JPH06223431A - Recording system for multilayer film magneto-optical disk - Google Patents

Abstract

PURPOSE:To record multi-valued information on one bit of an optical disk by optical modulation or by magnetic-field modulation recording. CONSTITUTION:The laser beam irradiates a multilayer film medium 15 with the Curie temperature consisting of four layers T4>T2>T1>T3, then the medium temperature Td becomes T4>Td>T2 to transfer a smaller magnetic area than that of light beam spot to a 1st layer 7. Then it is made T2>Td>T1 and cooled down naturally by inverting the external magnetic field. The spin of the 1st layer 7 and the 2nd layer 6 are matched and the 'intermediate value' is recorded. When it is cooled down naturally by rising to T4>Td>T2, the magnetization of the 2nd layer 6 and the 1st layer 7 are inverted by the recording magnetic field and '1' in the direction of an external magnetic field 18 is recorded. In this case, when it is cooled down less than T3, the spin of the 2nd layer 6 is initialized as well as the fourth layer 3 by the exchange coupling power. The magnetization direction '0' in the original deletion state is left at the part of T3>Td.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high density recording system for performing multilevel recording or multilevel recording on a multi-layered magneto-optical disk.

[0002]

2. Description of the Related Art A magneto-optical disk which is a rewritable magneto-optical disk has already been put into practical use. However, the existing magneto-optical disk has a drawback that the data transfer speed is slow because it is necessary to erase old information and then record new information when rewriting information. In order to overcome this drawback, an overwrite method has been proposed. In particular, the magnetic field modulation method is the most mainstream method in the past, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-214447, "Optomagnetic recording method", in which the direction of the magnetic field is recorded while continuously irradiating laser light. This is a method of reversing in correspondence with the data to be reproduced.

A conventional magnetic field modulation recording method will be described below with reference to the drawings. FIG. 11 shows the basic configuration of a conventional magnetic field modulation recording method. In FIG.
Reference numeral 48 is a magneto-optical disk, 55 is a laser beam, and 56 is a magnetic head.

The magnetic field modulation recording system is a magneto-optical disk 48.
Recording is performed by continuously irradiating the laser beam 55 on the magnetic field and inverting the direction of the external magnetic field according to the signal.
A laser beam 55 is applied to the area to be recorded on the magneto-optical disk 48.
By irradiating, the recording magnetic layer is heated to the Curie temperature or higher, and the magnetization disappears. At this time, the magneto-optical disk 4
By reversing the direction of the current flowing through the magnetic head 56 provided on the opposite side of the optical pickup with 8 in between, corresponding to whether the data to be recorded is "1" or "0", "N" or "S" is recorded. "A magnetic field is generated.

The area of the magneto-optical disk 48 heated by the laser beam 55 moves away from the irradiation position of the laser beam 55 as the magneto-optical disk 48 rotates. Accordingly, the temperature of this region is lowered, and when the temperature falls below the Curie temperature of the recording magnetic layer, a magnetic field of "N" or "S" corresponding to "1" or "0" of data is recorded. In this method, since the rewrite signal is recorded regardless of the magnetization direction before recording, overwriting is possible.

As described above, basically, the value that can be represented by the recording pit itself is binary information of "0" or "1", and in order to improve the recording density, the pit length and the pit interval are reduced. By doing so, the density can be increased to some extent, but in this case, since the pit length and the pit interval depend on the spot diameter of the laser light 55, the increase in density is limited.

This will be described in detail with reference to FIG.
FIG. 12 shows the MTF in an optical system without aberration. Generally, the frequency characteristic in recording and reproducing is MTF (Modulation Transfer Fu) which is a transfer function of an optical system.
nction). The MTF in the optical system of the optical pickup without aberration is the wavelength λ, the numerical aperture NA of the objective lens
12 is used to obtain the result as shown in FIG. The horizontal axis of the figure shows the spatial frequency, and the spatial frequency 2NA / λ at MTF = 0 is called the cutoff frequency.

The pit length at the cutoff frequency indicates the limit value at which the signal can be reproduced, and pits smaller than this cannot be read at all. Usually, half of the cutoff frequency is selected as a guide for stable reproduction, and the pit length required from this is the shortest pit length.

Therefore, when high density recording is performed in the magnetic field modulation recording system, high density can be achieved by high-speed modulating the applied magnetic field during recording, but regarding reproduction, the pit length that can be read during reproduction is as described above. M
Since it is determined by the TF characteristic, there is a limit to high density recording.

Therefore, in contrast to the magneto-optical recording method based on the binary information recording, the magneto-optical recording method capable of increasing the density by recording multi-valued information for one pit, and the magneto-optical recording method. A magneto-optical recording / reproducing system capable of identifying the generated multi-valued information is considered. Such a system is described in, for example, Japanese Patent Laid-Open No. 1-123341, "Optical magnetic disk recording / reproducing system".

This is to form a pattern of a magnetized region on the magneto-optical recording medium by irradiating the magneto-optical recording medium with a laser beam having a constant intensity and applying a magnetic field modulated according to a recording signal. Thus, in the magneto-optical recording method for recording information, recording is performed on the magneto-optical recording medium so that a plurality of information can be expressed per pit so that a plurality of recording states can be recognized.

That is, in the above magneto-optical recording system,
Forming minute pits on the magneto-optical recording medium that cannot be stably reproduced as data by increasing the modulation speed of the applied magnetic field, and reproducing as data by combining these minute pits. It is possible to construct a pit. Here, when a pit having a plurality of pieces of magnetization information is reproduced in the reproduction spot, reproduction is performed as a so-called gray level in which the reproduction magnetization direction is neither completely upward nor downward. Therefore, one pit can represent a plurality of information.

Further, when reproducing the information recorded by the magneto-optical recording method, each slice level is set so that the reproduction signal level of multi-valued information can be discriminated, and the magnitude relation between the reproduction signal level and the slice level is set. Multi-valued information is identified by the determination.

In such a multi-valued recording system, the applied magnetic field is modulated at a high speed to record, thereby forming minute pits which cannot be stably reproduced as data on the magneto-optical recording medium. Since a pit that can be reproduced as data is configured by combining these minute pits, one pit can represent a plurality of information.

The multi-valued recording on the conventional optical disk will be described below with reference to the drawings. Here, in order to simplify the description, a case of four-value recording is shown. Further, the direction of the applied magnetic field for each recording level is set as shown in Table 1.
Then, the correspondence between the pits at each recording level and the binary information to be recorded is, for example, in the conventional example, if two bits of binary information are expressed by one pit, the recording level "+3" is " 11 "and" +1 "are" 10 "and" -1 "
Correspond to "01" and "-3" correspond to "00". However, the correspondence between the binary information and each recording level as shown in Table 1 and the applied magnetic field is not limited to this embodiment.

[0016]

[Table 1]

Here, the recording levels of +3 and -3 are called "normal level", and the recording levels of +1 and -1 are called "intermediate level". The normal level corresponds to the conventional binary recording.

FIG. 13 is a conceptual diagram of a magneto-optical recording method in one conventional example, and FIG. 13 (a) shows an example of binary information recorded by the conventional magneto-optical recording method. As shown in the figure, the conventional magneto-optical recording system corresponds to binary information “1” or “0”,
An "N" or "S" magnetic field is recorded.

Further, FIG. 13B shows a conceptual diagram of conventional multi-value recording. In the figure, reference numeral 48 is a magneto-optical disk, 49 is a pit recorded at a normal level, 50 is a pit recorded at an intermediate level, and 51 is a minute pit forming the intermediate level pit 50.

As shown, the intermediate level pit 50
Are each composed of three minute pits 51. At this time, each minute pit 51 forming the intermediate level pit 50 uses a frequency near the cutoff frequency in FIG. 12, and modulates the applied magnetic field according to the above Table 1 to record on the magneto-optical disk 48. This is because by using a frequency near the cutoff frequency in FIG. 12 as the recording frequency, the minute pits 51 are not recognized as one data by themselves during reproduction, and the three minute pits 51 constitute the intermediate level pit 50. By doing so, it is recognized as one data.

The normal level pit 49 is recorded using a value of 1/3 of the frequency at which the intermediate level pit 50 is recorded, or is recorded without changing the direction of the applied magnetic field. This is for facilitating the generation of the clock signal that determines the timing of reading the signal during reproduction, and enabling the reproduction signal of each level to be discriminated.

Next, a data reproducing method will be described with reference to FIGS. 14 and 15. Data reproduction is based on the fact that, when a perpendicularly magnetized film is irradiated with linearly polarized laser light, the plane of polarization of reflected light rotates in the opposite direction depending on the direction of magnetization of the magneto-optical recording medium (Kerr effect).

FIG. 14 shows polarization planes of reflected light when a laser beam is applied to a pit formed by each recording level as shown in FIG. 1B. In FIG. 14, reference numeral 52 denotes the plane of polarization of the laser light with which the magneto-optical disk is irradiated. In the case of the intermediate level pits shown in FIGS. 14B and 14C, the signal is reproduced as the sum of the three minute pits, that is, the sum of the directions of the three magnetic fields.
The car rotation angle becomes smaller than that of the normal level pit as shown in (a) and (d), and the amplitude of the reproduction signal changes.

