JP2002133785A - Data recording reproducing method, data processing device, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the data record capacity of a storage medium by properly performing data reproduction even when the track pitch of the storage medium is reduced. SOLUTION: Data are recorded on the storage medium D having a plurality of tracks 50 and 51, and the data are reproduced by this method. The recording methods and/or reproducing methods of data for adjacent tracks 50 and 51 of the storage medium are made different from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recording medium such as a magneto-optical disk, an optical disk, and a magnetic disk;
The present invention relates to a data recording / reproducing method for a recording medium and a data processing device such as a magneto-optical disk device.

[0002]

2. Description of the Related Art In the field of storage such as magneto-optical disks, optical disks, and hard disks, the data recording capacity of recording media has been rapidly increasing in recent years. For example, in the field of a read-only optical disk represented by a CD, the data recording density has been increased by shortening the wavelength of laser light used for reproduction and increasing the numerical aperture of an objective lens that focuses the laser light. . Also, in the magnetic recording field represented by a hard disk, the areal density has been increased by downsizing a magnetic head used for recording / reproducing. Further, in a so-called removable rewritable type recording medium represented by a magneto-optical disk, a magnetic super-resolution method ((Magnetically induced
Super Resolution (MSR), hereinafter abbreviated as “MSR”), has achieved a large recording capacity.

[0003] However, the increase in the recording capacity of a recording medium cannot be said to be sufficient yet, and with the spread of the Internet and the like, there is a demand for a further increase in the recording capacity. There are various means for increasing the recording capacity of the recording medium. One of the means is to reduce the pitch of a track on which data is recorded on the recording medium as much as possible.

On the other hand, conventionally, when data is recorded on a recording medium and the data is reproduced, the same recording / reproducing method has been adopted for all of a plurality of tracks on the recording medium.

[0005]

Conventionally, if the track pitch of a recording medium is reduced in order to increase the recording density, cross writing or crosstalk occurs, and the data recorded on the recording medium cannot be properly reproduced. In some cases, it disappeared. Here, the cross write means that data is also recorded on the next track when data is recorded on the target track, or data on the next track is also erased when data on the target track is erased. This is a phenomenon of erasing. Crosstalk is a phenomenon in which when data recorded on a target track is reproduced, data recorded on an adjacent track is also reproduced. Conventionally, from the viewpoint of preventing the occurrence of such cross writing and cross talk, the track pitch of the recording medium cannot be sufficiently reduced, and increasing the data recording density by miniaturizing the track pitch is not constant. Had the limitations.

As for an effective method for increasing the data recording density of a magneto-optical disk or an optical disk, there is a method called land / groove recording. In this method, data is recorded on each of lands and grooves formed on one surface of a disk substrate. In such a method, when the width of each of the land and the groove is reduced, the problem of the cross light and the cross talk as described above occurs. In addition, in this method, the degree of filling of the component particles constituting the magnetic layer of the land and the groove and the surface roughness of the particles are often different, and the data recorded in the land and the groove are often different. When retrieving reproduced signals, there is also a problem that the quality of the signals is different and it becomes difficult to process them appropriately.

The present invention has been conceived under such circumstances, and enables data to be properly reproduced even when the track pitch of a recording medium is reduced. Accordingly, it is an object of the present invention to increase the data recording capacity of a recording medium.

[0008]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

[0009] A data recording / reproducing method provided by the first aspect of the present invention is a method for recording data on a recording medium having a plurality of tracks and reproducing the data. The data recording method and / or reproduction method for tracks adjacent to each other
It is characterized by being different from each other. The recording medium may be any one of a magnetic recording medium, an optical recording medium, and a magneto-optical recording medium.

[0010] A data processing device provided by the second aspect of the present invention is a data processing device provided with data processing means capable of recording and / or reproducing data on a recording medium having a plurality of tracks. , The data processing means sets a data recording method and / or a reproduction method for tracks adjacent to each other on the recording medium,
It is characterized in that it is configured to be different from each other.

According to such a configuration, since the data recording method and / or the reproduction method are different between the tracks adjacent to each other, for example, data recording or data reproduction for one of two tracks adjacent to each other is performed. When performing, even if the data is recorded on the other track or the data on the other track is reproduced, the data on the other track is clearly differentiated from the above-mentioned one data. Can be excluded so as not to be included in the reproduction data. Therefore, in the present invention, even if the track pitch of the recording medium is smaller than before, data can be appropriately reproduced, and the recording density is increased by miniaturizing the track pitch.
An increase in the recording capacity of the recording medium can be achieved.

