JPH06150423A - Magneto-optical recorder - Google Patents

Abstract

PURPOSE:To perform recording with high density by synchronizing the irradiation time of a modulated laser beam with the application time of a magnetic field, and changing the size of the magnetic field so as to be equal to the size of a write bit in the rotating radius direction of a medium. CONSTITUTION:A pulse signal can be generated when data shows recording data 1 corresponding to the recording data 0, 1 synchronized with a recording clock to take synchronism between laser beam irradiation time and magnetic field application time, and also, a magnetic pulse is generated simultaneously. Thence, laser beams are generated from laser beam generators 11, 12 so that they can be emitted as prescribed output on the disk of a magnetic disk 1, and plural kinds of laser beam irradiation time are selected and recorded. At this time, each means is adjusted in such a way that the magnetic field higher than ever can be obtained compared with an application magnetic field set in advance when such recording that a bit diameter formed by recording by an electromagnet 16 is decreased is performed. As a result, a mark with the same diameter of, for example, around 16g m is formed in the radius direction, and the shape of a bit of high accuracy can be obtained, and the recording with high density can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording information by light and magnetic field.

[0002]

2. Description of the Related Art As a conventional write-once optical disc, a method has been proposed in which pits (holes) B are formed on a plastic disc A by a laser beam or the like to record information, as shown in FIG. This method has a drawback that it cannot be rewritten because the digital information is formed by forming the pit B in the plastic thin film. Therefore, in order to eliminate this drawback, a magneto-optical recording method has been proposed in which digital information corresponding to information such as documents, voices, and images is recorded on a rewritable recording medium that can be freely recorded, reproduced, and erased by the user. ing.

This magneto-optical recording method is based on, for example, Tb-F.
e, Tb-Fe-Co, Gd-Tb-Fe, Gd-Co
A magnetic recording medium having a recording layer made of a magnetic film having perpendicular anisotropy, such as an amorphous film, is irradiated with a laser beam modulated based on information to be recorded,
The laser light irradiation area of the recording layer is heated to the Curie temperature, and the magnetic domain of the laser light irradiation area is magnetically reversed by a stray magnetic field around the recording layer or a forced magnetic field generated forcibly to perform magnetic recording. It is a thing.

[0004]

In such a magneto-optical recording device, the inventor has found the following.

(1) When the magnetic recording medium is rotated and recording is performed while increasing the irradiation time of the recording laser beam, as shown in FIG. 1, the shape of the recorded pits is initially circular, but then elliptical. Finally, the radial length of rotation is constant and the circumferential length is proportional to the irradiation time of the recording laser beam. (2) When recording is performed by changing the external magnetic field, as shown in FIG. 2, the radial length of the recorded pit increases in proportion to the increase of the external magnetic field. (3) When the recorded pit is reproduced, if the recording pit is larger than the spot diameter of the reproduction laser beam, a reproduction wave is obtained according to the circumferential length of the recording pit. on the other hand,
When the recording pit is as large as the spot diameter of the reproducing laser beam, a reproducing wave is obtained according to the length of the recording pit in the radius direction of rotation.

FIG. 1 is a diagram showing the shape of a writing pit on a moving magnetic recording medium (magnetic layer of Gd-Co), and the X-axis is the recording laser light irradiation time (paris width;
μS), the size of the recording pit on the Y axis (μm), v the moving speed of the magnetic recording medium (v = 0.65 m / s), a the size of the recording pit in the moving direction of the magnetic recording medium (μm), and b the magnetic field. The size (μm) of the recording pit in the direction perpendicular to the moving direction of the recording medium.

FIG. 2 is a diagram showing that the size of the recording pit changes depending on the strength of the applied magnetic field. The X-axis represents the strength of the applied magnetic field (Oe) and the Y-axis represents the diameter of the recording pit (μ).
m), P5, P6, and P8 are the power of the recording laser light (m
W) and Gd-Co are magnetic layers of the magnetic recording medium. The object of the present invention is to increase the amount of information per pit based on the above-mentioned findings and to move the magnetic recording medium (rotational circumferential direction).
Another object of the present invention is to provide a magneto-optical recording device capable of high-density recording in a direction (radial direction) perpendicular to the moving direction.