FIG. 15 is a diagram showing the amplitude of a reproduced signal when a signal of each recording level is reproduced. Here, FIG.
As shown in, the 3
Set one slice level. Here, the slice level A is a level for determining whether the recording level is "+" or "-", that is, whether the direction of the applied magnetic field is the N direction or the S direction, and the slice level B is "+". “Recording level”, that is, a level for determining whether it is a normal level or an intermediate level in the applied magnetic field in the N direction, the slice level C is a “−” recording level,
That is, it is a level for determining whether the applied magnetic field in the S direction is a normal level or an intermediate level.

Therefore, the four-valued information (signal of each level) is obtained by determining the magnitude relationship between each slice level and the reproduced signal amplitude at the read timing.
Can be identified.

In the above-mentioned conventional example, multi-value recording is performed by using 2 bits of binary information as one data, but the present invention performs multi-value conversion in units of more bits. It is also possible. Further, in the above embodiment,
Although a four-valued signal is used, it is a matter of course that the present invention can be made into a three-valued signal.

As described above, in the conventional multi-valued recording system, it is impossible to stably reproduce as data alone on the magneto-optical recording medium by recording by applying high speed modulation of the applied magnetic field. Since pits that can be reproduced as data are formed by forming small pits of a size and combining these small pits, one pit can represent multivalued information.
There is an effect that higher density can be realized as compared with recording of value information.

Further, since the recording / reproducing can be performed with the laser light of the current wavelength without shortening the spot diameter by shortening the wavelength of the laser light, the optical system of the current magneto-optical disk device can be used as it is.

The system for recording / reproducing multi-valued information using the magnetic field modulation head has been described above. However, in the above system, the magnetic field modulation head must be driven at a higher frequency than the recording pit rate during recording. First, in order to record a high-frequency modulation magnetic field required for multi-valued information at a level capable of magneto-optical recording, the magnetic field modulation head must be brought close to the magnetic surface of the disk, and the magnetic field modulation head should not move to the disk surface deviation It was necessary to devise such as following. In addition, when the signal rate becomes high in image recording or the like, the frequency for driving the magnetic field modulation head becomes too high and recording may become impossible.

In addition to the magnetic field modulation recording described above, as a overwrite recording system, a system has recently been proposed in which overwrite recording is performed by optical modulation using an exchange coupling two-layer film. In the conventional optical modulation recording, overwriting was impossible because, in principle, the obligatory function of overwriting that erases old data when the light intensity is zero is impossible.

The method of performing the optical modulation overwrite using the exchange coupling two-layer film is performed according to the principle shown in FIG. The light intensity is modulated between two levels, high and low, and in addition to the recording magnet 58, an initialization magnet 57 for aligning the magnetization of the second layer 59 in one direction is required.

When low level light is irradiated after the initialization, the transition metal spins of the first layer 60 are aligned in the same direction as the second layer 59 by the exchange coupling force, and the old data is erased to "0". "Is recorded.

When the high level light is irradiated, the magnetization of the second layer 59 having a high Curie temperature is also reversed by the recording magnet 58, so that the spin of the first layer 60 is also reversed.
"1" is recorded. For example, TbFeC is used for the first layer 60.
o, using TbDyFeCo for the second layer 59, an optical modulation overwrite can be achieved with an initializing magnet of 4 kOe.

The above-mentioned optical modulation overwrite system using the two-magnet system has a drawback that it requires an initialization magnet of several kOe.

Therefore, there has been proposed an optical modulation overwrite that employs a magnetic four-layer film and does not require an initializing magnetic field.
The principle is shown in FIG. 17, and the effective magnetic field by the exchange coupling force from the initialization layer 61 which is the fourth layer of the optical disk 15 is used as the initialization magnetic field.

In FIG. 17, the second line is shown before light irradiation.
The transition metal spins of the writing layer 6 that is the layer and the switching layer 5 that is the third layer are the fourth layer 6 by the exchange coupling force.
It is aligned with 1. First when illuminated by low level light
Since the spins of the memory layer 7, which is a layer, are aligned with the second layer 6, "0" is recorded.

When the high level light is irradiated, the Curie temperature T3 of the third layer 5 is low, so that the magnetization of the second layer 6 and then the first layer 7 is not affected by the fourth layer 61. Is reversed by, and "1" is recorded. When the temperature is cooled below the Curie temperature T ₃ of the third layer 5, the spins of the second layer 6 are initialized by the exchange coupling force and aligned with the fourth layer 61. Here, the third layer 5 has a fourth layer only at a low temperature that requires initialization.
It acts as a switch that allows the effective magnetic field from layer 61 to work.

[0038]

As described above, in the conventional light modulation overwrite method, overwriting is possible by making the medium layers of the optical disk 15 multi-layered, but pits smaller than the light spot. Was extremely difficult to record, and it was impossible to record and reproduce multi-valued information as it was.

Further, in the magnetic field modulation recording method, although it was possible to record and reproduce multi-valued information as described above, the recording frequency increases and it becomes difficult for the magnetic field modulation head to generate a high frequency magnetic field. However, the magnetic field modulation head has to be forced close to the medium surface, which causes a problem in reliability and the like.

Further, in the conventional multilayer film medium, since the layer in which information is finally recorded is one layer, it is impossible to record information over multiple layers and increase the amount of information.

The present invention has been made for the purpose of solving the problems of the magnetic field modulation recording method using the conventional multi-layered film medium as described above, and multi-level recording or multi-year recording is performed on the multi-layered magneto-optical disk. The purpose is to obtain a recording method that can be used.

[0042]

According to the present invention, a recording density smaller than the light spot diameter is previously recorded on the fourth layer and the first layer having a Curie temperature higher than that of the fourth layer by magnetic field modulation recording or magnetic transfer. Then, at the time of reproduction, by controlling the laser power, the recorded information smaller than the reproduction light spot diameter is transferred to the first layer by the exchange coupling force and reproduced as an intermediate value.
As a result, since binary recording is performed on the fourth layer by optical modulation as in conventional magneto-optical recording, ternary recording is performed in addition to the intermediate value by the exchange coupling magnetic transfer.

A recording density smaller than the light spot diameter is recorded in advance on the fourth layer and the first layer having a Curie temperature higher than that of the fourth layer by magnetic field modulation recording or magnetic transfer, and then the laser power is controlled. By increasing the temperature of the medium to a temperature at which magnetic transfer is possible, the first
The layer is erased by reproducing the intermediate value, and the magnetic field modulation recording is partially performed to record in the direction of the external magnetic field. As a result, since binary recording is performed on the fourth layer at a signal rate similar to that of the conventional magnetic field modulation recording, ternary recording is performed in addition to the intermediate value by exchange coupling magnetic transfer in the erased state. Be seen.

A recording density smaller than the light spot diameter is previously recorded on the fourth layer and the first layer having a Curie temperature higher than that of the fourth layer by magnetic field modulation recording or magnetic transfer. By modulating the light and raising the medium temperature to a temperature at which exchange-coupling magnetic transfer is possible, this is recorded, and when recording the magnetization direction other than the intermediate value, the medium temperature is changed by the laser light to the temperature recorded by the external magnetic field. By raising and partially performing the magnetic field modulation recording,
Record in the direction of the external magnetic field. As a result, since binary recording is performed on the fourth layer at the same signal rate as in conventional magnetic field modulation recording, ternary recording is performed in addition to the intermediate value by exchange coupling magnetic transfer, and magnetic field modulation is performed. It is possible to perform multi-valued recording by overwriting by combining and optical modulation.

After the first data is optically modulated and recorded on the first layer having a Curie temperature of the fourth layer and a Curie temperature higher than that of the fourth layer, with a high laser power exceeding the Curie temperature of the first layer. , The second information is optically modulated and recorded on the fourth layer with a laser power equal to or higher than the Curie point of the fourth layer and equal to or lower than the Curie point of the first layer. At the time of reproduction, first, the second information is reproduced by the laser power that cannot perform the exchange coupling magnetic transfer, and then the first data is reproduced by the exchange coupling magnetic transfer.

Further, after the first data is magnetically modulated and recorded on the first layer having a Curie temperature of the fourth layer and a Curie temperature higher than that of the fourth layer with a high laser power exceeding the Curie temperature of the first layer. , The second layer of the fourth layer by the laser power above the Curie point of the fourth layer and below the Curie point of the first layer.
Information is recorded by magnetic field modulation. At the time of reproduction, first, the second information is reproduced by the laser power that cannot perform the exchange coupling magnetic transfer, and then the first data is reproduced by the exchange coupling magnetic transfer.

Further, the optical head of the magneto-optical disk device for reproducing the multi-layered medium has a plurality of beams whose powers can be independently varied, and the medium temperature can be exchange-coupled by the first light spot running at the beginning. By raising the temperature to a high temperature and shifting the medium temperature high temperature portion to the rear of the light spot, the second recorded information recorded in the fourth layer is reproduced from the non-high temperature portion in the light spot, and When the high temperature part of the medium is naturally cooled, the first information recorded in the first layer is magnetically transferred to the fourth layer, and the first information is reproduced or erased by a light spot running in the rear.

[0048]

In the present invention, the intermediate value previously stored in the first layer can be freely transferred to the fourth layer by the exchange coupling magnetic transfer by adjusting the optical power during recording. Therefore, it is possible to write multilevel information (gray level) by optical modulation recording.

Further, the intermediate value previously stored in the first layer can be freely transferred to the fourth layer by the exchange coupling magnetic transfer by adjusting the optical power during erasing. Therefore, when magnetic field modulation recording is performed, the fourth layer can be magnetized in the direction of the external magnetic field,
When the external magnetic field is not modulated, it is possible to write multi-valued information (gray level) in the erased state.

