magnetic field with the magnetic head facing the magnetic head for modulating the magnetic field is provided. The magnetic field can be effectively strengthened. Therefore, a magnetic field required for light modulation can be obtained, and a magneto-optical recording device capable of performing not only magnetic field modulation recording but also light modulation recording can be provided by simply adding a simple magnetic field generation unit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a magneto-optical recording apparatus according to the present invention, FIG. 2 is an explanatory view showing the state of the magnetic field lines of the air-core coil and the distribution of the magnetic field intensity when the opposing magnetic pole is not used, The figure shows the operation of the main part of the present invention. FIG. 4 is an explanatory view showing the state of the lines of magnetic force of the air-core coil and the distribution of the magnetic field strength when the opposing magnetic poles are used. FIG. 5 is a time chart showing the operation of the conventional device. 1: Magneto-optical disk, 5: Optical head 7: Semiconductor laser, 8: Objective lens 9: Electromagnet, 11: Magnetic field modulation circuit 12: Air-core coil, 13: Current supply circuit 14: Light modulation circuit, 22: Flying head

Claims (4)

(57) [Claims] An optical head for irradiating a light spot on a magneto-optical recording medium by condensing the light beam into a minute spot; A magnetic head for applying a bias magnetic field modulated according to a signal, wherein the magneto-optical recording device is provided opposite to the magnetic head at a position above the optical head,
Magnetic field applying means for generating a magnetic field with the magnetic head as the opposing magnetic pole; and means for modulating the light beam of the optical head in accordance with a recording signal and irradiating the magnetic field applying portion of the medium by the magnetic field generating means. A magneto-optical recording device, characterized in that: 2. The magneto-optical recording device according to claim 1, wherein said magnetic field generating means is an air-core coil wound along the outer peripheral portion of the converging objective lens of said optical head. apparatus. 3. The magnetic field generating means, wherein the generated magnetic field is switched by a switching signal to a polarity opposite to that at the time of optical modulation recording, and by applying a magnetic field of the opposite polarity and direct current lighting of the light of the optical head,
2. The magneto-optical recording apparatus according to claim 1, wherein information on the medium is erased. 4. The magneto-optical recording apparatus according to claim 1, wherein said magnetic head is separated from said medium by a predetermined distance when performing optical modulation recording.