JP3506482B2 - Optical disk apparatus, recording method and reproducing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device, a recording method and a reproducing method thereof.

[0002]

2. Description of the Related Art Magneto-optical disks, which are rewritable optical disks, have already been put to 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. The conventional magnetic field modulation method is disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 3-214447, “Optomagnetic Recording Method”, in which the direction of the magnetic field is made to correspond to the data to be recorded while continuously irradiating the laser beam. It is a method of reversing.

A conventional magnetic field modulation recording method will be described below with reference to the drawings. FIG. 32 shows the basic structure of a conventional magnetic field modulation recording system. In FIG. 32,
Reference numeral 121 is a magneto-optical disk, 122 is a laser beam, and 123 is a magnetic field modulation head.

The magnetic field modulation recording method is used for the magneto-optical disk 12
Recording is performed by continuously irradiating the laser beam 122 on the first magnetic field and inverting the direction of the external magnetic field according to the signal. The recording magnetic layer is heated to the Curie temperature or higher by irradiating the region to be recorded on the magneto-optical disk 121 with the laser beam 122. At this time, the direction of the current flowing through the magnetic field modulation head 123, which is provided on the opposite side of the optical pickup with the magneto-optical disk 121 sandwiched, is reversed depending on whether the data to be recorded is "1" or "0". , "N" or "S" magnetic field is generated.

Laser light 122 on the magneto-optical disk 121
The region heated by is separated from the irradiation position of the laser beam 122 as the magneto-optical disk 121 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, it is possible to increase the density to some extent in the line direction, but in this case, since the reproducible pit length and the pit interval depend on the spot diameter of the laser light, there is a limit to the increase in reproduction density. Will be done.

This will be described in detail with reference to FIG.
FIG. 33 shows the MTF (Modulati
on Transfer Function). In general,
The frequency characteristic in recording / reproducing is expressed by MTF which is a transfer function of the optical system. The MTF in the optical system of an optical pickup without aberration is shown in FIG.
It becomes like 3. If the wavelength is λ and the numerical aperture NA of the objective lens is, the spatial frequency at MTF = 0 is represented by 2NA / λ,
This 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 as information. 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, the following super-resolution reproduction method has been proposed.

FIG. 34 is a principle diagram of a high-density reproducing system using the conventional magnetic super-resolution system described in Japanese Patent Application Laid-Open No. 5-73977, "Opto-magnetic recording medium and magneto-optical reproducing method". In the figure, a first magnetic layer 103 having a relatively low coercive force on a transparent substrate 101, and a second magnetic layer 103 having a coercive force higher than that of the first magnetic layer and exchange-coupled with the first magnetic layer 103. Of the first magnetic layer 10 is provided.
3 and the second magnetic layer 105, the first magnetic layer 103
The third magnetic body 104 having a Curie temperature lower than the Curie temperature of the second magnetic layer 105 is provided.

FIG. 35 is a diagram showing how the medium shown in FIG. 34 is reproduced. The upper part of the figure is a schematic view of the vicinity of the optical spot of the medium as seen from the optical head side, and shows the temperature distribution of the optical spot and the portion heated by the optical spot. The middle part of the figure is a schematic view of the vicinity of the light spot of the medium as seen from a cross section parallel to the scanning direction of the light spot, showing the magnetization of each magnetic layer. The lower part of the figure is a schematic diagram showing the light intensity distribution of the light spot and its effective range.

In FIG. 35, when reproducing information, the magnetization of the third magnetic layer 104 is extinguished in a part of the high temperature region of the region irradiated with the light beam to perform a mask function as a super-resolution film. The magnetization of the magnetic layer 103 is oriented in one direction so that the information in the mask area is not detected by the light beam. In this way, by masking a part of the light spot to prevent unnecessary information from entering, it becomes possible to read information with a spatial frequency higher than the cutoff frequency of the optical system, which is called the super-resolution reproduction method. Has been. Further, in such a method in which the mask region is generated in the high temperature portion heated by the light beam, the high temperature portion is generated in the backward direction with respect to the traveling direction of the light beam, so that the effective opening of the light spot is a crescent shape. Become. Such a super-resolution reproduction method will be referred to as "blur erase method".

According to the "magneto-optical recording / reproducing system" disclosed in Japanese Patent Laid-Open No. 5-101472, as shown in FIG.
Information is transferred to the magneto-optical recording medium 115 having at least the reproducing layer 111, the memory layer 112, and the recording layer 113, and the reproducing layer 11 is irradiated by an external recording magnetic field with high light intensity irradiation.
1, the memory layer 112, and the recording layer 113 are magnetized, and the recording information is reproduced only in the high temperature region due to the temperature distribution in the reproduction light spot as shown in FIG. The layer information is read while being transferred to the reproduction layer 111. In this case, the reproducing layer 111 acts as a super-resolution film, and conversely to the case of Japanese Patent Laid-Open No. 5-73977, masks outside the high temperature region. like this,
In the method in which the mask disappears at the high temperature portion heated by the light beam, the high temperature portion is generated from the rear side with respect to the traveling direction of the light beam, so that the effective opening of the light spot has a spindle shape. This kind of super-resolution playback method is called the "start-up method"
I will call it.

As described above, there are a magnetic field modulation recording method capable of high density recording and a magnetic super resolution method capable of high density reproduction. However, since the effective opening is a crescent in the fog-erasing method, the adjacent pits enter the light spot when reproducing as it is as shown in the schematic diagram of FIG. 38 (a). Therefore, even if both the magnetic field modulation recording and the magnetic super-resolution recording are combined, it is difficult to further reduce the reproduction limit pit length with respect to the recording pits having a high density in the linear direction.