Further, the intermediate value stored in advance in the first layer can be freely transferred to the fourth layer by the exchange coupling magnetic transfer by adjusting the optical power at the time of recording at the gray level. Therefore, when magnetic field modulation recording is performed, the fourth
It is possible to magnetize the layer or write multilevel information (gray level) by exchange coupling magnetic transfer by light modulation.

Further, by raising the medium temperature above the Curie temperature of the first layer, optical modulation recording of image information, voice, program data, etc. is performed, and search information etc. that does not need to be stored once read. Is recorded by heating the medium above the Curie temperature of the fourth layer and below the Curie temperature of the first layer, and at the time of reproducing, by reproducing at a medium temperature at which exchange coupling magnetic transfer does not occur, only the above search information is reproduced. The information stored in the first layer is reproduced by reproducing at the medium temperature at which exchange coupling magnetic transfer occurs.

By performing magnetic field modulation recording, the recording on the first layer and the fourth layer is overwritten.

Further, when the first light spot running at the head heats the medium to a temperature at which exchange coupling magnetic transfer is possible, the temperature distribution shifts to the rear of the light spot. At this time, therefore, the data of the fourth layer is reproduced. Then, the second light spot running behind the first light spot reproduces the data stored in the first layer after the exchange-coupling magnetic transfer with a laser power that does not cause the exchange-coupling magnetic transfer.

By inserting a diffraction grating in front of the objective lens in the optical head, the light beam is split, and exchange-coupling magnetic transfer is performed by the 0th-order light capable of concentrating the laser power. The information stored in the fourth layer before the exchange coupling is reproduced by the 1st-order diffracted light that is focused on the first-order diffracted light, and the 1st-order diffracted light that is focused after the 0th-order light is used after the exchange-coupling. The information stored in the first layer is reproduced.

[0055]

【Example】

Example 1. FIG. 1 is a diagram showing a recording principle of Embodiment 1 of the present invention. In FIG. 1A, 1 is a magnetic field modulation head, 2 is an oscillator, 3 is a protective film of an optical disk 15, 4 is an intermediate value storage layer, 5 Is a switching layer, 6 is a writing layer, 7 is a memory layer, 8 is a substrate, 9 is an optical head, and 10 is an objective lens for focusing laser light.

FIG. 1B shows the Curie temperature of each layer, FIG. 1C shows the relationship between the Curie temperatures of the respective layers, and FIG. 1D shows the initial magnetization of each layer of the multilayer optical disk 15. FIG. 1E is a diagram showing the state of magnetization of each layer when the temperature is raised to T4, and FIG. 1F is a diagram showing the state of magnetization of each layer after recording.

FIG. 2 shows a method of manufacturing the multi-valued information storage medium according to the first embodiment. In the figure, 14 is a magnetic sheet recorded in the radial direction with a density smaller than the light spot, and 15
Is a multilayer optical disk, 16 is a flash laser that instantly emits high energy, and 17 is a magnetic transfer device.

FIG. 3 shows a multilevel recording method on a multilevel information storage medium according to the first embodiment.
9 is an intermediate value storage layer in which intermediate values are stored in advance, 2
0 is an LD driver for modulating the semiconductor laser, 2
Reference numeral 1 is a multi-valued modulation circuit for modulating recorded digital data into multi-valued data, and 22 is a semiconductor laser.

FIG. 4 shows a method of reproducing a signal from the track of the multi-valued optical disc 15 of the first embodiment, in which 23 is a current-voltage conversion circuit.
Reference numerals 24a and 24b are operation amplifiers, 25a and 25b are photodetectors for receiving reflected light from the optical disk 15, and 26a and 2b.
Reference numeral 6b is an analyzer that allows only light having a specific Kerr rotation to pass through, and 27a and 27b are half mirrors.

FIG. 5 shows a method of erasing the tracks of the multi-valued optical disk 15 of the first embodiment.

Next, the operation of the first embodiment will be described. The optical disc 15 in this system has the following configuration. The magneto-optical recording medium formed on the disk-shaped substrate 8 made of plastic or glass is
First, the first layer has a Curie temperature T1 with respect to a magnetic field and is a layer for writing and reading information. This corresponds to the memory layer 7 in FIG.

The second layer thereabove is a recording auxiliary layer for determining the recording magnetization direction of the memory layer 7 when the Curie temperature is T2, and corresponds to the writing layer 6 in FIG. Third on it
The recording auxiliary layer 6 is a recording auxiliary layer for recording the magnetization direction of the bias magnetic field without being affected by the initializing layer at the time of high power recording with the Curie temperature T3, and corresponds to the switching layer 5 in FIG. To do. The fourth layer thereabove is an intermediate value storage layer having a Curie temperature of T4 and having a density of a plurality of light spots used in recording and reproduction in the linear direction in advance, and corresponds to the intermediate value storage layer 4 in FIG. To do. In this recording / reproducing apparatus, it is not necessary to set the medium temperature Td to T4 or higher. The uppermost protective layer 3 serves to protect the magnetic field modulation head 1 and the like from contact.

Next, a method of writing to the intermediate value storage layer 4 when the optical disc 15 is created will be described. Figure 1
The magnetic field modulation head 1 shown in FIG. 1 is driven by the AC signal 2 and the medium temperature is raised by the optical head 9 until Td> T4, so that the magnetization direction of the medium becomes as shown in FIG. ), The state shown in Fig. 1 (f) is obtained,
It becomes possible to magnetize the intermediate value storage layer 4 in a recording area smaller than the light spot diameter.

That is, in the magnetic field modulation recording, the recording linear density can be made sufficiently smaller than the light spot diameter. However, when it is impossible to record a high frequency with the magnetic field modulation head or when it is impossible to raise the temperature Td of the recording medium to Td> T4 by the optical head 9 when the number of revolutions of the optical disk is the same as during recording and reproduction. This can be dealt with by making the rotation speed of the optical disk lower than the rotation speed for recording and reproducing. Further, when the laser power is insufficient, it is not necessary to perform modulation. Therefore, not only a high output semiconductor laser but also a solid laser or the like may be used.

However, in the method shown in FIG. 1, when producing a large number of optical discs, it takes too much time to produce each disc, which may cause a problem.
Therefore, according to the method shown in FIG. 2, first, the disk-shaped magnetic medium 14 such as a magnetic sheet magnetized in advance with a recording density smaller than the light spot diameter is used as a master, and the recording surface of the disk-shaped magnetic medium 14 is used as the optical disk 15. To the recording surface (for example, the protective layer 3 or the intermediate value recording layer).

Next, the temperature of the recording medium is raised to Td> T4 for a short time by the flash laser 16 to change the magnetic recording pattern of the magnetic medium 14 to the optical disk 15.
The intermediate value can be stored in the intermediate value storage layer 4 by transferring the intermediate value to the intermediate value storage layer 4.

Such magnetic transfer is used for mass production of prerecorded magnetic tapes, etc., except for the temperature rising process of the medium. As described above, the intermediate value storage layer 4 is previously stored.
It is possible to form a magnetized area smaller than the recording / reproducing light spot diameter.

The Curie temperature of each of the multilayered magneto-optical disks 15 using the multilayered medium having the intermediate value storage layer 4 is T4>T2>T1> T as shown in FIG. 1 (c).
Since the relationship is 3, the external magnetic field is applied to raise the medium temperature Td to T4>Td> T2 by the laser power, and then natural cooling is performed, whereby a magnetized region smaller than the light spot is transferred to the first layer 7. It becomes possible. This is based on the same principle as a conventional optical modulation overwrite medium that does not require an initializing magnetic field by adopting a magnetic four-layer film, and instead of using an effective magnetic field by the exchange coupling force from the fourth layer 4 as the initializing magnetic field. In addition, a magnetized area smaller than the light spot diameter, that is, intermediate value information is used.

In FIG. 3, before the light irradiation,
The transition metal spins of the third layer are aligned with the fourth layer by the exchange coupling force. Next, when the external magnetic field 18 is reversed to raise the medium temperature Td to T2>Td> T1 and then low-level light for natural cooling is irradiated, spins of the first layer 7 are aligned with the second layer 6. Therefore, the "intermediate value" is recorded.

When the medium temperature Td is raised to T4>Td> T2 and then high-level light for natural cooling is irradiated, the Curie temperature of the third layer 5 is low, so the fourth layer 4
The magnetization of the second layer 6 and then of the first layer 7 is reversed by the recording magnetic field without being affected by, and "1" aligned in the direction of the external magnetic field 18 is recorded.

At this time, when the temperature further cools to the Curie temperature T3 or lower of the third layer 5, the spin of the second layer 6 is initialized to the fourth layer 4 by the exchange coupling force. Also, T
In the part where 3> Td, the magnetization direction in the original erased state remains. That is, when the emission power of the light spot is at the reproduction level, the magnetization direction "0" that was initially erased remains. As a result, it becomes possible to record three values of the magnetization direction in the erased state, the magnetization direction at the time of recording, and the intermediate value in which a fine magnetization region exists.
Here, the third layer 5 functions as a switch that allows the effective magnetic field from the fourth layer 4 to work only at a low temperature at which initialization is required.

