JPH0773519A - Magneto-optical recording medium and magneto-optical recording method using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] Even in a magneto-optical recording medium that reproduces data by utilizing the super-resolution phenomenon, it is possible to record and reproduce the sector management information at a high density and excellently. To enable good recording and playback. [Structure] A clock pit for generating a data clock used when recording data is recorded in advance on a magneto-optical recording medium that reproduces data by utilizing a super-resolution phenomenon. A data clock used when recording the recording data is generated, and the sector management information is recorded in the recording area of the sector management information using this data clock. Similarly, the recording data is recorded in the recording area of the recording data using this data clock. Also, when reproducing sector management information and recorded data, a data clock is generated from clock pits recorded in advance, and the sector management information and recorded data are reproduced based on this.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium and a magneto-optical recording method using the same, and more particularly to a magneto-optical disk capable of recording / reproducing information at high density and sector management information and recording data recording method thereof. Regarding

[0002]

2. Description of the Related Art Optical disk media used for recording and storing computer data, such as magneto-optical disk media, are easy to handle because of their easy handling.
The track is divided into a plurality of sectors and data processing is performed in sector units. Normally, each sector has sector management information including physical addresses such as its track number and sector number.

FIG. 2 shows, as an example, a sector format of the 90 mm magneto-optical disk defined by the ISO standard. In this example, one track is divided into 25 sectors, and each sector 2 has a header section 4 and a recording data section 3. The header section 4 includes a sector mark section (SM) composed of long pits representing the beginning of a sector, data
It is composed of a VFO part in which a close-packed pattern used for generating a clock is recorded, an address mark part (AM) indicating the beginning of the ID part, and an ID part in which address information such as track number and sector number is recorded. . Recorded data part 3
The recording data includes user data of 512 bytes per sector and an error detection code (C of 4 bytes).
RC) and an error correction code (ECC) of 80 bytes are recorded.

Conventionally, the header section 4 is recorded as pre-pits with the same modulation method as the recording data section 3 and with the same recording density.

[0005]

In recent years, various attempts have been made to increase the recording capacity of optical disk media.
One of them is Modified Constant Angular Velocity (MC
It is intended to increase the recording density on the outer circumference by adopting the AV format. Also, by shortening the wavelength of the light source and using an objective lens with a high numerical aperture, the spot diameter of the recording / reproducing beam is miniaturized, and the track
Attempts have also been made to narrow the pitch and increase the linear recording density.

Further, another attempt is made in Japanese Patent Laid-Open No. 3-93.
Data is reproduced using a so-called super-resolution phenomenon as shown in 058. This is a method in which a magneto-optical recording medium having a recording layer that is a multilayer film composed of at least a magnetically coupled reproducing layer and a recording holding layer is used to align the magnetization directions of the reproducing layer, and then the laser beam is applied to the reproducing layer. To raise the temperature of the reproducing layer and reproduce the magnetic signal recorded in the recording holding layer while transferring it to the reproducing layer, thereby making it possible to read a linear recording density without reducing the spot diameter of the recording / reproducing beam. , And to increase the track density.

In addition to this, in this attempt, a reproducing layer is irradiated with a laser beam using a magneto-optical recording medium having a recording layer which is a multilayer film including at least a magnetically coupled reproducing layer and a recording holding layer. By raising the temperature of the reproducing layer, extinguishing the magnetic coupling between the recording retaining layer and the reproducing layer, and reading the recorded data retained in the recording retaining layer from the reproducing layer in the laser light irradiation region excluding the magnetic coupling extinction region. Is also possible.

As described above, it is possible to increase the linear recording density and the track density by using the data reproducing system utilizing these super-resolution phenomena. However, the data reproducing method using the super-resolution phenomenon cannot be applied to the prepit signal, and therefore, when the header portion of the conventional method is reproduced, there arises a problem that a reproduced signal having sufficient characteristics cannot be obtained.

In order to solve this problem, Japanese Patent Laid-Open No. 4-25
There has been proposed a method of recording sector management information at a linear recording density lower than that of recording data, such as 9941.
However, in this case, the following problems will occur. The first problem is that since the sector management information is recorded at a low linear recording density, the area required for recording the sector management information of the same recording capacity is large, and the area for recording the recording data is reduced accordingly. As a result, the volume of recordable record data is reduced.

The second problem is that the sector recording information and the recording data have different linear recording densities, that is, the data clocks of the two differ. In this case, the recording / reproducing apparatus has to prepare two different types of data clocks for recording and reproduction, and switch them between the header section and the data section. As described above, when two kinds of signals having different frequencies exist in the same device, a beat may occur, which may cause an unexpected malfunction. In addition, the data clock is usually the PLL for the reproduced signal.
It is input to the circuit and generated so as to be synchronized with the reproduction signal, but in this case, in the worst case, it is necessary to have two systems of PLL circuits, the circuit becomes very complicated, and the cost of the recording / reproducing apparatus rises. I will end up. Data clock of sector management information is 1 / M of data clock of recording data
If (M is an integer of 2 or more), a frequency divider circuit or the like may be added to the PLL circuit of one system, but even in that case, the circuit becomes complicated as compared with the case of using the same data clock, and recording This will increase the cost of the playback device.

