JPH1166749A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reproduced signal whose characteristic is satisfactory by making the number of sectors per track of management information of a medium in which recording frequencies are different in a preformat part and a user data part an integer and making same preformat patterns so as to be adjacent in between adjacent tracks. SOLUTION: A data recording area and a medium information management area are formed on this optical recording medium in accordance with the ISO standard of a 90 mm-magneto-optical disk. However the logical length of the sector of the data recording area shown in the figure (a) is 2615 bytes, in a header part, data are recorded with a frequency half of the clock frequency of a data part and a physical length is equivalent to 126 bytes being double of a logical length and consequently the physical length of this sector becomes 2678 bytes. Besides, however the logical length of the sector of the medium information management area shown in the figure (b) is 1339 bytes, data are recorded with a frequency half of the clock frequency of a data part and the physical length of this sector is made to be 2678 bytes being the same physical length as that of the data recording area. Thus, number of sectors per one track of both areas is made to be an integer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium capable of recording and reproducing information at high density.

[0002]

2. Description of the Related Art Large-capacity optical disks which can be accessed at high speed have remarkably spread as storage media for computer data and recording media for music and images. Among them,
Magneto-optical disks that are often used as storage media for computer data are TbFeCo, GdFeCo
It has an amorphous magnetic film made of, for example, and records data according to its magnetization direction. At the time of recording, a magnetic film whose magnetization has been aligned in one direction is heated by irradiating a laser beam, and at the same time, a recording magnetic field having a reverse direction is applied to form a mark having a reverse magnetization. During reproduction, data is reproduced by rotating the plane of polarization of a linearly polarized laser beam using the magnetic Kerr effect.

In an optical disk used for recording and storing computer data such as a magneto-optical disk, a track formed in a spiral or concentric shape is divided into a plurality of sectors in order to easily handle the data. The data is processed on a sector-by-sector basis. FIG. 2 shows an ISO standard 150 for a 90 mm magneto-optical disk.
41 shows an example of a sector format having a sector recording capacity of 2048 bytes specified in 41.

[0004] In the ISO standard format of a 90 mm magneto-optical disk, a medium information management area (also called a control track, SFP, or the like) in which data necessary for the drive to perform recording / reproducing of the magneto-optical disk is stored. It consists of a data recording area for recording and reproduction. The recording area is divided into zones by the MCAV method. FIG. 2A shows the sector format of the data recording area, and FIG. 2B shows the sector format of the medium information management area.

According to this standard, the data recording area and the medium information management area have exactly the same sector format, but the data recording area has a header portion formed by prepits (preformatted), and the other portions have magneto-optical recording. Thus, data can be recorded and reproduced. On the other hand, the medium information management area is formed by pre-pits in both the header section and other sections. Nothing is recorded in the gap part of the data recording area, but the same pattern as VFO3 is recorded in the gap part of the medium information management area. Nothing is recorded in the buffer unit.

The header section includes a sector mark section (SM) composed of long pits representing the beginning of a sector, a VFO section in which a densest pattern used to generate a data clock is recorded, and an ID section. It comprises an address mark section (AM), an ID section in which address information such as a track number and a sector number is recorded, and the like. In the data portion of FIG. 2A, as data, for example, a 4-byte error detection code (CRC), for example, a 320-byte error correction code (ECC), for example, a 78-byte user data with 2048 bytes of user data per sector. A resync, for example, 8-byte dummy data is recorded.

[0007] In the medium information section of FIG. 2B, information necessary for the drive to perform recording and reproduction on the optical recording medium is recorded. The information recorded in the medium information section includes a modulation method, a servo method, the number of bytes of user data per sector, the interleave length of an error correction code, the number of sectors per track, the reflectance, the maximum reproduction power, and the type of medium. In addition, a track number of a data recording area or a medium information area, a recording / reproducing laser beam wavelength, a recording power, an erasing power, and the like are recorded. The medium information management area is composed of a plurality of tracks, and usually, about 16 tracks are provided on the inner periphery of the disk.

In recent years, data reproduction utilizing the magnetic super-resolution phenomenon has been attempted in order to increase the recording capacity of a magneto-optical disk medium (JP-A-3-93058). This is because, using a magneto-optical recording medium having at least a multilayer film composed of at least a magnetically coupled reproducing layer and a recording holding layer as a recording layer, the magnetization direction of the reproducing layer is aligned, and then the laser light is applied to the reproducing layer. To raise the temperature of the reproducing layer, and reproduce the magnetic signal recorded on the recording holding layer while transferring the magnetic signal to the reproducing layer. Thus, the readable linear recording density can be obtained without miniaturizing the spot diameter of the recording / reproducing beam. And to increase the track density.