In this case, a magnetized area smaller than the light spot stored in the intermediate value storage layer 19 is transferred to the first layer 7 by exchange coupling magnetic transfer. When this is reproduced by a light spot, as shown in FIG. 4, if the ratios of the upward magnetization and the downward magnetization are almost equal, the directions of the Kerr rotation angles in the reflected light for reproduction are different, so that the analyzers 26a, 2
A reproduction signal obtained by current-voltage converting the two signals that have passed through 6b and received by the photodetectors 25a and 25b to obtain a differential is reproduced as a so-called gray level.

As an erasing method, as shown in FIG.
First, the direction of the external magnetic field 18 is set to the opposite direction of the recording, and the medium temperature is T4>Td> T2 in the state where the external magnetic field is applied.
As a result, the magnetization of the first layer 7 is aligned in the direction of the external magnetic field 18. This is the erased state.

In the multilayer film medium, each layer is formed of an amorphous alloy film of a rare earth element and a transition metal having perpendicular magnetic anisotropy, like the four-layer overwrite medium shown in the conventional example. The composition of one storage layer 7 is made of TbFeCo, the second storage auxiliary layer 6 is made of GdDyFeCo, the third control layer 5 is made of TbFe, and the fourth intermediate value storage layer 19 is formed.
Can be realized by TbCo or the like.

The information previously written in the intermediate value storage layer 19 has different magnetization directions,
If the composition ratio is about 50% in the upward magnetic field and approximately 50% in the downward magnetic field, the information recorded as a result has three values. Also,
When the above composition ratio is changed, the amount of multi-valued recording per pit increases.

The method for detecting data detection from the multi-valued reproduction signal as described above is performed by the method shown in FIG. In the figure, the reproduction signal output from the differential amplifier 24 is first passed through a waveform equalization circuit 27 represented by a transversal filter or the like, and is restored to a shape close to the original recording waveform. Next, an edge detection circuit 28 typified by a differential detector detects a rising edge or a falling edge of this reproduction waveform, and at the same time, a level determination circuit 29 changes the reproduction signal level to "0""intermediatevalue"" 1 "is determined.

Further, the data clock included in the reproduced waveform is extracted from this reproduced signal via the PLL 30, and the data detection circuit 31 restores the multilevel information from the reproduced level and edge information. Since this multi-valued information is parallel information, the parallel-serial conversion circuit 32 finally outputs 2
Restore as value data.

Example 2. In the first embodiment, at the time of recording, the multi-valued information is recorded by the light modulation recording, for example, by modulating the semiconductor laser, but the multi-valued recording similar to the first embodiment can be performed by the magnetic field modulation recording. Is. In the multi-valued information recording by the magnetic field modulation recording shown in the conventional example, it was necessary to set the recording signal frequency of the magnetic field modulation head to a high frequency, but in the second embodiment, it is necessary to record the gray level also in the magnetic field modulation recording. Because there is no
There is no need to increase the signal recording rate of the magnetic field modulation head.

In this case, at the time of erasing, as shown in FIG. 5, the erasing power 1 is set to high level light (medium temperature T
d is T4>Td> T2) and not aligned in the direction of the external magnetic field 18, but low-level light with an erasing power of 2 (medium temperature Td is T2>Td> T1) is used. The first layer 7 is set to the “intermediate value” stored in 19.
Align. In the magnetic field modulation recording, setting the first layer 7 to the gray level as described above is the erased state.

At the time of recording, as shown in FIG. 1, the magnetic field modulation head 1 is energized with a recording signal so that the optical head 9
The medium temperature Td is changed to T by the laser power emitted from
By setting 4>Td> T2, the first layer 7 is aligned with the magnetic field from the magnetic field modulation head 1. At this time, if no current is passed through the magnetic field modulation head 1, the first layer 7 is in the original erased gray level, so that multilevel information is recorded.

Example 3. In the method of the first embodiment, although the magnetic field modulation head is used, overwrite recording cannot be performed, so that there is a problem that the erasing operation is necessary and the data becomes low. As a means for solving this, it is conceivable to implement overwrite recording by modulating the laser light of the optical head at the same time when modulating the magnetic field modulation head.

That is, in FIG. 1, when writing a gray level, the laser power is changed so that the medium temperature Td is T2>Td> T1, and the data is stored in the fourth layer 7 regardless of the presence or absence of the external magnetic field of the magnetic field modulation head 1. The obtained “intermediate value” is transferred to the first layer 7.

When the first layer 7 is aligned with the direction of the magnetic field generated by the external magnetic field modulation head 1, the laser power is varied and the medium temperature Td is set to T4>Td> T2. Magnetize in the direction of the magnetic field of 1.

In this way, if the laser of the optical head 9 is also modulated at the same time, overwrite recording can be performed. At this time, the laser emission power of the optical head 9 is
It is modulated only during gray level recording, and the medium temperature Td is changed to T2.
>Td> T1. As described above, by modulating both the magnetic field modulation head and the optical head during recording, it is possible to record multivalued information by the overwrite method.

Incidentally, at the time of reproduction, it can be realized by the same means as in the case of the first embodiment, that is, reproduction with a small laser power such that exchange coupling magnetic transfer does not occur.

Example 4. The method of storing intermediate value information necessary for multi-valued information in the multilayer medium in advance and calling this to the first layer at the time of recording has been described above. It is also possible to record different information on the first layer to increase the areal recording density.

FIG. 7 is a diagram for explaining the multiple recording / reproducing operation of the fourth embodiment, and the characteristics of each medium layer of the fourth embodiment are as follows. The Curie temperature with respect to the magnetic field of the second data layer 41 on the substrate side for writing and reading information is T1. Next, the second recording auxiliary layer 6 has a Curie temperature of T2.
Then, the second recording auxiliary layer is adjacent to the second data storage layer 41 for determining the recording magnetization direction of the second data recording layer 41.

When the Curie temperature is T3 and high power recording is performed, the second recording auxiliary layer 6 is provided with the third control layer 5 for recording the magnetization direction of the bias magnetic field without being affected by the initialization layer. The Curie temperature is T4 and the fourth first data storage layer 40 is adjacent to the third control layer 5 in which the second information is recorded.

Further, in this magneto-optical disk medium, the Curie temperatures of the above layers are in a relationship of T4>T2>T1> T3. However, the Curie temperature of T4 is a temperature that can be sufficiently exceeded by the light spot of the laser used in the recording / reproducing apparatus.

Next, a method of recording two data on the first layer 41 and the fourth layer 40 using such a medium will be described with reference to FIG. First, an external magnetic field 18a is applied to raise the medium temperature Td by the laser power to Td> T4 by the laser power, and then naturally cooled to erase the first and second information. After that, after applying the external magnetic field 18b in the opposite direction, the medium temperature Td is partially raised to Td> T4 by the blinking laser power in the same optical head 37 after the optical head 38 or the optical disk 15 makes one revolution. The first information is recorded on the first layer 41 by being naturally cooled.

Then, the fourth layer 40 is erased by setting the medium temperature to T2>Td> T1 by the optical head 37 with the external magnetic field 18a. Finally, with the external magnetic field 18b, the optical head 3
8 or after the optical disk 15 rotates, the medium temperature is raised to T2>Td> T1 by the same optical head 37 and then naturally cooled to record the second information in the fourth layer 40. In this way, two pieces of data can be recorded on one optical disc 15 having a multilayer film.

The medium composition at this time was the same as in Example 1.
Each layer can be formed of an amorphous alloy film of a rare earth and a transition metal having perpendicular magnetic anisotropy. For example, the composition of the storage layer 41 of the second data is TbFeCo, and the second storage auxiliary layer 6 is GdDyFeCo. And the third control layer 5 is made of TbFe, and the fourth data storage layer 40 is made of TbFe.
It can be configured with bCo.

However, in such an optical modulation recording system, an erasing process is required as shown in FIG.
It is necessary to mount a plurality of heads in order to reduce the signal recording rate and solve this problem.

Example 5. In order to solve the problem of the erasing process in the third embodiment as described above, a method of modulating the external magnetic field by the magnetic field modulation head in the multilayer magneto-optical disk can be considered. Here, the medium temperature Td is raised to Td> T4 by the laser power and then naturally cooled to overwrite-record the first information in the first information storage layer, and the medium temperature is raised to T2>Td> T1. After that, the second information can be overwritten and recorded on the fourth layer by naturally cooling.

The recording / reproducing mechanism at this time is illustrated in FIG. In the figure, when recording data, the laser power of the optical head 37 is controlled so that the medium temperature Td is higher than the Curie temperature T4 of the first data storage layer 40, and the magnetic field modulation head 33 is modulated by the data. Thus, the data is written in the first data storage layer 40.

Next, by controlling the laser power of the optical head 38 to set the medium temperature to T2>Td> T1, for example, the magnetic field modulation head 34 records search data that needs to be read only once. .

In this way, the first data storage layer 40
Stores data that needs to be read many times, and the second data storage layer 41 stores data that is temporarily stored. By using the two magnetic field modulation heads 33 and 34 in this way, overwrite recording becomes possible.

At the time of reproduction, first, the temporary data of the second data storage layer 41 is read by a weak laser power which does not cause exchange coupling magnetic transfer, and then the medium temperature is changed by the laser power of the optical head. After the data in the first data storage layer 40 is transferred to the second data storage layer 41 by raising the temperature to the exchange coupled magnetic transferable temperature, the same method as the temporary data reading on the second data storage layer 41 is performed. Read this out by.