For example, FIG. 39 (a) focuses on a specific pit when a pattern obtained when high density recording by magnetic field modulation recording is attempted to be read with a crescent-shaped effective aperture using the super-resolution phenomenon. This is a calculation of the aperture occupancy. In this example, the pit width and the read beam width are set to 1/6 of the laser beam diameter, the horizontal axis represents the read position normalized by the laser beam diameter, and the vertical axis represents the proportion of the focused pit in the effective opening of the read beam. Is shown. This is the case corresponding to FIG. In this example, the occupancy ratio of the focused pit is 50% at maximum.
It can be understood that the information of the pit of interest cannot be read correctly because the information of the pits adjacent in the scanning direction is mixed in the remaining portion. vice versa,
It can be seen that the information of the focused pit appears over several times the pit width and is mixed in the reproduction information of the adjacent pit. Such interference of information between the pits causes a reduction in reproduction signal and unnecessary reproduction jitter.

[0016]

When pits smaller than the light spot are recorded by magnetic field modulation recording,
Crescent-shaped recording pits are recorded on the magneto-optical disk medium. On the other hand, in the above-described fog-erasing super-resolution reproduction, the light spot that substantially contributes to the reproduction has a crescent shape that is opposite to the recording pits described above. It is difficult to reproduce the recording pits of the magnetic field modulation method, and the leading end of the crescent moon overlaps with the rear recording pit, which causes intersymbol interference, jitter, and a decrease in C / N.

Therefore, an attempt was made to improve the C / N by reversing the rotating direction of the magneto-optical disk at the time of recording and at the time of reproducing, but in this case, the recorded data is reproduced upside down. In addition, when the magneto-optical disk has spiral tracks, the head feeding direction is reversed.

When a magnetic field modulation head of the air levitation system is used, the structure of the magnetic field modulation head generally used for a magnetic disk having an air levitation portion on one side corresponds to rotation in only one direction. There was a problem that it could not be done.

Further, in the super-resolution reproducing method, the size and shape of the light spot that substantially contributes to signal reproduction change depending on the reproduction laser power, the linear velocity, and the external magnetic field strength for super-resolution reproduction. There is a problem that the minute pits cannot be read unless the laser power, the linear velocity, and the external magnetic field strength for super-resolution reproduction are maintained at optimum values.

[0020]

[0021]

[0022]

According to a first aspect of the present invention, there is provided control means for controlling the scanning direction of the scanning beam, and data exchange means for writing data in a predetermined block of digital data to be recorded as a reverse data sequence. It was made.

The invention of claim 2 has a control method for controlling the scanning direction of the scanning beam and a data exchange method for writing the data in a predetermined block of the digital data to be recorded as an opposite data sequence.

According to a third aspect of the present invention, a magneto-optical disk having concentric tracks is used, and control means for controlling the scanning direction of the scanning beam and data in a predetermined block of reproduced digital data are arranged in reverse order. Data replacement means for reading as, and track jump control means for jumping to a predetermined track are provided.

[0025]

[0026]

According to a fourth aspect of the present invention, a magneto-optical disk having concentric circular tracks is used, and a control method for controlling the scanning direction of the scanning beam, and data in a predetermined block of digital data to be recorded are set as reverse data rows. The data replacement method for writing and the track jump control method for jumping to a predetermined track are provided.

[0028]

According to a fifth aspect of the present invention, a slider portion for generating buoyancy in the magnetic field modulation head and a slider portion adjacent to the flying portion on the side receiving the buoyancy during recording are used for super-resolution reproduction necessary for super-resolution reproduction. In addition to forming an external magnetic field generating section, a magnetic field modulation head for recording information is formed on a slider section adjacent to a floating section on the side that receives buoyancy during reproduction.

[0030]

[0031]

According to a sixth aspect of the present invention, a trial writing area for recording / reproducing a sync pattern is provided before and after the information recording track, and the reproduction laser power is varied in the trial writing area during signal reproduction. The reproduction laser power is controlled so that the reproduction signal level in the trial writing area is maximized.

According to a seventh aspect of the present invention, a test writing area for recording / reproducing a sync pattern is provided before and after the information recording track, and the rotation speed of a motor for rotating the magneto-optical disk at the time of signal reproduction is changed. The motor rotation speed is controlled so that the reproduction signal level in the trial writing area becomes maximum.

According to an eighth aspect of the present invention, a trial writing area for recording / reproducing a sync pattern is provided before and after the information recording track, and an external magnetic field for super-resolution reproduction is changed in the trial writing area during signal reproduction. Then, the external magnetic field for super-resolution reproduction is controlled so that the reproduction signal level in the trial writing area becomes maximum.

[0035]

[0036]

[0037]

According to the first aspect of the present invention, the recorded data is recorded while the front and rear of the data sequence are interchanged so that the data can be correctly reproduced even in the reverse reproduction.

According to the second aspect of the present invention, the recording data is recorded while the front and rear of the data sequence are interchanged so that the data can be correctly reproduced even in the reverse reproduction.

According to the third aspect of the present invention, the scanning direction is reproduced in the reverse direction of the recording and the reproduction is performed while the front and rear of the data sequence of the reproduced data are interchanged, and the track jump is performed during the reproduction to perform the reverse reproduction. Also works to play properly.

[0040]

[0041]

According to the invention of claim 4 , the data sequence of the record data is recorded while the front and rear of the data sequence are interchanged, and the track jump is performed at the time of recording so that the normal reproduction can be performed even during the reverse reproduction.