In a preferred embodiment of the present invention, the data processing means is configured to be able to record data on tracks adjacent to each other on the recording medium by different modulation code systems.

According to such a configuration, the modulation coding method of data recorded on one track is different from the modulation coding method of data recorded on the adjacent track. When data recorded on one track is reproduced by a predetermined method, even if data of another track is mixed, since the mixed data has a different reproducing method, the mixed data is clearly described. It can be identified and removed.

In another preferred embodiment of the present invention, the data processing means is configured to be able to record data at mutually different bit recording densities on mutually adjacent tracks of the recording medium. .

According to such a configuration, when reproducing data of tracks adjacent to each other, the data can be distinguished based on a difference in bit recording density of the data. Therefore, the operation intended by the present invention can be obtained even with such a configuration.

[0016] In another preferred embodiment of the present invention, the recording medium is a magneto-optical recording medium, and the data processing means performs optical modulation recording on one of adjacent tracks of the recording medium. The system is configured to record data by a method and, on the other hand, to record data by a magnetic field modulation recording method.

According to such a configuration, the width of the data recording portion (recording mark) by the optical modulation recording method can be made smaller than the width of the data recording portion by the magnetic field modulation recording method. Crosstalk can be made less likely to occur when data is reproduced. Further, if each of the light modulation recording method and the magnetic field modulation recording method is used as the data recording method, it is suitable to make the reproduction methods of the data recorded by those methods different from each other.

In another preferred embodiment of the present invention, the recording medium is an optical recording medium or a magneto-optical recording medium, and the data processing means forms an elliptical laser spot on each of the tracks. Thus, the recording and reproducing processes of data on each track on the recording medium are performed, and when performing the reproducing process of each data of tracks adjacent to each other on the recording medium, the laser The ellipse of the spot is configured to be different in the major axis direction.

According to such a configuration, when performing data reproduction processing on two tracks adjacent to each other, the major axis directions of the ellipses of the laser spots formed on those tracks are different from each other. The state of the temperature distribution at the place where the laser spot is formed is also different. Therefore, for example, when data is reproduced by a domain wall movement detection method (described later) or another MSR method other than this, it is possible to realize appropriate data reproduction based on the difference in the temperature distribution.

In another preferred embodiment of the present invention, the recording medium is formed with lands and grooves adjacent to each other, and the data processing means records data on each of the lands and grooves. It is configured to be able to perform reproduction.

According to such a configuration, since each of the land and the groove of the recording medium is used as a data recording area, it is advantageous to increase the recording capacity of the recording medium. As described above, the quality of the signal obtained from the data (recording mark) stored in the land and the groove often differs, but in the present invention, the characteristics of the land and the groove are different from each other. Since a suitable data recording method or data reproducing method can be adopted, an appropriate data recording / reproducing process can be realized.

In another preferred embodiment of the present invention, when data is recorded on each track of the recording medium, the data processing means also transmits data on a recording method or a reproduction method corresponding to the recording method. It is configured to record on the recording medium.

According to such a configuration, when reproducing the data recorded on the recording medium, it is possible to previously confirm the data recording method for each track or the reproducing method suitable for recording the data. it can. Therefore, it is convenient to quickly and appropriately perform the data reproduction processing of each track.

The recording medium provided by the third aspect of the present invention has a plurality of tracks, and at least a part of the plurality of tracks is a recording medium on which desired data is recorded. In addition, data recorded on tracks adjacent to each other among the plurality of tracks is recorded by different recording methods.

In a recording medium having such a configuration, 1
When data is reproduced from one track, even if the data of the adjacent track is read and mixed at the same time, the mixed data can be separated and removed based on the difference in the recording method. Therefore, even if the track pitch is reduced, appropriate data reproduction can be performed. Also in this recording medium, it is possible to adopt a configuration in which data is recorded with respect to the data recording method or the reproduction method corresponding to the recording method. By doing so, it is possible to quickly and accurately detect a reproduction method corresponding to the data recording method of each track, and to appropriately perform data reproduction for each track.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows an example of a schematic configuration of a magneto-optical disk device as a data processing device according to the present invention.

As shown in FIG. 1, the magneto-optical disk drive A includes a laser beam emitting section 1, a light detecting section 2,
It comprises a spindle 44 for rotating the magneto-optical disk D at a high speed, a head unit 4, and other units to be described later. The laser beam emitting section 1, the light detecting section 2, and the head section 4 are sections for realizing data recording processing and reproduction processing on the magneto-optical disk D, and constitute an example of a data processing means according to the present invention. I have.