FIG. 8 shows the case where two heads, that is, the optical heads 37 and 38 are used, but it is also possible to perform the same recording and reproduction as described above by using one head many times. However, in this case, the rotation waiting time becomes long.

Example 6. One optical head of a magneto-optical disk device for reproducing the above-mentioned multilayer medium has a plurality of beams whose powers can be independently varied, and first, the medium temperature is set to T4>Td> T2 by the first light spot running at the head, The medium-temperature high-temperature portion is displaced rearward of the light spot, whereby the second recorded information recorded in the second data storage layer 40 is reproduced from the non-high-temperature portion in the light spot, and the medium high-temperature portion is After magnetically transferring the first information recorded in the first data storage layer 40 to the second data storage layer 41 when naturally cooled, the first information is reproduced or erased by a light spot running in the rear. . This can be achieved, for example, by mounting a plurality of lasers 44 and 45 on one optical head 43, as shown in FIG. At this time, by dividing the photodetector 25,
It becomes possible to take out the plurality of data from the operational amplifier 24.

Besides, as shown in FIG. 10, a method of splitting the light beam emitted from the laser 22 by the diffraction grating 46 may be considered. In this case, since the 0th-order diffracted light has a high light intensity, the light spot by this is used to raise the temperature of the medium capable of exchange coupling magnetic transfer described above. In addition, the 1st-order diffracted light traveling in front of the 0th-order light is
Used to reproduce the data in the data storage layer 41,
The 1st-order diffracted light that travels after the 0th-order light is used to reproduce the first data transferred to the second data storage layer 41 after the exchange coupling magnetic transfer.

As described above, by providing a layer for recording / reproducing temporary data in addition to the recording / reproducing data on one multi-layered film medium, the first recording information is converted into data such as image and sound. By using the second record information as a code or address information for editing or searching, it is possible to construct a system that is extremely easy to edit or search.

Image and sound data are recorded as the first record information, a data clock is recorded as the second record information, and the first record information is detected by the data clock. Is also possible. By doing so, a PLL circuit for data detection becomes unnecessary, and reliable data detection can be performed.

[0104]

As described above, according to the present invention, it is possible to write multi-valued information by optical modulation recording, which makes it possible to increase the areal recording density and to use the conventional magnetic field modulation head. Since it became possible to form a recording magnetized area smaller than the light spot that could not be written otherwise by optical modulation, it became possible to improve reliability and cope with a high signal rate.

Further, the recording of multi-valued information, which could not be realized unless the recording signal rate of the conventional magnetic field modulation head is made several times higher than that of the binary recording, can be made equal to or lower than the recording signal rate of the binary recording. Therefore, the reliability can be improved without forcibly reducing the flying height of the magnetic field modulation head.

By modulating the laser power at the same time as the external magnetic field is modulated by the magnetic field modulation head, it is possible to perform multilevel recording by overwriting without increasing the recording signal rate of the magnetic field modulation head, and waiting for rotation. The time can be eliminated, the data transfer rate can be increased, and the number of optical heads and the number of light beams can be reduced.

Further, two data can be physically multiplexed and recorded on one optical disk, and by multiplexing search data and the like in addition to the recorded data, data editing and automatic search can be easily performed. Become.

Further, it becomes possible to multiple-record two pieces of data on one disk with one optical head and reproduce them separately.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a recording principle on a multilevel recording medium according to first, second and third embodiments of the present invention.

FIG. 2 is a diagram for explaining another method for manufacturing the multilevel recording medium of Example 1.

FIG. 3 is a diagram showing a multilevel recording method according to the first embodiment of the present invention.

FIG. 4 is a diagram for explaining the principle of signal reproduction according to the first embodiment.

FIG. 5 is a diagram for explaining the principle of the erasing method of the first embodiment.

FIG. 6 is a diagram showing a data detection method at the time of reproducing a signal from a multilevel recording medium according to Examples 1, 2, and 3.

FIG. 7 is a diagram for explaining the principle of multiplex recording / reproducing of data according to the fourth embodiment of the present invention.

FIG. 8 is a diagram for explaining the principle of multiplex recording / reproducing of data according to a fifth embodiment of the present invention.

FIG. 9 is a diagram for explaining the principle of multiplex recording / reproducing of data according to the sixth embodiment of the present invention.

FIG. 10 is a diagram for explaining the principle of multiplex recording / reproducing of data according to the sixth embodiment.

FIG. 11 is a diagram showing a magnetization state of a medium which is a principle of multi-value recording in a conventional example.

FIG. 12 is a diagram showing a Kerr rotation angle which is the principle of multi-value recording in a conventional example.

FIG. 13 is a diagram for explaining the principle of signal reproduction of multilevel recording in a conventional example.

FIG. 14 is a diagram for explaining the principle of magnetic field modulation recording in a conventional example.

FIG. 15 is a diagram showing a spatial frequency of an optical head.

FIG. 16 is a diagram showing overwrite recording on a conventional 4-layer overwrite medium.

FIG. 17 is a diagram showing overwrite recording on a conventional two-layer overwrite medium.

[Description of Reference Signs] 1 magnetic field modulation head 2 AC signal generating means 4 intermediate value storage layer 5 switching layer 6 writing layer 7 memory layer 8 substrate 9 optical head 10 objective lens 14 magnetic sheet 15 optical disk 16 flash laser 17 magnetic transfer device 18 external Magnetic field 19 Intermediate value storage layer 20 LD driver 21 Multi-level modulation circuit 22 Laser oscillator 23 I-V conversion circuit 24 Operational amplifier 25 Photodetector 26 Analyzer 27 Waveform equivalent circuit 28 Edge detection circuit 29 Level determination circuit 30 PLL circuit 31 data Detection circuit 32 Parallel-serial conversion circuit 33 Magnetic field modulation head 34 Magnetic field modulation head 35 Magnetic field modulation driver 36 Modulation circuit 37 Optical head 38 Optical head 39 Data detection PLL circuit 40 First data storage layer 41 Second data storage layer 43 Optical head 4 laser oscillator 45 laser oscillator 46 diffraction grating 58 the external magnetic field

[Procedure amendment]

[Submission date] January 10, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Therefore, in comparison with the magneto-optical recording system based on the binary information recording, a high density recording is achieved by exceeding the above-mentioned limitation by the MTF characteristic.
In order to improve the efficiency, it is possible to discriminate multi-valued information recorded by the magneto-optical recording method capable of increasing the density by recording multi-valued information per pit. Various magneto-optical recording / reproducing methods are possible. Such a method is disclosed, for example, in Japanese Patent Laid-Open No. 1-1233.
No. 41 publication, "Optical magnetic disk recording / reproducing system".

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

[0042]

SUMMARY OF THE INVENTION The present invention is a multi-layered magneto-optical film.
Has a higher Curie temperature than the magneto-optical film on the surface of an air medium
A recording density smaller than the light spot diameter is recorded in advance on the deep magneto-optical film by magnetic field modulation recording or magnetic transfer, and at the time of reproduction, by controlling the laser power, information recorded smaller than the reproduction light spot diameter is recorded. Optical spot where data is reproduced by exchange coupling force
This is reproduced as an intermediate value by transferring it to the magneto-optical film on the surface to which it is applied . As a result, the magneto-optical film <br/> surface, and recording of the conventional magneto-optical recording and similar binary, together with the recording of the intermediate value by exchange coupling the magnetic transfer, the 3 value recording is performed .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

Further, a recording density smaller than the light spot diameter is previously recorded on the deep magneto-optical film having a Curie temperature higher than that of the surface magneto- optical film by magnetic field modulation recording or magnetic transfer, and then the laser power is controlled. By increasing the medium temperature to a temperature at which magnetic transfer is possible, data is reproduced by reproducing an intermediate value on the magneto-optical film on the surface to erase the data, and by performing magnetic field modulation recording partially, Record in the direction of the magnetic field. This results in data
Since binary recording is performed on the magneto-optical film on the surface where reproduction is performed at a signal rate similar to that of conventional magnetic field modulation recording, in addition to the above intermediate value by exchange coupling magnetic transfer in the erased state,
Tri-level recording is performed.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

A recording density smaller than the light spot diameter is previously recorded by magnetic field modulation recording or magnetic transfer on a deep magneto-optical film having a Curie temperature higher than that of the magneto-optical film on the surface. By modulating the light and raising the medium temperature to a temperature at which exchange-coupling magnetic transfer is possible, this is recorded, and when recording the magnetization direction other than the intermediate value, the medium temperature is changed by the laser light to the temperature recorded by the external magnetic field. Recording is performed in the direction of the external magnetic field by raising and partially performing the magnetic field modulation recording. This results in data
Binary recording is performed on the magneto-optical film on the surface where reproduction is performed at a signal rate similar to that of conventional magnetic field modulation recording. Therefore, in addition to the intermediate value by exchange coupling magnetic transfer, ternary recording is performed. That is, multi-level recording can be performed by overwriting by combining magnetic field modulation and optical modulation.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

After the first data is optically modulated and recorded on the deep magneto-optical film having a Curie temperature higher than that of the surface magneto-optical film , with a high laser power exceeding the Curie temperature of the deep magneto-optical film. The second information is optically modulated and recorded on the surface magneto-optical film by a laser power which is higher than the Curie point of the surface magneto- optical film and lower than the Curie point of the deep magneto- optical film . At the time of reproduction, first, the second information is reproduced by the laser power that cannot perform the exchange coupling magnetic transfer, and then the first data is reproduced by the exchange coupling magnetic transfer.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