[0043]

According to a fifth aspect of the present invention, the taper portions provided before and after the air levitation type magnetic field modulation head guide the air flow so that the air can be normally levitated even in the reverse operation, and super resolution reproduction is performed on the magnetic field modulation head. A magnetic field modulation head for magnetic field modulation is operated at the time of recording, and an external magnetic field generation unit for super-resolution reproduction is operated at the time of reproduction reverse to that at the time of recording.

[0045]

[0046]

According to the sixth aspect of the present invention, the laser power is adjusted by using the trial writing area for recording / reproducing the sync pattern at the time of super-resolution reproduction, and the reproduction is performed with the signal level at the maximum.

According to the seventh aspect of the invention, the linear velocity is adjusted by changing the motor rotation speed by using the trial writing area for recording / reproducing the sync pattern at the time of super-resolution reproduction, and the signal level is maximized. Reproduce.

According to the eighth aspect of the present invention, the external magnetic field for super-resolution reproduction is adjusted by using the trial writing area for recording / reproducing the sync pattern at the time of super-resolution reproduction, and reproduction is performed in the state where the signal level is maximum.

[0050]

【Example】

Example 1. 1 is a block circuit diagram of an optical disk device according to a first embodiment of the present invention. 1 is an optical head, 2 is a magneto-optical disk, 3 is a motor, 8 is an external magnetic field generator for super-resolution reproduction, and 9
Is a reproduction amplifier for amplifying a signal from the optical head, 10 is a demodulation circuit for extracting reproduction data from the reproduction signal, and 11 is a memory for temporarily storing the reproduction data.

FIG. 2 is a schematic view of a magneto-optical disk 2 having spiral tracks. Magneto-optical disk 2
Is the transparent substrate 37 and the super-resolution film 3 formed on the surface thereof.
8, a magneto-optical recording film 39, and a protective layer 40.

FIG. 3 is a flow chart showing the operation of the apparatus.

FIG. 39 and FIG. 4 are examples of the calculation results of the aperture occupancy rate during the forward rotation reproduction in which the magneto-optical disk is rotated in the same direction as during recording, and the reverse rotation reproduction in which the magneto-optical disk is rotated in the opposite direction during recording. .

FIG. 5 shows an example of the experimental result of the signal output at the time of the forward rotation reproduction and the reverse rotation reproduction, and FIG. 6 shows the experimental result of the signal output at the recording frequency and the forward rotation / reverse rotation reproduction. This is an example.

Next, the operation of the first embodiment will be described. In FIG. 1, normal magnetic field modulation writing is performed at the time of writing. Next, regarding the reproducing operation, first, the rotating direction of the magneto-optical disk 2 is reversed to perform the reproducing operation. At this time, by rotating the rotation direction of the magneto-optical disk 2 in the reverse direction, the heat distribution generated in the super-resolution film 38 is reversed to that in the normal rotation, and the heat distribution shown in FIG.
As shown in (d), the crescent pattern of the recording signal,
Match the orientation of the crescent shape of the reproduction spot shape due to the magnetic super-resolution phenomenon. By matching the recording pattern and the reproduction spot shape in this way, it is possible to prevent the information of the pits adjacent in the line direction from being mixed in the reproduction signal and accurately reproduce the signal recorded at high linear density. become.

For example, in FIG. 4, writing is performed so that the writing pit length becomes 1/6 of the laser beam diameter, and the reproducing spot width at the time of reproduction is also 1 / the laser beam diameter.
It is an example of calculating the aperture occupancy rate when super-resolution reproduction is performed so as to be 6. The characteristic (a) in FIG. 4 shows the aperture occupancy ratio when focusing on a specific bit in the case of forward rotation (rotation in the same direction as recording) and corresponding to FIG. 7B, and the characteristic (b) in FIG. 7) shows the opening occupancy ratio when focusing on the specific pit in the case of reverse rotation and corresponding to FIG. 7C. In the forward rotation, the aperture occupancy rate does not reach 50% at maximum in this example, whereas in the reverse rotation, the maximum aperture occupancy rate is 10%.
It is 0%, and it can be seen that the mixing of information in adjacent pits can be reduced.

Next, an example of an experimental result of a reproduced signal at the time of reverse rotation operation will be shown. FIG. 5 shows an example of the reproduction signal, and FIG.
Shows a result of an experiment during forward rotation and FIG. 5B shows a result of experiment during reverse rotation. It can be seen that a higher quality reproduction signal is obtained in the reverse rotation reproduction than in the reproduction signal. FIG. 6 is a diagram showing an example of an experimental result showing the relationship between the recording frequency and the C / N of the reproduction signal. The cutoff of this experimental system (the frequency at which reproduction cannot be performed due to the limitation of the optical spatial frequency) is near the recording pit frequency of 4 MHz, but in the vicinity of the cutoff, it is indicated by the triangle mark compared to the forward rotation reproduction represented by the circle mark. It can be seen that a higher C / N is obtained by the reverse rotation reproduction.

Next, the operation at the time of reproduction will be described using a flow chart. In FIG. 3, first, a signal is reproduced from the magneto-optical disk 2 rotating in the reverse direction via the optical head 1. At this time, the data obtained through the reproduction amplifier 9 and the demodulation circuit 10 is data for one round of the magneto-optical disk 2, but this signal is not directly extracted as reproduction data but is temporarily stored in the memory 11. To be This memory 11
When the data is taken out from the memory 11 by the method of replacing the data address, etc., the front and back of the data are replaced so that the reproduced data is taken out.

Since the magneto-optical disc 2 is rotated in the reverse direction, when the data for one round of the magneto-optical disc 2 is reproduced, the data to be reproduced next is at the position of returning by two rounds. So, do a track jump for 2 tracks,
The reading from the magneto-optical disk 2 is performed again. In this way, the data can be read in the correct order even when the magneto-optical disk 2 is rotated in the reverse direction during recording and during reproduction.