The laser light emitting section 1 makes the light emitted from the laser light source 10 incident on the collimator lens 12 so as to be collimated, and then passes through the beam splitter 13 and the quarter-wave plate 14 so as to pass through the galvanomirror 40. It is configured to proceed toward. The laser light source 10 can emit a pulse at a predetermined timing under the control of the driver 10A.

The head unit 4 has an objective lens 42 for converging the laser beam reaching the galvanometer mirror 40 to form a laser spot Ls on the magneto-optical disk D, and a slider 41 for holding the objective lens 42. are doing. The slider 41 is supported by a swing arm 45 via a suspension 43. When the magneto-optical disk D is rotated at a high speed by the spindle 44, air is generated between the slider 41 and the surface of the magneto-optical disk D. It is configured to float above the magneto-optical disk D at a small interval by the flowing action. The head unit 4 moves in a tracking direction of the magneto-optical disk D (orthogonal to a track of the magneto-optical disk D described later) in accordance with the swing operation of the swing arm 45 in the direction of the arrow N1 so that a so-called seek operation and a tracking control operation can be performed. Direction). Although not shown in the drawing, the head unit 4 is also provided with a magnetic head for generating a magnetic field at the position where the laser spot Ls is formed. The direction of the magnetic field generated by this magnetic head,
In addition, the switching on and off can be controlled at high speed.

As shown in FIG. 2, a transparent substrate 52 made of, for example, polycarbonate is used as the magneto-optical disk D.
Is formed such that a land 50 and a groove 51 are formed adjacent to each other on one side of the substrate. Each of the land 50 and the groove 51 is a portion corresponding to a track for recording data, and is provided in a spiral shape or a plurality of concentric circles. Each of the land 50 and the groove 51 has a structure in which a plurality of magnetic layers and non-magnetic layers made of a predetermined material necessary for recording and reproducing data are provided in a stacked manner.

The magneto-optical disk D is, for example, a CAD
(Center Aperture Detection) system. As shown in FIG. 3, for example, this medium has a reproducing layer 60 and a recording layer 6 on one surface of a transparent substrate (not shown).
1 is laminated, and the reproducing layer 60 becomes an in-plane magnetic film at room temperature and becomes a perpendicular magnetic film at 100 to 150 ° C. The recording layer 61 is composed of a perpendicular magnetization film. Actually, by providing an intermediate layer between the reproducing layer 60 and the recording layer 61, control of exchange coupling is facilitated. Further, a protective layer for protecting the reproducing layer 60 and the recording layer 61 and the like are provided as appropriate. This CA
In the D method, as shown in the figure, when the magneto-optical disk D moves and a temperature distribution occurs in the laser spot forming region, in the high temperature region, the reproducing layer 60 changes from an in-plane magnetic film to a perpendicular magnetic film, The magnetization of the recording layer 61 is transferred to the reproducing layer 60 by the exchange coupling force. In the low-temperature portion of the laser spot, since the reproducing layer 60 is an in-plane magnetic film, the information of the recording layer 61 in this portion is covered. Therefore, in the CAD method, data can be read only from a high-temperature area smaller than the laser spot diameter.

In FIG. 1, the processing of the recording data is performed by the signal processing unit 3. The signal processing unit 3 includes a modulation and coding unit 30. The recording data input to the signal processing unit 3 from the outside includes an NRZI modulation code,
The modulation coding can be performed by a method selected on the side selected from the (1, 7) RLL modulation code. Both of these two types of modulation coding systems are known. In the NRZI modulation coding system, as shown in FIG. 4, when the basic period of data is T, both the discrimination window width and the shortest magnetization reversal interval are set. T and the longest magnetization reversal interval is infinite. On the other hand, the (1,7) RLL modulation coding system has a valve window width of 2T / 3 and a minimum magnetization reversal interval of 4T.
T / 3, and the longest magnetization reversal interval is 16T / 3. When recording data on the magneto-optical disk D, the signal processing unit 3 modulates and encodes the data to be recorded on the land 50 by the NRZI method, and (1, 7) on the data to be recorded on the groove 51. RL
The modulation coding is performed by the L method.