[0046] Further, the magneto-optical film of deep having a higher Curie temperature than the magneto-optical film on the surface, after the first data at a high laser power exceeding the Curie temperature of the magneto-optical film and the magnetic field modulation recording, the surface The second information is magnetic field modulation recorded on the surface magneto-optical film by the laser power above the Curie point of the magneto-optical film above and below the Curie point of the deep magneto- optical film .
At the time of reproduction, first, the second information is reproduced by the laser power that cannot perform the exchange coupling magnetic transfer, and then the first data is reproduced by the exchange coupling magnetic transfer.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

Further, the optical head of the magneto-optical disk device for reproducing the multi-layered medium has a plurality of beams whose powers can be independently varied, and the medium temperature can be exchange-coupled by the first light spot running at the beginning. such temperature is raised, by the medium temperature high-temperature portion is shifted to the rear than the light spot, the light magnetic surface from the non-high-temperature portion in the light spot
The second recorded information recorded on the gas film is reproduced, and the magneto-optical information of the deep layer is generated when the high temperature portion of the medium is naturally cooled.
And magnetically transferring first information recorded in the film in the magneto-optical film on the surface, reproduces or erases the first information by the light spot running backward.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction content]

[0048]

In the present invention, the deep layer of the multilayer magneto-optical medium is
The intermediate value stored in advance in the magneto-optical film can be freely reproduced by adjusting the optical power during recording by exchange coupling magnetic transfer.
It can be transferred to the magneto-optical film on the applied surface . Therefore, it is possible to write multilevel information (gray level) by optical modulation recording.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction content]

[0049] Also, an intermediate value that is previously stored in the magneto-optical film of the deep, the I Ri vanishing prudent to exchange coupling magnetic transfer can be transferred to the magneto-optical film of freely surfaces in the regulation of the optical power. Therefore, when magnetic field modulation recording is performed, it is
The magneto-optical film on the surface can be magnetized, and when the external magnetic field is not modulated, it is possible to write multi-valued information (gray level) in an erased state.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0050

[Correction method] Change

[Correction content]

[0050] Also, an intermediate value that is previously stored in the magneto-optical film of the deep, when recording by rig Rereberu the exchange coupling magnetic transfer can be transferred to the magneto-optical film of freely surfaces in the regulation of the optical power. Therefore, you can magnetize the magneto-optical film of the surface in the direction of the outer <br/> unit magnetic field when performing magnetic field modulation recording, multivalued information by the exchange coupling magnetic transfer by light modulation (gray level)
It is possible to write

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction content]

Also, video information, audio, program data
Etc. , optical modulation recording is performed by raising the medium temperature above the Curie temperature of the deep magneto-optical film , and search information that does not need to be stored once it has been read is stored above the Curie temperature of the magneto-optical film on the surface. Recording is performed by heating the medium to a temperature below the Curie temperature of the deep magneto-optical film, and at the temperature of the medium that does not cause exchange-coupling magnetic transfer during reproduction, only the above search information is reproduced, and exchange-coupling magnetic transfer occurs. By reproducing at the medium temperature, the information stored in the deep magneto-optical film is reproduced.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction content]

Further, by performing magnetic field modulation recording, it is possible to obtain a deep magneto-optical field.
Overwrite recording on the gas film and the magneto-optical film on the surface .

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction content]

[0053] Also, when the first light spot running the head heats the medium exchange coupling magnetic transferable temperature, the temperature distribution is shifted to the rear than the light spot, the table at this time
Reproduces the data of the magneto-optical film surface, the second light spot runs behind the first light spot by the laser power to the extent that does not cause the exchange coupling magnetic transfer, the deep after the exchange coupling magnetic transfer light Reproduce the data stored in the magnetic film .

[Procedure Amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0054

[Correction method] Change

[Correction content]

By inserting a diffraction grating in front of the objective lens in the optical head, the light beam is split, and exchange-coupling magnetic transfer is performed by the 0th-order light capable of concentrating the laser power. The information stored in the magneto-optical film on the surface before the exchange coupling is reproduced by the first-order diffracted light focused on
The information stored in the deep magneto-optical film after the exchange coupling is reproduced by the first-order diffracted light collected after the zero-order light.

[Procedure Amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0068

[Correction method] Change

[Correction content]

The Curie temperature of each of the multilayered magneto-optical disks 15 using the multilayered medium having the intermediate value storage layer 4 is T4>T2>T1> T as shown in FIG. 1 (c).
Since the relationship is 3, the external magnetic field is applied to raise the medium temperature Td to T4>Td> T2 by the laser power, and then natural cooling is performed, whereby a magnetized region smaller than the light spot is transferred to the first layer 7. It becomes possible. This is based on the same principle as that of a conventional optical modulation overwrite medium that employs a magnetic four-layer film and does not require an initializing magnetic field, and uses an effective magnetic field due to the exchange coupling force from the intermediate value storage layer 4 as an initializing magnetic field. Instead, use a magnetized region smaller than the light spot diameter, that is, intermediate value information.

[Procedure Amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0069

[Correction method] Change

[Correction content]

In FIG. 3, the first layer 7 is a laser beam.
It is in contact with the transparent base (the base is not shown in the figure)
However, before the light irradiation, the transition metal spins of the second layer 6 and the third layer 5 are caused by the exchange coupling force to the intermediate value storage layer 19.
It is aligned with. Next, when the external magnetic field 18 is reversed to raise the medium temperature Td to T2>Td> T1 and then low-level light for natural cooling is irradiated, it contributes to reproduction.
Since the spin of the magneto-optical film 7 on the surface is aligned with the second layer 6, the "intermediate value" is recorded.

[Procedure 18]

[Document name to be amended] Statement

[Name of item to be corrected] 0070

[Correction method] Change

[Correction content]

Further, when the medium temperature Td is raised to T4>Td> T2 and then high-level light for natural cooling is irradiated, the Curie temperature of the third layer 5 is low, so that the light of the deep layer is not irradiated.
The magnetization of the second layer 6 and then the magneto-optical film 7 on the surface that contributes to reproduction was reversed by the recording magnetic field without being affected by the intermediate value storage layer 19 which was a magnetic film , and was aligned in the direction of the external magnetic field 18. "1" is recorded.

[Procedure Amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction content]

At this time, when the temperature further cools to below the Curie temperature T3 of the third layer 5, the exchange coupling force causes the deep layer
The spins of the second layer 6 are initialized along with the intermediate value storage layer 19 which is the magneto-optical film . Further, in the portion where T3> Td, the magnetization direction in the original erased state remains. That is, when the emission power of the light spot is at the reproduction level, the magnetization direction "0" that was initially erased remains. As a result, it becomes possible to record three values of the magnetization direction in the erased state, the magnetization direction at the time of recording, and the intermediate value in which a fine magnetization region exists. Here, the third layer 5 is a deep magneto-optical film only at a low temperature that requires initialization.
It plays the role of a switch that allows the effective magnetic field from the value storage layer 19 to work.

[Procedure amendment 20]

[Document name to be amended] Statement

[Name of item to be corrected] 0072

[Correction method] Change

[Correction content]

In this case, a magnetized area smaller than the light spot stored in the intermediate value storage layer 19 is transferred to the magneto- optical film 7 on the surface which contributes to reproduction by exchange coupling magnetic transfer. When this is reproduced by the light spot, as shown in FIG. 4, if the ratios of the upward magnetization and the downward magnetization are almost equal, the directions of the Kerr rotation angles in the reflected light for reproduction are different, so that the light passes through the analyzers 26a and 26b. , Photo detector 25
A reproduced signal obtained by current-voltage converting the two signals received at a and 25b and taking a differential is reproduced as a so-called gray level.

[Procedure correction 21]

[Document name to be amended] Statement

[Correction target item name] 0073

[Correction method] Change

[Correction content]

As an erasing method, as shown in FIG.
First, the direction of the external magnetic field 18 is set to the opposite direction of the recording, and the medium temperature is T4>Td> T2 in the state where the external magnetic field is applied.
As a result, the magnetization of the magneto-optical film 7 on the surface that contributes to reproduction is aligned in the direction of the external magnetic field 18. This is the erased state.

[Procedure correction 22]

[Document name to be amended] Statement

[Correction target item name] 0082

[Correction method] Change

[Correction content]

That is, in FIG. 1, when writing a gray level, the laser power is varied so that the medium temperature Td is T2>Td> T1, and a deep magneto-optical film is used regardless of the external magnetic field of the magnetic field modulation head 1. Some intermediate value storage layer 4
Magnetomagnetism of the surface that contributes to the reproduction of the "intermediate value" stored in
Transfer to film 7.

[Procedure amendment 23]

[Document name to be amended] Statement

[Name of item to be corrected] 0083

[Correction method] Change

[Correction content]

In the direction of the magnetic field generated by the external magnetic field modulation head 1,
When the magneto-optical film 7 on the surface that contributes to reproduction is matched, the laser power is changed and the medium temperature Td is set to T4>Td> T2.
The magneto-optical film 7 on the surface that contributes to reproduction by
Are magnetized in the direction of the magnetic field of the magnetic field modulation head 1.

[Procedure correction 24]

[Document name to be amended] Statement

[Correction target item name] 0086

[Correction method] Change

[Correction content]

Example 4. The above has described the method of storing the intermediate value information necessary for the multi-valued information in the multilayer medium in advance and calling this to the deep magneto-optical film of the multilayer magneto-optical medium at the time of recording. re-using the media
It is also possible to increase the areal recording density by recording different information on the surface magneto-optical film and the deep magneto-optical film that contribute to the reproduction .