The method for temporarily performing reproduction for one round of the magneto-optical disk 2 has been described above.
N rounds of may be played together, in this case 2n
Of course, you have to jump back a week. It is also possible to read with n multi-beams. In this case, it is necessary to jump to the place where 2n rounds have been returned and perform data replacement work in units of one round or n rounds. Become.

Example 2. FIG. 8 is a block circuit diagram of an optical disk device according to a second embodiment of the present invention, in which 1 is an optical head, 2 is a magneto-optical disk, 3 is a motor, and 4 is a magnetic field modulation head. Further, 7 is a memory for temporarily storing data to be recorded, 15 is a microcomputer, 6 is a modulation circuit for converting the data to be recorded into an actual recording signal, 5 is a magnetic field modulation head 4 according to the recording signal. Is a recording amplifier for operating.

Next, the operation will be described. As shown in the flow chart of FIG. 9, one round of the magneto-optical disk 2 of the data to be recorded at the time of the recording operation is temporarily stored in the memory 7, and the memory 7 is replaced by a method such as exchanging the data address on the memory 7. When data is to be taken out from, the data is taken out so that the front and back of the data are replaced, and the replaced data is written as a recording signal by the magnetic field modulation head 4. Also, in order to reverse the direction of writing data, a track jump of two tracks is performed every time one recording is performed. The information thus written can be read while the data arrangement is normal even when read by the optical head 1 with the magneto-optical disk 2 rotated in the reverse direction during reproduction.

Example 3. In the third embodiment of the present invention, FIG.
A magneto-optical disk 2 having concentric tracks as shown in FIG. FIG. 11 shows a block circuit diagram of the third embodiment. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding portions, 12 is a tracking driver, 13 is a tracking control circuit, and 14 is a position of a light spot upon receiving a signal from a microcomputer 15. It is a track jump circuit that causes a jump. Further, 16 is a motor control circuit, which is configured so that the number of rotations of the motor can be changed as necessary.

Next, the operation will be described. FIG. 12 is a flowchart showing the operation. At the time of reproduction, the rotation direction of the magneto-optical disk 2 is reverse to that at the time of recording, and the reproduction speed is higher than that at the time of recording. First, the data for one round of the magneto-optical disk 2 is read from the magneto-optical disk 2 and stored in the memory 11, so that the front and rear of the data can be exchanged and retrieved by a method such as address exchange.

After that, the data is taken out at a necessary speed. However, since the magneto-optical disk 2 is rotated at a higher speed than that at the time of recording, the data taken into the memory 11 is taken out from the memory 11. It is faster than data and data can be taken out without interruption even during an operation such as a track jump by the track jump circuit 14. Further, when the data is accumulated in the memory 11 too much, the track jump by the track jump circuit 14 is temporarily stopped to stop the reading, and the next track is reproduced when the next need arises.

Example 4. Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 13 is a block circuit diagram showing the fourth embodiment. At the time of recording operation, as shown in the flow chart of FIG. 14, data for one rotation of the magneto-optical disk 2 is temporarily stored in the memory 7, and the modulation circuit 6 is read by replacing the front and rear of the data by a method such as address replacement.
Writing is performed on the magneto-optical disk 2 via the recording amplifier 5 and the data for one round is written, and the next track is jumped if necessary. At this time, since the rotation speed of the magneto-optical disk 2 and the writing speed to the magneto-optical disk 2 are set to be faster than the reading speed of the data to the memory 7, the writing is correctly performed from the next position even during an operation such as a track jump. be able to.

Although the method of temporarily writing data for one round of the magneto-optical disk 2 has been described above, data for n rounds of the magneto-optical disk 2 may be used. It goes without saying that the same can be done by the method of writing in every one sector or every several sectors.

Example 5. Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 15 is a schematic view of the fifth embodiment when viewed from the side with respect to the scanning direction of the slider. 20
Is a slider, and 4 is a magnetic field modulation head embedded in the slider 20. In this embodiment, the taper portion 2 which is a floating portion both front and rear with respect to the scanning direction.
0a and 20c are provided. 20b is a slider 2
It is the bottom of 0. Further, the slider 20 is attached to the magneto-optical disk 2 as shown in FIG.

Next, the operation will be described. First, since the magneto-optical disk 2 is rotated forward during recording, the slider 2
An airflow flows in from the front tapered portion 20a of 0. At this time, the airflow is guided by the taper portion 20a at the front portion of the slider 20 to generate buoyancy, and the slider 20 floats up with the front portion slightly lifted as shown in FIG. 17A. The magnetic field modulation head 4 is placed at a position closest to the magneto-optical disk 2 when flying in forward rotation, and generates a magnetic field necessary for magnetic field modulation recording.

At the time of reproduction, the magneto-optical disk 2 is rotated in the reverse direction so that the flow of the air flow is reversed and flows from the taper portion 20c at the rear portion of the slider 20. In this case, the airflow is guided by the taper portion 20c at the rear portion of the slider 20, and buoyancy is generated to levitate as shown in FIG.

In this way, the bottom portion 20b of the slider 20 is levitated regardless of the rotating direction of the magneto-optical disk 2, and contact with the magneto-optical disk 2 can be avoided. In addition,
Although not shown in the figure, at the time of stop or when the buoyancy is not sufficient, a non-recording band is provided on the disk and a slider is brought into contact with the non-recording band, or a holding device is provided so that the slider contacts the disk. Is designed to prevent

Example 6. Next, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 18 is a schematic view of the slider 20 as seen from the side with respect to the scanning direction according to the sixth embodiment. Reference numeral 8 denotes an external magnetic field generator for super-resolution reproduction, which is mounted at a position closest to the magneto-optical disk 2 during reverse rotation.