The light detecting section 2 is configured to receive, by the light receiving section 20, light returned to the beam splitter 13 by being reflected by the magneto-optical disk D. Then, based on the deflection angle, a reading signal of the recording data is output from the light detection unit 2. This read signal is amplified by an amplifier (not shown) and then filtered by filters 21a and 21b.
And then demodulation and decoding unit 22
a, 22b. The demodulation / decoding sections 22a and 22b correspond to the NRZI modulation coding scheme and the (1,7) RLL modulation coding scheme, respectively. Therefore, the signal read from the land 50 is transmitted to the demodulation and decoding unit 2 corresponding to the NRZI modulation coding system.
Reproduced data is obtained by demodulation and decoding by 2a. On the other hand, the signal read from the groove 51 is demodulated and decoded by the demodulation / decoding unit 22b corresponding to the (1, 7) RLL modulation coding method, thereby obtaining reproduction data. These reproduced data are sent to the signal processing unit 3
Once, and the data output order can be arranged and then output to the outside.

Next, in the first embodiment of the data recording / reproducing method according to the present invention, the above-described magneto-optical disk drive A
The case where is used will be described as a specific example.

First, data recording processing on the magneto-optical disk D is performed by, for example, a magnetic field modulation method, and data recording is performed on each of the land 50 and the groove 51 as shown in FIG. Symbols M0 and M1 indicate the recording marks. In the magnetic field modulation method, the recording marks M0 and M1 can be formed in a smaller size than the laser spot if the light emission timing is appropriately controlled by causing the laser light source 10 to emit pulses. In this case, one of the two ends of the recording marks M0 and M1 bulges in an arc shape, and the other has a concave shape in an arc shape.

In the data recording process described above, data modulated and coded by the NRZI method with the shortest mark length of, for example, 0.235 μm is recorded on the land 50. On the other hand, in the groove 51, data modulated and coded by the (1,7) RLL method in which the shortest mark length is, for example, 0.31 μm is recorded. Along with such a data recording process, the magneto-optical disk D also records data indicating the contents of the modulation coding scheme of the data recorded on the land 50 and the groove 51, respectively. Since the magneto-optical disk is provided with a pre-format portion in which servo information, address information, and the like are written, data on the above-described modulation code system may be written in the pre-format portion in advance. This data writing only needs to be executed at the beginning of the start of use of the magneto-optical disk D, unless the content of the modulation coding method is changed thereafter.

Next, the reproduction of the data recorded on the magneto-optical disk D is performed by the CAD method described with reference to FIG. For the signal read from the land 50, for example, 10 KHz to 11M
After narrowing down to the Hz band, demodulation and decoding are performed by the demodulation and decoding unit 22a. On the other hand, the signal read from the groove 51 is narrowed down to a band of, for example, 10 KHz to 15 MHz by the filter 21b, and then demodulated and decoded by the demodulation and decoding unit 22b.

If the widths of the land 50 and the groove 51 are small, for example, when data is read from the land 50, the data of the adjacent groove 51 may be read at the same time. However, the modulation and coding scheme of the data recorded on the land 50 is different from that of the data recorded on the groove 51, and the band of the main signal read from the land 50 is
Is different from the band of the noise signal read from Therefore, such a noise signal can be distinguished from the main signal read from the land 50, and this can be eliminated. Specifically, the noise signal from the groove 51 can be removed by filtering by the filter 21. Such an operation can be obtained in the same manner when the data recorded in the groove 51 is reproduced.

In the present embodiment, the finally obtained reproduced data does not include the noise data of the adjacent track or has a small amount. Therefore, it is possible to increase the recording density by reducing the track pitch of the magneto-optical disk D, thereby increasing the recording capacity of the magneto-optical disk D. When reproducing data recorded on the magneto-optical disk D, the data written in the pre-format section of the magneto-optical disk D is referred to in advance, so that the data of each of the land 50 and the groove 51 can be reproduced. It is possible to accurately judge whether or not reproduction should be performed by the method. Therefore, it is possible to promptly start an appropriate data reproducing process.

FIG. 6 shows experimental data for the above-described embodiment. The data indicated by the dashed line in FIG. 3 is recorded on the land and the groove of the magneto-optical disk by recording appropriate data modulated and coded only by the NRZI method with the shortest mark length of 0.235 μm. Is the data on the relationship between the recording power at the time of data recording and the bit error rate of the reproduced data when the data is reproduced. The recording power on the horizontal axis represents the recording power when the bit error rate is minimized.
This is a value that has been made dimensionless so as to be zero. In the data shown by the solid line in FIG. 3, appropriate data modulated and coded by the NRZI method with the shortest mark length of 0.235 μm is recorded on the land of the magneto-optical disk, and the shortest mark length is set to 0 in the groove. (1,7) R to be .31 μm
This is data on the relationship between the recording power and the bit error rate of the reproduced data when the land data is reproduced after recording the appropriate data modulated and encoded by the LL method. In this experiment, all the conditions other than the above-mentioned conditions, such as the structure of the magneto-optical disk used and the track pitch, were set to be the same, and the specific method such as the data reproduction method was described in the above embodiment. Was the same as the content of