[0008]

According to the present invention, a magneto-optical recording medium is irradiated with a laser beam modulated based on information to be recorded to heat the surface of the recording medium, and at the same time, to the heated region. In a magneto-optical recording apparatus having means for applying a magnetic field to the modulated laser beam, the modulation laser beam is recorded in a shape such that the size of the recording pits is constant in the radial direction of rotation of the medium. There is provided a magneto-optical recording apparatus comprising means for synchronizing the irradiation time of light with the application time of the magnetic field and changing the magnitude of the magnetic field.

[0009]

According to the present invention, when recording is performed on the magnetic recording medium, the characteristics shown in FIG. 2 are used to set the strength and the application time of the applied magnetic field in correspondence with the information to be recorded. The shape pit is recorded. Further, if the irradiation time of the recording laser beam is set corresponding to the information to be recorded by utilizing the characteristics shown in FIG. 1, a pit having a shape corresponding thereto is recorded.

When the recording laser light irradiation time and the magnetic field application time of both technical means utilizing both characteristics shown in FIGS. 1 and 2 are synchronized, a recording pit of the same shape is formed. In this case, a more precise pit shape can be obtained, and when recording pits having different shapes are set, recording pits having a shape different from those of the two are obtained. As a result, not only recording in the circumferential direction of rotation of the magnetic recording medium but also recording in the radial direction of rotation can be performed with high density. Also,
A reproduction wave corresponding to the shape of the recording pit can be obtained during reproduction. In this case, if the change of the duty ratio (the ratio of the pit length and the pit pitch) is further added to the recording condition, the information amount per pit further increases.

[0011]

The structure of the present invention will be described below with reference to an embodiment. FIG. 3 is a diagram showing a schematic configuration of an embodiment of the present invention. In FIG. 3, reference numeral 1 denotes a magnetic disk, a magnetic layer 3 is formed on a circular transparent substrate 2 made of a transparent synthetic resin material or transparent glass by a vapor deposition method, a sputtering method or the like, and further on the magnetic layer 3. The antireflection film 4 is formed.

The magnetic layer 3 comprises heavy rare earths and transition metals such as Tb-Fe, Tb-Fe-Co and Gd-Tb-F.
e, Gd-Co, etc. can be used as an amorphous medium, and MnCuBi as a polycrystalline medium, hexagonal as an oxide system, and a part of Fe atoms of barium ferrite as A
BaAlxFe ₁₂ -xO ₁₉ was replaced with l, Ti, and replaced with _{Co Ba (Ti 1. 5 Co} 0. 5) such xFe ₁₂ -xO ₁₉ is used. The magnetic layer 3 has a relatively low Curie temperature (about 250 ° C.) and a large coercive force (1 KOe or more).
Things are good.

The center of the magnetic disk 1 is attached to the rotary shaft 6 of the drive motor 5 so that the surface on the magnetic layer 3 side is directed upward and horizontally.

Numeral 10 is a magneto-optical head, and as shown by an arrow, the magnetic disk 1 is moved by a moving mechanism (not shown).
It is designed to move in a radial direction at a predetermined speed.
Reference numerals 11 and 12 denote laser light generators such as semiconductor laser devices that emit laser light. Reference numeral 13 is a modulator for controlling the irradiation time of laser light and its interval in accordance with the information to be recorded.

Reference numeral 14 is a polarization beam splitter for combining the laser beams emitted from both the laser beam generators 11 and 12 so as to irradiate the laser beams orthogonal to each other in the same direction. The polarization beam splitter 14 linearly polarizes only a component (hereinafter referred to as P component) perpendicular (90 °) to the reflection surface, and reflects only a component parallel to the reflection surface (hereinafter referred to as S component). It is a polarizing prism. For example, a polarizing prism such as a Glan-Thompson prism or a Nicol prism can be used.

Reference numerals 15 and 18 are objective lenses, 16 is an electromagnet, and 17 is a magnetic field control circuit for controlling a current value applied to the electromagnet and an application time. Reference numeral 19 is an analyzer, 20 is a photodetector, and Q is a laser light irradiation point.

The magnetic field control circuit 17 is provided with means (not shown) for synchronizing the irradiation time of the recording laser light and the magnetic field application time.