[Procedure correction 25]

[Document name to be amended] Statement

[Correction target item name] 0092

[Correction method] Change

[Correction content]

The medium composition at this time was the same as in Example 1.
Each layer can be formed of an amorphous alloy film of a rare earth and a transition metal having perpendicular magnetic anisotropy. For example, the composition of the storage layer 41 of the second data is TbFeCo, and the second storage auxiliary layer 6 is GdDyFeCo. The third control layer 5 is made of TbFe, and the first data storage layer 40 of the magneto-optical film on the surface that contributes to reproduction can be made of TbCo.

Claims (29)

[Claims] 1. A magneto-optical recording material on a substrate is composed of a multilayer film, and by heating the multilayer film to a predetermined temperature, a light spot is irradiated from a layer magnetized in a predetermined direction in advance. The magnetization state is transferred to the layer that contributes to the signal reproduction on the side, and by heating the medium to a temperature higher than the heating temperature, the layer that contributes to the reproduction signal has a property of aligning with the external magnetization direction. In the multi-layered medium having the above characteristic, the pre-magnetized layer of the multi-layered recording medium is magnetized at a density such that a plurality of layers are linearly arranged within the diameter of the light spot used for recording / reproducing, After aligning and erasing the contributing layers in the direction of a constant external magnetic field, the external magnetic field is reversed at the time of recording information on the medium, and the irradiation power of the light spot is changed to "reverse the above". Recording method for a multi-layered magneto-optical disk characterized in that it is magnetized in the "direction of an external magnetic field", "magnetization that enters a plurality of transferred light spot line directions" and "direction of the original external magnetic field in an erased state". . 2. A first memory layer on the side of the substrate for writing and reading information having a Curie temperature of T1 with respect to a magnetic field, which is formed on a disk-shaped substrate made of plastic or glass, and a Curie temperature of T2. A second recording auxiliary layer adjacent to the first storage layer for determining the recording magnetization direction of the information recording layer, and the recording auxiliary layer affects the effect of the initialization layer during recording at high power with a Curie temperature of T3. The third control layer adjacent to the second auxiliary recording layer for recording the magnetization direction of the bias magnetic field without being received, and the Curie temperature of T4
In advance, a fourth intermediate value storage layer adjacent to the third control layer, which is recorded with a density that linearly enters within the light spot diameter used for recording and reproduction, is provided, and the Curie temperature of each of the above is T4> Using a multi-layered magneto-optical disk having a relationship of T2>T1> T3, an external magnetic field is applied to increase the medium temperature Td to T4>Td> T2 by laser power, and then the medium is naturally cooled to be erased. Magnetization of the reversal external magnetic field is performed by reversing the magnetic field to raise the medium temperature to T2>Td> T1 and then naturally cooling the medium value, and raising the medium temperature to T4>Td> T2 and then naturally cooling. The multi-layered magneto-optical disk recording method according to claim 1, wherein the direction is recorded. 3. Each of the layers is formed of an amorphous alloy film of rare earth and transition metal having perpendicular magnetic anisotropy, for example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is GdDyFeCo. And the third control layer is TbF
The recording method for a multilayered magneto-optical disk according to claim 1, wherein the recording medium is made of e and the fourth intermediate value storage layer is made of TbCo. 4. Each of the layers is formed of an amorphous alloy film of a rare earth and a transition metal having perpendicular magnetic anisotropy. For example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is DyFeCo. And the third control layer is TbFeC
The recording method for a multilayered magneto-optical disk according to claim 1, wherein the fourth intermediate value storage layer is made of o and the fourth intermediate value storage layer is made of TbFeCo. 5. The information written in advance in the intermediate value storage layer has alternating magnetization directions, and the resulting information is ternary. A recording method for a multilayered magneto-optical disk as set forth in claim 1. 6. A magneto-optical recording material on a substrate is composed of a multilayer film, and by heating the multilayer film to a predetermined temperature, a light spot is irradiated from a layer magnetized in a predetermined direction in advance. The magnetization state is transferred to the layer that contributes to the signal reproduction on the side, and by heating the medium to a temperature higher than the heating temperature, the layer that contributes to the reproduction signal has a property of aligning with the external magnetization direction. In the multilayer film medium having the above characteristic, the pre-magnetized layer of the multilayer film recording medium is magnetized at a density such that a plurality of layers are preliminarily magnetized in the diameter of the light spot used for recording / reproducing. A recording method for a multi-layered magneto-optical disk, characterized in that when the information is recorded, the external magnetic field is modulated to raise the medium temperature to a predetermined temperature so that the medium is magnetized in the "magnetization direction of the magnetic field modulation head". 7. Before information is recorded, the layer contributing to the reproduction signal is magnetically transferred by raising the temperature to a predetermined temperature so that the layer has the same magnetization state as the previously magnetized layer, and then information is recorded on the medium. At this time, the external magnetic field is modulated to raise the medium temperature to a predetermined temperature, so that the "magnetization direction of the magnetic field modulation head" and the "magnetization that enters in the direction of the light spot line which has been erased in advance" are magnetized. A recording system for a multilayered magneto-optical disk according to claim 6, characterized in that 8. A first memory layer on the side of the substrate for writing and reading information having a Curie temperature of T1 formed on a disk-shaped substrate made of plastic or glass, and a Curie temperature of T2. A second recording auxiliary layer adjacent to the first storage layer for determining the recording magnetization direction of the information recording layer, and the recording auxiliary layer affects the effect of the initialization layer during recording at high power with a Curie temperature of T3. The third control layer adjacent to the second auxiliary recording layer for recording the magnetization direction of the bias magnetic field without being received, and the Curie temperature of T4
In advance, a fourth intermediate value storage layer adjacent to the third control layer, which is recorded with a density that linearly enters within the light spot diameter used for recording and reproduction, is provided, and the Curie temperature of each of the above is T4> Using a multi-layered magneto-optical disk having a relationship of T2>T1> T3, an external magnetic field is applied to raise the medium temperature Td to T2>Td> T1 by laser power, and then natural cooling is performed to transfer an intermediate value. By erasing, the medium temperature is adjusted to T by the light spot while modulating the external magnetic field.
The direction of the external magnetic field was recorded by increasing the temperature to 4>Td> T2 and then naturally cooling, and the medium temperature was made to be T2>Td> T1 by the laser power and then naturally cooled or increased to T4>Td> T2. 7. The recording method for a multilayered magneto-optical disk according to claim 6, wherein the magnetization direction of the reversal external magnetic field is recorded by natural cooling without applying an external magnetic field. 9. Each of the layers is formed of an amorphous alloy film of a rare earth and a transition metal having perpendicular magnetic anisotropy, for example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is GdDyFeCo. And the third control layer is TbF
7. The recording system for a multi-layered magneto-optical disk according to claim 6, wherein the recording medium is made of e and the fourth intermediate value storage layer is made of TbCo. 10. Each of the layers is formed of an amorphous alloy film of a rare earth and a transition metal having perpendicular magnetic anisotropy. For example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is DyFeCo. And the third control layer is TbFe
7. The multi-layered magneto-optical disk recording method according to claim 6, wherein the recording medium is made of Co and the fourth intermediate value storage layer is made of TbFeCo. 11. The information written in advance in the intermediate value storage layer is such that the magnetization directions are alternately different, and the resulting information is ternary. A recording method for a multilayered magneto-optical disk as set forth in claim 6. 12. An optical-magnetic recording material on a substrate is composed of a multilayer film, and the multilayer film is heated to a predetermined temperature,
From the layer pre-magnetized in a predetermined direction, the magnetization state is transferred to the layer that contributes to signal reproduction on the side irradiated with the light spot, and by heating the medium to a temperature higher than the heating temperature, By using a multi-layered film medium having a characteristic that the layer contributing to the reproduction signal has the property of aligning with the external magnetization direction, by modulating the laser light mounted on the optical head at the time of recording by the magnetic field modulation head, By raising the temperature of the signal recording layer so that it aligns with the direction of the external magnetic field without performing the erasing operation, "the magnetization direction of the magnetic field modulation head".
Is recorded, and the medium temperature is increased to a temperature at which exchange-coupling magnetic transfer is possible, whereby the multi-layer magneto-optical disk is magnetized to "magnetization that enters in the direction of the light spot line, which is in a previously erased state". Recording method. 13. A first storage layer on the substrate side for writing and reading information having a Curie temperature of T1 with respect to a magnetic field, formed on a disk-shaped substrate made of plastic or glass, and a Curie temperature of T2. A second recording auxiliary layer adjacent to the first storage layer for determining the recording magnetization direction of the information recording layer, and the recording auxiliary layer affects the effect of the initialization layer during recording at high power with a Curie temperature of T3. The third control layer adjacent to the second recording auxiliary layer for recording the magnetization direction of the bias magnetic field without being received, and the Curie temperature T
4 has a fourth intermediate value storage layer adjacent to the third control layer, which is recorded in advance with a density that linearly enters a plurality of light spot diameters used for recording and reproduction, and the Curie temperature of each of them is T4. Using a multi-layered magneto-optical disk having a relationship of>T2>T1> T3, the medium temperature Td is raised to T2>Td> T1 by the laser power and then naturally cooled to transfer an intermediate value, thereby erasing. , The medium temperature is T4>Td> T2 by the light spot while modulating the external magnetic field.