According to the experimental data shown in FIG. 6, in the range where the recording power is greater than 1.0, the NRZI system (RZI) and (NRZI) data are not recorded on the lands and grooves. 1,7) R
It can be seen that the bit error rate is lower when data modulated and encoded by the LL modulation code system is recorded. From this, it can be understood that making the modulation code schemes of the data recorded on the lands and the grooves different from each other is effective for performing appropriate data reproduction.

Of course, in the present invention, the modulation coding method of the recording data is not limited to the contents of the above embodiment. Instead of the NRZI method and the (1,7) RLL method, another modulation code method such as the FM method, the MFM method, and the (2,7) RLL method can be adopted.

FIGS. 7 and 8 show a second embodiment of the data recording / reproducing method according to the present invention. FIG.
In the following drawings, the same or similar elements as those of the above embodiment are denoted by the same reference numerals as those of the above embodiment.

In this embodiment, the magneto-optical disk D
As domain wall displacement detection (DWDD: Domain Wall Displa
cement detection). This DWDD method is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-114750,
Alternatively, it is disclosed in the paper Tech. Dgst. MORIS 1999, pp. 60-61. More specifically, as shown in FIG. 7, the medium of this system is such that a magnetic layer of a reproducing layer 62, a magnetic domain expansion layer 63, an intermediate layer 64, and a recording layer 65 are laminated on one surface of a substrate 52. It is. The magnetic domain expansion layer 63 has a smaller domain wall resistance than the other magnetic layers, and the intermediate layer 64 has the lowest Curie temperature. The Curie temperature of the recording layer 65 is a perpendicular magnetization film having a higher Curie temperature than the magnetic domain expansion layer 63 and the intermediate layer 64.

In the DWDD system, at room temperature before laser light irradiation, the four magnetic layers are exchange-coupled, and the magnetic domains of the recording layer 65 are transferred to the reproducing layer 62.
At this time, a domain wall 66 exists in each layer between magnetic domains having opposite magnetization directions. Magneto-optical disk D
When the laser spot is irradiated while moving,
In the region above the Curie temperature of the intermediate layer 64, the intermediate layer 64
Is lost and the exchange coupling between the magnetic domain enlarging layer 63 and the recording layer 65 is broken, so that the magnetic domain enlarging layer 63 has no force for holding the domain wall, and moves the domain wall to the high temperature side at high speed. Therefore, a magnetic domain larger than the magnetic domain of the recording layer 65 is transferred to the magnetic domain expansion layer 63. The reproduction layer 62 is a perpendicular magnetization film in which the magnetic domains of the magnetic domain expansion layer 63 are transferred by exchange coupling with the magnetic domain expansion layer 63 in a region below the Curie temperature of the magnetic domain expansion layer 63. On the other hand, the magnetic domain expansion layer 63 of the reproducing layer 62
The portion where the exchange coupling with the substrate is broken becomes an in-plane magnetized film. As a result, a magnetic domain larger than the magnetic domain of the recording layer 65 is obtained in the laser spot, and the magnetic domain located substantially at the front edge of the laser spot can be enlarged and reproduced.

In this embodiment, the magneto-optical disk D
When data is recorded in the groove 51, the shortest mark length L1 of the recording mark M1 is set to 0.1 in the groove 51 as shown in FIG.
Data recording is performed according to the (1,7) RLL modulation coding method with μm. On the other hand, on the land 50, the shortest mark length L2 of the recording mark M0 is set to 0.2 μm (1,7) RLL.
Data recording is performed by the modulation coding method. That is, the bit recording density differs between the land 50 and the groove 51. The data recording process for the land 50 and the groove 51 is, for example, a pulse light emission type magnetic field modulation recording method in which the laser light source 10 emits light at a predetermined timing. The data recording / reproducing process according to the present embodiment includes:
This can be performed by using a magneto-optical disk device having the same basic configuration as the magneto-optical disk device A shown in FIG.
This is the same for other embodiments described later.