As another means for solving the above-mentioned problem, all information including sector management information is recorded by the same method as the recording data, and the sector management information is reproduced by utilizing the super-resolution phenomenon. A method can be considered. However, this method has the following problems.
In general, a recording / reproducing apparatus used by a user to record / reproduce recorded data is more accurate than a master recording apparatus (a so-called cutting machine) for recording prepits on a glass master, that is, data clock accuracy, stability, and spindle Shaft runout,
The rotation accuracy, rotation jitter, recording beam feed accuracy, feed unevenness, and eccentricity when mounting the recording medium are considerably large. When all information including sector management information is recorded by this recording / reproducing apparatus, the data clock of the sector management information to be recorded has a large deviation and jitter from the reference value of the frequency, and in addition, Since the shaft runout and the eccentricity when the recording medium is mounted are large, the accuracy of the recording position also deteriorates. In the worst case, not only recording / reproducing cannot be performed by another recording / reproducing apparatus, but also recording / reproducing cannot be performed even with the same recording / reproducing apparatus after mounting / removing the recording medium. At the very least, the compatibility between the recording / reproducing devices will be hindered, and one of the major characteristics of the optical disk, that is, the portability will be impaired. In order to prevent this, a highly accurate and highly stable recording / reproducing device is required, which is expensive.

According to the present invention, in a magneto-optical recording medium of the type in which recorded data is reproduced by utilizing the super-resolution phenomenon, sector management information can be recorded and reproduced with high density and excellent recording data. The purpose is to enable good recording and reproduction.

[0013]

In order to solve the above-mentioned object, in the present invention, prior to recording sector management information and recording data on a magneto-optical recording medium for reproducing data by utilizing super-resolution phenomenon. The clock pits used to generate the data clock used when recording the recorded data are recorded accurately in advance, and the data clock is generated based on these clock pits. The sector management information is recorded by the same recording method as the recording data.

The present invention has at least a reproducing layer and a recording layer, irradiates the reading light while changing the magnetization state of the reproducing layer, and performs magneto-optical reading of the recording in an area smaller than the spot of the reading light. In a magneto-optical recording medium performed by the effect, a clock pit used for generating a data clock used when recording the record data is pre-recorded as a pre-pit before recording the record data.・ Data based on pits
A clock is generated, and the sector management information is recorded as magneto-optical bits in the recording area of the sector management information by using the clock, and the minimum repetition frequency is higher than the minimum repetition frequency of clock pits. Using this magneto-optical recording medium and this magneto-optical information recording medium, a data clock is generated based on clock pits, and the recording data is recorded at the same recording density as that of the sector management information. The method is a magneto-optical recording method.

[0015]

[Function] Since clock pits are recorded in advance with high precision on a magneto-optical recording medium that reproduces data by utilizing the super-resolution phenomenon, it is necessary to generate stable data clocks using these clock pits. Is possible. By recording the sector management information by the same recording method as the recording data using this stable data clock, the sector management information can be recorded at the same high density as the recording data. Further, the stable data clock can be used when reproducing the sector management information and the recorded data, and the sector management information and the recorded data can be reproduced well.

[0016]

EXAMPLES Examples of the present invention will be described below. Figure 1
An example of the continuous groove servo system is shown in FIG. Reference numeral 1 denotes a magneto-optical disk having a magneto-optical recording film of a type which reproduces data by utilizing the above-mentioned super-resolution phenomenon, and information is recorded on a track formed between spiral grooves. At the beginning of each sector, there is a sector mark part (SM) 11 indicating the beginning of the sector and a clock pit part (CLOCK PIT) 8 used to generate a data clock, and these are the entire reproduction beam spot. Pre-pits are recorded at a sufficiently low linear recording density so as to be reproducible by a conventional reproduction method using reflected light from the. Since these pre-pits are recorded by the master recording machine, the recording frequency, jitter, and recording position are very accurate.