Next, the operation will be described. At the time of reproduction, the magneto-optical disk 2 rotates in the reverse direction, and the air flow enters from the taper portion 20c at the rear portion of the slider 20. The airflow is guided to the taper portion 20c at the rear portion of the slider 20 to generate buoyancy,
The slider 20 is levitated. At this time, as shown in FIG. 19B, the slider 20 flies with the rear part slightly lifted, so that the part from the front part of the slider 20 becomes the closest contact point with the magneto-optical disk 2. An external magnetic field generator 8 for super-resolution reproduction is installed at this position, and generates an external magnetic field necessary for reproduction.

At the time of recording, the slider 2 rotates in the forward direction, and the operation reverse to the above is performed. Therefore, as shown in FIG.
The front part of 0 is lifted, and the recording magnetic field of the magnetic field modulation head 4 on the rear side of the bottom part 20b of the slider 20 is applied to the magneto-optical disk 2. At this time, the entire slider 20 is moved at a right angle to the track direction at the time of recording and at the time of reproducing, so that the light spot focusing position can be moved to the positions of the external magnetic field for super-resolution reproduction and the recording magnetic field. Alternatively, on the contrary, the entire optical head 1 may be moved at right angles to the track direction.

In this way, recording and reproduction can be performed by making the slider 20 correspond to the normal and reverse rotation of the magneto-optical disk 2 and moving it to the light spot position or the position of the slider 20 in accordance with the recording / reproducing operation. Becomes

Example 7. Next, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 20 shows a slider 2 showing the seventh embodiment.
It is a schematic diagram at the time of seeing from the side with respect to the scanning direction of 0.
In the seventh embodiment, the magnetic field modulation head 4 is arranged near the center of the slider 20, and the bottom surface of the slider 20 has an arc shape with the magnetic field modulation head as the tip.

Next, the operation will be described. First, since the magneto-optical disk 2 is rotated forward during recording, the slider 2
An airflow enters from the front of 0. At this time, the slider 20
The airflow is guided from the front part of the
0 floats in a posture where the front part is slightly lifted. The magnetic field modulation head is placed in the vicinity of the center closest to the magneto-optical disk 2 when flying, and generates a magnetic field necessary for magnetic field modulation recording.

At the time of reproduction, the magneto-optical disk 2 is rotated in the reverse direction so that the flow of the air flow is reversed and the air flows from the rear portion of the slider 20. In this case as well, the airflow is guided from the rear portion of the slider 20 to generate buoyancy and levitate. In this way, the slider 20 is levitated regardless of the rotating direction of the magneto-optical disk 2, and contact with the magneto-optical disk 2 can be avoided.

Example 8. Next, an eighth embodiment of the present invention will be described with reference to the drawings. In the eighth embodiment, as shown in FIG. 21, both the magnetic field modulation head 4 and the super-resolution reproducing external magnetic field generator 8 are provided near the center of the slider 20, and the magnetic field modulation head 4 and its vicinity are in an arc shape. It is a bottom shape.

Next, the operation will be described. When the magneto-optical disk 2 is normally rotated at the time of recording, an airflow flows in from the front part of the slider 20 and the slider 20 floats. At this time, the closest contact point with the magneto-optical disk 2 is near the center of the slider 20, and the magnetic field modulation head 4 mounted at this position.
Generates an external magnetic field required for recording to record information.

When the magneto-optical disk 2 is reversed during reproduction, the air flow is reversed and flows in from the rear of the slider 20. Although the slider 20 is levitated by this air flow, the closest contact point with the magneto-optical disk 2 is also near the center of the slider 20. Therefore, the external magnetic field for super-resolution reproduction 8 near the center of the slider 20 generates an external magnetic field required for super-resolution reproduction, and the reproduction is performed.

Example 9. Next, a ninth embodiment of the present invention will be described with reference to the drawings. FIG. 22 is a block circuit diagram of the magneto-optical disk apparatus according to the ninth embodiment, and the same reference numerals as those in FIG. 1 denote the same or corresponding portions. The reproduction signal strength from the optical head 1 is taken into the microcomputer 15 through the reproduction circuit 30 and the A / D converter 31. Further, the indication value of the laser power for reproduction is output by the microcomputer 15, and the D / A converter 32, ALP
It is transmitted to the optical head 1 through the C circuit 33.

FIG. 23 is a schematic diagram showing a state of data written on the magneto-optical disk 2. As shown in the figure, it is composed of a sample pit used for controlling the optical head, a trial reproduction area area, a preamble sync address area, and a data area.

FIG. 24 is a flow chart showing the state of laser control in the ninth embodiment. During the reproduction in the trial reproduction area, first, the reproduction circuit 30 from the optical head 1
The reproduction signal level obtained via the A / D converter 3
1 through the microcomputer 15, and then the laser power is checked by the microcomputer 15.
Command to control the ALPC circuit 33 via the D / A converter 32, and increase, for example, 0.1 mW. This allows
If the reproduction signal level is increased, the laser power is further increased, and if the reproduction signal level is decreased by increasing the laser power, then the laser power is reduced. The relationship between the laser power and the reproduction signal intensity is as shown in FIG. 25, and by repeating this, reproduction can always be performed with the optimum laser power.