When reproducing the data recorded in the land 50 and the groove 51, the data is filtered so as to extract a signal in a frequency band most suitable for the shortest mark length. The land 50 and the groove 51 have different frequency bands for filtering the read signal.
Therefore, for example, even if a signal serving as a noise from the groove 51 is mixed in a read signal from the land 50, the signal serving as a noise is removed due to a difference in the frequency band between the read signal and the data recorded on the land 50. Can be appropriately reproduced. Such an operation can be obtained similarly in the case of reproducing data recorded in the groove 51.

In the present embodiment, the following advantages are obtained in addition to the above points. That is, in general, when data is recorded on each of the land and the groove of the magneto-optical disk, the land and the groove often have different recording / reproducing characteristics. This is because the land and the groove differ in the film quality of the magnetic layer and the like. Also, DWDD
In the method, when a short recording mark is reproduced from a land, an error rate tends to be deteriorated (Japanese Patent Laid-Open No. 10-275369 indicates such a problem). On the other hand, a groove is suitable for reproducing a short recording mark, but when reproducing a long recording mark, a so-called ghost signal serving as noise tends to be easily output. However, in the present embodiment, since the shortest mark length is recorded on the land 50 and the shortest mark length is recorded on the groove 51, the above-described disadvantage is solved. Is also possible.

FIG. 9 shows the results of an experiment performed by the present inventor. The data indicated by reference numerals n1 and n2 in FIG. 1 are recorded as data modulated and coded by the (1,7) RLL method with the shortest mark length of 0.15 μm on each of the land and groove of the magneto-optical disk. Thus, the data on the relationship between the reproduction power and the bit error rate of the reproduction data when the data of each of the lands and grooves is reproduced. On the other hand, the symbols n1 ′, n
The data indicated by 2 'indicates that the land has a minimum mark length of 0.2.
μm, and data modulated and coded by the (1,7) RLL method is recorded on the groove, and data modulated and coded by the (1,7) RLL method having the shortest mark length of 0.1 μm is recorded in the groove. Then, it is data on the relationship between the reproduction power and the bit error rate when the data of each of the lands and grooves is reproduced. Of course, in this experiment, all conditions other than the above-mentioned conditions such as the structure of the magneto-optical disk used and the track pitch were set to be the same, and the specific method such as the data reproduction method was described in the above-mentioned method. The contents were the same as those of the second embodiment.

According to the experimental data shown in FIG. 9, when the bit recording densities of the data recorded on the lands and the grooves are made different, compared to the case where the bit recording densities are not made different, the lands and the grooves have the same reproduction power in the fixed area of both the lands and the grooves. It can be seen that the bit error rate can be reduced.
From this, it can be understood that making the bit recording densities of the data recorded on the lands and the grooves different is effective for performing appropriate data reproduction.

FIG. 10 shows a third embodiment of the data recording / reproducing method according to the present invention.

In the method of this embodiment, the magneto-optical disk D
A medium capable of reproducing data in the DWDD system shown in FIG. 7 is used, and an optical modulation recording system using multi-pulse light emission is used for data recording on the land 50. According to the optical modulation recording method, it is possible to make the width s1 of the recording mark M0 smaller than the track width (the width of the land 50). On the other hand, for recording data in the groove 51, a pulse light emission type magnetic field modulation method is used. In this magnetic field modulation method, the recording mark M1 has a form similar to that described in the above embodiment. Land 50 and groove 51
The modulation coding of the data recorded in the NRZI system is performed in the NRZI system in which the shortest mark length is, for example, 0.235 μm.

In the data reproducing process in this embodiment, the data recorded on the land 50 is
(Front Aperture Detection) method is used for MSR reproduction. In the FAD method, as shown in FIG. 11, by applying a reproducing magnetic field, the magnetization direction of the reproducing layer 66 in the high-temperature region of the laser spot is aligned to perform masking, and the recording layer 68 in the low-temperature region in the laser spot is formed. And the direction of magnetization of the reproducing layer 66 exchange-coupled to the intermediate layer 67. On the other hand, the data recorded in the groove 51 is reproduced by the DWDD method described with reference to FIG. In the DWDD method, no reproducing magnetic field is applied.

According to the method of the present embodiment, the land 50 can be set in a state where the recording mark M0 is not provided to the full track width.
This is preferable for suppressing crosstalk between 0 and the groove 51. In the FAD system, the so-called reproduction power can be relatively small. Therefore, when the data of the land 50 is reproduced by the FAD method, it is possible to suppress the noise from the groove 51 from being mixed due to the small power. On the other hand, when the data of the groove 51 is reproduced by the DWDD method, the reproduction power needs to be relatively large.
Since data of the groove 51 is reproduced because the value of “0” is reduced, it is also possible to suppress the noise from the land 50 from being mixed.