Another attempt is to irradiate the reproducing layer with a laser beam by using a magneto-optical recording medium having a recording layer of a multilayer film composed of at least a magnetically coupled reproducing layer and a recording holding layer. By raising the temperature of the reproducing layer, eliminating the magnetic coupling between the recording holding layer and the reproducing layer, and reading out the data held by the recording holding layer from the reproducing layer in the laser beam irradiation area excluding the magnetic coupling disappearance area. It is possible.

[0010]

As described above, if a data reproducing method utilizing these super-resolution phenomena is used,
It is possible to increase the linear recording density and the track density. However, the data reproducing method utilizing the super-resolution phenomenon cannot be applied to the pre-pit signal, and therefore, when reproducing the conventional header portion or medium information management area, a reproduced signal having sufficient characteristics cannot be obtained. The problem arises. As a solution to this problem, Japanese Patent Application Laid-Open No.
9753 proposes a method of recording a preformat area at a lower clock frequency than a data part.

However, in this method, when the clock frequency of the header section and the medium information section, which are the preformat areas in FIG. 2, is reduced and recorded, for example, the sector of FIG. 2B is compared with the sector of FIG. The physical length of the sector (physical sector length) becomes long. At this time, if the clock frequency is set so that the number of sectors per track in the data recording area becomes an integer, the number of sectors per track becomes a non-integer in the medium information management area, and the sector start position may shift for each track. Is high.

Generally, the same information is recorded in all the sectors of the medium information management area. Therefore, if the number of sectors per track is an integer, the same preformat pattern is adjacent between adjacent tracks. However, when the sector start position for each track is shifted, different preformat patterns are adjacent to each other. However, at this time, it was found that a reading error was likely to occur at the time of reproducing the medium information.
FIG. 3 is an explanatory diagram when different preformat patterns are adjacent to each other. Prepit patterns such as prepits 2, 3, 4, and 5 are formed between the plurality of grooves 1.

The preformat is usually performed by applying a photoresist on a glass master or the like, exposing it to a laser to record grooves and prepits as latent images, and then developing the pattern to form a pattern. Since the recording process involves a thermal reaction in addition to a photoreaction, if there are pits of various lengths, the groove 1 adjacent to the long pits 2 and 5 is formed to be slightly wider. There is. Since long-pit exposure is performed by irradiating a laser beam for a long time, heat is accumulated in the periphery, and the thermal reaction of the photoresist is accelerated when forming the groove.

Such a change in the groove width causes a change in the reflectivity during reproduction, which has an adverse effect. In particular, the length of the short pits 3 and 4 of the adjacent track and the length of the space therebetween are easily misread. . As described above, when different preformat patterns are adjacent to each other, there is a very high possibility that the long pits and the short pits are adjacent to each other across the groove, which is a serious problem. Further, when different pit patterns are adjacent to each other, deterioration of a reproduced signal due to crosstalk tends to occur.

Although the sector start position for each track in the medium information management area can be adjusted by changing the recording clock frequency of the medium information management area, the medium information such as the header section of the data recording area and the data section of the data recording area can be adjusted. It is complicated to properly use three types of clock frequencies in the management area. As another problem, when the medium information management area is recorded at a low clock frequency, an area necessary for recording the medium information of the same number of sectors becomes large, and an area for recording data is reduced by that amount, and as a result, In other words, the capacity of data that can be recorded on the media is reduced.

As described above, the present invention solves the problem of the medium information management area which occurs when the preformat area is recorded at a lower clock frequency than the data part, and satisfactorily records and reproduces the medium information management information and data. The purpose is to make it possible.

[0017]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a data recording area in which user data can be recorded and a medium information management area formed in a preformat, and a preformat recording clock frequency of the user data. An optical recording medium lower than a recording clock frequency, wherein a logical length of a sector in the medium information management area is different from a logical length of a sector in the data recording area.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, by making the logical length of the sector in the medium information management area different from the logical length of the sector in the data recording area, the same preformat pattern can be obtained between adjacent tracks with the number of sectors per track being an integer. Be adjacent. Preferably, by making the logical length of the sector in the medium information management area smaller than the logical length of the sector in the data recording area, the same preformat pattern is adjacent between adjacent tracks with the number of sectors per track being an integer. And the medium information management area is kept small.