Next, the operation of this embodiment will be described with reference to FIG. (1) In the case of recording When the laser beam irradiation time of the laser beam generators 11 and 12 and its interval are controlled and emitted by the modulator 13, and enter the polarization beam splitter 14, they are mutually actuated by the action of the polarization beam splitter 14. The two laser beams are combined in the same phase with almost no energy loss, and the combined laser beams are focused and irradiated through the objective lens 15 onto the magnetic layer 3 of the magnetic recording medium. As a result, the laser beam irradiation point Q of the magnetic layer 3
When the temperature rises to near the Curie point, the coercive force of the magnetic layer 3 weakens and the magnetization is inverted by the magnetic field of the electromagnet.

The irradiation time and the irradiation interval of the laser light are the intervals at which the size of b shown in FIG. 1 becomes constant and the magnetic disk 1 rotates by the length of the size of a and does not overlap the front and rear recording pits. It's set to time.

The size of the recording pit can be changed by changing the power of the laser light of the laser light generators 11 and 12, but since the power of the laser light required for recording is predetermined. As described above, it is preferable to change the size of the recording pit by changing the strength of the external magnetic field. Further, the irradiation time of the recording laser light and the magnetic field application time are synchronized.

(2) Reproduction When the laser light generator 11 emits laser light of a predetermined intensity, the photodetector 20 is turned on. At this time, the laser light generator 12 and the electromagnet 16 are not operated.

The laser light of a predetermined intensity emitted from the laser light generator 11 is transmitted through the polarization beam splitter 14, and the linearly polarized laser light transmitted through the polarization beam splitter is transmitted through the objective lens 15. The magnetically recorded magnetic layer 3 of the magnetic disk 1 is irradiated in spots. The laser light at the irradiation point Q is rotationally polarized at a rotation angle α as known from the Faraday effect according to the state of the magnetic layer 3,
It penetrates the magnetic layer 3. This transmitted laser light is an objective lens
18, the component that is rotated and polarized through the analyzer 19 is a photodetector 20.
Information is reproduced. The magnetic layer 3 may reflect the laser light and the Kerr effect may be used for detection and reproduction.

(3) When erasing Recording is performed by continuously radiating laser light of a predetermined intensity from the laser light generators 11 and 12, and applying a magnetic field reverse to that in the recording operation from the electromagnet 16 to the magnetic disk 1. Erase information. As described above, this embodiment is applicable as a rewritable optical audio device and optical video device.

[0024]

As described above, according to the technical means disclosed in the description of the present specification and the accompanying drawings, the following effects can be obtained.

(1) Since the magneto-optical recording method is adopted, the information recorded on the magnetic recording medium can be rewritten.

(2) Since the shape of the recording pit is changed by changing the irradiation time of the recording laser beam and the irradiation interval thereof, the amount of information per pit can be increased,
Moreover, it is possible to increase the recording density per fixed medium.

(3) Since the size and shape of the recording pits are changed by changing the strength of the magnetic field and the application time of the electromagnet, the amount of information per pit can be increased and the amount of information per fixed medium can be increased. The recording density can be increased.

(4) The effects of (2) and (3) can be improved with high accuracy by changing the irradiation time of the recording laser light and the application time of the magnetic field in synchronization.

(5) Especially in a magnetic disk or the like, the recording density in the radial direction of rotation (direction perpendicular to the moving direction) can be increased.

The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a diagram showing a write pit shape on a moving magnetic recording medium.

FIG. 2 is a diagram showing that the size of a writing pit on a magnetic recording medium changes depending on the strength of an applied magnetic field.

FIG. 3 is a diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 4 is a diagram for explaining an example of a conventional write-once optical disc.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic disk 2 ... Circular transparent substrate 3 ... Magnetic layer 4 ... Antireflection film 5 ... Drive motor 6 ... Rotating shaft 10 ... Magneto-optical head 11, 12 ... Laser light generator 13 ... Modulator 14 ... Polarization beam splitter 15, 18 ... Objective lens 16 ... Electromagnet 17 ... Magnetic field control circuit 19 ... Analyzer 20 ... Photodetector

[Procedure amendment]

[Submission date] February 5, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Magneto-optical recording device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording information by light and magnetic field.