In general, in the case of performing the DWDD reproduction, if the height difference between the land and the groove is small, the magnetic layer on which the domain wall moves is not separated from the magnetic layer of the adjacent groove on the land. However, there is a problem that it is difficult to reproduce the data of the land. However, in the present embodiment, since the data of the land 50 is reproduced by the FAD method using the reproducing magnetic field, such a problem can be appropriately avoided.

FIG. 12 shows another example of a schematic configuration of a magneto-optical disk device as a data processing device according to the present invention.

In the magneto-optical disk device Aa shown in FIG. 1, a plate 15 having an elliptical opening 15a is provided on the light emitting side of the quarter wavelength plate 14 of the laser light emitting unit 1. However, this is different from the magneto-optical disk device A shown in FIG. The plate 15 is rotatable about the optical axis of the laser beam in the direction of the arrow N2. In the magneto-optical disk device Aa, since the laser light passing through the opening 15a is focused by the objective lens 42,
An elliptical laser spot Ls is formed at a predetermined location on the magneto-optical disk D. The direction of the ellipse can be changed as appropriate by rotating the plate 15 in the direction of the track or in the direction perpendicular thereto.

FIGS. 13 and 14 show a fourth embodiment of the data recording / reproducing method according to the present invention. In the present embodiment, the above-described magneto-optical disk device Aa is used.

In the method of this embodiment, data is recorded on each of the land 50 and the groove 51 of the magneto-optical disk D by a magnetic field modulation method. In this case, the direction of the laser spot Ls is the direction in which the major axis of the ellipse is orthogonal to the track direction in both the land 50 and the groove 51, as shown in FIG. The modulation code system is the same for both the land 50 and the groove 51, and is, for example, the (1, 7) RLL system.

Next, reproduction of each data of the land 50 and the groove 51 is performed by, for example, the DWDD method.
However, at the time of data reproduction of the land 50, the direction of the ellipse of the laser spot Ls is the same as that at the time of data recording, as shown by a virtual line in FIG. On the other hand, at the time of data reproduction of the groove 51, the direction of the ellipse of the laser spot Ls is changed so that the major axis thereof becomes the track direction.

According to such a method, at the time of data reproduction of the land 50, the temperature gradient in the tangential direction of the magnetic layer in the laser spot Ls can be made tight, so that the domain wall movement becomes faster. Therefore, it is possible to reduce the error rate during reproduction by that much. On the other hand, at the time of data reproduction of the groove 51, generally, there is a characteristic that a ghost signal is easily generated. However, according to the above-described method, such a temperature gradient in the tangential direction of the magnetic layer is reduced to reduce such a ghost signal. Defects can be suppressed.

The present invention is not limited to the contents described above. In the present invention, various combinations other than those described above can be adopted as specific data recording methods and data reproduction methods for the recording medium.

The tracks adjacent to each other on the recording medium are not limited to lands and grooves. For example, tracks adjacent to each other may be formed at the same height, and may be separated from each other by V-shaped grooves.

The recording medium is not limited to a magneto-optical disk, but may be a phase-change disk such as a DVD-RAM or a CD-RW, or a magnetic disk. Also,
The recording medium according to the present invention is not necessarily limited to a rewritable recording medium, but may be a write-once recording medium. This is because, even with a write-once system, data can be reproduced with less influence of crosstalk when reading data recorded on the medium.
As described above, in the present invention, the type of the recording medium is not particularly limited. Therefore, the data processing device according to the present invention is not limited to the magneto-optical disk device.
Other optical disk devices or magnetic disk devices represented by hard disks can be used.