The logical length can be changed by changing the lengths of various portions inside the sector, but it is relatively easy and preferable to change the capacity of the data portion and the buffer portion. In particular, the logical length of a sector can be greatly changed by changing the recording capacity of the sector, which is the most preferable. More preferably, in order to keep the medium information management area small, the recording capacity of the sector in the medium information management area is made smaller than the recording capacity of the sector in the data recording area.

ISO standard 15 for 90 mm magneto-optical disk
In the case of a medium such as the one defined in No. 041, the same medium information is usually recorded in each sector of the medium information management area, but the data amount of the medium information is 512 bytes or less, and the rest is dummy data. Is buried in Therefore,
There is no problem even if the sector capacity of the medium information management area is reduced. When recording the preformat area at a lower clock frequency than the data part, if the recording clock frequency of the preformat area is (1 / integer) times the data part,
The clock is easy to generate and is preferably used.
/ 2 to times. This is because the capacity of the preformat area is not unnecessarily increased. Particularly preferably, it is 1/2, 1/3 or 1/4.

At this time, it is preferable that the logical length of the sector in the medium information management area is approximately 2 to 4 times the logical length of the sector in the data recording area because the physical sector length can be made equal. Alternatively, it is preferable that the recording capacity of the sector in the medium information management area be 2 to 4 times the recording capacity of the sector in the data recording area. For example, when the sector recording capacity of the data recording area is 2048 bytes, if the clock frequency is 倍 times, if the sector capacity of the medium information management area is reduced to about 1024 bytes, the physical sector length in the data recording area is reduced. It can be almost equal, and the number of sectors per track can be an integer. If the clock frequency is 1/4, the sector capacity may be 1/4, that is, about 512 bytes.

It is preferable that the sector recording capacity of 1024 bytes or 512 bytes is used for the sector recording capacity of 2048 bytes because the compatibility can be easily obtained for the drive. In particular, for a sector recording capacity of 2048 bytes of a 90 mm magneto-optical disk defined by ISO standard 15041, 512 sector defined by the same standard is used.
Compatibility is most easily achieved with a sector recording capacity of bytes. In addition, 130 mm / 5.
With a 2 GB magneto-optical disk, the sector recording capacity is 2048.
Bytes, 1024 bytes and 512 bytes are specified, so that a sector recording capacity of 2048 bytes is 1024 bytes or 512 bytes and 1 byte.
Compatibility is most easily achieved with a sector recording capacity of 512 bytes for a sector recording capacity of 024 bytes.

However, even when the sector capacity of the medium information management area is set to 1024 bytes, only 512 bytes of medium information and its error detection code (CRC) and error correction code (ECC) are recorded in the medium information section, and the remaining data is recorded. Is filled with dummy data, the same effect as when the sector capacity is set to 512 bytes can be obtained. Alternatively, 512-byte medium information and its error detection code (CRC) and error correction code (ECC) may be repeatedly written twice. In addition,
The application of the present invention is not limited to a magneto-optical recording medium that performs reproduction using the magnetic super-resolution effect. As long as the medium records the preformat area at a lower clock frequency than the data part, it can be applied to optical recording media in general, such as phase change media and magneto-optical recording media.

[0024]

Hereinafter, the present invention will be described in more detail with reference to examples. A magneto-optical disk having a magneto-optical recording film of a type for reproducing data by utilizing the above-described super-resolution phenomenon was formed on a substrate. The substrate has a 90 mm magneto-optical disk I
In accordance with the SO standard 15041, a data recording area and a medium information management area are formed by preformatting, and information is recorded on tracks formed between spiral grooves. FIGS. 1A and 1B are diagrams showing sector formats of a data recording area and a medium information management area, respectively.

The logical length (logical sector length) of the sector in the data recording area shown in FIG. 1A is 2615 bytes, including 63 bytes for a header portion formed by prepits, 16 bytes for a gap portion, The VFO3 section is 27 bytes, the sync is 4 bytes, the data section is 2458 bytes, the PA is 1 byte, and the buffer section is 46 bytes. The data section is composed of 2048 bytes of user data, 4 bytes of CRC, 320 bytes of ECC, 78 bytes of resync, and 8 bytes of dummy data.