[0002]

2. Description of the Related Art As a conventional write-once type optical information recording system,
As shown in FIG. 4, a method has been proposed in which pits (holes) B are formed on a plastic disk A by laser light or the like to record information. This method has a drawback that it cannot be rewritten because the digital information is formed by forming the pit B in the plastic thin film. Therefore, in order to eliminate this drawback, a magneto-optical recording method has been proposed in which digital information corresponding to information such as documents, voices, and images is recorded on a rewritable recording medium on which a user can freely record, reproduce, and erase. ing.

This magneto-optical recording method is based on, for example, Tb-F.
e, Tb-Fe-Co, Gd-Tb-Fe, Gd-Co
A magneto-optical recording medium having a recording layer made of a magnetic film having perpendicular magnetic anisotropy, such as an amorphous film, is irradiated with laser light modulated based on the information to be recorded, Magnetic recording is performed by heating the laser light irradiation region to the Curie temperature and reversing the magnetization of the magnetic domain in the laser light irradiation region by a stray magnetic field around the recording layer or a forced magnetic field generated forcibly.

[0004]

In the case of a magneto-optical recording apparatus to which such a magneto-optical recording method is applied, particularly a magneto-optical recording apparatus for applying an external magnetic field to perform magnetization reversal, FIG. As shown in Fig. 4, when recording a long recording mark, the bit diameter in the radial direction of rotation of the recording mark tends to be thicker than that of other short recording marks, and it may come into contact with the recording marks of adjacent recording tracks. Or it will be partially duplicated. As a result, there is a problem that an error signal is generated during reproduction, and faithful reproduction corresponding to recording cannot be performed. In order to solve the problem, it is conceivable to widen the track pitch, but in this case, there arises a problem that the recording density is lowered.

The present invention improves the instability of the shape of the recording bit, which is a drawback of the above-described conventional magneto-optical recording apparatus, and provides a magneto-optical recording apparatus capable of stable recording / reproduction of characteristics, and higher recording. It is an object of the present invention to provide a magneto-optical recording device capable of improving the density.

[0006]

The present inventor discovered the following in the process of studying a new magneto-optical recording apparatus which can solve the above-mentioned drawbacks of the conventional magneto-optical recording apparatus.

(1) When the magneto-optical recording medium is rotated and recording is performed while increasing the irradiation time of the recording laser light, the shape of the recorded bit is initially circular as shown in FIG. The shape becomes elliptical, and finally the length in the rotation radius direction becomes constant and the length in the circumferential direction becomes proportional to the irradiation time of the recording laser light. (2) When recording is performed by changing the external magnetic field, as shown in FIG. 2, the radial length of the recorded bit increases in proportion to the increase of the external magnetic field. (3) When the recorded bit is reproduced, if the recorded bit is larger than the spot diameter of the reproduction laser beam, a reproduced wave is obtained according to the circumferential length of the recorded bit. on the other hand,
When the recording bit is as large as the spot diameter of the reproduction laser beam, a reproduction wave is obtained according to the length of the recording bit in the radius gyration direction.

FIG. 1 is a view showing the shape of a write bit to a moving magneto-optical recording medium (magnetic layer of Gd-Co), and the X-axis is the recording laser light irradiation time (pulse width;
μs), the size of the recording bit on the Y axis (μm), v is the moving speed of the magneto-optical recording medium (v = 0.65 m / s), a is the size of the recording bit in the moving direction of the magneto-optical recording medium (μm), b
Is the size (μm) of the recording bit in the direction perpendicular to the moving direction of the magneto-optical recording medium.

FIG. 2 is a diagram showing that the size of the recording bit changes depending on the strength of the applied magnetic field. The X-axis represents the strength of the applied magnetic field (Oe) and the Y-axis represents the diameter of the recording bit (μ).
m), P5, P6, and P8 are the power of the recording laser light (m
W) and Gd-Co are magnetic layers of the magneto-optical recording medium.

The present invention has been made in view of the above-mentioned findings, and its purpose is to improve recording / reproducing characteristics and recording density, as described above.