Example 10. Next, a tenth embodiment of the present invention will be described with reference to the drawings. FIG. 26 is a block circuit diagram of the optical disk device of the tenth embodiment. The same reference numerals as in FIG. 1 denote the same or corresponding portions, and the reproduction signal strength from the optical head 1 is the reproduction circuit 30 and the A / D converter 31. It is taken into the microcomputer 15 through the. Also,
The linear velocity instruction value is generated by the microcomputer 15 and transmitted to the motor 3 through the motor control circuit 16.

FIG. 27 is a flow chart showing the state of linear velocity control in the tenth embodiment. During the reproduction in the trial reproduction area, first, the reproduction circuit 30 from the optical head 1
The reproduction signal level obtained via the A / D converter 3
1, the linear velocity is increased by 0.1% by way of the motor control circuit 16 according to a command from the microcomputer 15. As a result, if the reproduction signal level is increased, the linear velocity is further increased, and if the reproduction signal level is decreased due to the increased linear velocity, then the linear velocity is decreased this time. The relationship between the linear velocity and the reproduction signal strength is shown in FIG.
8 has a relationship as shown in FIG. 8, and by repeating this, reproduction can always be performed at an optimum linear velocity.

Example 11. Next, an eleventh embodiment of the present invention will be described with reference to the drawings. FIG. 29 is a schematic diagram of the external magnetic field strength control for super-resolution reproduction in the eleventh embodiment. The reproduction signal strength from the optical head 1 is the reproduction circuit 30 and the A / D converter 31.
It is taken into the microcomputer 15 through the. The instruction value of the magnetic field output of the super-resolution reproducing external magnetic field generating unit is generated by the microcomputer 15 and transmitted to the super-resolution reproducing external magnetic field generating unit 8 through the D / A converter 35 and the external magnetic field control circuit 36. .

FIG. 30 is a flowchart of the super-resolution reproducing external magnetic field strength control in the eleventh embodiment. During reproduction in the trial reproduction area, first, the reproduction signal level obtained from the optical head 1 via the reproduction circuit 30 is checked by the microcomputer 15 via the A / D converter 31, and then the super-resolution reproduction external The current supplied to the magnetic field generator 8 is increased by 0.1 A by the external magnetic field control circuit 36 via the D / A converter 35 according to a command from the microcomputer 15. As a result, if the reproduction signal level is increased, the current supplied to the super-resolution reproduction external magnetic field generation unit 8 is further increased, and the current supplied to the super-resolution reproduction external magnetic field generation unit 8 is increased. As a result, if the reproduction signal level has decreased, the current flowing through the external magnetic field generation unit for super-resolution reproduction 8 is decreased this time. The relationship between the external magnetic field strength for super-resolution reproduction and the reproduction signal strength is as shown in FIG. 31, and by repeating this, it is possible to always reproduce with the optimum external magnetic field strength for super-resolution reproduction. .

[0089]

[0090]

[0091]

As described above , according to the first aspect of the present invention, the control is performed such that the magneto-optical disk having the spiral track is used and the scanning directions at the time of reproduction and at the time of recording are opposite to each other. Means and a data exchange means for writing the data in a predetermined block of the digital data to be recorded as an inverted data sequence, and the data of the recorded data is exchanged before and after the writing, so that the correct data can be reproduced even in the reverse reproduction. Can be read, and the quality of the reproduced signal can be improved even during high-density recording.

According to the second aspect of the present invention, a magneto-optical disk having spiral tracks is used, the scanning directions during reproduction and recording are controlled to be opposite to each other, and the digital data to be recorded is recorded. Since the data in the predetermined block is set as the reverse data array and writing is performed while the front and rear of the recorded data are exchanged, it is possible to perform the recording so that the data can be correctly read even in the reverse reproduction, and even in the high density recording. The quality of the reproduced signal can be improved.

According to the third aspect of the present invention, a magneto-optical disk having concentric tracks is used, and the control means for controlling the scanning direction during reproduction and the scanning direction during recording are opposite to each other. Since the data replacement means for reading the data in the predetermined block of the digital data as a reverse data arrangement and the means for performing the track jump so as to advance one track per revolution are provided, the data can be read correctly even during the reverse reproduction. Therefore, the quality of the reproduced signal can be improved even at the time of high density recording.

[0094]

[0095]

According to the invention of claim 4 , a magneto-optical disk having concentric circular tracks is used, control is performed so that the scanning directions at the time of reproduction and at the time of recording are opposite, and the digital data to be recorded is recorded. Since the data in the predetermined block of is arranged in the reverse order and the track jump is performed so as to advance one track per lap,
It is possible to perform recording so that the data can be read correctly even during reverse reproduction, and it is possible to improve the quality of the reproduction signal even during high-density recording.

[0097]

According to the fifth aspect of the present invention, taper portions are provided on both the front and rear portions of the slider portion on which the magnetic field modulation head is mounted, so that the slider can float in both forward and reverse rotations. The risk of damaging the magneto-optical disk during reverse rotation is eliminated, and the external magnetic field generation unit for super-resolution reproduction is also mounted on the slider and used as the external magnetic field generation unit for super-resolution reproduction at the time of reproduction. The magnetic field modulation head and the external magnetic field generator for super-resolution reproduction can be levitated.

[0099]

[0100]

According to the invention of claim 6 , the laser power is controlled so that the reproduction signal is maximized by using the trial reproduction area provided on the magneto-optical disk, and the portion contributing to the signal reproduction of the light spot is controlled. Since the size is always constant, the optimum reproduction state can be maintained.

Further, according to the invention of claim 7 , the linear velocity is controlled so that the reproduction signal is maximized by using the trial reproduction area provided on the magneto-optical disk, and the portion that contributes to the signal reproduction of the light spot is controlled. Since the size is always constant,
The optimum reproduction state can be maintained.