However, the header portion composed of the prepits is recorded at a clock frequency which is half the clock frequency of the data portion. Therefore, when one byte of the data part is used as a reference for the physical length, the physical length of the header part is twice as large as one.
This corresponds to 26 bytes, and the physical length of this sector (physical sector length) is 2678 bytes. For example, an ID section for recording address information such as a sector mark, a VFO, a track number, and a sector number, and an address mark (AM) indicating the head of the ID section are recorded in the header section.

On the other hand, the logical length (logical sector length) of the sector in the medium information management area shown in FIG. 1B is 1339 bytes, including 63 bytes for the header portion formed by the prepits and the gap portion for the gap portion. 16 bytes, VFO
3 copies of 27 bytes, sync of 4 bytes, media information of 6 bytes
58 bytes, PA is 1 byte, dummy data (2T tone signal) is 524 bytes, and buffer part is 46 bytes. The media information section is composed of 512 bytes of user data, 4
It is composed of a CRC of bytes, an ECC of 80 bytes, a resync of 58 bytes, and dummy data of 4 bytes.

The recording method of the data portion and the medium information portion is not particularly limited, but pit edge recording (PWM recording) using (1, 7) RLL modulation is used for higher density. However, the sector shown in FIG. 1B is recorded at a clock frequency which is half the clock frequency of the data part shown in FIG. Therefore, when one byte of the data portion is used as a reference for the physical length, the physical length (physical sector length) of the sector in the medium information management area is 2678 bytes, which is the same physical sector length as the data recording area. Since both physical sector lengths are equal in this way, if the number of sectors per track in the data recording area is an integer,
Also in the medium information management area, the number of sectors per track can be an integer.

Further, with such a configuration, the capacity of the medium information management area can be suppressed to about half of the conventional one, and the recording capacity of the user data can be increased accordingly. The medium information management area according to the present invention conforms to ISO standard 1.
5041, such as a control track portion, for example, a recording / reproducing laser wavelength, a reflectance, a recording / reproducing erasing power,
Information such as the type of medium is recorded.

[0030]

As described above, according to the present invention, in the optical recording medium having different recording clock frequencies in the preformat section and the user data section, one of the medium information management information is used.
Since the same preformat pattern is adjacent between adjacent tracks with the number of sectors per track being an integer, medium information management information and user data can be recorded and reproduced well. Further, the medium information management area can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an example of a sector format of a conventional optical recording medium.

FIG. 3 is an explanatory diagram of a preformat unit.

[Explanation of symbols]

 1 groove 2, 3, 4, 5 pits

Claims (10)

[Claims] 1. An optical recording medium having a data recording area in which user data can be recorded and a medium information management area formed in a preformat, wherein a preformat recording clock frequency is lower than a user data recording clock frequency. An optical recording medium, wherein a logical length of a sector in the medium information management area is different from a logical length of a sector in the data recording area. 2. The optical recording medium according to claim 1, wherein the logical length of the sector in the medium information management area is smaller than the logical length of the sector in the data recording area. 3. The optical recording medium according to claim 1, wherein the recording capacity of the sector in the medium information management area is different from the recording capacity of the sector in the data recording area. 4. The optical recording medium according to claim 3, wherein the recording capacity of the sector in the medium information management area is smaller than the recording capacity of the sector in the data recording area. 5. At least a readout layer and a recording layer, wherein a readout light is irradiated while changing a magnetization state of the readout layer, and a readout of recording is performed by a magneto-optical effect in a region smaller than a spot of the readout light. The optical recording medium according to claim 1, wherein the recording is performed. 6. The recording clock frequency of the preformat is set to 1/2 to 1/1 / of the recording clock frequency of the user data.
The optical recording medium according to any one of claims 1 to 4, wherein the ratio is four times. 7. The logical length of a sector in a medium information management area is approximately two to two times the logical length of a sector in a data recording area.
7. The optical recording medium according to claim 6, wherein the ratio is four times. 8. The optical recording medium according to claim 6, wherein the recording capacity of the sector in the medium information management area is 2 to 4 times the recording capacity of the sector in the data recording area. 9. The optical recording medium according to claim 8, wherein the recording capacity of the sector in the data recording area is 2048 bytes, and the sector recording capacity of the medium information management area is 1024 bytes or 512 bytes. 10. The optical recording medium according to claim 8, wherein the recording capacity of the sector in the data recording area is 1024 bytes, and the recording capacity of the sector in the medium information management area is 512 bytes.