[Supplementary Note 1] A method for recording data on a recording medium having a plurality of tracks and reproducing the data, wherein a data recording method and / or reproduction for tracks adjacent to each other on the recording medium. A data recording / reproducing method, wherein the methods are different from each other. [Supplementary Note 2] A data processing device provided with a data processing unit capable of recording and / or reproducing data on a recording medium having a plurality of tracks, wherein the data processing unit includes a plurality of adjacent tracks on the recording medium. A data processing apparatus characterized in that a data recording method and / or a reproduction method for the data are different from each other. [Supplementary Note 3] The data processing device according to Supplementary Note 2, wherein the data processing means is configured to be able to record data on tracks adjacent to each other on the recording medium by different modulation code systems. [Supplementary Note 4] The data processing device according to supplementary note 2, wherein the data processing means is configured to be able to record data at mutually different bit recording densities on tracks adjacent to each other on the recording medium. [Supplementary Note 5] The recording medium is a magneto-optical recording medium,
The data processing means is configured to record data on one of adjacent tracks of the recording medium by a light modulation recording method, and to record data on the other track by a magnetic field modulation recording method. 3. The data processing device according to claim 2, wherein [Supplementary Note 6] The recording medium is an optical recording medium or a magneto-optical recording medium, and the data processing means forms an elliptical laser spot on each of the tracks so that each of the tracks on the recording medium is While performing the recording process and the reproducing process of the data to the, when performing the reproducing process of each data of the tracks adjacent to each other on the recording medium, the major axis direction of the ellipse of the laser spot is different. 3. The data processing apparatus according to claim 2, wherein the data processing apparatus is configured to perform the processing. [Supplementary Note 7] On the recording medium, lands and grooves adjacent to each other are formed, and the data processing means is configured to be able to record and reproduce data on each of the lands and grooves. 7. The data processing device according to any one of supplementary notes 2 to 6. [Supplementary Note 8] The data processing means is configured to, when recording data on each track of the recording medium, also record data on the recording method or a reproduction method corresponding to the recording method on the recording medium. 8. The data processing device according to any one of supplementary notes 2 to 7. [Supplementary Note 9] A recording medium having a plurality of tracks, and at least a part of the plurality of tracks is a recording medium on which desired data is recorded. Recording data recorded in different recording methods. [Supplementary Note 10] The recording medium according to Supplementary Note 9, wherein data on a recording method of the data or a reproduction method corresponding to the recording method is recorded.

[0068]

As will be understood from the above description, according to the present invention, even if the track pitch of the recording medium is reduced, data from adjacent tracks containing no or little noise is obtained. Can be reproduced. Therefore, it is possible to increase the data recording capacity of the recording medium by reducing the track pitch.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a schematic configuration of a magneto-optical disk drive to which the present invention is applied.

FIG. 2 is a sectional view showing a schematic structure of a magneto-optical disk.

FIG. 3 is an explanatory diagram showing a reproduction principle of a CAD system.

FIG. 4 is an explanatory diagram of a modulation code system.

FIG. 5 is an explanatory diagram showing a data recording state in the first embodiment of the data recording / reproducing method according to the present invention.

FIG. 6 is an explanatory diagram of experimental data.

FIG. 7 is an explanatory diagram showing the playback principle of the DWDD system.

FIG. 8 is an explanatory diagram showing a data recording state in a second embodiment of the data recording / reproducing method according to the present invention.

FIG. 9 is an explanatory diagram of experimental data.

FIG. 10 is an explanatory diagram showing a data recording state in a third embodiment of the data recording / reproducing method according to the present invention.

FIG. 11 is an explanatory diagram showing a reproduction principle of the FAD system.

FIG. 12 is a perspective view showing another example of a schematic configuration of a magneto-optical disk device to which the present invention is applied.

FIG. 13 is an explanatory diagram showing a data recording state in a fourth embodiment of the data recording / reproducing method according to the present invention.

FIG. 14 is an explanatory diagram showing the direction of an elliptical laser spot during recording.

[Explanation of symbols]

 A, Aa Magneto-optical disk device (data processing device) D Magneto-optical disk (recording medium) Ls Laser spot 1 Laser light emitting unit 2 Light detecting unit 50 Land 51 Groove

Claims (5)

[Claims] 1. A method for recording data on a recording medium having a plurality of tracks and reproducing the data, the method comprising: recording data and / or reproducing data on tracks adjacent to each other on the recording medium. , A data recording / reproducing method characterized by making them different from each other. 2. A data processing device comprising a data processing unit capable of recording and / or reproducing data on a recording medium having a plurality of tracks, wherein the data processing units are adjacent to each other on the recording medium. A data processing apparatus characterized in that a data recording method and / or a reproduction method for a track are different from each other. 3. The recording medium has lands and grooves adjacent to each other, and the data processing means is configured to be able to record and reproduce data on each of the lands and grooves. The data processing device according to claim 2, wherein 4. The data processing means is configured to, when recording data on each track of the recording medium, also record data on the recording method or a reproduction method corresponding to the recording method on the recording medium. The data processing device according to claim 2, wherein 5. A recording medium having a plurality of tracks, and at least a part of the plurality of tracks on which desired data is recorded, wherein the plurality of tracks are adjacent to each other. A recording medium, wherein data recorded on a track is recorded by different recording methods.