According to the invention of claim 8 , the external magnetic field for super-resolution reproduction is controlled so that the reproduction signal is maximized by using the trial reproduction area provided on the magneto-optical disk, and the signal reproduction of the light spot is performed. Since the size of the portion that contributes to the above is always constant, the optimum reproduction state can be maintained.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an optical disk device according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a magneto-optical disk having spiral tracks.

FIG. 3 is a flowchart showing an operation during reproduction in the first embodiment.

FIG. 4 is a diagram showing an example of aperture occupancy calculation focusing on a specific pit during forward rotation and during reverse rotation.

FIG. 5 is a diagram showing an example of an experimental result of a reproduced signal during forward rotation and during reverse rotation.

FIG. 6 is a diagram showing an example of an experimental result of C / N of a recording frequency and a reproduction signal at the time of forward rotation and at the time of reverse rotation.

FIG. 7 is a schematic diagram showing a relationship between a recording pattern and a reproduction spot during forward / reverse rotation reproduction.

FIG. 8 is a block circuit diagram of an optical disk device according to a second embodiment of the present invention.

FIG. 9 is a flowchart showing a write operation according to the second embodiment.

FIG. 10 is a schematic view of a magneto-optical disk having concentric tracks.

FIG. 11 is a block circuit diagram of an optical disc device in Embodiment 3 of the present invention.

FIG. 12 is a flowchart showing an operation during reproduction in the third embodiment.

FIG. 13 is a block circuit diagram of an optical disc device in Embodiment 4 of the present invention.

FIG. 14 is a flowchart showing a write operation according to the fourth embodiment.

FIG. 15 is a schematic diagram of a slider portion according to a fifth embodiment of the present invention.

FIG. 16 is a schematic diagram showing an example of mounting a slider in the fifth embodiment.

FIG. 17 is a schematic diagram showing how a slider floats in Example 5;

FIG. 18 is a schematic diagram of a slider portion according to a sixth embodiment of the present invention.

FIG. 19 is a schematic diagram showing how a slider floats in Example 6;

FIG. 20 is a schematic diagram of a slider portion according to a seventh embodiment of the present invention.

FIG. 21 is a schematic diagram of a slider section according to Example 8 of the present invention.

FIG. 22 is a block circuit diagram of an optical disc device in Embodiment 9 of the present invention.

FIG. 23 is a schematic diagram showing data on a magneto-optical disk in Example 9.

FIG. 24 is a flowchart of laser power control in the ninth embodiment.

FIG. 25 is a schematic diagram showing the relationship between the laser power and the reproduction signal level in Example 9.

FIG. 26 is a block circuit diagram of an optical disk device in Embodiment 10 of the present invention.

FIG. 27 is a flowchart of motor control according to the tenth embodiment.

FIG. 28 is a schematic diagram showing the relationship between the linear velocity and the reproduction signal level in the tenth embodiment.

FIG. 29 is a block circuit diagram of an optical disc device in Embodiment 11 of the present invention.

FIG. 30 is a flowchart of external magnetic field strength control for super-resolution reproduction according to the eleventh embodiment.

FIG. 31 is a schematic diagram showing the relationship between the external magnetic field strength for super-resolution reproduction and the reproduction signal level in the eleventh embodiment.

FIG. 32 is a schematic diagram showing conventional magnetic field modulation writing.

FIG. 33 is a diagram showing an MTF of an optical system.

FIG. 34 is a diagram showing an example of a conventional magnetic super-resolution medium.

FIG. 35 is a schematic diagram showing a state of reproduction by a conventional magnetic super-resolution medium.

FIG. 36 is a diagram showing an example of a conventional magnetic super-resolution medium.

FIG. 37 is a schematic diagram showing a state of reproduction by a conventional magnetic super-resolution medium.

FIG. 38 is a schematic diagram showing a relationship between a recording pattern and a reproduction spot during forward rotation reproduction.

FIG. 39 is a diagram showing an example of calculating an aperture occupancy rate focusing on a specific pit at the time of forward rotation.

[Explanation of symbols]

1 optical head, 2 optical magnetic disk, 3 motor, 4
Magnetic field modulation head, 5 recording amplifier, 6 modulation circuit, 7 memory, 8 super-resolution reproducing external magnetic field generator, 9 reproducing amplifier, 10 demodulating circuit, 11 memory, 12 driver,
13 tracking control circuit, 14 track jump control circuit, 15 microcomputer, 16 motor control circuit, 20 slider, 20a, 20c taper part, 20b bottom part, 30 reproducing circuit, 31 A / D converter, 32 D / A converter, 33 ALPC Circuit, 35 D / A converter, 36 external magnetic field control circuit, 37 transparent substrate, 38 super-resolution film, 39 magneto-optical recording film, 40 protective layer.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI G11B 11/105 566 G11B 11/105 566D 581 581B 581H

Claims (8)