According to the present invention, the magneto-optical recording medium is irradiated with the laser beam modulated based on the information to be recorded, the surface of the recording medium is heated, and the magnetic field is applied to the heating region. In a magneto-optical recording apparatus including means, the irradiation time of the modulated laser light corresponding to the information to be recorded and the application time of the magnetic field are synchronized, and the size of the write bit to be recorded in the radial direction of the medium rotation radius. There is provided a magneto-optical recording apparatus comprising means for changing the magnitude of the magnetic field such that

[0012]

When recording on a magneto-optical recording medium, the irradiation time of the recording laser beam and the magnetic field application time of both technical means utilizing both the characteristics shown in FIGS. 1 and 2 are synchronized, and the recording mark to be recorded. By changing the magnitude of the applied magnetic field in accordance with the circumferential length of the recording mark, a stable and highly accurate bit shape having a constant radial length regardless of the circumferential length of the recording mark can be obtained. As a result, recording / reproducing with stable characteristics can be performed, and not only recording in the circumferential direction of the magneto-optical recording medium but also recording in the radial direction of the rotation can be performed at a high density, resulting in a higher recording density. Can be measured.

[0013]

The structure of the present invention will be described below with reference to an embodiment. FIG. 3 is a diagram showing a schematic configuration of an embodiment of the present invention. In FIG. 3, reference numeral 1 is a magneto-optical disk, and a magnetic layer 3 is formed on a circular transparent substrate 2 made of a transparent synthetic resin material or transparent glass by a vapor deposition method, a sputtering method or the like. The antireflection film 4 is formed on the surface.

The magnetic layer 3 includes heavy rare earths and transition metals such as Tb-Fe, Tb-Fe-Co and Gd-Tb-F.
e, Gd-Co, etc. can be used as an amorphous medium, and a part of Fe atoms of MnCuBi as a polycrystalline medium or hexagonal barium ferrite as an oxide system is Al.
In substituted BaAlxFe ₁₂ -xO _19, Ti, Ba was replaced by _{Co (Ti 1. 5 Co 0} . 5) xTi 12 -xO 19 and the like are used. The magnetic layer 3 preferably has a relatively low Curie temperature (about 250 ° C.) and a large coercive force (1 KOe or more).

The center of the magneto-optical disk 1 is attached to the rotary shaft 6 of the drive motor 5 so that the surface on the magnetic layer 3 side is directed upward and horizontally.

Reference numeral 10 denotes a magneto-optical head, which is moved in the radial direction of the magneto-optical disk 1 at a predetermined speed by a moving mechanism (not shown) as shown by an arrow. Reference numerals 11 and 12 denote laser light generators such as semiconductor laser devices that emit laser light. Reference numeral 13 is a modulator for controlling the irradiation time of laser light and its interval in accordance with the information to be recorded.

Reference numeral 14 is a polarization beam splitter for coupling the laser beams emitted from both the laser beam generators 11 and 12 so as to irradiate the laser beams orthogonal to each other in the same direction. The polarization beam splitter 14 linearly polarizes only a component (hereinafter referred to as P component) perpendicular (90 °) to the reflection surface, and reflects only a component parallel to the reflection surface (hereinafter referred to as S component). It is a polarizing prism. For example, a polarizing prism such as a Glan-Thompson prism or a Nicol prism can be used.

Reference numerals 15 and 18 are objective lenses, 16 is an electromagnet, and 17 is a magnetic field control circuit for controlling a current value applied to the electromagnet and an application time. Reference numeral 19 is an analyzer, 20 is a photodetector, and Q is a laser light irradiation point.

The magnetic field control circuit 17 is provided with means (not shown) for synchronizing the irradiation time of the recording laser beam and the magnetic field application time.

In the apparatus having the above structure, in order to synchronize the laser beam irradiation time and the magnetic field application time, a pulse is applied when the recording data is "1" corresponding to the recording data "0" and "1" synchronized with the recording clock. A magnetic pulse is generated at the same time as the signal is generated. Next, laser light is generated from the laser light generators 11 and 12 on the surface of the magneto-optical disk 1 so that the output is, for example, 8 mW, and a plurality of laser light irradiation times shown in FIG. 1 are selected. I tried to record it. At that time, the electromagnet 16
From the above, when recording a mark such that the diameter of the bit formed by the recording becomes small, each means of the magneto-optical recording apparatus is applied so that a magnetic field larger than an applied magnetic field set separately beforehand is applied. It was adjusted. As a result, a mark having the same diameter of, for example, about 15 μm was formed in the radial direction, a highly accurate bit shape was obtained, and as a result, high density recording was performed.