The recording pattern recorded in the clock pit portion 8 is 1 / N of the frequency of the data clock used when recording the recording data in the recording data portion 3.
A single pattern (N is an integer of 4 or more) is used. In the case of the above-mentioned super-resolution magneto-optical disk, it is assumed that the linear recording density of recording data can be increased to J times the linear recording density of pre-pits.
On the other hand, the shortest pit period of the recorded data portion differs depending on the modulation method, and the pit interval is (L + 1) data clocks or more and (M + 1) data clocks or less (L, M).
In the case of the pit position recording system, the shortest pit cycle is (L + 1) times the data clock of the recording data. Further, the pit length and space length are not less than (L + 1) data clocks and not more than (M + 1) data clocks (L, M).
In case of pit edge recording system, the shortest pit cycle is 2x
(L + 1) times. Therefore, the frequency of the recording pattern recorded in the clock pit portion is equal to or less than 1 / {JxKx (L + 1)} of the recording frequency of the recording data portion (K is 1 in the pit position recording method and 1 in the pit edge recording method). In this case, 2) is preferable.

At present, the ratio J of the recording data and the pre-pit linear recording density is preferably about 1.3 in practical use.
When the (2, 7) pit position recording method is used, the frequency of the recording pattern recorded in the clock / pit portion is
1/4 or less of the recording frequency of the recorded data portion, 1/6 or less when the (1,7) pit edge recording method is used,
1 if the (2,7) pit / edge recording method is used
/ 8 or less is desirable.

In the future, it is considered that the ratio J of the recording data and the linear recording density of the pre-pits can be increased to 2 or more. For example, when the (2,7) pit position recording system is used,
The frequency of the recording pattern recorded in the clock pit portion is 1/6 or less of the recording frequency of the recording data portion, (1,
It is desirable that the value is 1/8 or less when the 7) pit-edge recording method is used, and 1/12 or less when the (2, 7) pit-edge recording method is used.

The sector mark portion 11 is a pattern that can be discriminated from the pattern recorded in the clock pit portion 8 and can be discriminated without the need to synchronize the data clock. Alternatively, since the pre-pit signal does not exist other than the sector mark portion 11 and the clock pit portion 8, the sector mark portion 11 may be omitted. Following the sector mark portion 11 and the clock pit portion 8, a VFO portion in which a close-packed pattern used for generating a data clock is recorded, an address mark portion (AM) indicating the beginning of the ID portion, and a track number. , An ID part for recording address information such as a sector number is a clock pit part 8
Using the same clock as the data clock generated in step 3 and used in the recording data section 3, the magneto-optical signal can be reproduced at a high linear recording density by utilizing the super-resolution phenomenon similarly to the recording data.

In the recording data section 3, by using the same data clock, user data of 512 bytes per sector as recording data together with error detection code (CRC) of 4 bytes and error correction code (ECC) of 80 bytes. Is recorded. The data clock used here is very accurate and stable because it is generated from the clock pits of the clock pit portion 8 recorded with extremely high precision, and therefore, the VFO portion, the ID portion, AM section,
The data recorded in the recording data section is also accurately recorded.

Further, if the VFO section and the subsequent sections are made to be the same as the current sector format, the reproducing circuit currently used can be diverted by changing only the data clock, leading to a reduction in the cost of the recording / rewriting device. Of course, the recording density may be improved by omitting the VFO section at the beginning. FIG. 3 shows a sector of one embodiment of the sample servo system.
Indicates the format. Track 5 is composed of 40 sectors, and each sector is divided into 76 blocks. At the beginning of each block is an access code 6 used for track access and a wobble for tracking servo.
There is a servo bite section 10 consisting of pits 7. In the block 0, following the servo byte portion 10, there are a sector mark portion 11 indicating the beginning of a sector and an ID portion 12 indicating the track number and sector number. In the blocks after the block 1, there is a recording data section 3 in which recording data is recorded following the servo byte section 10.

Here, the clock pit 8 composed of the wobble pit 7 and the last pit of the wobble pit 7 and the head pit of the sector mark portion 11 is recorded as a pre-pit. Further, the interval of the clock pits 8 is set as an interval that does not appear in other parts, this is detected in each sector, the time interval is input to the PLL circuit, and the data clock is used when recording data by multiplying it. Is generated.

For example, a 4/11 code code (however, "1" is represented by 8-bit user data as a combination of 4 "1" s and 7 "0" s) with 11-bit code data.
The maximum interval between "1" and "1" is 13 code bits. In this case, the interval between clock pits must be 14 code bits or more. This is 16 code bits in Fig. 3. Since the intervals of the clock pits 8 are wide enough in this way, even when recording as pre-pits, the reflected light from the entire reproduction beam spot is The wobble pits 7 can be reproduced by the conventional reproducing method used and the linear recording density is sufficiently low so that the conventional reproducing method using the reflected light from the entire reproducing beam spot can be used. In FIG. 3, this is 6 code bits.

A data clock is generated from this clock pit 8, and by using this, while further performing tracking servo based on the wobble pit 7, the sector mark portion 11 and the ID portion 12 are used as recorded data. It records as a magneto-optical signal with the same high linear recording density. Similarly, for the recording data, the same data clock is used for the recording data section 3
To record.