(57) [Claims] 1. An information surface is optically scanned with a scanning beam which forms a scanning spot by focusing on a magneto-optical disk substrate on which tracks are spirally or continuously or intermittently formed, and the scanning beam is irradiated. With the temperature change due to the presence of an area where information can be read and an area where information cannot be read within the scanning spot,
In a magneto-optical recording / reproducing apparatus that records information by a magnetic field modulation head that modulates the external magnetic field of a minute portion of the magneto-optical disk medium to which the scanning spot on the magneto-optical disk substrate is irradiated at the time of recording information, Control means for controlling the scanning directions of the scanning beams during recording and reproduction to be opposite directions, and data exchange means for writing the data arrangement in a predetermined block of digital data to be recorded as the opposite data arrangement. An optical disk device characterized by. 2. An information surface is optically scanned by a scanning beam which forms a scanning spot by focusing on a magneto-optical disk substrate on which tracks are spirally or continuously or intermittently formed, and the scanning beam is irradiated. With the temperature change due to the presence of an area where information can be read and an area where information cannot be read within the scanning spot,
In a magneto-optical recording / reproducing apparatus that records information by a magnetic field modulation head that modulates an external magnetic field of a minute portion of the magneto-optical disk medium irradiated with the scanning spot on the magneto-optical disk substrate during information recording, The scanning direction of the scanning beam at the time of recording and reproduction is controlled to be opposite directions, and the data arrangement in a predetermined block of the digital data to be recorded is reversed as the data arrangement to be written. Optical disc recording method. 3. An information surface is optically scanned by a scanning beam which forms a scanning spot by focusing on a magneto-optical disk substrate on which tracks are concentrically formed continuously or intermittently, and the scanning beam is irradiated. A temperature change due to the temperature change causes an area where information can be read and an area where information cannot be read to exist in the scanning spot, and at the time of recording the information, the magneto-optical disc irradiated with the scanning spot on the magneto-optical disk substrate. In a magneto-optical recording / reproducing apparatus that records information by a magnetic field modulation head that modulates an external magnetic field of a minute portion of a disk medium, control is performed so that the scanning directions of the scanning beam at the time of recording and at the time of reproducing the information are opposite to each other. And a data exchange for reading the data sequence in a predetermined block of the reproduced digital data as a reverse data sequence. An optical disk device comprising means and track jump control means for performing a track jump to a predetermined track. 4. An information surface is optically scanned with a scanning beam which forms a scanning spot by focusing on a magneto-optical disk substrate on which tracks are concentrically formed continuously or intermittently, and the scanning beam is irradiated. A region where information can be read out and a region where information cannot be read out are caused to exist in the scanning spot due to a temperature change due to, and the light irradiated onto the scanning spot on the magneto-optical disk substrate at the time of recording the information. In a magneto-optical recording / reproducing method in which information is recorded by a magnetic field modulation head that modulates an external magnetic field in a minute portion of a magnetic disk medium, the scanning direction of the scanning beam at the time of recording of the information and the scanning direction of the scanning beam at the time of reproduction are reversed. Data entry that controls and writes the data sequence in a predetermined block of digital data to be recorded as the reverse data sequence Alternatively, the optical disk recording method is characterized in that a track jump is performed on a predetermined track. 5. A super-resolution reproduction is performed on a side of a slider portion that receives a buoyant force at the time of recording, in which a taper-shaped floating portion is formed in the front and rear in the scanning direction, and an air flow is passed between the slider and the magneto-optical disk to generate a buoyant force. 4. An optical disk apparatus according to claim 3 , wherein an external magnetic field generating section for super-resolution reproduction, which is required at times, is provided, and a magnetic field modulation head for recording information is provided on the side receiving buoyancy during reproduction. 6. An information surface can be optically scanned by a scanning beam which forms a scanning spot by focusing on a magneto-optical disk substrate, and information can be read into the scanning spot by a temperature change caused by irradiation of the scanning beam. A magnetic field modulation head for allowing an external area and an area from which information is not read to exist and modulating an external magnetic field of a minute portion of the magneto-optical disk medium to which the scanning spot on the magneto-optical disk substrate is irradiated at the time of recording the information. In the magneto-optical recording / reproducing method for recording information by means of the method, the scanning direction of the scanning beam at the time of recording and reproducing the information is reversed, and a sync pattern is recorded and reproduced before and after the information recording track. By providing a trial writing area and changing the laser power in the trial writing area during signal reproduction or recording. Thus, the optical disk reproducing method is characterized in that the laser power is controlled so that the reproduction signal level in the trial writing area becomes maximum. 7. An information surface can be optically scanned by a scanning beam which forms a scanning spot by focusing on a magneto-optical disk substrate, and information can be read into the scanning spot by temperature change caused by irradiation of the scanning beam. Magnetic field modulation head for allowing an external area and an area from which information is not read to exist and modulating the external magnetic field of a minute portion of the magneto-optical disk medium to which the scanning spot on the magneto-optical disk substrate is irradiated at the time of recording the information. In the magneto-optical recording / reproducing method for recording information by the method, the scanning direction of the scanning beam at the time of recording and reproducing the information is reversed, and a sync pattern for recording / reproducing a sync pattern before and after the information recording track is recorded. A test writing area is provided, and the test speed is changed by changing the rotation speed of the motor that rotates the magneto-optical disk during signal reproduction. An optical disk reproducing method characterized in that the rotation speed of the motor is controlled so that the reproduction signal level in the writing area becomes maximum. 8. An information surface can be optically scanned by a scanning beam which forms a scanning spot by focusing on a magneto-optical disk substrate, and information can be read into the scanning spot by a temperature change caused by irradiation of the scanning beam. Magnetic field modulation head for allowing an external area and an area from which information is not read to exist and modulating the external magnetic field of a minute portion of the magneto-optical disk medium to which the scanning spot on the magneto-optical disk substrate is irradiated at the time of recording the information. In the magneto-optical recording / reproducing method for recording information by the method, the scanning direction of the scanning beam at the time of recording and reproducing the information is reversed, and a sync pattern for recording / reproducing a sync pattern before and after the information recording track is recorded. By providing a trial writing area, and changing the external magnetic field generator for super-resolution reproduction in the trial writing area during signal reproduction. The optical disc reproducing method is characterized in that the external magnetic field generator for super-resolution reproduction is controlled so that the reproduction signal level in the trial writing area becomes maximum.