13. The recording method for a multilayered magneto-optical disk as claimed in claim 12, wherein the direction of the external magnetic field is recorded by raising the temperature to 0.degree. 14. Each of the layers is formed of an amorphous alloy film of rare earth and transition metal having perpendicular magnetic anisotropy. For example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is GdDyFeCo. And the third control layer is Tb
13. The recording method for a multilayered magneto-optical disk according to claim 12, wherein the recording medium is made of Fe and the fourth intermediate value storage layer is made of TbCo. 15. Each of the layers is formed of an amorphous alloy film of a rare earth and a transition metal having perpendicular magnetic anisotropy. For example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is DyFeCo. And the third control layer is TbFe
15. The recording method for a multilayered magneto-optical disk according to claim 14, wherein the recording medium is made of Co and the fourth intermediate value storage layer is made of TbFeCo. 16. The information written in advance in the intermediate value storage layer has alternating magnetization directions, and the resulting information is ternary. A recording method of the multilayered magneto-optical disk as set forth in claim 14. 17. A multi-layered magneto-optical disk, which is formed on a disk-shaped substrate made of plastic or glass and is capable of magnetic transfer by exchange coupling force from a predetermined first data storage layer to a predetermined second data storage layer. A laser that flashes the medium temperature Td by applying an external magnetic field in the opposite direction after erasing the first and second storage layers by applying an external magnetic field to raise the medium temperature and then naturally cooling The first information is recorded by partially raising the temperature to higher than the Curie temperature of the first data storage layer by power and then naturally cooling, and then naturally cooling after raising the medium temperature so that exchange coupling magnetic transfer is possible. A second type of recording method for multi-layered magneto-optical discs. 18. A first information storage layer on the side of the substrate for writing and reading information having a Curie temperature of T1 with respect to a magnetic field formed on a disk-shaped substrate made of plastic or glass, and a Curie temperature of T2. A second recording auxiliary layer adjacent to the first storage layer for determining the recording magnetization direction of the information recording layer, and the recording auxiliary layer affects the effect of the initialization layer during recording at high power with a Curie temperature of T3. Adjacent to the third control layer adjacent to the second recording auxiliary layer for recording the magnetization direction of the bias magnetic field without being received, and to the third control layer in which the Curie temperature is T4 and the second information is recorded. Using a multi-layered magneto-optical disk having a fourth second information storage layer and having Curie temperatures of T4>T2>T1> T3, an external magnetic field is applied to change the medium temperature Td to laser power. By T After erasing the first and second information by raising the temperature to d> T4 and then allowing it to cool naturally, an external magnetic field in the opposite direction is applied to flash the medium temperature Td to partially change Td> T4. The first information is recorded by raising the temperature and then allowing it to cool naturally.
18. The recording method for a multilayered magneto-optical disk according to claim 17, wherein the second information is recorded by raising Td> T1 and then naturally cooling. 19. Each of the layers is formed of an amorphous alloy film of rare earth and transition metal having perpendicular magnetic anisotropy, for example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is GdDyFeCo. And the third control layer is Tb
18. The multi-layered magneto-optical disk recording system according to claim 17, wherein the recording medium is made of Fe and the fourth layer is made of TbCo. 20. Each of the layers is formed of an amorphous alloy film of a rare earth element and a transition metal having perpendicular magnetic anisotropy. For example, the composition of the first storage layer is TbFeCo, and the second storage auxiliary layer is DyFeCo. And the third control layer is TbFe
18. The recording system for a multilayer magneto-optical disk according to claim 17, wherein the recording medium is made of Co and the fourth intermediate value storage layer is made of TbFeCo. 21. The magneto-optical recording material on a substrate is composed of a multilayer film, and the multilayer film is heated to a predetermined temperature,
The above-mentioned magnetization state is transferred from the layer capable of magneto-optical recording to the layer that contributes to signal reproduction, which is the side irradiated with the light spot, and the above-mentioned reproduction is performed by heating the medium to a temperature lower than the heating temperature. In a multilayer film medium having a characteristic that a layer contributing to a signal has a characteristic of aligning with an external magnetization direction, both of the transfer layer and the layer contributing to the reproduction signal of the multilayer recording medium have a constant external magnetic field. After erasing in the same direction, the external magnetic field is reversed at the time of recording information on the medium, the irradiation power of the light spot is changed to record information on the layer to be transferred, and then the reproduction signal is reproduced. By heating the medium at a temperature T1 which is equal to or higher than the Curie temperature of the layer that contributes to the above and is equal to or lower than the Curie temperature of the layer to be transferred, the external magnetic field is reversed after being aligned and erased in the direction of the constant external magnetic field. By blinking the laser, by partially the medium temperature T1, to record the second information layer contributing to the playback signal, multilayer magneto-optical disc recording system. 22. A first layer on the side of the substrate for writing and reading information having a Curie temperature of T1 with respect to a magnetic field formed on a disk-shaped substrate made of plastic or glass, and a Curie temperature of T2 for the first layer. Second auxiliary recording layer adjacent to the first recording layer for determining the recording magnetization direction of the second recording layer, and the recording auxiliary layer is not affected by the initializing layer during recording at high power with a Curie temperature of T3. At the third control layer adjacent to the second auxiliary recording layer for recording the magnetization direction of the bias magnetic field at, and the third control layer adjacent to the third control layer at which the Curie temperature is T4 and the second information is recorded. 4 layers, and the Curie temperature of each of the above is T4>T2>T1> T3.
Using a multi-layered magneto-optical disk having the above relationship, the magnetic field modulation head modulates the external magnetic field and the medium temperature Td.
To increase the temperature to Td> T4 by laser power and then to naturally cool the first information in the first information storage layer, and to raise the medium temperature to T2>Td> T1 and then to naturally cool. And a recording method of a multilayer magneto-optical disk device for recording the second information on the fourth layer. 23. Each of the layers is formed of an amorphous alloy film of a rare earth and a transition metal having perpendicular magnetic anisotropy. For example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is GdDyFeCo. And the third control layer is Tb
23. The recording system for a multilayered magneto-optical disk according to claim 22, wherein the recording medium is made of Fe and the fourth intermediate value storage layer is made of TbFeCo. 24. Each of the layers is formed of an amorphous alloy film of rare earth and transition metal having perpendicular magnetic anisotropy. For example, the composition of the first memory layer is TbFeCo, and the second memory auxiliary layer is DyFeCo. And the third control layer is TbFe
23. The recording method for a multilayered magneto-optical disk according to claim 22, wherein the recording medium is made of Co and the fourth intermediate value storage layer is made of TbFeCo. 25. A multi-layered magneto-optical disk, which is formed on a disk-shaped substrate made of plastic or glass and is capable of magnetic transfer from a predetermined first data storage layer to a predetermined second data storage layer by exchange coupling force. By using one optical head of the magneto-optical disk device for reproducing the above-mentioned multi-layered medium, it has a plurality of beams whose powers can be independently changed, and the medium temperature can be exchange-coupling magnetically transferred by the first light spot running at the beginning. Temperature, and the medium temperature high temperature portion is shifted rearward of the light spot to reproduce the second record information recorded in the second data storage layer from the non-high temperature portion in the light spot, and at the same time, the medium When the high temperature part is naturally cooled, the first information recorded in the first data storage layer is magnetically transferred to the second data storage layer, and the first information is recorded by the light spot running behind. A recording system for a multi-layered magneto-optical disk device characterized by reproducing or erasing information. 26. A second data storage layer on the side of the substrate for writing and reading information having a Curie temperature of T1 with respect to a magnetic field formed on a disk-shaped substrate made of plastic or glass, and a Curie temperature of T2. A second recording auxiliary layer for determining the recording magnetization direction of the information recording layer, and the magnetization direction of the bias magnetic field without the influence of the initialization layer on the recording auxiliary layer at the time of high power recording with Curie temperature T3. Has a third control layer adjacent to the second recording auxiliary layer and a second data storage layer adjacent to the third control layer in which the Curie temperature is T4 and the second information is recorded. However, the Curie temperature of each of the above is T4>T2>T1>
When a multi-layered magneto-optical disk having the relationship of T3 is used, the optical head of the magneto-optical disk device for reproducing the multi-layered medium has a plurality of beams whose powers can be independently varied, and the first light traveling at the beginning The medium temperature is set to T4>Td> T2 by the spot, and the medium temperature high temperature portion is shifted rearward of the light spot, thereby reproducing the information of the second data storage layer from the non-high temperature portion in the light spot and at the same time, the medium When the high temperature portion is naturally cooled, the first information recorded in the second data storage layer is magnetically transferred to the second data storage layer, and the first information is reproduced or erased by a light spot running in the rear. 26. The recording system for a multilayer magneto-optical disk device according to claim 25. 27. The recording system for a multilayer optical disc according to claim 25, wherein the plurality of light spots are emitted from one laser light source and are divided into a plurality by a diffraction grating. 28. The first record information is data such as an image and a sound, and the second data has a code and address information for editing and searching recorded therein. 25. A recording method for a multilayer magneto-optical disk device according to claim 22 or 25. 29. Image or audio data is recorded as the first record information, a data clock is recorded as the second record information, and the first data detection is performed by the data clock. A recording method for a multilayered magneto-optical disk according to claim 22 or 25.