These wobble pits 7 and clocks
Since the pit 8 is recorded by the master recorder, the recording frequency, jitter, and recording position are very accurate. Therefore, the data clock generated based on the clock pit 8 has high stability and small jitter, and the scanning position of the beam spot controlled by the tracking servo based on the wobble pit 7 is also accurate. Therefore, the sector mark, the ID, and the recording data are recorded with high accuracy. This means that when reproducing data, the data can be reproduced stably.

Further, in the case of a super-resolution magneto-optical disk of the type in which the recording film reproduces the magnetic signal recorded on the recording holding layer while transferring it to the reproducing layer, the width of the reproduced magneto-optical mark is narrow. Since it is possible to
As shown in 19532, it is possible to increase the track recording density by alternating wobble pits that generate tracking error signals having polarities opposite to each other and by making the total number per track cycle an odd number. .

FIG. 4 shows a sector format of an embodiment in which the clock pit used in the sample servo system is applied to the continuous groove servo system. A track 5 is formed between the spiral grooves 9, and the track 5 is composed of 40 sectors, and each sector is divided into 76 blocks. At the beginning of each block, there is a clock pit 8 used to generate a data clock. In the block 0, following the clock pit 8, there are a sector mark portion 11 indicating the beginning of the sector and an ID portion 12 indicating the track number and sector number. In the blocks after the block 1, there is a recording data section 3 in which recording data is recorded following the clock pit 8.

Here, the clock pits 8 are recorded as pre-pits at intervals that do not appear in other parts. This is detected in each block, the time interval is input to the PLL circuit, and multiplied to generate a data clock used when recording the recording data. For example, 8-bit user data is represented by 15-bit code data as a combination of 4 "1" s and 11 "0" s.
Using a 15-code code, the longest interval between "1" and "1" is 18 code bits. In this case, the spacing between clock pits must be 19 code bits or more. In FIG. 4, this is 19 code bits. Since the intervals between the clock pits are sufficiently wide as described above, even if the recording is performed as pre-pits, the reproduction can be performed by the conventional reproduction method using the reflected light from the entire reproduction beam spot.

A data clock is generated from the clock pit 8 while tracking servo is applied based on the groove 9 and is used to generate the sector mark portion 11 and the ID.
The portion 12 is recorded as a magneto-optical signal at the same high linear recording density as the recording data. Similarly, the recording data is recorded in the recording data section 3 by using the same data clock. These grooves 9
Since the clock pit 8 and the clock pit 8 are recorded by the master recording machine, the position where the groove is formed, the recording frequency of the clock pit 8, the jitter, and the recording position are very accurate. Therefore, the data clock generated based on the clock pit 8 is highly stable and has a small jitter, and the scanning position of the beam spot controlled by the tracking servo based on the groove 9 is accurate. Therefore, the sector mark, the ID, and the record data are recorded with high accuracy. This means that when reproducing data, the data can be reproduced stably.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a sector format of an information recording medium according to the present invention.

FIG. 2 is a diagram showing an example of a sector format of a magneto-optical disk.

FIG. 3 is a diagram showing another embodiment of the sector format of the information recording medium according to the present invention.

FIG. 4 is a diagram showing another embodiment of the sector format of the information recording medium according to the present invention.

[Explanation of symbols]

 1 Magneto-optical disk 2 Sector 3 Recording data part 4 Header part 5 Track 6 Access code 7 Wobble pit 8 Clock pit 9 Groove 10 Servo byte part 11 Sector mark part 12 ID part

Claims (5)

[Claims] 1. A read-out light is irradiated while changing a magnetization state of the read-out layer, which has at least a read-out layer and a recording layer, and read-out of recording is performed by a magneto-optical effect in an area smaller than a spot of the read-out light. In the magneto-optical recording medium to be performed, a clock pit used for generating a data clock used when recording the record data is recorded in advance as a pre-pit before recording the record data. A data clock is generated based on the pits, and the sector management information is recorded as magneto-optical bits in the sector management information recording area using this.
A magneto-optical recording medium characterized in that its minimum repetition frequency is higher than the minimum repetition frequency of clock pits. 2. The repetition frequency of clock pits is
2. The magneto-optical recording medium according to claim 1, which is 1 / N (N is an integer of 4 or more) of a data clock used when recording the recording data. 3. A groove for detecting a tracking error is provided between or on recording tracks spirally or concentrically formed, and recording data is recorded on this recording track. The magneto-optical recording medium according to claim 1, which is a continuous groove servo system. 4. A sample servo having a large number of wobble pits for detecting a tracking error on a recording track formed spirally or concentrically, and recording data is recorded on this recording track. Method claim 1 or 2
The magneto-optical recording medium described in. 5. The magneto-optical information recording medium according to claim 1, a data clock is generated based on clock pits, and recording data is recorded at the same recording density as the sector management information. A magneto-optical recording method characterized by the above.