Next, the operation of this embodiment will be described with reference to FIG. (1) In the case of recording When the laser light generation time of the laser light generators 11 and 12 and its interval are controlled and emitted by the modulator 13, and enter the polarization beam splitter 14, the polarization beam splitter 14 causes the same. The laser beams are combined into a state in which the energy of the two laser beams is added with almost no energy loss in the phase, and the magnetic layer 3 of the magneto-optical recording medium 1 is focused and irradiated through the objective lens 15. As a result, when the temperature of the laser light irradiation point Q of the magnetic layer 3 rises to the vicinity of the Curie point, the coercive force of the magnetic layer 3 weakens, and the magnetization is reversed by the magnetic field of the electromagnet.

The irradiation time of the laser beam and its irradiation interval are determined based on the information signal to be recorded, but the irradiation interval is the length of the size of the bit to be recorded shown in FIG. The interval time is set so that the magneto-optical disk 1 rotates and does not overlap the preceding and following recording bits.

The size of the recording bit can be changed by changing the power of the laser light of the laser light generators 11 and 12, but since the power of the laser light required for recording is predetermined. As described above, it is preferable to change the recording bit size by changing the strength of the external magnetic field. Further, the irradiation time of the recording laser light and the magnetic field application time are synchronized.

(2) Reproduction When the laser light generator 11 emits laser light of a predetermined intensity, the photodetector 20 is turned on. At this time, the laser light generator 12 and the electromagnet 16 are not operated.

The laser light of a predetermined intensity emitted from the laser light generator 11 is transmitted through the polarization beam splitter 14, and the linearly polarized laser light transmitted through this polarization beam splitter is transmitted through the objective lens 15. , Magneto-optical disk 1
The magnetically recorded magnetic layer 3 is irradiated with spots. As is known by the Faraday effect, the laser light at the irradiation point Q is rotationally polarized at the rotation angle α and passes through the magnetic layer 3 as is known by the Faraday effect. This transmitted laser light passes through the objective lens 18 and the analyzer 19, and the component which is rotationally polarized is incident on the photodetector 20 to reproduce information. The magnetic layer 3 may reflect the laser light and the Kerr effect may be used for detection and reproduction.

(3) In the case of erasing Laser light having a predetermined intensity is continuously emitted from the laser light generators 11 and 12, and a magnetic field reverse to that in the recording operation is applied to the magneto-optical disk 1 from the electromagnet 16. Delete recorded information.

As described above, this embodiment can be applied as a rewritable optical audio device or optical video device.

[0028]

As described above, according to the magneto-optical recording apparatus of the present invention disclosed in the description of this specification and the accompanying drawings, the size of the recording bit recorded on the magneto-optical disk in the medium radial direction. Can be made constant, so that the recording density can be improved and the recording / reproducing characteristics can be made excellent.

[Brief description of drawings]

FIG. 1 is a diagram showing a write bit shape on a moving magneto-optical recording medium.

FIG. 2 is a diagram showing that the size of a write bit in a magneto-optical recording medium changes depending on the strength of an applied magnetic field.

FIG. 3 is a diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 4 is a diagram for explaining an example of a conventional write-once type optical information recording system.

[Explanation of reference numerals] 1 ... Magneto-optical disk 2 ... Circular transparent substrate 3 ... Magnetic layer 4 ... Antireflection film 5 ... Drive motor 6 ... Rotation shaft 10 ... Magneto-optical head 11, 12 ... Laser light generator 13 ... Modulator 14 … Polarizing beam splitter 15, 18… Objective lens 16… Electromagnet 17… Magnetic field control circuit 19… Analyzer 20… Photodetector ──────────────────────── ──────────────────────────────

[Procedure amendment]

[Submission date] June 17, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 3]

[Figure 4]

[Figure 1]

[Fig. 2]

Claims (1)

[Claims] 1. A means for irradiating a magneto-optical recording medium with laser light modulated based on information to be recorded to heat the surface of the recording medium and to apply a magnetic field to the heated region. In the magneto-optical recording device, the shape of a plurality of recording pits recorded by the modulated laser beam is
A means for synchronizing the irradiation time of the modulated laser light and the application time of the magnetic field and changing the size of the magnetic field is provided so that the size of the medium in the radial direction of rotation becomes constant. Magneto-optical recording device.